Battery cell, battery device, and electric device

Abstract

A battery cell (100), a battery device (1100), and an electric device (1000). The battery cell (100) comprises a casing (200) and an electrode assembly (101); the casing (200) is provided with an electrode lead-out portion (2011); the electrode assembly (101) is at least partially accommodated in the casing (200), and the electrode assembly (101) comprises a first electrode sheet (1) and an insulating member (40); the first electrode sheet (1) comprises a conductive member (30), a current collector (10) and an active material layer (20); the current collector (10) comprises an insulating substrate (11) and a metal layer (12); the conductive member (30) is connected to the electrode lead-out portion (2011) and the metal layer (12); the insulating substrate (11), the metal layer (12) and the active material layer (20) are stacked in the thickness direction of the current collector (10); 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 main body portion (121) and at least one protruding portion (122); the protruding portion (122) extends outward from the end of the main body portion (121) in a first direction; the first direction is perpendicular to the thickness direction of the current collector (10); at least part of the main body portion (121) is covered with the active material layer (20), and at least part of the protruding portion (122) is not covered with the active material layer (20); the insulating member (40) comprises a first insulating portion (42), and the first insulating portion (42) is located at the side of the main body portion (121) facing away from the insulating substrate (41); and in the direction from the main body portion (121) to the protruding portion (122), the first insulating portion (42) protrudes from the end of the main body portion (121) facing the protruding portion (122).

Description

Battery cell, battery device and electric device TECHNICAL FIELD

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

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

[0003] A battery device includes one or more battery cells to meet different capacity usage requirements; however, in the technology of battery cells, how to improve the use reliability of the battery cells 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, including but not limited to improving the use reliability of the battery cell.

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

[0008] In some embodiments, a battery cell is provided, which includes a 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, and the electrode assembly includes a first electrode sheet and an insulating piece, the first electrode sheet includes a conductive member, a current collector and an active material layer; the current collector includes an insulating base body and a metal layer, the conductive member connects the electrode lead-out portion and the metal layer; the insulating base body, the metal layer and the active material layer are stacked along the thickness direction of the current collector, and at least part of the metal layer is located between the insulating base body and the active material layer; the metal layer includes a main body portion and at least one protruding portion, the protruding portion extends outward from the end of the main body portion along a first direction perpendicular to the thickness direction of the current collector; at least part of the main body portion is covered with the active material layer, and at least part of the protruding portion is not covered with the active material layer; the insulating piece includes a first insulating portion, and the first insulating portion is located on the side of the main body portion away from the insulating base body; along the direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from the end of the main body portion towards the protruding portion.

[0009] The first insulation part can prevent the burr at the end surface of the protruding part from penetrating the separator and contacting the second pole piece to reduce the short circuit risk of the battery monomer, and the use reliability of the battery monomer is improved. In addition, the current collector adopts the composite structure of the insulating base body and the metal layer, the thickness of the metal layer is small compared with the pure metal current collector, the burr generated by the metal layer is small, the internal short circuit risk 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 present application can better balance the overcurrent capacity and the use reliability.

[0010] 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 a 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 on the surface of the metal layer away from the insulating base body to form a first welding mark, and the second connecting part is located on the side of the protruding part away from the main body part. In the first direction, the first welding mark is located on the side of the active material layer close to the protruding part.

[0011] By adopting the technical scheme of the embodiment, the first connecting part is welded with the metal layer, the conductive member is connected with the metal layer in a welding manner, and the manufacturing of the first pole piece is facilitated. In addition, the thickness of the metal layer is small, and the surface of the metal layer away from the insulating base body is large, which is beneficial to increase the welding area between the conductive member and the metal layer, increase the overcurrent area between the conductive member and the metal layer, improve the overcurrent capacity of the first pole piece, and improve the fast charging performance of the battery monomer. The second connecting part protrudes out of the main body part, and the second connecting part can be conveniently connected with the electrode lead-out part, and the processing and manufacturing are more convenient. At the same time, the risk of false welding and other problems can be reduced, the connection reliability of the metal layer and the conductive member is improved, the overcurrent capacity of the first pole piece is improved, and the fast charging performance of the battery monomer is improved.

[0012] In some embodiments, the first insulation part covers at least part of the first welding mark.

[0013] By adopting the technical scheme of the embodiment, the first insulation part can prevent the burr at the end surface of the protruding part from penetrating the separator and contacting the second pole piece to reduce the short circuit risk of the battery monomer, and the use reliability of the battery monomer is improved. In addition, the current collector adopts the composite structure of the insulating base body and the metal layer, the thickness of the metal layer is small compared with the pure metal current collector, the burr generated by the metal layer is small, the internal short circuit risk 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 present application can better balance the overcurrent capacity and the use reliability.

[0014] In some embodiments, the first connecting part and the active material layer are arranged at intervals along the first direction.

[0015] By adopting the technical scheme of the embodiment, the first connecting part is welded with the metal layer, the conductive member is connected with the metal layer in a welding manner, and the manufacturing of the first pole piece is facilitated. In addition, the thickness of the metal layer is small, and the surface of the metal layer away from the insulating base body is large, which is beneficial to increase the welding area between the conductive member and the metal layer, increase the overcurrent area between the conductive member and the metal layer, improve the overcurrent capacity of the first pole piece, and improve the fast charging performance of the battery monomer. The second connecting part protrudes out of the main body part, and the second connecting part can be conveniently connected with the electrode lead-out part, and the processing and manufacturing are more convenient. At the same time, the risk of false welding and other problems can be reduced, the connection reliability of the metal layer and the conductive member is improved, the overcurrent capacity of the first pole piece is improved, and the fast charging performance of the battery monomer is improved.

[0016] In some embodiments, the insulating member comprises a second insulating portion covering the surface of the metal layer away from the insulating base, and the entire second insulating portion is located between the first welding mark and the active material layer.

[0017] By adopting the technical scheme of this embodiment, the risk of false welding between the first connecting portion and the metal layer can be reduced, the risk of false welding between the first connecting portion and the metal layer can be reduced, the connection reliability of the first connecting portion and the metal layer can be improved, and the overcurrent capacity can also be improved.

[0018] In some embodiments, the second insulating portion is located between the first connecting portion and the active material layer.

[0019] By adopting the technical scheme of this embodiment, the second insulating portion can support the part of the metal layer located between the first connecting portion and the active material layer, and can reduce the damage such as cracks and fractures of this part during the manufacturing process of the battery device, so as to improve the electronic transmission capacity of this part, improve the fast charging performance and use reliability of the battery monomer; in addition, the first insulating portion can also realize the insulation of this part, reduce the short circuit risk of the battery monomer, and improve the use reliability of the battery monomer.

[0020] In some embodiments, along the first direction, one side of the first insulating portion covers the first welding mark, and the other side of the first insulating portion covers at least part of the second insulating portion.

[0021] By adopting the technical scheme of this embodiment, the second insulating portion and the first insulating portion jointly cover the metal layer, which can realize double-layer insulation, reduce the short circuit risk of the battery monomer, and improve the use reliability of the battery monomer.

[0022] In some embodiments, along the first direction, one side of the first insulating portion covers the first welding mark, and the other side of the first insulating portion covers at least part of the second insulating portion.

[0023] By adopting the technical scheme of this embodiment, the first insulating portion extends from the first welding mark to the active material layer, the coverage area of the first insulating portion is wide, the insulation effect is good, and the use reliability of the battery monomer can be improved.

[0024] In some embodiments, the first welding mark comprises a first welding mark portion, the first connecting portion is welded to the surface of the protruding portion away from the insulating base and forms the first welding mark portion, and the first insulating portion covers at least part of the first welding mark portion.

[0025] By adopting the technical scheme of the embodiment, the first connecting part and the protruding part are connected by welding, the connection mode is simple, and the first pole piece is convenient to manufacture; the first connecting part and the protruding part can directly pass current through the first welding mark part, which is beneficial to improve the current passing capacity between the first connecting part and the protruding part; the first insulating part can block burrs, metal scraps and other components on the first welding mark part from passing through the isolation piece to be connected with the second pole piece, which is beneficial to improve the use reliability of the battery monomer.

[0026] In some embodiments, the first welding mark part includes a first welding mark subpart, the protruding part includes a first protruding subpart and a second protruding subpart, the first protruding subpart is connected between the second protruding subpart and the main body part; along the second direction, the size of the first protruding subpart is greater than the size of the second protruding subpart, the second direction is perpendicular to the first direction and the thickness direction of the current collector; the first connecting part is welded to the surface of the first protruding subpart away from the insulating base and forms the first welding mark subpart, and the first insulating part covers at least part of the first welding mark subpart.

[0027] By adopting the technical scheme of the embodiment, the first connecting part and the first protruding subpart are welded and form the first welding mark subpart, the size of the first protruding subpart along the second direction is large, which is beneficial to improve the welding area of the protruding part and the first connecting part, improve the current passing area between the protruding part and the first connecting part, improve the current passing capacity, reduce the heating of the battery monomer, and improve the fast charging performance and use reliability of the battery monomer; in addition, along the second direction, the size of the second protruding subpart is small, which is beneficial to reduce the occupied space of the protruding part and improve the energy density of the battery monomer; in addition, the first insulating part can block burrs, metal scraps and other components on the first welding mark subpart from passing through the isolation piece to be connected with the second pole piece, which is beneficial to improve the use reliability of the battery monomer.

[0028] In some embodiments, along the direction in which the main body part points to the protruding part, the first insulating part protrudes from the end surface of the first protruding subpart away from the main body part.

[0029] By adopting the technical scheme of the embodiment, along the second direction, the size of the first welding mark subpart is large, which is beneficial to improve the welding area of the protruding part and the first connecting part, improve the current passing area between the protruding part and the main body part, improve the current passing capacity, reduce the heating of the battery monomer, and improve the fast charging performance and use reliability of the battery monomer.

[0030] In some embodiments, along the second direction, the first welding mark subpart extends from one side edge of the first protruding subpart to the other side edge of the first protruding subpart.

[0031] By adopting the technical scheme of the embodiment, the size of the first welding sub-part is large in the second direction, which is beneficial to increase the welding area between the protruding part and the first connecting part, increase the flow area between the protruding part and the main body part, and improve 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.

[0032] In some embodiments, the first welding part further comprises a second welding sub-part, the first connecting part is welded to the surface of the second protruding sub-part away from the insulating base, and the second welding sub-part is formed, and the first insulating part covers at least part of the second welding sub-part.

[0033] By adopting the technical scheme of the embodiment, the second protruding sub-part is also welded to the first connecting part, which is beneficial to increase the flow area between the first connecting part and the protruding part and improve the flow capacity between the first connecting part and the protruding part. In addition, the first insulating part can block the burrs, metal chips and other components on the second welding sub-part from passing through the isolation piece to connect with the second pole piece, thereby improving the use reliability of the battery monomer.

[0034] In some embodiments, in the direction of the main body part pointing to the protruding part, the first insulating part protrudes from the edge of the second welding sub-part away from the first protruding sub-part.

[0035] By adopting the technical scheme of the embodiment, the first insulating part can completely cover the second welding sub-part and the first welding sub-part, thereby reducing the risk of short circuit caused by burrs, metal chips and other components on the second welding sub-part and the first welding sub-part, and improving the use reliability of the battery monomer.

[0036] In some embodiments, in the second direction, the second welding sub-part extends from one side edge of the second protruding sub-part to the other side edge of the second protruding sub-part.

[0037] By adopting the technical scheme of the embodiment, the size of the second welding sub-part in the second direction is large, which is beneficial to increase the welding area between the first connecting part and the protruding part, increase the flow area between the first connecting part and the protruding part, and improve the flow capacity between the first connecting part and the protruding part.

[0038] In some embodiments, the number of protruding parts is multiple, and the multiple protruding parts are arranged at intervals in the second direction, each protruding part 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.

[0039] By adopting the technical scheme of the embodiment, the plurality of protruding portions are arranged at intervals along the second direction, which is beneficial to divide the main body portion into a plurality of 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 in the main body portion are transmitted in a region-by-region manner, the transmission path of the electrons in each region is short to the corresponding protruding portion, which is beneficial to reduce the transmission distance of the electrons, reduce the overall resistance of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer.

[0040] In some embodiments, the first connecting portion includes a plurality of first connecting sub-portions, the plurality of first connecting sub-portions are arranged at intervals along the second direction, the number of the second connecting portions is a plurality, and each first connecting sub-portion is connected to each second connecting portion in a one-to-one correspondence; each first connecting sub-portion is welded to the surface of each protruding portion away from the insulating base in a one-to-one correspondence.

[0041] By adopting the technical scheme of the embodiment, the plurality of first connecting sub-portions of the first connecting portion are arranged at intervals along the second direction, and there is a gap between the two adjacent first connecting sub-portions, which can reduce the required material of the first connecting portion and reduce the manufacturing cost of the battery monomer.

[0042] In some embodiments, the main body portion includes a conductive portion and a transition portion, the transition portion is connected between the conductive portion and the protruding portion, the transition portion and the protruding portion are not covered with an active material layer, and the conductive portion is covered with an active material layer; the first insulating portion covers at least part of the surface of the transition portion away from the insulating base; along the direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from the end of the transition portion away from the conductive portion.

[0043] By adopting the technical scheme of the embodiment, the surface of the transition portion in the main body portion away from the insulating base is connected to the first connecting portion, so that part of the current can flow into or out of the first connecting portion through the transition portion, reducing the flow pressure between the protruding portion and the main body portion, which is beneficial to reduce the heat generation at the first protruding sub-portion, improve the fast charging performance and use reliability of the battery monomer.

[0044] In some embodiments, along the second direction, the size of the conductive portion is L1, the size of the transition portion is L2, and 0.8≤L2 / L1≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0045] By adopting the technical scheme of the embodiment, the size of the transition portion along the second direction is large, which is beneficial to increase the connection area between the first connecting portion and the transition portion, improve the flow capacity at the connection between the first connecting portion and the transition portion, improve the flow capacity of the first pole piece, reduce the heating of the battery monomer, and improve the fast charging performance of the battery monomer.

[0046] In some embodiments, the first welding mark further comprises a second welding mark portion, the first connecting portion is welded to the surface of the transition portion away from the insulating base and forms the second welding mark portion, and the first insulating portion covers at least part of the second welding mark portion.

[0047] By adopting the technical scheme of this embodiment, the first connecting portion and the transition portion are connected in a welding manner, which is simple and facilitates the manufacturing of the first pole piece. In addition, the second welding mark portion can be directly used for current conduction between the first connecting portion and the transition portion, which facilitates improving the current conduction capacity between the first connecting portion and the transition portion and reducing the heat generation of the battery monomer. In addition, the first insulating portion can block burrs, metal debris and other components on the second welding mark portion from passing through the isolation piece to connect with the second pole piece, which facilitates improving the use reliability of the battery monomer.

[0048] In some embodiments, along a direction in which the protruding portion points to the main body portion, the first insulating portion protrudes from the second welding mark portion toward the edge of the active material layer.

[0049] By adopting the technical scheme of this embodiment, the first insulating portion can completely cover the second welding mark portion, and the first insulating portion can block burrs, metal debris and other components on the entire second welding mark portion from passing through the isolation piece to connect with the second pole piece, which facilitates improving the use reliability of the battery monomer.

[0050] In some embodiments, along the second direction, the size of the transition portion is L2, the size of the second welding mark portion is L3, and 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0051] By adopting the technical scheme of this embodiment, the size of the transition portion along the second direction is large, which facilitates improving the connection area between the first connecting portion and the transition portion, improving the current conduction capacity at the connection between the first connecting portion and the transition portion, improving the current conduction capacity of the first pole piece, reducing the heat generation of the battery monomer, and improving the fast charging performance of the battery monomer.

[0052] In some embodiments, the number of protruding portions is multiple, the multiple protruding portions are arranged at intervals along the second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; the first connecting portion comprises a second connecting sub-portion and multiple first connecting sub-portions, the multiple first connecting sub-portions are arranged at intervals along the second direction, and each first connecting sub-portion is welded to the surface of each protruding portion away from the insulating base one by one; the number of second connecting portions is multiple, along the first direction, one side of each first connecting sub-portion is connected to each second connecting portion one by one, the other side of each first connecting sub-portion is connected to the second connecting sub-portion, and the second connecting sub-portion is arranged continuously along the second direction; and the second connecting sub-portion is welded to the surface of the transition portion away from the insulating base.

[0053] By adopting the technical scheme of the embodiment, the second connecting sub-parts are arranged continuously along the second direction, the plurality of first connecting sub-parts can be connected as a whole, the second connecting sub-parts can play a good supporting role on the first connecting sub-parts, the risk of the first connecting sub-parts bending to be inserted between the first and second pole pieces can be reduced, the short circuit risk can be reduced, and the use reliability of the battery monomer can be improved; in addition, along the second direction, the size of the second connecting sub-parts is large, which is beneficial to improve the welding area between the second connecting sub-parts and the transition part, is beneficial to improve the overcurrent capacity of the connection between the first connecting part and the transition part, improves the overcurrent capacity of the first pole piece, and improves the fast charging performance and use reliability of the battery monomer.

[0054] 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 cover the two metal layers respectively; the number of conductive members is two, the first connecting parts of the two conductive members are welded to the surfaces of the two metal layers away from the insulating base and form two first welding marks respectively; the number of insulating members is two, and the first insulating parts of the two insulating members cover at least part of the two first welding marks respectively.

[0055] By adopting the technical scheme of the embodiment, the first connecting parts of the two conductive members are welded to the metal layers located on opposite sides of the insulating base, and the second connecting parts of the two conductive members are located on the side of the protruding part away from the main part, so that the two metal layers can be directly connected by the second connecting parts of the two conductive members, thereby breaking the insulation limitation of the insulating base, effectively improving the conductive capacity of the first pole piece, improving the fast charging performance of the battery monomer, reducing the heat generation of the battery monomer, and improving the use reliability of the battery monomer.

[0056] In some embodiments, the first insulating part includes a first part and a second part connected to each other, the first part covers at least part of the main part along the direction of the main part towards the protruding part, and the second part protrudes from the main part, and the second part is located on the side of the protruding part along the second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0057] By adopting the technical scheme of the embodiment, along the direction of the main part pointing to the protruding part, the metal debris and other components at the end face of the main part towards the protruding part can be located between the second parts of the two insulating members, so that the risk of the metal debris falling into the electrode assembly can be reduced, and the short circuit risk can be reduced.

[0058] In some embodiments, the second parts of the two insulating members are in contact.

[0059] By adopting the technical scheme of the embodiment, after the second portions of the two insulating pieces are attached, the metal scraps and the like on the end face of the main body portion towards the protruding portion can be covered, so that the metal scraps and the like are not easy to fall into the electrode assembly, and the risk of short circuit of the battery monomer can be better reduced.

[0060] In some embodiments, the second connecting portions of the two conductive members are welded and form a second welding mark.

[0061] By adopting the technical scheme of the embodiment, the second connecting portions of the two conductive members can connect the metal layers on the opposite sides of the insulating base, thereby breaking the insulation limitation of the insulating base, effectively improving the conductive capacity of the first pole piece, the fast charging performance of the battery monomer, reducing the heat generation of the battery monomer, and improving the use reliability of the battery monomer.

[0062] In some embodiments, the first insulating portion covers at least part of the second welding mark.

[0063] By adopting the technical scheme of the embodiment, the first insulating portion can block the sharp protrusions, metal scraps and the like on the second welding mark from piercing the separator to connect with the second pole piece, reduce the risk of short circuit, and improve the use reliability of the battery monomer.

[0064] In some embodiments, along the direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from the edge of the second welding mark away from the main body portion.

[0065] By adopting the technical scheme of the embodiment, the first insulating portion can completely cover the second welding mark, and can block the sharp protrusions, metal scraps and the like on the entire second welding mark from piercing the separator to connect with the second pole piece, reduce the risk of short circuit, and improve the use reliability of the battery monomer.

[0066] In some embodiments, along the first direction, the distance between the first welding mark and the active material layer is S1, where 0.3mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

[0067] By adopting the technical scheme of the embodiment, the first welding mark will not be welded to the active material layer, reducing the problem of false welding and the like, which is conducive to improving the connection reliability of the first connecting portion and the metal layer. In addition, the distance between the active material layer and the first welding mark is small, and the active material layer can be closer to the first welding mark. Therefore, under the condition that the size of the metal layer in the first direction is constant, the active material layer can cover a larger area, which is conducive to improving the energy density of the battery monomer.

[0068] In some embodiments, the current collector further comprises a conductive protective layer, and at least part of the conductive protective layer is located between the active material layer and the metal layer.

[0069] By adopting the technical scheme of the embodiment, the conductive protective layer can separate the active material layer and the metal layer while protecting the metal layer, reduces the risk of cracks in the metal layer caused by rolling the active material layer, and is conducive to improving the overcurrent capacity of the metal layer.

[0070] In some embodiments, along a direction of the main body portion towards the protruding portion, the conductive protective layer protrudes from an end surface of the active material layer towards the protruding portion.

[0071] By adopting the technical scheme of the embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the protective ability of the conductive protective layer to the metal layer is better, the overcurrent capacity of the first pole piece is better, and the fast charging performance and use reliability of the battery monomer are improved.

[0072] In some embodiments, along a direction of the main body portion towards the protruding portion, a protruding length of the conductive protective layer protruding from the end surface of the active material layer towards the protruding portion ranges from 0.3mm to 0.8mm.

[0073] By adopting the technical scheme of the embodiment, the overcurrent capacity and energy density of the battery monomer can be better balanced.

[0074] In some embodiments, along the first direction, the conductive protective layer and the first welding mark are arranged at intervals.

[0075] By adopting the technical scheme of the embodiment, the first connecting portion will not be welded to the conductive protective layer, which can reduce the risk of false welding and improve the reliability of welding the first connecting portion to the metal layer.

[0076] In some embodiments, along the first direction, the size of the portion of the active material layer covered by the insulating piece is H, where 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm.

[0077] By adopting the technical scheme of the embodiment, along the first direction, the size of the portion of the active material layer covered by the first insulating portion is reasonable, and the burr at the end of the main body portion towards the protruding portion and the energy density of the battery monomer can be balanced at the same time.

[0078] In some embodiments, the first insulating portion is connected to the first pole piece.

[0079] By adopting the technical scheme of the embodiment, the first insulating portion is connected to the first pole piece, and the first insulating portion can be fixed, thereby stably blocking the burr at the end of the main body portion towards the protruding portion, and improving the use reliability of the battery monomer.

[0080] In some embodiments, the first insulating portion includes an insulating base layer and an adhesive layer, and the adhesive layer is bonded between the insulating base layer and the first pole piece.

[0081] By adopting the technical scheme of the embodiment, the first insulating part adopts the structure of the insulating base layer and the adhesive layer, the insulating base layer can improve the structural strength of the first insulating part, reduce the deformation in the process of bonding of the first insulating part, and be beneficial to improving the insulation effect; the adhesive layer can stably fix the insulating base layer on the first pole piece, and reduce the risk of falling of the insulating tape.

[0082] In some embodiments, the layer thickness of the insulating base layer ranges from 6 μm to 15 μm; and / or, the layer thickness of the adhesive layer ranges from 0.5 μm to 3 μm.

[0083] By adopting the technical scheme of the embodiment, the internal insulation and the energy density of the battery monomer can be simultaneously considered.

[0084] In some embodiments, the size of the insulating part along the first direction is W, wherein 3 mm≤W≤9 mm, and optionally, 4.5 mm≤W≤6.5 mm.

[0085] By adopting the technical scheme of the embodiment, the insulation reliability and the energy density of the battery monomer can be simultaneously considered.

[0086] In some embodiments, the electrode assembly further includes a second pole piece opposite in polarity to the first pole piece, the second pole piece including a main body functional part and a tab part, the tab part protruding from the main body functional part along the first direction; along a direction of the main body part towards the protruding part, the main body functional part protrudes from an end surface of the insulating part close to the active material layer, and the main body functional part does not protrude from an end surface of the insulating part away from the active material layer.

[0087] By adopting the technical scheme of the embodiment, the insulating part can block the burr at the end surface of the main body functional part of the second pole piece close to the tab part from piercing the insulating part to connect with the first pole piece, reduce the short circuit risk of the first pole piece and the second pole piece, and be beneficial to improving the use reliability of the battery monomer.

[0088] In some embodiments, the electrode assembly further includes a second pole piece opposite in polarity to the first pole piece, the second pole piece including a main body functional part and a tab part, the tab part protruding from the main body functional part along the first direction; along a direction of the main body part towards the protruding part, the main body functional part protrudes from an end surface of the insulating part close to the active material layer, and the main body functional part does not protrude from an end surface of the insulating part away from the active material layer.

[0089] By adopting the technical scheme of the embodiment, the burr at the end surface of the main body functional part of the second pole piece towards the tab part corresponds to the hollowed-out area of the main body part not extending out of the protruding part, which can also reduce the short circuit risk of the battery monomer and improve the use reliability of the battery monomer.

[0090] In some embodiments, the main body part includes a transition part and a conductive part, the transition part being connected between the protruding part and the conductive part, the conductive part being covered with the active material layer, and the transition part not being covered with the active material layer; the transition part is connected with the conductive member; and at least part of the thickness of the conductive part is smaller than the thickness of the transition part.

[0091] By adopting the technical scheme of this embodiment, the thickness of the transition portion is large, the flow capacity of the transition portion is good, the flow capacity of the first tab is improved, the heating of the battery monomer is reduced, and the fast charging performance and use reliability of the battery monomer are improved.

[0092] In some embodiments, 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 transition portion, the first sub-portion and the second sub-portion are covered with an 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 transition portion is greater than or equal to the thickness of the first sub-portion.

[0093] By adopting the technical scheme of this embodiment, the flow capacity of the first sub-portion close to the transition portion is greater than the flow capacity of the second sub-portion away from the transition portion, which can reduce the limitation on the current, improve the flow capacity of the first tab, reduce the heating of the battery monomer, and improve the use reliability of the battery monomer.

[0094] In some embodiments, 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.

[0095] By adopting the technical scheme of this embodiment, the surface of the conductive protective layer away from the surface of the insulating base is close to a plane, which is conducive to reducing the roll damage and improving the flow capacity of the metal layer; in addition, the winding bulging problem of the current collector can also be reduced.

[0096] In some embodiments, the conductive protective layer further includes a third protective portion, the third protective portion covers the surface of the transition portion away from the insulating base, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

[0097] By adopting the technical aspect of this embodiment, the third protective portion is provided, which can make the conductive protective layer protrude from the active material layer, so that the active material layer and the metal layer can be well separated, in addition, the thickness of the third protective portion is not too large, which is conducive to reducing the waste of materials and saving the manufacturing cost of the battery monomer.

[0098] In some embodiments, the thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

[0099] By adopting the technical scheme of this embodiment, the thickness of the protruding portion is thick, which can improve the flow capacity of the protruding portion, improve the flow capacity of the first tab, reduce the heating of the battery monomer, and improve the fast charging performance and use reliability of the battery monomer.

[0100] In a second aspect, a battery device is provided, comprising the battery cell of the above embodiment.

[0101] The battery device of the embodiments of the present application adopts the battery cell described above, and the use reliability of the battery cell is good, which is conducive to improving the use reliability of the battery device.

[0102] In a third aspect, a power consumption device is provided, comprising the battery device of the above embodiment.

[0103] The battery device of the embodiments of the present application adopts the battery cell described above, and the use reliability of the battery device is good, which is conducive to improving the use reliability of the power consumption device.

[0104] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, and can 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

[0105] In order to more clearly illustrate the technical solutions 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 for those skilled in the art, other drawings can also be obtained without creative labor.

[0106] Fig. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0107] Fig. 2 is an exploded schematic diagram of a battery device provided by some embodiments of the present application.

[0108] Fig. 3 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application.

[0109] Fig. 4 is a structural schematic diagram of an electrode assembly provided by some embodiments of the present application.

[0110] Fig. 5 is a sectional view along line A-A in Fig. 4.

[0111] Fig. 6 is a structural schematic diagram of a first electrode sheet provided by some embodiments of the present application.

[0112] Fig. 7 is a sectional view along line B-B in Fig. 6.

[0113] Fig. 8 is a structural schematic diagram of a first electrode sheet provided by some other embodiments of the present application.

[0114] Fig. 9 is a partial enlarged view of C in Fig. 8.

[0115] Fig. 10 is a schematic view of a structure of the first pole piece after hiding the conductive member according to some embodiments of the present application.

[0116] Fig. 11 is an enlarged view of a portion of Fig. 10 at D.

[0117] Fig. 12 is a schematic view of a structure of the first pole piece according to yet some embodiments of the present application.

[0118] Fig. 13 is an enlarged view of a portion of Fig. 12 at F.

[0119] Fig. 14 is a schematic view of a structure of the first pole piece after hiding the conductive member according to Fig. 13.

[0120] Fig. 15 is an enlarged view of a portion of Fig. 14 at G.

[0121] Fig. 16 is a schematic view of a structure of the first pole piece according to yet some embodiments of the present application.

[0122] Fig. 17 is a cross-sectional view along line H-H of Fig. 16.

[0123] Fig. 18 is a cross-sectional view along line I-I of Fig. 16.

[0124] Fig. 19 is a schematic view of a structure of the first pole piece according to yet some embodiments of the present application.

[0125] Fig. 20 is an enlarged view of a portion of Fig. 19 at J.

[0126] Fig. 21 is a schematic view of a structure of the first pole piece according to yet some embodiments of the present application.

[0127] Fig. 22 is a cross-sectional view along line K-K of Fig. 21.

[0128] Fig. 23 is a schematic view of a structure of the first insulating portion according to some embodiments of the present application.

[0129] Fig. 24 is a cross-sectional view along line N-N of Fig. 23.

[0130] 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, main body portion; 1211, transition portion; 1212, conductive portion; 12121, first sub-portion; 12122, second sub-portion; 122, protruding portion; 1221, first protruding sub-portion; 1222, 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, second insulating portion; 42, first 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 cover; 2011, electrode lead-out portion; 202, case; 300, box body; 301, first box body portion; 302, second box body portion. DETAILED DESCRIPTION

[0131] 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 1-24 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.

[0132] 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.

[0133] 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.

[0134] 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 " / " herein generally represents an "or" relationship between the associated objects before and after it.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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 (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode.

[0148] 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.

[0149] 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 (e.g., polypropylene), a composite metal case (e.g., a copper-aluminum composite case), or an aluminum-plastic film, and the like.

[0150] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode can be a negative electrode sheet, which can include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0151] 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 pierce the separator to cause internal short circuit, which causes a high risk of fire and explosion of the battery cell.

[0152] 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 process of foreign matter piercing the pole piece is small and is not easy to pierce the separator. However, in the actual pole piece manufacturing process, the edge of the pole piece needs to be cut, so that the metal layer is divided into a protruding part and a main part, and the end surface of the main part towards the protruding part is obtained by cutting. The end surface obtained by cutting is prone to generate a large burr, thereby affecting the use reliability of the battery cell.

[0153] Based on this, the embodiments of the present application provide a technical scheme, which sets an insulating piece, and the first insulating part of the insulating piece protrudes from the end of the main part towards the protruding part, so that the first insulating part can block the burr at the end surface of the main part towards the protruding part, reduce the risk of short circuit caused by the burr piercing the separator at this place, and is beneficial to improve the use reliability of the battery cell.

[0154] The battery cell described in the embodiments of the present application is suitable for a battery device and a power utilization device using the battery device.

[0155] The battery device disclosed in the embodiments of the present application can be used in a power utilization 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 utilization device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric automobile toy, an electric ship toy, and an electric aircraft toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0156] The following embodiments take a vehicle as an example for convenience of description.

[0157] 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.

[0158] 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.

[0159] 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 battery cells, the battery cells being accommodated in the box 300.

[0160] The box 300 is configured to accommodate the battery cells, 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 a space for accommodating the battery cells. 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 space for accommodating the battery cells. 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 space for accommodating the battery cells. Of course, the first box part 301 and the second box part 302 can have various shapes, such as a cylinder or a cuboid.

[0161] 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.

[0162] 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 300.

[0163] In the battery device 1100, the battery cells can be one or multiple. If the battery cells are multiple, the multiple battery cells can be connected in series, in parallel, or in a mixed manner, the mixed manner referring to a combination of series connection and parallel connection.

[0164] The plurality of battery cells can be directly connected in series, in parallel, or in a hybrid manner, and the plurality of battery cells can be accommodated in the case 300. Alternatively, the plurality of battery cells can be connected in series, in parallel, or in a hybrid manner to form a plurality of battery modules, and the plurality of battery modules can be connected in series, in parallel, or in a hybrid manner to form a whole and can be accommodated in the case 300.

[0165] The battery cell can be a smallest unit constituting the battery device 1100.

[0166] As shown in FIG. 3, in some embodiments, the battery cell 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, 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 between the positive electrode and the negative electrode, while allowing the active ions to pass through.

[0167] The housing 200 is configured to encapsulate the electrode assembly 101 and other components such as electrolyte.

[0168] In some embodiments, the housing 200 includes a shell 202 having an opening and an end cap 201 configured to cover the opening.

[0169] The shell 202 is a component configured to cooperate with the end cap 201 to form an internal cavity of the battery cell, which can be configured to accommodate the electrode assembly 101, electrolyte, and other components.

[0170] The shell 202 and the end cap 201 can be separate components. For example, the shell 202 can be provided with an opening, and the end cap 201 can be configured to cover the opening to form the internal cavity of the battery cell.

[0171] The shell 202 can have various shapes and sizes, such as a cuboid shape, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 202 can be determined according to the specific shape and size of the electrode assembly 101. The shell 202 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0172] The end cap 201 can have a shape that is adapted to the shape of the shell 202 to cooperate with the shell 202. The material of the end cap 201 can be the same as or different from the material of the shell 202. Optionally, the end cap 201 can be made of a material having a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 201 is less likely to deform when subjected to extrusion and impact, and the battery cell can have higher structural strength and improved reliability.

[0173] The end cap 201 is connected to the housing 202 by welding, adhesion, clamping, or other means.

[0174] The housing 202 can be open at one end or at both ends. In some examples, the housing 202 can be a structure open at one side, and the end cap 201 is provided as one and covers the housing 202. In other examples, the housing 202 can also be a structure open at both sides, and the end cap 201 is provided as two, and the two end caps 201 cover the two openings of the housing 202, respectively.

[0175] In some embodiments, the battery cell includes electrode leads 2011. The number of electrode leads 2011 is two, and the two electrode leads 2011 are connected to the positive and negative electrode sheets, respectively, for outputting or inputting the electrical energy of the battery cell.

[0176] In some embodiments, the battery cell also includes an electrolyte contained in the housing 200. The electrolyte serves to conduct ions between the positive and negative electrodes. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0177] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0178] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalate borate, lithium di-oxalate borate, lithium difluoro di-oxalate phosphate, and lithium tetrafluoro oxalate phosphate.

[0179] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyrosulfone, methyl ethyl sulfone, and diethyl sulfone.

[0180] The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0181] In some embodiments, the gel-state electrolyte includes a polymer as a skeleton network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0182] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, a composite solid-state electrolyte.

[0183] 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, a cellulose, or the like.

[0184] 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.

[0185] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0186] Referring to FIGS. 4 and 5, the electrode assembly 101 of the embodiments of the present application includes first and second polar plates 1 and 2 having opposite polarities.

[0187] 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.

[0188] 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.

[0189] As an example, the positive current collector has two surfaces opposite in the thickness direction thereof, and the positive active material layer is disposed on either one or both of the two opposite surfaces of the positive current collector.

[0190] As an example, the positive current collector can employ carbon, a metal foil, or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, a carbon electrode, nickel, titanium, silver surface-treated aluminum, or stainless steel, or the like 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, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0191] 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 alone only one or in combination of two or more. Examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which can also be referred to as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite 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 (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to as NCM811), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.80 Co 0.15 Al 0.05 O2), and modified compounds thereof.

[0192] In some embodiments, the negative electrode tab can include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0193] As an example, the negative current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, nickel, or titanium, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, or the like. 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, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0194] As an example, the negative active material layer includes a negative active material. The negative active material can employ a negative active material for a battery cell known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, and the like. 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 active material of the present application can also use other conventional materials that can be used as a negative active material of the battery device 1100. These negative active materials can be used alone only one or two or more can be used in combination.

[0195] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0196] 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 short circuit between the positive and negative electrodes while allowing the active ions to pass through.

[0197] 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.

[0198] 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, and 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.

[0199] In some embodiments, the separator 3 is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode sheet and the negative electrode sheet and functions to transport ions and separate the positive and negative electrodes.

[0200] In some embodiments, the electrode assembly 101 is in a winding structure. For example, the first electrode sheet 1 and the second electrode sheet 2 are both in a strip shape, and the first electrode sheet 1, the separator 3 and the second electrode sheet 2 are wound into the winding structure.

[0201] In some embodiments, the electrode assembly 101 is in a stacking structure.

[0202] For example, a plurality of the first electrode sheet 1 and a plurality of the second electrode sheet 2 are alternately stacked.

[0203] For example, a plurality of the first electrode sheet 1 are provided, and the second electrode sheet 2 is folded to form a plurality of folded segments which are stacked, and one of the first electrode sheet 1 is clamped between adjacent folded segments.

[0204] For example, a plurality of the first electrode sheet 1 and a plurality of the second electrode sheet 2 are alternately stacked.

[0205] For example, a plurality of the separator 3 are provided, and each of the separators 3 is provided between any adjacent first electrode sheet 1 or second electrode sheet 2.

[0206] For example, the separator 3 is continuously provided, and is provided between any adjacent first electrode sheet 1 or second electrode sheet 2 by folding or winding.

[0207] In some embodiments, the electrode assembly 101 can be in a cylindrical shape, a flat shape or a multi-prism shape, etc.

[0208] Please refer to FIG. 6 and FIG. 7, in some embodiments, a battery cell is provided, the battery cell 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 and an insulating piece 40, the first electrode tab 1 comprises a conductive member 30, a current collector 10 and an active material layer 20; the current collector 10 comprises an insulating base 11 and a metal layer 12, the conductive member 30 connects the electrode lead-out portion 2011 and the metal layer 12; the insulating base 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction of the current collector 10, at least part of the metal layer 12 is located between the insulating base 11 and the active material layer 20; the metal layer 12 comprises a main body portion 121 and at least one protruding portion 122, the protruding portion 122 extends outwardly from the end of the main body portion 121 along a first direction, the first direction is perpendicular to the thickness direction of the current collector 10; at least part of the main body portion 121 is covered with the active material layer 20, at least part of the protruding portion 122 is not covered with the active material layer 20; the insulating piece 40 comprises a first insulating portion 42, the first insulating portion 42 is located at the side of the main body portion 121 away from the insulating base 11; along the direction of the main body portion 121 pointing to the protruding portion 122, the first insulating portion 42 protrudes from the end of the main body portion 121 towards the protruding portion 122.

[0209] 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.

[0210] 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 adopts a composite current collector structure, and the active material layer 20 is a negative active material layer.

[0211] 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.

[0212] 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 to output or input electric energy; the electrode lead-out portion 2011 can also be referred to as a pole, the electrode lead-out portion 2011 can be provided on the shell 202 or on the end cover 201.

[0213] 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.

[0214] 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 in the current collector 10 which is made of an insulating material (for example, the above-mentioned high polymer base material), and the metal layer 12 can refer to a component in the current collector 10 which is made of the above-mentioned metal material.

[0215] 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.

[0216] In some examples, one surface of the insulating base body 11 is covered with the metal layer 12.

[0217] 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.

[0218] 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.

[0219] 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).

[0220] 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).

[0221] The metal layer 12 includes a main body part 121 and a protruding part 122. The main body part 121 is a main body part of the metal layer 12. The protruding part 122 extends outward from an end of the main body part 121 in a first direction. The protruding part 122 can be a protruding structure formed on an edge of the main body part 121 in the first direction. In a second direction, the size of the protruding part 122 is smaller than the size of the main body part 121, so that the protruding part 122 and the main body part 121 form a stepped structure. The number of the protruding part 122 can be one or more. The plurality of protruding parts 122 are arranged at intervals in the second direction. In the direction of the main body part 121 pointing to the protruding part 122, the direction can be referred to as the direction indicated by the arrow Z in FIG. 6.

[0222] The active material layer 20 can cover a part of the main body part 121 or the entire main body part 121. The active material layer 20 can cover the entire protruding part 122 or a part of the protruding part 122, for example, the root part of the protruding part 122 close to the main body part 121.

[0223] The insulating part 40 can be a component capable of insulation. The insulating part 40 can be an integrated structure or a plurality of parts assembled together. The insulating part 40 includes a first insulating part 42. The first insulating part 42 can be, but is not limited to, an insulating coating, an insulating glue (for example, hot melt glue, etc.), or an insulating adhesive tape.

[0224] The first insulating part 42 is located on the side of the first electrode tab 1 in the thickness direction. The first insulating part 42 at least partially covers the junction of the main body part 121 and the protruding part 122. For example, in the thickness direction of the current collector 10, the projection of the end surface of the main body part 121 towards the protruding part 122 coincides with the projection of the first insulating part 42, so that the first insulating part 42 can cover the end surface of the main body part 121 leading to the protruding part 122.

[0225] In the case of normal use of the battery cell 100, the electrode lead-out part 2011 is used for input or output of electric energy, realizing charging and discharging of the battery cell 100. The first insulating part 42 can block the burr at the end surface of the main body part 121 towards the protruding part 122 from piercing the separator 3 to contact the second electrode tab 2, thereby reducing the risk of short circuit of the battery cell and improving the use reliability of the battery cell. In addition, the current collector 10 adopts a composite structure of the insulating base body 11 and the metal layer 12. Compared with the pure metal current collector 10, the thickness of the metal layer 12 is small, and the burr generated in the manufacturing process of the current collector 10 is small, thereby reducing the risk of internal short circuit of the battery cell and improving the use reliability of the battery cell. Therefore, the battery cell of the present application can better balance the overcurrent capacity and the use reliability.

[0226] In some embodiments, the active material layer 20 includes a first active material portion 21 and a second active material portion 22, the first active material portion 21 and the second active material portion 22 are connected towards the end of the protruding portion 122, the thickness of the first active material portion 21 is less than the thickness of the second active material portion 22.

[0227] In some examples, the first active material portion 21 is located at the side of the active material layer 20 towards the protruding portion 122, the first active material portion 21 and the second active material portion 22 both cover the conductive portion 1212, the first active material portion 21 can be substantially an equal-thickness structure, the thickness of the first active material portion 21 is less than the thickness of the second active material portion 22, so that the first active material portion 21 and the second active material portion 22 form a stepped structure; in other examples, the thickness of the first active material portion 21 can also be steppedly reduced, so that the first active material portion 21 is a stepped structure; or, along the direction of the main body portion 121 towards the protruding portion 122, the thickness of the first active material portion 21 can also slowly decrease, so that the thickness of the first active material portion 21 slowly decreases, and the shape of the first active material portion 21 is more smooth or flat.

[0228] In the forming process of the first electrode tab 1, the active material layer 20 can be rolled to compress the active material layer 20; and the arrangement of the first active material portion 21 can reduce the rolling pressure on the side of the active material layer 20, and reduce the risk of cracking of the side of the active material layer 20.

[0229] Please refer to Figs. 8-14, 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 welded to the surface of the metal layer 12 away from the insulating substrate 11 to form a first welding mark 51, and the second connecting portion 32 is located at the side of the protruding portion 122 away from the main body portion 121; along the first direction, the first welding mark 51 is located at the side of the active material layer 20 close to the protruding portion 122.

[0230] The first connecting portion 31 can be a part for welding the conductive member 30 and the metal layer 12, and the second connecting portion 32 can be a part for connecting the conductive member 30 and the electrode lead-out portion 2011.

[0231] In some examples, the first connecting portion 31 can be covered on the metal layer 12 and welded with the metal layer 12, and the second connecting portion 32 can be led out from the side of the first connecting portion 31 away from the active material layer 20 in the first direction, that is, in the thickness direction of the current collector 10, the projection of the first connecting portion 31 is located within the projection of the metal layer 12, and the projection of the second connecting portion 32 is located outside the projection range of the metal layer 12; in this way, the connection positions of the metal layer 12 and the electrode lead-out portion 2011 on the conductive member 30 are different, which facilitates connection and can also reduce the mutual influence between the two connections, thereby facilitating connection reliability.

[0232] In some cases, when the pole piece is wound to form the electrode assembly 101, the insulating base body 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 outwardly across the insulating base body 11, so that the current can almost only be transmitted outwardly by the outermost layer of the metal layer 12, resulting in poor conductivity, low fast-charging performance, and easy local overheating, which affects the use reliability of the battery monomer 100; while the battery monomer 100 of the embodiment of the application utilizes the first connecting portion 31 of the conductive member 30 to be welded with the metal layer 12, and the second connecting portion 32 of the conductive member 30 to protrude out of the insulating base body 11, so that the second connecting portion 32 can be used to electrically connect the adjacent two layers of the metal layer 12, thereby breaking the insulation limitation of the insulating base body 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, and improving the use reliability of the battery monomer 100.

[0233] When the pole pieces are stacked to form the electrode assembly 101, the insulating base body 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 outwardly, so that the current can almost only be transmitted outwardly by the metal layer 12 located at the outermost side, resulting in poor conductivity, low fast-charging performance, and easy local overheating, which affects the use reliability of the battery monomer 100. While the battery monomer 100 of the embodiment of the application utilizes the first connecting portion 31 of the conductive member 30 to be welded with the metal layer 12, and the second connecting portion 32 of the conductive member 30 to protrude out of the insulating base body 11, so that the second connecting portion 32 can be used to electrically connect the adjacent two metal layers 12, thereby breaking the insulation limitation of the insulating base body 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, and improving the use reliability of the battery monomer 100.

[0234] The first connecting portion 31 is stacked on the surface of the metal layer 12 away from the insulating base body 11 and is welded with the surface of the metal layer 12 away from the insulating base body 11, and the trace formed by welding is the first welding mark 51.

[0235] In the first direction, the first welding mark 51 is located on the side of the active material layer 20 facing the protruding portion 122. In the first direction, the first welding mark 51 is spaced apart from the active material layer 20, so that the portion of the metal layer 12 facing the protruding portion 122 is not covered by the active material layer 20 and is welded to the first connecting portion 31, so that the first connecting portion 31 is not welded to the active material layer 20, which helps to reduce the risk of problems such as false welding, and helps to improve the connection reliability and current-carrying capacity of the metal layer 12 and the conductive member 30; or the edge of the first welding mark 51 is in contact with the edge of the active material layer 20 facing the protruding portion 122, that is, the first connecting portion 31 is welded to the edge of the active material layer 20, and the first welding mark 51 only coincides with the edge of the active material layer 20, which reduces the risk of false welding and helps to improve the connection reliability of the first connecting portion 31 and the metal layer 12.

[0236] In some examples, the first connecting portion 31 can be welded only to the protruding portion 122.

[0237] In some examples, the first connecting portion 31 is welded to the protruding portion 122, and the first connecting portion 31 is also welded to the portion of the main body portion 121 facing the protruding portion 122 and not covered by the active material layer 20.

[0238] In some examples, the second connecting portion 32 and the electrode lead-out portion 2011 can be connected by direct welding, or can be welded by a conductive member such as a jumper, which is convenient for connection and processing.

[0239] By adopting the technical solutions of the embodiment, the first connecting portion 31 is welded to the metal layer 12, and the conductive member 30 is connected to the metal layer 12 by welding, which facilitates the manufacturing of the first tab 1. In addition, the metal layer 12 has a small thickness and a large surface area facing away from the insulating substrate 11, which helps to increase the welding area between the conductive member 30 and the metal layer 12, increase the current-carrying area between the conductive member 30 and the metal layer 12, improve the current-carrying capacity of the first tab 1, and improve the fast-charging performance of the battery device 1100. The second connecting portion 32 protrudes outward from the main body portion 121, which facilitates the connection of the second connecting portion 32 and the electrode lead-out portion 2011, and facilitates processing and manufacturing. In addition, the risk of problems such as false welding can be reduced, which helps to improve the connection reliability of the metal layer 12 and the conductive member 30, and also helps to improve the current-carrying capacity of the first tab 1 and the fast-charging performance of the battery device 1100.

[0240] In some embodiments, the first insulating portion 42 covers at least part of the first welding mark 51.

[0241] The first insulating part 42 covers the surface of the first connecting part 31 away from the metal layer 12 and covers at least part of the first welding mark 51. The first insulating part 42 can cover part of the first welding mark 51 or the entire first welding mark 51.

[0242] After the first connecting part 31 is welded to the metal layer 12, a pointed protrusion, metal debris or the like can be generated on the surface of the first welding mark 51. The first insulating part 42 of the embodiment of the present application covers the surface of the first welding mark 51, which can prevent the pointed protrusion, metal debris or the like on the surface of the first welding mark 51 from piercing the separator 3 and connecting with the second pole piece 2, thereby reducing the risk of short circuit of the battery monomer and improving the use reliability of the battery monomer.

[0243] In some embodiments, the first connecting part 31 and the active material layer 20 are spaced apart in the first direction.

[0244] The first connecting part 31 is not in direct contact with the active material layer 20 but has a certain gap, so that the first connecting part 31 is not in contact with the active material layer 20.

[0245] In some examples, the first pole piece 1 is a positive pole piece, and the first connecting part 31 is not in contact with the active material layer 20, which can reduce the risk of lithium precipitation and the like and is conducive to improving the use reliability of the battery monomer. In other examples, the first pole piece 1 is a negative pole piece, and the first connecting part 31 can be in contact with the active material layer 20 or not.

[0246] By adopting the technical solution of the embodiment, the first connecting part 31 is not in contact with the active material layer 20, which can reduce the mutual influence between the two and improve the use reliability of the battery monomer.

[0247] Please refer to FIGS. 15-17, in some embodiments, the insulating part 40 includes a second insulating part 41, which covers the surface of the metal layer 12 away from the insulating base 11, and the entire second insulating part 41 is located between the first welding mark 51 and the active material layer 20.

[0248] The second insulating part 41 can be an insulating part covering the surface of the metal layer 12 away from the active material layer 20. The second insulating part 41 can be but is not limited to an insulating coating, an insulating glue (for example, hot melt glue or the like) or an insulating adhesive tape.

[0249] In the thickness direction of the current collector 10, the second insulating part 41 is not coincident with the first welding mark 51, and the second insulating part 41 is arranged in a spaced manner with the first welding mark 51, so that the first connecting part 31 will not be welded to the second insulating part 41, which is conducive to reducing the risk of false welding between the first connecting part 31 and the metal layer 12; or, the second insulating part 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 second insulating part 41, which can also reduce the risk of false welding between the first connecting part 31 and the metal layer 12.

[0250] By adopting the technical scheme of this embodiment, the risk of false welding between the first connecting part 31 and the metal layer 12 is reduced, the risk of false welding between the first connecting part 31 and the metal layer 12 is reduced, the connection reliability of the first connecting part 31 and the metal layer 12 is improved, and the overcurrent capacity is also improved.

[0251] In some embodiments, the second insulating part 41 is located between the first connecting part 31 and the active material layer 20.

[0252] The second insulating part 41 can refer to the part of the second insulating part 41 located between the first connecting part 31 and the active material layer 20.

[0253] In some examples, the entire second insulating part 41 is located between the first connecting part 31 and the active material layer 20.

[0254] By adopting the technical scheme of this embodiment, the second insulating part 41 can support the part of the metal layer 12 located between the first connecting part 31 and the active material layer 20, which can reduce the damage such as cracks and fractures of this part during the manufacturing process of the battery device 1100, and is conducive to improving the electronic transmission capability of this part and improving the fast charging performance and use reliability of the battery device 1100. In addition, the first insulating part 42 can also achieve insulation of this part, reduce the risk of short circuit of the battery device 1100, and improve the use reliability of the battery device 1100.

[0255] In some embodiments, in the first direction, one side of the first insulating part 42 covers the first welding mark 51, and the other side of the first insulating part 42 covers at least part of the second insulating part 41.

[0256] It can be understood that, in the first direction, one side of the first insulating part 42 covers the first welding mark 51, and the other side of the first insulating part 42 covers the entire second insulating part 41, or covers part of the second insulating part 41, or even covers the active material layer 20.

[0257] In the first direction, the first insulating part 42 extends from the first welding mark 51 to the second insulating part 41; or, the first insulating part 42 extends from the first welding mark 51 to the active material layer 20, thereby covering the second insulating part 41 completely.

[0258] By adopting the technical scheme of this embodiment, in addition to covering the first solder print 51 and at least part of the second insulating part 41, the first insulating part 42 can also cover the part of the first connecting part 31 located between the second insulating part 41 and the first solder print 51, the coverage of the insulating piece 40 is more comprehensive, which is more conducive to reducing the risk of short circuit and improving the use reliability of the battery monomer.

[0259] Please refer to Figs. 18-21, in some embodiments, along the first direction, one side of the first insulating part 42 covers the first solder print 51, and the other side of the first insulating part 42 covers at least part of the active material layer 20.

[0260] It can be understood that, among the two sides of the first insulating part 42 relatively distributed along the first direction, one side covers the first solder print 51, and the other side covers at least part of the active material layer 20, wherein the first insulating part 42 can cover the end of the active material layer 20 towards the first connecting part 31, or can cover the entire active material layer 20.

[0261] Along the first direction, the first insulating part 42 extends from the first solder print 51 to the active material layer 20, so that the metal layer 12 and the part of the first connecting part 31 located between the first solder print 51 and the active material layer 20 are covered. Among them, the second insulating part 41 can be arranged between the first insulating part 42 and the metal layer 12, or the second insulating part 41 can not be arranged.

[0262] In some examples, the metal layer 12 is covered with the second insulating part 41, and after the first insulating part 42 completely covers the second insulating part 41, the first insulating part 42 can further extend onto the active material layer 20 to cover the active material layer 20, so that the metal layer 12 is covered with the second insulating part 41 and the first insulating part 42, realizing two-layer insulation and good insulation effect.

[0263] In some examples, the metal layer 12 is not covered with the second insulating part 41, and the first insulating part 42 extends from the first solder print 51 to the active material layer 20, so that the part of the metal layer 12 located between the first connecting part 31 and the active material layer 20 can be covered, reducing the risk of short circuit in this part and improving the use reliability of the battery monomer. In addition, the second insulating part 41 can also be omitted to save costs, and at the same time, the active material layer 20 can be used to cover the original position of the second insulating part 41, so that the coverage area of the active material layer 20 on the metal layer 12 can be increased, which is conducive to improving the energy density of the battery monomer.

[0264] By adopting the technical scheme of this embodiment, the first insulating part 42 extends from the first solder print 51 to the active material layer 20, the coverage area of the first insulating part 42 is wide, the insulation effect is good, and the use reliability of the battery monomer can be improved.

[0265] In some embodiments, the size of the portion of the active material layer 20 covered by the insulating member 40 along the first direction is H, where 0.2 mm≤H≤1.0 mm, and optionally, 0.3 mm≤H≤0.8 mm.

[0266] In some examples, the value of H can be 0.2 mm, 1 mm, or any value between 0.2 mm and 1.0 mm, for example, the value of H can be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.6 mm, 0.8 mm, 0.9 mm, 1 mm.

[0267] The design of H≥0.2 mm enables the insulating member 40 to cover the end of the active material layer 20 towards the protruding portion 122, and the insulating member 40 can block burrs at the end of the active material layer 20 towards the protruding portion 122, thereby improving the use reliability of the battery monomer. The design of H≤1.0 mm enables the portion of the active material layer 20 covered by the insulating member 40 not to be too large, which is conducive to reducing the weight and volume of the insulating member 40, and is conducive to improving the energy density of the battery monomer.

[0268] In some examples, the insulating member 40 includes a second insulating portion 41 covering the end of the active material layer 20 towards the protruding portion 122. The portion of the active material layer 20 covered by the second insulating portion 41 can refer to the interpenetrating region formed by the second insulating portion 41 and the active material layer 20, so that the fixation of the second insulating portion 41 is more stable.

[0269] In some examples, the insulating member 40 includes a first insulating portion 42 covering the end of the active material layer 20 towards the protruding portion 122.

[0270] By adopting the technical solution of this embodiment, the size of the portion of the active material layer 20 covered by the first insulating portion 42 along the first direction is reasonable, and the burrs at the end of the main body portion 121 towards the protruding portion 122 and the energy density of the battery monomer can be considered at the same time.

[0271] In some embodiments, 0.3 mm≤H≤0.8 mm.

[0272] By adopting the technical solution of this embodiment, the size of the portion of the active material layer 20 covered by the first insulating portion 42 along the first direction is more reasonable, and the burrs at the end of the main body portion 121 towards the protruding portion 122 and the energy density of the battery monomer can be considered at the same time.

[0273] Please refer to Figs. 6-11, in some embodiments, the first welding mark 51 includes a first welding mark portion 511, the first connecting portion 31 is welded to the surface of the protruding portion 122 away from the insulating substrate 11 and forms the first welding mark portion 511, and the first insulating portion 42 covers at least part of the first welding mark portion 511.

[0274] The first connecting portion 31 is stacked on the surface of the protruding portion 122 away from the insulating substrate 11 and is welded to the protruding portion 122, and the trace formed by welding is the first welding mark portion 511.

[0275] In some examples, the first connecting portion 31 can be welded to the entire protruding portion 122, or the first connecting portion 31 can be welded to part of the protruding portion 122, and the other part of the protruding portion 122 is not welded to the first connecting portion 31.

[0276] The first insulating portion 42 can cover part of the first welding mark portion 511, or cover the entire first welding mark portion 511.

[0277] By adopting the technical scheme of the embodiment, the first connecting portion 31 and the protruding portion 122 are connected by welding, which is simple and convenient for manufacturing the first tab 1; the first welding mark portion 511 can be directly used for current conduction between the first connecting portion 31 and the protruding portion 122, which is conducive to improving the current conduction capacity between the first connecting portion 31 and the protruding portion 122; the first insulating portion 42 can block burrs, metal debris and other components on the first welding mark portion 511 from passing through the separator 3 to connect with the second tab 2, which is conducive to improving the use reliability of the battery monomer.

[0278] In some embodiments, in the second direction, the first welding mark portion 511 extends from one side of the protruding portion 122 to the other side of the protruding portion 122.

[0279] In the first direction, the projection of the first welding mark portion 511 falls within the projection of the protruding portion 122.

[0280] In the manufacturing process of the first tab 1, the conductive member 30 can be welded to the edge of the equal-length current collector 10 by ultrasonic welding (for example, double-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, which is convenient for connecting with the electrode lead-out portion 2011; and in the cutting process, first cutting is performed in the second direction between the equal-width welding mark and the active material layer 20, then cutting is performed in the direction toward the equal-width welding mark until the equal-width welding mark is left, then cutting is continued in the direction away from the active material layer 20 for a distance, then cutting is performed in the second direction for a distance, then cutting is performed in the direction toward the equal-width welding mark until the equal-width welding mark is left, and then cutting is performed in the second direction, so that a first welding mark portion 511 is obtained, and the above process is repeated to obtain multiple first welding mark portions 511.

[0281] By adopting the technical solutions of this embodiment, the size of the first welding portion 511 in the second direction is large, which is beneficial to increase the flow area between the first connecting portion 31 and the protruding portion 122, increase the flow capacity between the first connecting portion 31 and the protruding portion 122, reduce the risk of heating, and improve the fast-charging performance and use reliability of the battery monomer.

[0282] In some embodiments, the first welding portion 511 includes a first welding sub-portion 5111, the protruding portion 122 includes a first protruding sub-portion 1221 and a second protruding sub-portion 1222, and the first protruding sub-portion 1221 is connected between the second protruding sub-portion 1222 and the main body portion 121; in the second direction, the size l1 of the first protruding sub-portion 1221 is greater than the size l2 of the second protruding sub-portion 1222; the second direction is perpendicular to the first direction and the thickness direction of the current collector 10; the first connecting portion 31 is welded to the surface of the first protruding sub-portion 1221 away from the insulating substrate 11 and forms the first welding sub-portion 5111, and the first insulating portion 42 covers at least part of the first welding sub-portion 5111.

[0283] For example, the protruding portion 122 has a stepped structure, and in the first direction, the protruding portion 122 is divided into two parts, the part close to the main body portion 121 is the first protruding sub-portion 1221, and the part away from the main body portion 121 is the second protruding sub-portion 1222; in the second direction, the size of the first protruding sub-portion 1221 is greater than the size of the second protruding sub-portion 1222, which is equivalent to increasing the size of the first protruding sub-portion 1221 in the second direction, increasing the flow area between the protruding portion 122 and the main body portion 121, increasing the flow capacity, and reducing the heating of the battery monomer 100.

[0284] The first protruding sub-portion 1221 can refer to the root of the protruding portion 122 close to the main body portion 121; for example, in the second direction, the size l3 of the first protruding sub-portion 1221 can refer to the length of the dividing line (see dashed line Q) of the protruding portion 122 and the main body portion 121. The size l3 of each first protruding sub-portion 1221 in the second direction can be the same or different.

[0285] In the second direction, the size l2 of the second protruding sub-portion 1222 is equal to the length of the dividing line (see dashed line M) of the first protruding sub-portion 1221 and the second protruding sub-portion 1222. The size l2 of each second protruding sub-portion 1222 in the second direction can be the same or different.

[0286] l1>l2, which is equivalent to increasing the size l3 of the first protruding sub-portion 1221 in the second direction, increasing the flow area between the protruding portion 122 and the main body portion 121, increasing the flow capacity, and reducing the heating of the battery monomer 100.

[0287] The first connecting part 31 is welded to the surface of the first protruding sub-part 1221 away from the insulating base 11, and the trace generated by the welding is the first welding mark sub-part 5111.

[0288] For example, the first connecting part 31 can be welded to the side of the first protruding sub-part 1221 toward the main body part 121, so that the first welding mark sub-part 5111 is directly connected with the main body part 121; in this way, the first connecting part 31 and the main body part 121 can directly pass current through the first welding mark part 511, which is conducive to improving the current passing capacity between the first connecting part 31 and the main body part 121, reducing the heat generation of the battery monomer 100, and improving the fast charging performance and use reliability of the battery monomer; of course, the first connecting part 31 can also be welded to the side of the first protruding sub-part 1221 away from the main body part 121, so that the first welding mark sub-part 5111 is arranged in a spaced manner with the main body part 121.

[0289] The first insulating part 42 can cover part of the first welding mark sub-part 5111, or cover the entire first welding mark sub-part 5111.

[0290] By adopting the technical scheme of this embodiment, the first connecting part 31 is welded to the first protruding sub-part 1221 to form the first welding mark sub-part 5111, and the size of the first protruding sub-part 1221 along the second direction is large, which is conducive to increasing the welding area of the protruding part 122 and the first connecting part 31, increasing the current passing area between the protruding part 122 and the first connecting part 31, improving the current passing capacity, reducing the heat generation of the battery monomer 100, and improving the fast charging performance and use reliability of the battery monomer; in addition, along the second direction, the size of the second protruding sub-part 1222 is small, which is conducive to reducing the occupied space of the protruding part 122 and improving the energy density of the battery monomer; in addition, the first insulating part 42 can block the burrs, metal debris and other components on the first welding mark sub-part 5111 from passing through the separator 3 to connect with the second pole piece 2, which is conducive to improving the use reliability of the battery monomer.

[0291] In some embodiments, the sum of the sizes l3 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction is 0.5 times or more of the size l4 of the main part 121, and it can be understood that 0.5≤l3 / l4<1, so that the sum of the sizes l3 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction is greater than or equal to half or more of the size l4 of the main part 121, increasing the total flow area between the protruding parts 122 and the main part 121 and improving the total flow capacity between the protruding parts 122 and the main part 121; for example, the sum of the sizes l3 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction can be increased by increasing the number of protruding parts 122, or the sum of the sizes l3 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction can be increased by increasing the size l4 of a single first protruding sub-part 1221 in the second direction.

[0292] In some examples, the value of l3 / l4 can be 0.5 and any value between 0.5 and 1, for example; wherein the value of l3 / l4 can be but is not limited to 0.5, 0.6, 0.7, 0.8, 0.9, 0.99.

[0293] In some embodiments, the end face of the first protruding sub-part 1221 away from the main part 121 protrudes from the first insulating part 42 in the direction of the main part 121 pointing to the protruding part 122.

[0294] The projection of the end face of the first protruding sub-part 1221 away from the main part 121 falls within the projection of the first insulating part 42 in the thickness direction of the current collector 10.

[0295] In the manufacturing process of the pole piece, the end face of the first protruding sub-part 1221 away from the main part 121 is obtained by cutting, which causes burrs to easily occur at the end face of the first protruding sub-part 1221 away from the main part 121, and the first insulating part 42 can block the burrs at the end face of the first protruding sub-part 1221 away from the main part 121, reducing the risk of short circuit inside the battery monomer and being conducive to improving the use reliability of the battery monomer; in addition, the first insulating part 42 can completely cover the first solder sub-part 5111, reducing the risk of short circuit caused by burrs, metal debris and other components on the first solder sub-part 5111, and being conducive to improving the use reliability of the battery monomer.

[0296] In some embodiments, the first solder sub-part 5111 extends from one side of the first protruding sub-part 1221 to the other side of the first protruding sub-part 1221 in the second direction.

[0297] The projection of the first solder sub-part 5111 falls within the projection of the first protruding sub-part 1221 in the first direction.

[0298] By adopting the technical scheme of this embodiment, the first welding sub-part 5111 has a large size along the second direction, which is beneficial to increase the welding area of the protruding part 122 and the first connecting part 31, increase the flow area between the protruding part 122 and the main body part 121, improve the flow capacity, reduce the heat generation of the battery monomer 100, and improve the fast-charging performance and use reliability of the battery monomer.

[0299] In some embodiments, the first welding part 511 further comprises a second welding sub-part 5112, the first connecting part 31 is welded to the surface of the second protruding sub-part 1222 away from the insulating base 11 and forms the second welding sub-part 5112, and the first insulating part 42 covers at least part of the second welding sub-part 5112.

[0300] For example, the surface of the second protruding sub-part 1222 away from the insulating base 11 is welded to the first connecting part 31, and the trace generated by the welding is the second welding sub-part 5112.

[0301] The first insulating part 42 can cover part of the second welding sub-part 5112 or cover the entire second welding sub-part 5112.

[0302] By adopting the technical scheme of this embodiment, the second protruding sub-part 1222 is also welded to the first connecting part 31, which is beneficial to increase the flow area between the first connecting part 31 and the protruding part 122 and improve the flow capacity between the first connecting part 31 and the protruding part 122; in addition, the first insulating part 42 can block the burrs, metal scraps and other components on the second welding sub-part 5112 from passing through the isolation piece 3 to connect with the second pole piece 2, which is beneficial to improve the use reliability of the battery monomer.

[0303] In some embodiments, along the direction in which the main body part 121 points to the protruding part 122, the first insulating part 42 protrudes from the edge of the second welding sub-part 5112 away from the first protruding sub-part 1221.

[0304] Along the thickness direction of the current collector 10, the projection of the edge of the second welding sub-part 5112 away from the first protruding sub-part 1221 falls within the projection of the first insulating part 42, so that the first insulating part 42 can completely cover the second welding sub-part 5112 and the first welding sub-part 5111.

[0305] By adopting the technical scheme of this embodiment, the first insulating part 42 can completely cover the second welding sub-part 5112 and the first welding sub-part 5111, reduce the risk of short circuit caused by burrs, metal scraps and other components on the second welding sub-part 5112 and the first welding sub-part 5111, and improve the use reliability of the battery monomer.

[0306] In some embodiments, along the second direction, the second welding sub-part 5112 extends from one side edge of the second protruding sub-part 1222 to the other side edge of the second protruding sub-part 1222.

[0307] Along the first direction, the projection of the second welding sub-part 5112 falls within the projection of the second protruding sub-part 1222. The second welding sub-part 5112.

[0308] 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 increasing the welding area between the first connecting part 31 and the protruding part 122, increasing the flow area between the first connecting part 31 and the protruding part 122, and improving the flow capacity between the first connecting part 31 and the protruding part 122.

[0309] Please refer to FIGS. 12-22, in some embodiments, the main body part 121 includes a conductive part 1212 and a transition part 1211, the transition part 1211 is connected between the conductive part 1212 and the protruding part 122, the transition part 1211 and the protruding part 122 are not covered with the active material layer 20, and the conductive part 1212 is covered with the active material layer 20; the first insulating part 42 covers at least part of the surface of the transition part 1211 away from the insulating base 11; along the direction of the main body part 121 pointing to the protruding part 122, the first insulating part 42 protrudes from the end of the transition part 1211 away from the conductive part 1212.

[0310] For example, along the first direction, the main body part 121 is divided into two parts, the part close to the protruding part 122 is the transition part 1211, and the part away from the protruding part 122 is the conductive part 1212, and the protruding part 122 protrudes away from the edge of the transition part 1211 away from the conductive part 1212 and away from the conductive part 1212; the conductive part 1212 is covered with the active material layer 20, and the transition part 1211 and the protruding part 122 are not covered with the active material layer 20, so as to facilitate the connection with the first connecting part 31.

[0311] In some examples, the first connecting part 31 is connected to the surface of the transition part 1211 away from the insulating base 11 by welding or conductive glue, etc., to realize the connection between the first connecting part 31 and the transition part 1211.

[0312] By adopting the technical solutions of this embodiment, the surface of the transition part 1211 in the main body part 121 away from the insulating base 11 is connected with the first connecting part 31, so that part of the current can flow into or out of the first connecting part 31 through the transition part 1211, reducing the flow pressure between the protruding part 122 and the main body part 121, which is conducive to reducing the heat generation at the first protruding sub-part 1221 and improving the fast-charging performance and use reliability of the battery monomer.

[0313] In some embodiments, along the second direction, the size of the conductive portion 1212 is L1, and the size of the transition portion 1211 is L2, and 0.8≤L2 / L1≤1.

[0314] 0.8≤L2 / L1≤1, along the second direction, the size L2 of the transition portion 1211 is less than or equal to the size L1 of the conductive portion 1212, and the size L2 of the transition portion 1211 is greater than or equal to 0.8 times the size L1 of the conductive portion 1212, the size L2 of the transition portion 1211 exceeds more than half of the size L1 of the conductive portion 1212, the larger the size L2 of the transition portion 1211, the larger the connection area of the transition portion 1211 and the first connecting portion 31 can be set, and the better the flow capacity between the transition portion 1211 and the first connecting portion 31.

[0315] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1211 can be located at the middle position of the conductive portion 1212, and the two ends of the transition portion 1211 are flush with the conductive portion 1212.

[0316] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1211 can be located at the middle position of the conductive portion 1212, and the two ends of the transition portion 1211 are flush with the conductive portion 1212.

[0317] By adopting the technical scheme of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion 1211 along the second direction large, which is beneficial to improve the connection area between the first connecting portion 31 and the transition portion 1211, improve the flow capacity at the connection between the first connecting portion 31 and the transition portion 1211, improve the flow 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.

[0318] In some embodiments, L2=L1.

[0319] L2 / L1=1, along the second direction, the size L2 of the transition portion 1211 is equal to the size L1 of the conductive portion 1212, along the second direction, the two ends of the transition portion 1211 are flush with the conductive portion 1212, and the main body portion 121 is an equal-length structure.

[0320] By adopting the technical scheme of this embodiment, the design of L2=L1 makes the size of the transition portion 1211 in the second direction larger, which is beneficial to design the connection area between the first connecting portion 31 and the transition portion 1211 to be larger, the flow capacity at the connection between the first connecting portion 31 and the transition portion 1211 is best, the flow capacity of the first tab 1 can be effectively improved, the heating of the battery monomer 100 is reduced, and the fast charging performance of the battery monomer is improved.

[0321] In some embodiments, the first welding mark 51 further comprises a second welding mark portion 512, the first connecting portion 31 is welded to the surface of the transition portion 1211 away from the insulating base 11 and forms the second welding mark portion 512, and the first insulating portion 42 covers at least part of the second welding mark portion 512.

[0322] The first connecting portion 31 is welded to the surface of the transition portion 1211 away from the insulating base 11, and the trace generated by the welding of the transition portion 1211 and the first connecting portion 31 is the second welding mark portion 512.

[0323] In some examples, the first welding mark 51 only comprises the second welding mark portion 512, that is, the first connecting portion 31 is only welded to the transition portion 1211.

[0324] In some examples, the first welding mark 51 comprises the second welding mark portion 512 and the first welding mark portion 511, and 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 1211 and the protruding portion 122 at the same time.

[0325] The first insulating portion 42 can cover part of the second welding mark portion 512, or the entire first insulating portion 42.

[0326] By adopting the technical scheme of this embodiment, the first connecting portion 31 and the transition portion 1211 are connected by welding, which is simple in connection mode and is beneficial to facilitate the manufacturing of the first tab 1; in addition, the first connecting portion 31 and the transition portion 1211 can directly utilize the second welding mark portion 512 for flow, which is beneficial to improve the flow capacity between the first connecting portion 31 and the transition portion 1211 and reduce the heating of the battery monomer 100; in addition, the first insulating portion 42 can block the burrs, metal debris and other components on the second welding mark portion 512 from passing through the isolation piece 3 to connect with the second tab 2, which is beneficial to improve the use reliability of the battery monomer.

[0327] In some embodiments, in the direction of the protruding portion 122 pointing to the body portion 121, the first insulating portion 42 protrudes from the second welding mark portion 512 towards the edge of the active material layer 20.

[0328] Along the thickness direction of the current collector 10, the projection of the edge of the second welding portion 512 facing away from the active material layer 20 falls within the projection of the first insulating portion 42, so that the first insulating portion 42 can completely cover the second welding portion 512.

[0329] By adopting the technical solutions of this embodiment, the first insulating portion 42 can completely cover the second welding portion 512, and the first insulating portion 42 can block the burrs, metal debris and other components on the entire second welding portion 512 from passing through the separator 3 to connect with the second tab 2, thereby facilitating the improvement of the use reliability of the battery monomer.

[0330] In some embodiments, along the second direction, the size of the transition portion 1211 is L2, and the size of the second welding portion 512 is L3, and 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0331] 0.8≤L3 / L2≤1, along the second direction, the size L3 of the second welding portion 512 can be less than or equal to the size L2 of the transition portion 1211, the size L3 of the second welding portion 512 is greater than or equal to 0.8 times the size L2 of the transition portion 1211, the size L3 of the second welding portion 512 exceeds more than half the size L2 of the transition portion 1211, the longer the size L3 of the second welding portion 512, the larger the welding area of the transition portion 1211 and the first connecting portion 31, and the better the flow capacity of the connection between the transition portion 1211 and the first connecting portion 31.

[0332] In some examples, 0.8≤L3 / L2<1, along the second direction, the second welding portion 512 can be located at the middle position of the transition portion 1211, and the two ends of the second welding portion 512 are not flush with the transition portion 1211.

[0333] In some examples, 0.8≤L2 / L1<1, along the second direction, the second welding portion 512 can also be arranged to be deviated from one end of the transition portion 1211, so that one end of the transition portion 1211 is flush with the transition portion 1211, and the other end is not flush, or both ends are not flush.

[0334] The value of L3 / L2 can be but is not limited to 0.8, 1, or any value between 0.8 and 1. For example, the value of L3 / L2 can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0335] By adopting the technical scheme of the embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the transition portion 1211 along the second direction larger, which is beneficial to increase the connection area between the first connection portion 31 and the transition portion 1211, improve the flow capacity at the connection between the first connection portion 31 and the transition portion 1211, 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.

[0336] In some embodiments, L3=L2.

[0337] L3 / L2=1, along the second direction, the size L3 of the second soldering portion 512 is equal to the size L2 of the transition portion 1211, and the two ends of the second soldering portion 512 are flush with the transition portion 1211.

[0338] In some examples, the convex portion 122 is welded with the first connection portion 31 at the same time as the transition portion 1211, so as to form an entire soldering, and the first connection portion 31 is welded to the transition portion 1211, which can effectively increase the welding area of the first connection portion 31 and the metal layer 12 and improve the flow area between the first connection portion 31 and the metal layer 12, and is beneficial to improve the flow capacity between the first connection portion 31 and the metal layer 12.

[0339] In the process of cutting the conductive member 30, first, cutting is performed on the equal-width soldering in the second direction, then cutting is performed in the direction away from the active material layer 20 until the equal-width soldering is left, then 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 the equal-width soldering is cut for a distance, then cutting is continued in the second direction on the equal-width soldering, and so on, so as to obtain the first soldering 51; wherein, based on the cutting position of cutting in the second direction on the equal-width soldering as a reference, along the first direction, the part of the first soldering 51 on the side of the cutting position toward the active material layer 20 is the second soldering portion 512, and the part on the side of the cutting position away from the active material layer 20 is the first soldering portion 511, and the first soldering portion 511 can be a convex structure away from the active material layer 20 of the second soldering portion 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 convex portion 122, and during the cutting process in the second direction, the part between the convex portion 122 and the active material layer 20 forms the transition portion 1211.

[0340] By adopting the technical scheme of this embodiment, the design of L3 / L2=1 makes the size of the second welding portion 512 along the second direction larger, which is beneficial to designing the welding area between the first connecting portion 31 and the transition portion 1211 to be larger, the overcurrent capacity at the connection between the first connecting portion 31 and the transition portion 1211 is best, the overcurrent 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 is improved.

[0341] In some examples, the second welding portion 512 and the first welding portion 511 are directly connected.

[0342] The second welding portion 512 and the first welding portion 511 form a whole first welding 51, and there is no obvious boundary between the two; the whole first welding 51 can cover the junction of the convex portion 122 and the transition portion 1211; in the actual manufacturing process, the second welding portion 512 and the first welding portion 511 are formed by cutting the above-mentioned welding portion with equal width.

[0343] In some examples, the second welding portion 512 and the first welding portion 511 adopt the structure form of welding points, the welding point spacing in the second welding portion 512 is the same as the welding point spacing of the first welding portion 511; for example, the welding points in the second welding portion 512 and the first welding portion 511 are not welded to the junction line of the convex portion 122 and the transition portion 1211, and the spacing between the two adjacent welding points in the second welding portion 512 and the first welding portion 511 is equal to the welding point spacing in the second welding portion 512; for example, the welding points are welded to the junction line of the convex portion 122 and the transition portion 1211, so as to connect the second welding portion 512 and the first welding portion 511 into a whole welding.

[0344] By adopting the technical scheme of this embodiment, the first welding 51 can cover the junction of the convex portion 122 and the transition portion 1211, and a part of the current can directly flow to the first connecting portion 31 through the first welding 51 when flowing to the junction of the transition portion 1211 and the convex portion 122, which reduces the overcurrent pressure at the junction of the convex portion 122 and the transition portion 1211, is beneficial to improve the overcurrent 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.

[0345] In some embodiments, the number of the convex portions 122 is multiple, and the multiple convex portions 122 are arranged at intervals along the second direction, each convex portion 122 is welded with the first connecting portion 31, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0346] The number of the convex portions 122 is multiple, for example, two, three, four, etc.; the multiple convex portions 122 are arranged at intervals along the second direction.

[0347] In some examples, after the first pole piece 1 is wound or stacked, the plurality of protrusions 122 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.

[0348] The plurality of protrusions 122 are arranged at intervals along the second direction, such that along the second direction, the sum of the sizes of all the protrusions 122 is less than the size of the main body portion 121, the sum of the sizes L4 of all the first welding portions 511 is less than the size L3 of the second welding portion 512, and the size L3 of the second welding portion 512 is large, which is conducive to improving the welding area of the transition portion 1211 and the first connecting portion 31, improving the current-carrying capacity of the connection between the transition portion 1211 and the conductive member 30, improving the current-carrying 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.

[0349] Among the plurality of first welding portions 511, along the second direction, some of the first welding portions 511 can have the same size, all of the first welding portions 511 can have completely different sizes, or all of the first welding portions 511 can have the same size.

[0350] By adopting the technical scheme of this embodiment, the plurality of protrusions 122 are arranged at intervals along the second direction, which is conducive to dividing the main body portion 121 into a plurality of regions along the second direction, and one region can correspond to one protrusion 122. The electrons in each region can be transmitted to the electrode lead-out portion 2011 through the corresponding protrusion 122, so that the electrons in the main body portion 121 are transmitted in a region-by-region manner, the transmission path of the electrons in each region is short to the corresponding protrusion 122, 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 device 1100.

[0351] 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; and each first connecting sub-portion 311 is welded to the surface of each protrusion 122 away from the insulation base 11 one by one.

[0352] The first connecting sub portion 311 can refer to the portion of the first connecting portion 31 covering the protruding portion 122. The number of the first connecting sub portions 311, the number of the second connecting portions 32, and the number of the protruding portions 122 are the same, one first connecting sub portion 311 corresponds to one protruding portion 122, one first connecting sub portion 311 corresponds to one second connecting portion 32, and one first connecting sub portion 311 and one protruding portion 122 are welded to form one first welding portion 511.

[0353] 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 the gap between the two adjacent first connecting sub portions 311 can reduce the required material of the first connecting portion 31 and reduce the manufacturing cost of the battery device 1100 monomer.

[0354] In some embodiments, the number of the protruding portions 122 is a plurality, and the plurality of protruding portions 122 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 the 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 122 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 1211 away from the insulating base body 11.

[0355] The second connecting sub portion 312 can refer to the portion of the first connecting portion 31 covering the transition portion 1211; 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 1211 to the other side of the transition portion 1211.

[0356] The second connecting sub portion 312 is welded to the surface of the transition portion 1211 away from the insulating base body 11 to form a second welding portion 512.

[0357] By adopting the technical scheme 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 device 1100 monomer 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 1211, improve the overcurrent capacity of the connection part 31 and the transition part 1211, improve the overcurrent capacity of the first pole piece 1, and improve the fast charging performance and use reliability of the battery device 1100 monomer.

[0358] 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 welding marks 51; the number of insulating members 40 is two, and the first insulating parts 42 of the two insulating members 40 respectively cover at least part of the two first welding marks 51.

[0359] The number of metal layers 12, the number of insulating members 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 1212 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 welding mark 51, the first connecting part 31 of the other conductive member 30 is welded to the other metal layer 12 and also forms a first welding mark 51, and the first insulating parts 42 of the two insulating members 40 are located on opposite sides of the insulating base 11 along the thickness direction and respectively cover the two first welding marks 51.

[0360] By adopting the technical scheme of the embodiment, the first connecting parts 31 of the two conductive members 30 are respectively welded to the metal layers 12 located on opposite sides of the insulating base 11, and the second connecting parts 32 of the two conductive members 30 are located on the side of the protruding part 122 away from the main part 121, so that the two metal layers 12 can be directly connected by the second connecting parts 32 of the two conductive members 30, thereby breaking the insulation limitation of the insulating base 11, effectively improving the conductive capacity of the first pole piece 1, improving the fast charging performance of the battery device 1100 monomer, reducing the heat generation of the battery device 1100 monomer, and improving the use reliability of the battery device 1100 monomer.

[0361] In some embodiments, the first insulating part 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 main body part 121 in the direction of the main body part 121 pointing to the protruding part 122, and the second portion 422 protrudes from the main body part 121, and the second portion 422 is located at the side of the protruding part 122 in the second direction, which is perpendicular to the first direction and the thickness direction of the current collector 10.

[0362] In some examples, the insulating part 40 is of an equal-width structure, and the insulating part 40 covers the first welding mark 51 and the end surface of the main body part 121 in the direction of the main body part 121 pointing to the protruding part 122 along the length direction of the first tab 1; and in the thickness direction of the current collector 10, the part of the first insulating part 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 first insulating part 42 located outside the projection range of the metal layer 12 and the conductive member 30 is the second portion 422.

[0363] In some examples, burrs are easily formed at the end surface of the transition part 1211 pointing to the protruding part 122 during the cutting of the conductive member 30, in particular, larger burrs are easily formed at the end surface of the transition part 1211 pointing to the protruding part 122 during the cutting of the conductive member 30 at the first welding mark 51; and the first insulating part 42 of the embodiments of the present application can block the burrs at the end surface of the transition part 1211 pointing to the protruding part 122 from piercing the separator 3 and contacting the second tab 2, thereby reducing the risk of short circuit of the battery monomer 100 and facilitating the improvement of the use reliability of the battery monomer 100.

[0364] In some examples, the end of the main body part 121 pointing to the protruding part 122 is easily impacted to generate metal debris, and the metal debris is easily dropped into the electrode assembly 101, thereby causing the short circuit of the battery monomer 100. For example, the end of the transition part 1211 pointing to the protruding part 122 is easily impacted to generate metal debris, and the metal debris is easily dropped into the electrode assembly 101, thereby causing the short circuit of the battery monomer 100.

[0365] By adopting the technical solutions of the embodiments, the metal debris and the like at the end surface of the main body part 121 pointing to the protruding part 122 can be located between the second portions 422 of the two insulating parts 40 in the direction of the main body part 121 pointing to the protruding part 122, which can reduce the risk of the metal debris dropping into the electrode assembly 101 and facilitate the reduction of the risk of short circuit.

[0366] In some embodiments, the second portions 422 of the two insulating parts 40 are in abutment.

[0367] In some examples, the second portions 422 of the two insulating pieces 40 are located in the hollowed-out area of the protruding portion 122 where the transition portion 1211 does not extend, so that the second portions 422 of the two insulating pieces 40 can be close to each other and thus fit together.

[0368] The second portions 422 of the two insulating pieces 40 can be pasted or statically adsorbed together, and of course can also be other fitting modes.

[0369] By adopting the technical solutions of this embodiment, after the second portions 422 of the two insulating pieces 40 fit together, the main body portion 121 can cover the metal debris and other components on the end face of the protruding portion 122, 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 device 1100 can be better reduced.

[0370] In some embodiments, the second connecting portions 32 of the two conductive members 30 are welded and form second welding marks 52.

[0371] In some examples, along the direction in which the main body portion 121 points to the protruding portion 122, the portions of the conductive members 30 protruding from the protruding 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.

[0372] 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 substrate 11, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductive capacity of the first tab 1, improving the fast-charging performance of the battery monomer 100, reducing the heat generation of the battery monomer 100, and improving the use reliability of the battery monomer 100.

[0373] In some embodiments, the first insulating portion 42 covers at least part of the second welding mark 52.

[0374] The first insulating portion 42 covers part of the second welding mark 52, and can also cover the entire second welding mark 52.

[0375] By adopting the technical solutions of this embodiment, the first insulating portion 42 can block the burrs, metal debris and other components on the second welding mark 52 from piercing the separator 3 and connecting with the second tab 2, thereby reducing the risk of short circuit and improving the use reliability of the battery monomer.

[0376] In some embodiments, along the direction in which the main body portion 121 points to the protruding portion 122, the first insulating portion 42 protrudes from the edge of the second welding mark 52 away from the main body portion 121.

[0377] By adopting the technical scheme of this embodiment, the first insulation portion 42 can completely cover the second welding mark 52, and can block burrs, metal debris and other components on the entire second welding mark 52 from penetrating the separator 3 to be connected with the second pole piece 2, thereby reducing the risk of short circuit and improving the use reliability of the battery monomer.

[0378] In some embodiments, the distance between the first welding mark 51 and the active material layer 20 in the first direction is S1, where 0.3mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

[0379] In some examples, the first welding mark 51 includes the first welding mark portion 511, and S1 is the distance between the first welding mark portion 511 and the active material layer 20 without the second welding mark portion 512.

[0380] In some examples, the first welding mark 51 includes the first welding mark portion 511 and the second welding mark portion 512, and S1 is the distance between the second welding mark portion 512 and the active material layer 20.

[0381] The design of S1≥0.3mm makes the first welding mark 51 have a distance with the active material layer 20, so that the conductive member 30 will not be welded to the active material layer 20, thereby reducing the risk of problems such as false welding; the design of S1≤5mm makes the distance between the first welding mark 51 and the active material layer 20 not too large, which is conducive to increasing the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery monomer.

[0382] The value of S1 can be 0.3mm, 5mm and any value between 0.3mm and 5mm, for example, the value of S1 can be but is not limited to 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, 5mm.

[0383] By adopting the technical scheme of this embodiment, the design of 0.3mm≤S1≤5mm makes the first welding mark 51 not be welded to the active material layer 20, thereby reducing problems such as false welding and improving the connection reliability of the first connection portion 31 and the metal layer 12, in addition, the distance between the active material layer 20 and the first welding mark 51 is small, and the active material layer 20 can be relatively close to the first welding mark 51, so that the active material layer 20 can cover a larger area under the condition that the size of the metal layer 12 in the first direction is constant, which is conducive to improving the energy density of the battery monomer.

[0384] In some embodiments, 0.5mm≤S1≤2.8mm.

[0385] By adopting the technical scheme of the embodiment, the distance between the active material layer 20 and the first welding mark 51 is more reasonable in the design of 0.5mm≤S1≤2.8mm, and the connection reliability of the conductive member 30 and the energy density of the battery monomer can be better balanced.

[0386] In some embodiments, along the first direction, the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20 are spaced apart.

[0387] In some examples, the first pole piece 1 is a positive pole piece, and there is a gap 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 face of the first welding mark 51 and the first connecting part 31 towards the active material layer 20, so that the first welding mark 51 does not extend to the end face of the first connecting part 31 towards the active material layer 20, reducing the risk of the end face of the first connecting part 31 towards the active material layer 20 being welded through or cracked, and being conducive to reducing burrs generated by welding and improving the use reliability of the battery monomer.

[0388] In some examples, the first pole piece 1 is a negative pole piece, and there is a gap between the first welding mark 51 and the active material layer 20. The gap can provide a spacing space for the end face of the first welding mark 51 and the first connecting part 31 towards the active material layer 20, so that the second welding mark part 512 does not extend to the end face of the first connecting part 31 towards the active material layer 20, reducing the risk of the end face of the first connecting part 31 towards the active material layer 20 being welded through or cracked, and being conducive to reducing burrs generated by welding and improving the use reliability of the battery monomer; wherein the conductive member 30 can or can not be connected with the active material layer 20.

[0389] There is a gap between the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20, so that the first welding mark 51 does not extend to the end face of the first connecting part 31 towards the active material layer 20, reducing the risk of the end face of the first connecting part 31 towards the active material layer 20 being welded through or cracked, and being conducive to reducing burrs generated by welding and improving the use reliability of the battery monomer.

[0390] In some embodiments, along the first direction, the distance between the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20 is in the range of 0.3mm~1.2mm.

[0391] Along the first direction, the distance between the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20 is S2, wherein 0.3mm≤S2≤1.2mm.

[0392] The design of S2≥0.3mm makes the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20 have a spacing, so that the first welding mark 51 does not extend to the end face of the first connecting part 31 towards the active material layer 20, reducing the risk of the end face of the first connecting part 31 being welded through or cracked, etc.; the design of S2≤1.2mm makes the spacing between the first welding mark 51 and the end face of the first connecting part 31 towards the active material layer 20 not too large, which is conducive to improving the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell.

[0393] The value of S2 can be 0.3mm, 1.2mm, and any value between 0.3mm and 1.2mm, for example, the value of S2 can be but not limited to 0.3mm, 0.6mm, 0.8mm, 1mm, 1.2mm.

[0394] By adopting the technical scheme of the embodiment, the use reliability and energy density of the battery cell can be well balanced.

[0395] In some embodiments, the current collector 10 further comprises a conductive protective layer 13, at least part of the conductive protective layer 13 is located between the active material layer 20 and the metal layer 12.

[0396] The conductive protective layer 13 can refer to a conductive structure arranged between the active material layer 20 and the metal layer 12, which can conduct electricity so that the battery cell can output or input electric energy. The conductive protective layer 13 can be an equal-thickness structure or a non-equal-thickness structure.

[0397] For example, part of the conductive protective layer 13 is located between the active material layer 20 and the conductive part 1212, and the other part covers the transition part 1211 and protrudes out of the active material layer 20.

[0398] For example, the entire conductive protective layer 13 is located between the active material layer 20 and the conductive part 1212.

[0399] In some examples, the conductive protective layer 13 can contain conductive carbon black and a binder, which on the one hand plays a buffering and lubricating role between the active material and the metal layer, and can alleviate the damage of 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 use performance of the battery cell.

[0400] In 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 cracks and other problems. The conductive protective layer 13 of the embodiment of the 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 being conducive to improving the overcurrent capacity of the metal layer 12.

[0401] In some embodiments, the conductive protective layer 13 protrudes from the active material layer 20 toward the end face of the protruding portion 122.

[0402] The conductive protective layer 13 protrudes from the active material layer 20, and the conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20. In addition, it can also provide an extension space for the active material layer 20 during rolling, which is conducive to the subsequent conductive protective layer 13 that can completely separate the metal layer 12 and the active material layer 20.

[0403] 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, and the overcurrent capacity of the first pole piece 1 is better, which is conducive to improving the fast charging performance and use reliability of the battery monomer.

[0404] The protruding distance of the conductive protective layer 13 from the end face of the active material layer 20 toward the protruding portion 122 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.

[0405] 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 protective ability of the conductive protective layer 13 to the metal layer 12 is better, and the overcurrent capacity of the first pole piece 1 is better, which is conducive to improving the fast charging performance and use reliability of the battery monomer; the design of S3≤0.8mm makes the conductive protective layer 13 not too large, and occupies space, which is conducive to saving the internal space of the battery monomer and improving the energy density of the battery monomer.

[0406] By adopting the technical scheme of the embodiment, the overcurrent capacity and energy density of the battery monomer can be better balanced.

[0407] In some embodiments, the current collector 10 further comprises an electrically conductive protective layer 13, at least part of the electrically conductive protective layer 13 is located between the active material layer 20 and the metal layer 12, and the electrically conductive protective layer 13 is spaced apart from the first welding mark 51 along the first direction.

[0408] In some examples, the electrically conductive protective layer 13 is spaced apart from the first connecting portion 31, and the second insulating portion 41 covers the part of the electrically conductive protective layer 13 between the first connecting portion 31 and the active material layer 20.

[0409] By adopting the technical scheme of this embodiment, the first connecting portion 31 will not be welded to the electrically conductive protective layer 13, which can reduce the risk of false welding and the like, and is conducive to improving the reliability of welding of the first connecting portion 31 to the metal layer 12.

[0410] Please refer to FIGS. 22-44, in some embodiments, the first insulating portion 42 is connected to the first tab 1.

[0411] The first insulating portion 42 can be connected to the metal layer 12, or to the electrically conductive member 30, or to the active material layer 20, wherein the first insulating portion 42 can be connected to the first tab 1 by means of adhesion or affixing or the like.

[0412] By adopting the technical scheme of this embodiment, the first insulating portion 42 is connected to the first tab 1, and the first insulating portion 42 can be fixed, thereby stably blocking burrs at the end of the protruding portion 122 toward the main body portion 121, which is conducive to improving the use reliability of the battery monomer.

[0413] In some embodiments, the first insulating portion 42 comprises an insulating base layer 423 and an adhesive layer 424, and the adhesive layer 424 is adhered between the insulating base layer 423 and the first tab 1.

[0414] The first insulating portion 42 adopts the structure of a tape; the insulating base layer 423 can refer to the main body portion 121 of the first insulating portion 42, and the adhesive layer 424 can refer to an adhesive covering the surface of the insulating base layer 423. The material of the first insulating portion 42 adopting the structure of a tape comprises at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and block copolymers thereof. The material of the adhesive layer 424 comprises at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0415] By adopting the technical scheme of the embodiment, the first insulation part 42 adopts the structural form of the adhesive tape, the adhesive tape is easy to cover comprehensively, which is beneficial to reduce the risk of incomplete coverage and reduce the risk of internal short circuit of the battery monomer 100; the insulation base layer 423 can improve the structural strength of the first insulation part 42, reduce the deformation of the first insulation part 42 in the process of bonding, and is beneficial to improve 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 of the insulation tape.

[0416] In some embodiments, the layer thickness of the insulation base layer 423 ranges from 6 μm to 15 μm.

[0417] The layer thickness of the insulation base layer 423 is T1, 6 μm≤T1≤15 μm, and 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 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.

[0418] 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 beneficial to reduce the volume occupied by the first insulation part 42 and improve the energy density of the battery monomer.

[0419] By adopting the technical scheme of the embodiment, the internal insulation and energy density of the battery monomer can be considered at the same time.

[0420] In some embodiments, the layer thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0421] The layer thickness of the adhesive layer 424 is T2, 0.5 μm≤T2≤3 μm, and 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 not limited to 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm.

[0422] The design of T2≥0.5 μm makes the adhesive layer 424 have a certain thickness, so that the first insulation part 42 can be stably bonded on the first pole piece 1, and the insulation reliability of the first insulation part 42 is good; the design of T2≤3 μm makes the thickness of the adhesive layer 424 not too large, which is beneficial to reduce the volume occupied by the first insulation part 42 and improve the energy density of the battery monomer.

[0423] By adopting the technical scheme of the embodiment, the insulation reliability and energy density of the battery monomer can be considered at the same time.

[0424] In some embodiments, the thickness of the insulating base layer 423 is in the range of 6-15 μm, and the thickness of the adhesive layer 424 is in the range of 0.5-3 μm.

[0425] By adopting the technical solutions of this embodiment, the insulation reliability and the energy density of the battery cell can be simultaneously considered.

[0426] In some embodiments, the size of the insulating member 40 along the first direction is W, where 3 mm≤W≤9 mm.

[0427] In some examples, the insulating member 40 includes the first insulating part 42, and W is equal to the size of the first insulating part 42 along the first direction.

[0428] In some examples, the insulating member 40 includes the first insulating part 42 and the second insulating part 41, and W is equal to the overall size of the first insulating part 42 and the insulating coating along the first direction.

[0429] 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, or 9 mm.

[0430] The design of W≥3 mm makes the insulating member 40 have a certain size along the first direction, so that the insulating member 40 can better block the burr at the end of the protruding part 122 toward the main part 121, and realize the internal insulation of the battery cell 100. The design of W≤9 mm makes the size of the insulating member 40 along the first direction not too large, which is beneficial to reduce the volume occupied by the insulating member 40 and improve the energy density of the battery cell.

[0431] By adopting the technical solutions of this embodiment, the insulation reliability and the energy density of the battery cell can be simultaneously considered.

[0432] In some embodiments, 4.5 mm≤W≤6.5 mm.

[0433] By adopting the technical solutions of this embodiment, the size of the insulating member 40 along the first direction is reasonable, and the insulation reliability and the energy density of the battery cell can be simultaneously considered.

[0434] In some embodiments, the electrode assembly 101 further comprises a second tab 2 opposite in polarity to the first tab 1, the second tab 2 comprising 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 from the main portion 121 to the protruding portion 122, the main functional portion 210 protrudes from an end surface of the insulating member 40 close to the active material layer 20, and the main functional portion 210 does not protrude from an end surface of the insulating member 40 away from the active material layer 20.

[0435] The second tab 2 can refer to a tab opposite in polarity to the first tab 1, wherein 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.

[0436] The second tab 2 comprises a main functional portion 210 and a tab portion 220, the main functional portion 210 can refer to a main portion 121 of the second tab 2, and the tab portion 220 can refer to a portion of the second tab 2 protruding from the main functional portion 210; in the case where the second tab 2 is a negative tab, the tab portion 220 can refer to a protruding structure at the edge of the negative current collector, and the main functional portion 210 can include the negative current collector except the protruding structure and the negative active material layer. In the case where the second tab 2 is a positive tab, the tab portion 220 can refer to a protruding structure at the edge of the positive current collector, and the main functional portion 210 can include the positive current collector except the protruding structure and the positive active material layer.

[0437] During the manufacturing process of the second tab 2, the edge of the second tab 2 is die-cut to obtain the tab portion 220 and the main functional portion 210, and during the die-cutting process, burrs are easily generated at the end surface of the main functional portion 210 facing the tab portion 220.

[0438] 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 second insulating portion 41 or the projection of the first insulating portion 42.

[0439] By adopting the technical scheme of this embodiment, the burrs at the end surface of the main functional portion 210 of the second tab 2 close to the tab portion 220 can be blocked by the insulating member 40 from piercing the separator 3 to connect with the first tab 1, thereby reducing the risk of short circuit between the first tab 1 and the second tab 2, and facilitating improvement of the use reliability of the battery cell.

[0440] In some embodiments, the electrode assembly 101 further comprises a second tab 2 opposite to the first tab 1 in polarity, the second tab 2 comprising 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 from the main portion 121 to the protruding portion 122, the main functional portion 210 protrudes from an end of the main portion 121 towards the protruding portion 122.

[0441] In a thickness direction of the current collector 10, a projection of the main functional portion 210 towards an end surface of the tab portion 220 does not coincide with a projection of the main portion 121, so that burrs at the end surface of the tab portion 220 of the main functional portion 210 of the second tab 2 correspond to a hollowed region of the main portion 121 not extending out of the protruding portion 122.

[0442] In some examples, in a thickness direction of the current collector 10, a projection of the second welding portion 512 can fall within a projection of the main functional portion 210, and the second welding portion 512 can be covered with the first insulating portion 42, so that the first insulating portion 42 can block burrs, metal debris and other components on the first welding 51 from piercing the separator 3 to connect with the second tab 2, reducing the risk of short circuit and improving the use reliability of the battery cell.

[0443] By adopting the technical solutions of this embodiment, the burrs at the end surface of the tab portion 220 of the main functional portion 210 of the second tab 2 correspond to the hollowed region of the main portion 121 not extending out of the protruding portion 122, which can also reduce the risk of short circuit of the battery cell and improve the use reliability of the battery cell.

[0444] In some embodiments, the electrode assembly 101 further comprises a second tab 2 opposite to the first tab 1 in polarity, the second tab 2 comprising 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 from the main portion 121 to the protruding portion 122, the main functional portion 210 protrudes from an end of the main portion 121 towards the protruding portion 122.

[0445] In some embodiments, the main portion 121 comprises a transition portion 1211 and a conductive portion 1212, the transition portion 1211 being connected between the protruding portion 122 and the conductive portion 1212, the conductive portion 1212 being covered with the active material layer 20, and the transition portion 1211 not being covered with the active material layer 20; the transition portion 1211 is connected with the conductive member 30; at least part of the thickness of the conductive portion 1212 is smaller than the thickness of the transition portion 1211.

[0446] For example, the transition portion 1211 is of an equal thickness structure or substantially an equal thickness structure, and the conductive portion 1212 is also of an equal thickness structure or substantially an equal thickness structure, and the thickness t1 of the transition portion 1211 is greater than the thickness of the conductive portion 1212.

[0447] For example, the conductive part 1212 can be of unequal thickness, and the thickness of the conductive part 1212 gradually increases in the direction from the main body part 121 to the protruding part 122. Specifically, the thickness of the conductive part 1212 can gradually increase in steps, or gradually increase slowly. The thickness of the part of the conductive part 1212 away from the transition part 1211 is less than the thickness of the transition part 1211.

[0448] By adopting the technical scheme of this embodiment, the thickness t1 of the transition part 1211 is large, and the transition part 1211 has good flow capacity, which is conducive to improving the flow capacity of the first tab 1, reducing the heat generation of the battery monomer 100, and improving the fast-charging performance and use reliability of the battery monomer.

[0449] In some embodiments, the conductive part 1212 includes a first sub-part 12121 and a second sub-part 12122, the first sub-part 12121 is connected between the second sub-part 12122 and the transition part 1211, the first sub-part 12121 and the second sub-part 12122 are covered with an active material layer 20, the thickness of the first sub-part 12121 is greater than the thickness of the second sub-part 12122, and the thickness of the transition part 1211 is greater than or equal to the thickness of the first sub-part 12121.

[0450] The conductive part 1212 can be of unequal thickness, and the conductive part 1212 is divided into two parts in the direction from the main body part 121 to the protruding part 122. The part close to the transition part 1211 is the first sub-part 12121, and the part away from the transition part 1211 is the second sub-part 12122. The first sub-part 12121 and the second sub-part 12122 are both covered with an active material layer 20.

[0451] In some examples, the first sub-part 12121 can be of equal thickness, and the second sub-part 12122 can be of equal thickness. The thickness t2 of the first sub-part 12121 is greater than the thickness t3 of the second sub-part 12122, the thickness t1 of the transition part 1211 is greater than or equal to the thickness t2 of the first sub-part 12121, so that the first sub-part 12121 and the second sub-part 12122 form a stepped structure. The thickness t1 of the transition part 1211 can be equal to the thickness t2 of the first sub-part 12121, so that the transition part 1211 and the first sub-part 12121 form an equal-thickness structure. Alternatively, the thickness t1 of the transition part 1211 can be greater than the thickness t3 of the second sub-part 12122, so that the first sub-part 12121 and the transition part 1211 form a stepped structure.

[0452] In some examples, the first sub-part 12121 can also be a multi-section structure, and the thickness of each section gradually increases in the direction from the main body part 121 to the protruding part 122; for example, the first sub-part 12121 includes a first section and a second section, the first section is located between the second section and the second sub-part 12122, and the thickness of the first section gradually increases in the direction from the main body part 121 to the protruding 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 1211; the thickness of the first section gradually increases from the thickness t3 of the second sub-part 12122 to the thickness of the second section, so that the first section can smoothly connect the second section and the second sub-part 12122, 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 1211, and the thickness t1 of the transition part 1211 can also be greater than the thickness of the first section.

[0453] In the use process of the battery cell, in the direction from the main body part 121 to the protruding part 122, the electrons and ions generated by the active material layer 20 gradually flow to the transition part 1211 through the conductive part 1212, and the electrons and ions flowing through the part of the conductive part 1212 close to the transition part 1211 are more than those flowing through the part of the conductive part 1212 away from the transition part 1211, so it is required that the overcurrent capacity of the part of the conductive part 1212 close to the transition part 1211 is greater than that of the part of the conductive part 1212 away from the transition part 1211.

[0454] The first sub-part 12121 of the embodiment of the application is connected between the second sub-part 12122 and the transition part 1211, and the thickness t2 of the first sub-part 12121 is greater than the thickness t3 of the second sub-part 12122, so that the overcurrent capacity of the first sub-part 12121 close to the transition part 1211 is greater than that of the second sub-part 12122 away from the transition part 1211, which can reduce the limitation on the current, improve the overcurrent capacity of the first tab 1, reduce the heating of the battery cell 100, and is beneficial to improve the use reliability of the battery cell.

[0455] In some examples, the current collector 10 further includes a conductive protective layer 13, and the conductive protective layer 13 includes a first protective part 131 and a second protective part 132, the first protective part 131 is located between the first sub-part 12121 and the active material layer 20, and the second protective part 132 is located between the second sub-part 12122 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, and the thickness of the third protective part 133 is less than or equal to the thickness of the first protective part 131.

[0456] In some examples, along the first direction, the portion of the conductive protective layer 13 between the first sub-portion 12121 and the active material layer 20 can be a first protective portion 131, and the portion of the conductive protective layer 13 between the second sub-portion 12122 and the active material layer 20 can be a second protective portion 132, wherein the thickness t4 of the first protective portion 131 is less than the thickness t5 of the second protective portion 132, and the thickness t2 of the first sub-portion 12121 is greater than the thickness t3 of the second sub-portion 12122, so as to reduce the difference between the thickness of the current collector 10 at the first protective portion 131 and the thickness of the current collector 10 at the second protective portion 132.

[0457] For example, the first sub-portion 12121 is divided into a third portion and a fourth portion, the third portion is between the first section and the active material layer 20, and the fourth portion is between the second section and the active material layer 20, the third portion is between the fourth portion and the second protective portion 132, and along the direction of the main portion 121 pointing to the protruding portion 122, the thickness of the third portion gradually decreases, and the fourth portion is generally of an equal-thickness structure, so that the thickness t4 of the first protective portion 131 can be adapted to the thickness t2 of the first sub-portion 12121, and the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane.

[0458] By adopting the technical scheme of this embodiment, the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane, which is beneficial to reduce the roll damage and improve the overcurrent capacity of the metal layer 12, and in addition, the winding bulging problem of the current collector 10 can also be reduced.

[0459] In some embodiments, the conductive protective layer 13 further comprises a third protective portion 133, the third protective portion 133 covers the surface of the transition portion 1211 facing away from the insulating substrate 11, and the thickness of the third protective portion 133 is less than or equal to the thickness of the first protective portion 131.

[0460] In some examples, along the first direction, the conductive protective layer 13 can be divided into three portions, a portion close to the conductive member 30 is a third protective portion 133, a portion far from the conductive member 30 is a second protective portion 132, and a portion in the middle is a first protective portion 131, wherein the thickness t4 of the first protective portion 131 is less than the thickness t5 of the second protective portion 132, and the thickness t2 of the first sub-portion 12121 is greater than the thickness t5 of the second protective portion 132, so as to reduce the difference between the thickness of the current collector 10 at the first protective portion 131 and the thickness of the current collector 10 at the second protective portion 132; similarly, the thickness t6 of the third protective portion 133 is less than or equal to the thickness t4 of the first protective portion 131, and the thickness t1 of the transition portion 1211 is greater than or equal to the thickness t2 of the first sub-portion 12121, so as to reduce the difference between the thickness of the current collector 10 at the first protective portion 131 and the thickness of the current collector 10 at the third protective portion 133, and the surface of the conductive protective layer 13 facing away from the metal layer 12 is close to a plane.

[0461] For example, the second protection part 132, the third protection part 133, the transition part 1211 and the second sub-part 12122 are all equal-thickness structures, and the first sub-part 12121 and the first protection part 131 are all unequal-thickness structures; the thickness t2 of the first sub-part 12121 and the thickness t4 of the first protection part 131 are matched to make the surface of the conductive protection layer 13 away from the insulating substrate 11 close to a plane.

[0462] By adopting the technical aspect of this embodiment, the third protection part 133 is arranged to make the conductive protection layer 13 protrude from the active material layer 20, so that the active material layer 20 and the metal layer 12 can be better separated, and in addition, the thickness of the third protection 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.

[0463] In some embodiments, the thickness t7 of the protruding part 122 is greater than or equal to the thickness t1 of the transition part 1211.

[0464] For example, the thickness t7 of the protruding part 122 can be equal to the thickness t1 of the transition part 1211, so that the protruding part 122 and the transition part 1211 form an equal-thickness structure.

[0465] For example, the thickness t7 of the protruding part 122 can also be greater than the thickness t1 of the transition part 1211, so that the protruding part 122 and the transition part 1211 form a stepped structure.

[0466] By adopting the technical solution of this embodiment, the thickness t7 of the protruding part 122 is relatively thick, which can improve the flow capacity of the protruding part 122, 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.

[0467] In some embodiments, the thickness of the second active material part 22 is t8, and 0.002≤(t1-t3) / t8≤0.08.

[0468] t1-t3 can be the difference between the thicknesses of the transition part 1211 and the second sub-part 12122, to represent the thickening degree of the transition part 1211.

[0469] 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.

[0470] By adopting the technical scheme of the embodiment, the setting of 0.002≤(t1-t3) / t8≤0.08 makes the thickness difference between the transition part 1211 and the second sub part 12122 be within the thickness error range of the active material layer 20, so that the thickening of the transition part 1211 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 improve the use reliability of the battery monomer.

[0471] In some embodiments, 0.003≤(t1-t3) / t8≤0.06.

[0472] By adopting the technical scheme of the embodiment, the setting of 0.003≤(t1-t3) / t8≤0.06 makes the thickness difference between the transition part 1211 and the second sub part 12122 be within the thickness error range of the active material layer 20, so that the thickening of the transition part 1211 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 improve the use reliability of the battery monomer.

[0473] In some embodiments, 60μm≤t8≤250μm.

[0474] It can be understood that the value of t8 can be 60μm, 250μm and any value within 60μm-250μm; for example, the value of t8 can be but is not limited to 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 250μm.

[0475] The design of t8≥60μm makes the battery monomer 100 have a higher capacity; the design of t3≤250μm makes the distance of electron extraction in the part of the active material layer 20 close to the metal layer 12 not too long, and the electron extraction in the part of the active material layer 20 close to the metal layer 12 is easy, which is beneficial to improve the capacity of the battery monomer 100.

[0476] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is within a suitable range, the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion extraction difficulty in the region of the active material layer 20 close to the conductive layer, and improve the performance of the battery monomer 100.

[0477] In some embodiments, 80μm≤t8≤180μm.

[0478] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is in a more suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion release difficulty in the region of the active material layer 20 close to the conductive layer, and improve the performance of the battery monomer 100.

[0479] In some embodiments, 0.2 μm≤t1-t3≤4.5 μm.

[0480] 0.2 μm≤t1-t3≤4.5 μm, it can be understood that the value of t1-t3 can be 0.2 μm, 4.5 μm and any value between 0.2 μm and 4.5 μm; for example, the value of t1-t3 can be but not limited to 0.2 μm, 0.3 μm, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 1.75 μm, 2 μm, 3 μm, 4 μm, 4.5 μm.

[0481] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is in a more suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion release difficulty in the region of the active material layer 20 close to the conductive layer, and improve the performance of the battery monomer 100.

[0482] In some embodiments, 0.3 μm≤t1-t3≤1.75 μm.

[0483] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is in a more suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion release difficulty in the region of the active material layer 20 close to the conductive layer, and improve the performance of the battery monomer 100.

[0484] In some embodiments, 1

[0485] t1 / t3, which can be the ratio of the thickness t1 of the transition part 1211 to the thickness t3 of the second sub-part 12122, can also represent the thickening degree of the transition part 1211.

[0486] 1

[0487] By adopting the technical scheme of the embodiment, the design of 1 < t1 / t3 ≤ 4 makes the thickening degree of the transition part 1211 reasonable, and on the basis of improving the flow capacity, in addition, the thickness of the transition part 1211 is not too large to occupy a large space and weight, which is beneficial to improve the energy density of the battery monomer 100.

[0488] In some embodiments, 1.5 < t1 / t3 ≤ 2.5.

[0489] By adopting the technical scheme of the embodiment, the design of 1.5 < t1 / t3 ≤ 2.5 makes the thickening degree of the transition part 1211 more reasonable, and the flow capacity is better, and it is also more beneficial to improve the energy density of the battery monomer.

[0490] In some embodiments, 1 μm ≤ t1 ≤ 5 μm.

[0491] 1 μm ≤ t1 ≤ 5 μm, and 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, 5 μm.

[0492] By adopting the technical scheme of the embodiment, the design of 1 μm ≤ t1 ≤ 5 μm makes the thickness design of the transition part 1211 reasonable, which is beneficial to improve the flow capacity, in addition, the thickness of the transition part 1211 is not too large to occupy a large space and weight, which is beneficial to improve the energy density of the battery monomer 100.

[0493] In some embodiments, 1.2 μm ≤ t1 ≤ 3.5 μm.

[0494] By adopting the technical scheme of the embodiment, the design of 1.2 μm ≤ t1 ≤ 3.5 μm makes the thickness design of the transition part 1211 more reasonable, and the flow capacity is better, and it is also more beneficial to improve the energy density of the battery monomer.

[0495] In some embodiments, 0.03 ≤ t6 / t5 ≤ 0.95.

[0496] t6 / t5 can refer to the ratio of the thickness of the third protection part 133 to the thickness of the second protection part 132, which can represent the thinning degree of the third protection part 133 relative to the second protection part 132.

[0497] 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 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.

[0498] 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, can better adapt to the thickening degree of the transition part 1211, is conducive to the surface of the conductive protective layer 13 facing away from the metal layer 12 being close to a plane, is conducive to reducing roll damage and improving the flow capacity of the metal layer 12.

[0499] In some embodiments, 0.125≤t6 / t5≤0.8.

[0500] 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, can better adapt to the thickening degree of the transition part 1211, is conducive to the surface of the conductive protective layer 13 facing away from the metal layer 12 being close to a plane, is conducive to reducing roll damage and improving the flow capacity of the metal layer 12.

[0501] In some embodiments, 0.5μm≤t6≤4μm.

[0502] 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 not limited to 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 4μm, 5μm.

[0503] By adopting the technical scheme of this embodiment, the setting of 0.5μm≤t6≤4μm makes the third protective part 133 have a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, the third protective part 133 will not protrude from the second protective part 132 due to the third protective part 133 being too thick, and material accumulation and manufacturing cost can also be reduced.

[0504] In some embodiments, 1μm≤t6≤2μm.

[0505] By adopting the technical scheme of this embodiment, the setting of 1μm≤t6≤2μm makes the third protective part 133 have a more reasonable thickness, thereby better reducing the risk of cracking of the metal layer 12 and manufacturing cost.

[0506] In some embodiments, along the first direction, the size of the first sub-part 12121 is W1, and the size of the second sub-part 12122 is W2, where W1 / (W1+W2)≤0.45.

[0507] For example, the size W1 of the first sub-part 12121 can refer to the width of the first sub-part 12121, and the size W2 of the second sub-part 12122 can refer to the width of the second sub-part 12122. W1+W2 can refer to the width of the conductive part 1212.

[0508] W1 / (W1+W2) can refer to the proportion of the conductive part 1212 occupied by the first sub-part 12121 in the width direction of the first pole piece 1.

[0509] 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.

[0510] By adopting the technical solution of this embodiment, the design of W1 / (W1+W2)≤0.45 makes the active material layer 20 cover the first sub-part 12121, 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 12121 does not occupy too much area, which is conducive to reducing the occupied space and weight of the first sub-part 12121 and improving the energy density of the battery monomer 100.

[0511] In some embodiments, along the first direction, the size of the first sub-part 12121 is W2, where 10mm≤W2≤100mm.

[0512] It can be understood that the value of W2 can be 10mm, 100mm and any value between 10mm and 100mm; for example, the value of W2 can be, but is not limited to, 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0513] By adopting the technical solution of this embodiment, the design of 10mm≤W2≤100mm makes the active material layer 20 cover the first sub-part 12121, 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 12121 does not occupy too much area, which is conducive to reducing the occupied space and weight of the first sub-part 12121 and improving the energy density of the battery monomer 100.

[0514] The battery monomer of the present application is described below in combination with some embodiments.

[0515] Embodiment One

[0516] Referring to FIGS. 3-11, in the present embodiment, the battery cell includes an end cover 201, a shell 202, and an electrode assembly 101, the electrode assembly 101 is installed at the shell 202, the end cover 201 covers the opening of the shell 202 to seal the shell 202, and the end cover 201 is provided with an electrode lead-out portion 2011.

[0517] In the present embodiment, the electrode assembly 101 includes a first electrode tab 1, a second electrode tab 2, and a separator 3, the separator 3 is located between the first electrode tab 1 and the second electrode tab 2, and the first electrode tab 1 and the second electrode tab 2 have opposite polarities, wherein the first electrode tab 1 can be a positive electrode tab, and the second electrode tab 2 can be a negative electrode tab.

[0518] In the present embodiment, the first electrode tab 1 includes a current collector 10, an active material layer 20, and a conductive member 30, the current collector 10 includes an insulating base body 11, 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 conductive protective layer 13 covers the surface of the metal layer 12 away from the insulating base body, and the active material layer 20 covers the surface of the conductive protective layer 13 away from the insulating base body.

[0519] In the present embodiment, the two metal layers 12 are both welded with the conductive member 30, the conductive member 30 includes 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.

[0520] In the present embodiment, the electrode assembly 101 further includes an insulating member 40, the insulating member 40 includes a second insulating portion 41, and the second insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0521] In the present embodiment, the metal layer 12 includes a main body portion 121 and at least one protruding portion 122, the main body portion 121 includes a transition portion 1211 and a conductive portion 1212, the transition portion 1211 is connected between the conductive portion 1212 and the protruding portion 122, the protruding portion 122 protrudes from the transition portion 1211 along a first direction, the active material layer 20 covers the metal layer 12, the protruding portion 122 and the transition portion 1211 are not covered with the active material layer 20, and the first direction is perpendicular to the thickness direction of the current collector 10.

[0522] In the present embodiment, the number of the protruding portions 122 is plural, and the plural protruding portions 122 are arranged at intervals along a second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0523] In the embodiment, the protruding portion 122 includes a first protruding sub-portion 1221 and a second protruding sub-portion 1222, the first protruding sub-portion 1221 is connected between the second protruding sub-portion 1222 and the transition portion, the second protruding sub-portion 1222 has a dimension along the second direction smaller than that of the first protruding sub-portion 1221 along the second direction, the first protruding sub-portion 1221 is welded with the first connecting portion 31 to form a first welding sub-portion 5111, the second protruding sub-portion 1222 is welded with the first connecting portion 31 to form a second welding sub-portion 5112, the first welding sub-portion 5111 and the second welding sub-portion 5112 form the first welding portion 511, and the first welding portion 511 is the first welding 51.

[0524] In the embodiment, the insulating member 40 includes the first insulating portion 42, the first insulating portion 42 covers the first welding 51, and the first insulating portion 42 protrudes from the end of the main body portion 121 toward the protruding portion 122.

[0525] Embodiment Two

[0526] Referring to FIGS. 12-18, the embodiment is different from the embodiment one in that the first connecting portion 31 is welded with the protruding portion 122 to form the first welding portion 511, the first connecting portion 31 is welded with the transition portion 1211 to form the second welding portion 512, the first welding portion 511 and the second welding portion 512 form the first welding 51.

[0527] In the embodiment, the insulating member 40 further includes the first insulating portion 42, one side of the first insulating portion 42 covers the first welding 51 and the second welding 52, and the other side of the first insulating portion 42 covers the second insulating portion 41.

[0528] In the embodiment, the protruding portion 122 is welded with the first connecting portion 31 to form the first welding portion 511, and the transition portion 1211 is welded with the first connecting portion 31 to form the second welding portion 512; the first welding portion 511 and the second welding portion 512 form the first welding 51.

[0529] Embodiment Three

[0530] The embodiment is different from the embodiment two in that, referring to FIGS. 19-22, the insulating member 40 includes the first insulating portion 42 and does not include the second insulating portion 41, one side of the first insulating portion 42 covers the first welding 51, and the other side of the first insulating portion 42 covers the active material layer 20.

[0531] In some embodiments, referring to FIG. 2, a battery device 1100 is provided, which includes the battery cell of the above-mentioned embodiments.

[0532] The battery device 1100 of the embodiment of the present application adopts the battery monomer described above, and the use reliability of the battery monomer is good, which is conducive to improving the use reliability of the battery device 1100.

[0533] In some embodiments, referring to FIG. 1, a power consuming device is provided, which includes the battery device 1100 of the above-described embodiments.

[0534] The battery device 1100 of the embodiment of the present application adopts the battery monomer described above, and the use reliability of the battery device 1100 is good, which is conducive to improving the use reliability of the power consuming device.

[0535] 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 the sake of brevity, will not be repeated here.

[0536] 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: 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, which 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 and an insulating member, the first electrode tab comprising a conductive member, a current collector and an active material layer; the current collector comprises an insulating base and a metal layer, the conductive member connects the electrode lead-out portion and the 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 comprises a main body portion and at least one protruding portion, the protruding portion extends outward from the end of the main body portion along a first direction, the first direction is perpendicular to the thickness direction of the current collector; at least part of the main body portion is covered with the active material layer, at least part of the protruding portion is not covered with the active material layer; the insulating member comprises a first insulating portion, the first insulating portion is located on the side of the main body portion away from the insulating base; along the direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from the end of the main body portion towards the protruding portion.

2. The battery cell of claim 1, 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 with the electrode lead-out portion, the first connecting portion is welded to the surface of the metal layer away from the insulating base to form a first welding mark, the second connecting portion is located on the side of the protruding portion away from the main body portion; along the first direction, the first welding mark is located on the side of the active material layer close to the protruding portion.

3. The battery cell of claim 2, wherein: the first insulating portion covers at least part of the first welding mark.

4. The battery cell of claim 2 or 3, wherein: along the first direction, the first connecting portion and the active material layer are arranged at intervals.

5. The battery cell of any one of claims 2-4, wherein, the insulating member comprises a second insulating portion, the second insulating portion covers the surface of the metal layer away from the insulating base, the entire second insulating portion is located between the first welding mark and the active material layer.

6. The battery cell of claim 5, wherein: the second insulating portion is located between the first connecting portion and the active material layer.

7. The battery cell of claim 6, wherein: along the first direction, one side of the first insulating portion covers the first welding mark, and the other side of the first insulating portion covers at least part of the second insulating portion.

8. The battery cell of any one of claims 2-7, wherein: along the first direction, one side of the first insulating portion covers the first welding mark, and the other side of the first insulating portion covers at least part of the active material layer.

9. The battery cell of any one of claims 2-8, wherein: the first welding mark comprises a first welding mark portion, the first connecting portion is welded to the surface of the protruding portion away from the insulating base to form the first welding mark portion, and the first insulating portion covers at least part of the first welding mark portion.

10. The battery cell of claim 9, wherein: the first welding mark portion comprises a first welding sub-portion, the protruding portion comprises a first protruding sub-portion and a second protruding sub-portion, the first protruding sub-portion is connected between the second protruding sub-portion and the main body portion; along a second direction, the size of the first protruding sub-portion is greater than the size of the second protruding sub-portion, the second direction is perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion is welded to a surface of the first protruding sub-portion opposite to the insulating base and forms the first solder sub-portion, and the first insulating portion covers at least part of the first solder sub-portion.

11. The battery cell of claim 10, wherein: In a direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from an end of the first protruding sub-portion opposite to the main body portion.

12. The battery cell of claim 10 or 11, wherein: In the second direction, the first solder sub-portion extends from one side of the first protruding sub-portion to the other side of the first protruding sub-portion.

13. The battery cell of any one of claims 10-12, wherein: The first solder portion further comprises a second solder sub-portion, the first connecting portion is welded to a surface of the second protruding sub-portion opposite to the insulating base and forms the second solder sub-portion, and the first insulating portion covers at least part of the second solder sub-portion.

14. The battery cell of claim 13, wherein: In a direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from an edge of the second solder sub-portion opposite to the first protruding sub-portion.

15. The battery cell of claim 13 or 14, wherein: In the second direction, the second solder sub-portion extends from one side of the second protruding sub-portion to the other side of the second protruding sub-portion.

16. The battery cell of any one of claims 2-15, wherein: The number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals in a second direction, each of the protruding portions is welded to the first connecting portion, and the second direction is perpendicular to the first direction and a thickness direction of the current collector.

17. The battery cell of claim 16, wherein: The first connecting portion comprises multiple first connecting sub-portions arranged at intervals in the second direction, and the number of the second connecting portions is multiple, each of the first connecting sub-portions corresponds to each of the second connecting portions in connection; Each of the first connecting sub-portions is welded to a surface of each of the protruding portions opposite to the insulating base.

18. The battery cell of any one of claims 2-17, wherein: The main body portion comprises a conductive portion and a transition portion, the transition portion is connected between the conductive portion and the protruding portion, the transition portion and the protruding portion are not covered by the active material layer, and the conductive portion is covered by the active material layer; the first insulating portion covers at least part of a surface of the transition portion opposite to the insulating base. In a direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from an end of the transition portion opposite to the conductive portion.

19. The battery cell of claim 18, wherein: In the second direction, the size of the conductive portion is L1, the size of the transition portion is L2, and 0.8≤L2 / L1≤1, wherein the second direction is perpendicular to the first direction and a thickness direction of the current collector.

20. The battery cell of claim 18 or 19, wherein: The first solder portion further comprises a second solder sub-portion, the first connecting portion is welded to a surface of the transition portion opposite to the insulating base and forms the second solder sub-portion, and the first insulating portion covers at least part of the second solder sub-portion.

21. The battery cell of claim 20, wherein: In a direction of the protruding portion pointing to the main body portion, the first insulating portion protrudes from an edge of the second solder sub-portion toward the active material layer.

22. The battery cell of any one of claims 20 or 21, wherein: In the second direction, the size of the transition portion is L2, the size of the second solder sub-portion is L3, and 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and a thickness direction of the current collector.

23. The battery cell of any one of claims 18-22, wherein: The number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals in a second direction, the second direction is perpendicular to the first direction and a thickness direction of the current collector; The first connecting part includes a second connecting subpart and a plurality of first connecting subparts, the plurality of first connecting subparts are arranged at intervals along the second direction, and each of the first connecting subparts is welded to a surface of each of the protruding parts away from the insulating base. The second connecting part is in a plurality in number, and along the first direction, one side of each of the first connecting subparts is connected to each of the second connecting parts one by one, and the other side of each of the first connecting subparts is connected to the second connecting subpart, and the second connecting subpart is arranged continuously along the second direction. The second connecting subpart is welded to a surface of the transition part away from the insulating base.

24. The battery cell of any one of claims 2-23, wherein: The metal layer is in two in number, and the two metal layers are arranged on opposite sides of the insulating base along the thickness direction of the current collector, and the active material layer is in two in number, and the two active material layers are respectively covered on the two metal layers. The conductive member is in two in number, and the first connecting part of the two conductive members is respectively welded to a surface of the two metal layers away from the insulating base and forms two first welding marks. The insulating member is in two in number, and the first insulating part of the two insulating members is respectively covered on at least part of the two first welding marks.

25. The battery cell of claim 24, wherein: The first insulating part includes a first part and a second part connected to each other, the first part is covered on at least part of the main part along a direction of the main part towards the protruding part, and the second part protrudes from the main part, and the second part is located on a side of the protruding part along a second direction perpendicular to the first direction and the thickness direction of the current collector.

26. The battery cell of claim 25, wherein: The second part of the two insulating members is in abutment.

27. The battery cell of any one of claims 24-26, wherein: The second connecting part of the two conductive members is welded and forms a second welding mark.

28. The battery cell of claim 27, wherein: The first insulating part is covered on at least part of the second welding mark.

29. The battery cell of claim 28, wherein: Along a direction of the main part towards the protruding part, the first insulating part protrudes from an edge of the second welding mark away from the main part.

30. The battery cell of any one of claims 2-29, wherein: Along the first direction, the distance between the first welding mark and the active material layer is S1, wherein 0.3mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

31. The battery cell of any one of claims 2-30, wherein: The current collector further includes a conductive protective layer, and at least part of the conductive protective layer is located between the active material layer and the metal layer.

32. The battery cell of claim 31, wherein: Along a direction of the main part towards the protruding part, the conductive protective layer protrudes from an end surface of the active material layer towards the protruding part.

33. The battery cell of claim 32, wherein: Along a direction of the main part towards the protruding part, the protruding length of the conductive protective layer from the end surface of the active material layer towards the protruding part ranges from 0.3mm to 0.8mm.

34. The battery cell of any one of claims 31-33, wherein: Along the first direction, the conductive protective layer and the first welding mark are arranged at intervals.

35. The battery cell of any one of claims 1-34, wherein: Along the first direction, the size of the part of the insulating member covered on the active material layer is H, wherein 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm.

36. The battery cell of any one of claims 1-35, wherein: The first insulating part is connected to the first pole piece.

37. The battery cell of claim 36, wherein: The first insulating part includes an insulating base layer and an adhesive layer, and the adhesive layer is bonded between the insulating base layer and the first pole piece.

38. The battery cell of claim 37, wherein: The insulating base layer has a thickness in a range of 6 μm to 15 μm; and / or, the adhesive layer has a thickness in a range of 0.5 μm to 3 μm.

39. The battery cell of any one of claims 1-38, wherein: In the first direction, the insulating member has a dimension W, wherein 3 mm ≤ W ≤ 9 mm, and optionally, 4.5 mm ≤ W ≤ 6.5 mm.

40. The battery cell of any one of claims 1-39, wherein: The electrode assembly further comprises a second tab having a polarity opposite to that of the first tab, the second tab comprising a main body portion and a tab portion, the tab portion protruding the main body portion in the first direction; In a direction of the main body portion towards the protruding portion, the main body portion protrudes from an end surface of the insulating member closer to the active material layer, and the main body portion does not protrude from an end surface of the insulating member farther from the active material layer.

41. The battery cell of any one of claims 1-40, wherein: The electrode assembly further comprises a second tab having a polarity opposite to that of the first tab, the second tab comprising a main body portion and a tab portion, the tab portion protruding the main body portion in the first direction; In a direction of the main body portion towards the protruding portion, the main body portion protrudes from an end surface of the insulating member closer to the active material layer, and the main body portion does not protrude from an end surface of the insulating member farther from the active material layer.

42. The battery cell of any one of claims 1-41, wherein: The main body portion comprises a transition portion and a conductive portion, the transition portion being connected between the protruding portion and the conductive portion, the conductive portion being covered with the active material layer, and the transition portion not being covered with the active material layer; the transition portion is connected with the conductive member; at least a portion of the conductive portion has a thickness smaller than a thickness of the transition portion.

43. The battery cell of claim 42, wherein: The conductive portion comprises a first sub-portion and a second sub-portion, the first sub-portion being connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion being covered with the active material layer, the first sub-portion having a thickness greater than a thickness of the second sub-portion, and the transition portion having a thickness greater than or equal to the thickness of the first sub-portion.

44. The battery cell of claim 43, wherein: The current collector further comprises a conductive protective layer, the conductive protective layer comprising a first protective portion and a second protective portion, the first protective portion being located between the first sub-portion and the active material layer, and the second protective portion being located between the second sub-portion and the active material layer; wherein the first protective portion has a thickness smaller than a thickness of the second protective portion.

45. The battery cell of claim 44, wherein: The conductive protective layer further comprises a third protective portion, the third protective portion covering a surface of the transition portion facing away from the insulating base, and the third protective portion having a thickness smaller than or equal to the thickness of the first protective portion.

46. The battery cell of any one of claims 42-45, wherein: The protruding portion has a thickness greater than or equal to the thickness of the transition portion.

47. A battery device, wherein: The battery cell comprises any one of the battery cells of claims 1 to 46.

48. An electrical device, comprising: The battery device comprises the battery cell of claim 47.

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