Battery monomer, battery device and electric device

Abstract

The invention discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell and an electrode assembly, wherein the shell is provided with an electrode leading-out part; the electrode assembly is at least partially accommodated in the shell, the electrode assembly comprises a first pole piece, and the first pole piece comprises a conductive component, a current collector and an active material layer; the conductive member is connected with the electrode lead-out part; the current collector comprises an insulating substrate and a metal layer, and the insulating substrate, the metal layer and the active material layer are stacked in sequence; the metal layer comprises a main body part and at least one protruding part which extends outwards from the end part of the main body part along the first direction; the main body part comprises a transition part and a conductive part, the transition part is connected between the conductive part and the protruding part, the conductive part is covered with an active material layer, and the protruding part and the transition part are not covered with the active material layer; the conductive member is connected to the surface of the transition portion back to the insulating substrate.

Description

Battery cells, battery packs and electrical devices Technical Field

[0001] This application belongs to the field of battery fast charging technology, and in particular relates to a battery cell, a battery device, and an electrical device. Background Technology

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

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

[0004] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art.

[0005] Application content

[0006] The purpose of this application is to provide a battery cell, a battery device, and an electrical device that can improve the fast charging performance of the battery cell.

[0007] The technical solution adopted in the embodiments of this application is:

[0008] In a first aspect, in some embodiments, a battery cell is provided, the battery cell including a housing and an electrode assembly: the housing has an electrode lead-out portion; the electrode assembly is at least partially housed within the housing, the electrode assembly including a first electrode plate, the first electrode plate including a conductive member, a current collector, and an active material layer; the conductive member is connected to the electrode lead-out portion; the current collector includes an insulating substrate and a metal layer, the insulating substrate, the metal layer, and the active material layer are stacked along the thickness direction of the current collector, at least a portion of the metal layer is located between the insulating substrate and the active material layer; the metal layer includes a main portion and at least one protrusion extending outward from an end of the main portion along a first direction perpendicular to the thickness direction of the current collector; the main portion includes a transition portion and a conductive portion, the transition portion connecting the conductive portion and the protrusion, the conductive portion being covered by the active material layer, the protrusion and the transition portion not being covered by the active material layer; the conductive member is connected to the surface of the transition portion facing away from the insulating substrate.

[0009] By adopting the technical solution of this embodiment, under normal use of the battery cell, the electrode leads are used for inputting or outputting electrical energy, realizing the charging and discharging of the battery cell; while the surface of the transition portion in the main body facing away from the insulating substrate is connected to the conductive component, allowing current to flow directly into or out of the conductive component through the transition portion. This way, the current can pass through the root of the protrusion near the main body, or a portion of the current can pass through the root of the main body, reducing the current restriction imposed by the root of the protrusion near the main body. This is beneficial for improving the current-carrying capacity of the first electrode, reducing heat generation in the battery cell, improving the charging efficiency of the battery cell, and enhancing the fast-charging performance of the battery cell. Furthermore, the current collector adopts a composite structure of insulating substrate and metal layer. Compared to a pure metal current collector, the metal layer is thinner, resulting in fewer burrs generated during the manufacturing process, reducing the risk of internal short circuits in the battery cell and improving its reliability. Therefore, the battery cell of this embodiment can effectively balance current-carrying capacity and reliability.

[0010] 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.

[0011] In some embodiments, L2 = L1.

[0012] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition part along the second direction large, which is beneficial to increase the connection area between the conductive member and the transition part, increase the current carrying capacity at the connection between the conductive member and the transition part, increase the current carrying capacity of the first electrode, reduce the heat generation of the battery cell, and improve the fast charging performance of the battery cell.

[0013] In some embodiments, along the second direction, the size of the protrusion is smaller than the size of the transition portion.

[0014] By adopting the technical solution of this embodiment, the design of L2=L1 makes the size of the transition part along the second direction larger, which is beneficial to design the connection area between the conductive member and the transition part to be larger. The current carrying capacity at the connection between the conductive member and the transition part is the best, which can effectively improve the current carrying capacity of the first electrode, reduce the heat generation of the battery cell, and improve the fast charging performance of the battery cell.

[0015] In some embodiments, the conductive member includes a first connecting portion and at least one second connecting portion, the first connecting portion and the second connecting portion are arranged along a first direction, the first connecting portion and the second connecting portion are connected, the second connecting portion is connected to the electrode lead-out portion, the first connecting portion is soldered to the surface of the metal layer facing away from the insulating substrate to form a first solder mark, and the second connecting portion is located on the side of the protrusion facing away from the main body portion; along the first direction, the first solder mark is located on the side of the active material layer facing the protrusion.

[0016] By adopting the technical solution of this embodiment, the first connecting part is welded to the metal layer, and the conductive component is connected to the metal layer by welding, which facilitates the fabrication of the first electrode. In addition, the metal layer has a small thickness and a large surface area facing away from the insulating substrate, which helps to increase the welding area between the conductive component and the metal layer, increase the current flow area between the conductive component and the metal layer, improve the current flow capacity of the first electrode, and improve the fast charging performance of the battery cell. The second connecting part protrudes from the protruding part, which facilitates the connection between the second connecting part and the electrode lead-out part. This makes the processing and manufacturing more convenient and reduces the risk of problems such as poor soldering. This helps to improve the connection reliability between the metal layer and the conductive component, and also helps to improve the current flow capacity of the first electrode and improve the fast charging performance of the battery cell.

[0017] In some embodiments, the first solder mark includes a first solder mark portion, wherein the first connecting portion is soldered to the surface of the transition portion facing away from the insulating substrate and forms the first solder mark portion.

[0018] By adopting the technical solution of this embodiment, the first connecting part and the transition part are connected by welding, which is simple and facilitates the production of the first electrode sheet. In addition, the first connecting part and the transition part can directly use the first solder mark to carry current, which helps to improve the current carrying capacity between the first connecting part and the transition part and reduce the heat generation of the battery cell.

[0019] In some embodiments, along the second direction, the size of the transition portion is L2, the size of the first solder 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.

[0020] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the transition part along the second direction larger, which is beneficial to increase the connection area between the first connection part and the transition part, increase the current carrying capacity at the connection between the first connection part and the transition part, increase the current carrying capacity of the first electrode, reduce the heat generation of the battery cell, and improve the fast charging performance of the battery cell.

[0021] In some embodiments, L3 = L2.

[0022] By adopting the technical solution of this embodiment, the design of L3 / L2=1 makes the size of the first solder mark portion along the second direction larger, which is beneficial to design the welding area between the first connection portion and the transition portion to be larger. The current carrying capacity at the connection between the first connection portion and the transition portion is the best, which can effectively improve the current carrying capacity of the first electrode, reduce the heat generation of the battery cell, and improve the fast charging performance of the battery cell.

[0023] In some embodiments, the first solder mark further includes a second solder mark portion, wherein the first connecting portion is welded to the protrusion to form the second solder mark portion.

[0024] By adopting the technical solution of this embodiment, the first connecting part and the protrusion are connected by welding, which is simple and convenient for the fabrication of the first electrode sheet; in addition, the first connecting part and the protrusion can directly pass through the second solder joint, which is beneficial to improving the current passing capacity between the first connecting part and the protrusion.

[0025] In some embodiments, the size of the second solder mark is smaller than the size of the first solder mark along the second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0026] By adopting the technical solution of this embodiment, along the second direction, the size of the first solder mark is large, and the welding area between the transition part and the first connection part is large, which is beneficial to improving the overcurrent capacity of the first connection part and the transition part, and to improving the fast charging performance and reliability of the battery cell.

[0027] In some embodiments, along a second direction, the second solder mark extends from one side of the protrusion to the other side of the protrusion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0028] By adopting the technical solution of this embodiment, the size of the second solder mark is large along the second direction, which is beneficial to increasing the overcurrent area between the first connection part and the protrusion, improving the overcurrent capacity between the first connection part and the protrusion, reducing the risk of heat generation, and improving the fast charging performance and reliability of the battery cell.

[0029] In some embodiments, there are multiple protrusions, which are spaced apart along a second direction. Each protrusion is welded to a first connecting portion to form a second solder mark. Along the second direction, the sum of the dimensions of all the second solder marks is less than the dimension of the first solder mark. The second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0030] By adopting the technical solution of this embodiment, multiple protrusions are spaced apart along the second direction, which is beneficial to divide the main body into multiple regions along the second direction, and each region can correspond to one protrusion. Electrons in each region can be transmitted to the electrode lead-out portion through the corresponding protrusion, so that the electrons in the main body are transmitted in regions, and the electron transmission path in each region to the corresponding protrusion is short, which is beneficial to reduce the transmission distance of electrons, reduce the overall resistance of the first electrode, and improve the fast-start performance and reliability of the battery cell.

[0031] In some embodiments, the first connecting portion includes a plurality of first connecting sub-ports, which are spaced apart along a second direction. The number of second connecting portions is also plurality of, with each first connecting sub-port and each second connecting portion corresponding to each other. Each first connecting sub-port is welded to the surface of each protrusion facing away from the insulating substrate.

[0032] By adopting the technical solution of this embodiment, a plurality of first connecting sub-parts of the first connecting part are spaced apart along the second direction, and there is a gap between two adjacent first connecting sub-parts, which can reduce the material required for the first connecting part and reduce the manufacturing cost of the battery cell.

[0033] In some embodiments, the first connecting portion further includes a second connecting sub-portion. 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 in a one-to-one correspondence. The other side of each first connecting sub-portion is connected to the second connecting sub-portion. The second connecting sub-portions are continuously arranged along the second direction. The second connecting sub-portions are welded to the surface of the transition portion facing away from the insulating substrate.

[0034] By adopting the technical solution of this embodiment, the second connecting sub-parts are continuously arranged along the second direction, which can connect multiple first connecting sub-parts into a whole. The second connecting sub-parts can provide good support for the first connecting sub-parts, reduce the risk of short circuit when the first connecting sub-parts are bent and inserted between the first and second electrodes, and improve the reliability of the battery cell. In addition, the second connecting sub-parts are larger in size along the second direction, which helps to increase the welding area between the second connecting sub-parts and the transition part, improve the current carrying capacity at the connection between the first connecting part and the transition part, improve the current carrying capacity of the first electrode, and improve the fast charging performance and reliability of the battery cell.

[0035] In some embodiments, the first solder pad and the second solder pad are directly connected.

[0036] By adopting the technical solution of this embodiment, the first solder mark can be covered at the junction of the protrusion and the transition. When a portion of the current flows to the junction of the protrusion and the transition, it can flow directly to the first connecting portion through the first solder mark, reducing the overcurrent capacity at the junction of the protrusion and the transition, which is beneficial to improving the overcurrent capacity of the first electrode, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0037] In some embodiments, the first connecting portion is spaced apart from the active material layer along the first direction.

[0038] By adopting the technical solution of this embodiment, the first connecting part does not come into contact with the active species layer, which can reduce the mutual influence between the two and improve the reliability of the battery cell.

[0039] In some embodiments, the electrode assembly further includes an insulating element, which includes a first insulating portion covering the surface of the metal layer facing away from the insulating substrate, with the entire first insulating portion located between the first solder mark and the active material layer.

[0040] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of poor soldering between the first connection part and the metal layer, improve the connection reliability between the first connection part and the metal layer, and also improve the current carrying capacity.

[0041] In some embodiments, the first insulating portion is located between the first connecting portion and the active material layer.

[0042] By adopting the technical solution of this embodiment, the first insulating part can support the portion of the metal layer located between the first connecting part and the active material layer, which can reduce damage such as cracks and fractures that occur in this part during the battery device manufacturing process, and is conducive to improving the electron transmission capability of this part, improving the fast charging performance and reliability of the battery cell; in addition, the first insulating part can also achieve insulation of this part, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0043] In some embodiments, the insulating member further includes a second insulating portion, at least partially covering the first solder mark.

[0044] By adopting the technical solution of this embodiment, the second insulating part can prevent burrs, metal debris and other components on the surface of the first solder print from piercing the separator and connecting with the second electrode, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0045] In some embodiments, along a first direction, one side of the second insulating portion covers the first solder mark, and the other side of the second insulating portion covers at least a portion of the first insulating portion.

[0046] By adopting the technical solution of this embodiment, the second insulating part and the first insulating part together cover the extension part, which can achieve double-layer insulation, which helps to reduce the short-circuit risk of battery cells and improve the reliability of battery cells.

[0047] In some embodiments, the electrode assembly further includes an insulating element, the insulating element including a second insulating portion, at least partially covering the first solder mark.

[0048] By adopting the technical solution of this embodiment, the second insulating part covers the surface of the first solder mark, which can prevent sharp protrusions, metal debris and other components on the surface of the first solder mark from piercing the separator and connecting with the second electrode, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0049] In some embodiments, along a first direction, one side of the second insulating portion covers the first solder mark, and the other side of the second insulating portion covers at least a portion of the active material layer.

[0050] By adopting the technical solution of this embodiment, the second insulating part extends from the first solder mark to the active material layer. The second insulating part has a wide coverage area and good insulation effect, which is conducive to improving the reliability of the battery cell.

[0051] In some embodiments, there are two metal layers disposed on opposite sides of the insulating substrate along the thickness direction of the current collector; there are two active material layers, each covering one of the two metal layers; there are two conductive members, each having a first connecting portion welded to the surface of the two metal layers facing away from the insulating substrate to form two first solder marks; and there are two insulating members, each having a second insulating portion covering at least a portion of the two first solder marks.

[0052] By adopting the technical solution of this embodiment, the first connecting parts of the two conductive components are respectively welded to the metal layers located on opposite sides of the insulating substrate, and the second connecting parts of the two conductive components are located on the side of the protrusion facing away from the main body. In this way, the two metal layers can be directly connected by the second connecting parts of the two conductive components, thereby breaking the insulation limitation of the insulating substrate, effectively improving the conductivity of the first electrode, improving the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the reliability of the battery cell.

[0053] In some embodiments, the second insulating portion includes a first portion and a second portion connected together, the first portion covering at least a portion of the main body portion along the direction of the main body portion toward the protrusion, the second portion protruding from the transition portion, the second portion being located on the side of the protrusion portion along a second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0054] By adopting the technical solution of this embodiment, metal debris and other components at the end of the transition portion facing the protrusion portion can be located between the second parts of the two insulating components, which can reduce the risk of metal debris falling into the electrode assembly and help reduce the risk of short circuit.

[0055] In some embodiments, the second portions of the two insulating elements are bonded together.

[0056] By adopting the technical solution of this embodiment, along the direction from the main body to the protrusion, metal debris and other components at the end face of the main body facing the protrusion can be located between the second parts of the two insulating members. This reduces the risk of metal debris falling into the electrode assembly and helps to reduce the risk of short circuit.

[0057] In some embodiments, the second connection portion of the two conductive components is welded to form a second solder mark.

[0058] By adopting the technical solution of this embodiment, the second connecting part of the two conductive components can connect the metal layers located on opposite sides of the insulating substrate, thereby breaking the insulation limitation of the insulating substrate, effectively improving the conductivity of the first electrode, improving the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the reliability of the battery cell.

[0059] In some embodiments, the second insulating portion covers the second solder mark and protrudes from the edge of the second solder mark opposite to the transition portion in the direction from the main body portion to the protrusion portion.

[0060] By adopting the technical solution of this embodiment, the second insulating part can completely cover the second solder mark, which can prevent burrs, metal debris and other parts on the second solder mark from piercing the separator and connecting with the second electrode, reducing the risk of short circuit and improving the reliability of the battery cell.

[0061] In some embodiments, the electrode assembly includes a second electrode with a polarity opposite to that of the first electrode. The second electrode includes a main functional portion and an electrode tab. The electrode tab protrudes from the main functional portion along a first direction. Along the direction from the main portion to the protrusion, the main functional portion protrudes from the end face of the insulating member facing the active material layer, and the main functional portion does not protrude from the end face of the insulating member away from the active material layer.

[0062] By adopting the technical solution of this embodiment, the insulating component can prevent burrs on the end face of the main functional part of the second electrode near the tab from piercing the insulating component and connecting with the first electrode, thereby reducing the risk of short circuit between the first and second electrodes and improving the reliability of the battery cell.

[0063] In some embodiments, the distance between the first solder mark and the active material layer is S1, wherein 0.3mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

[0064] By adopting the technical solution of this embodiment, the first solder mark will not be soldered to the active material layer, reducing problems such as poor soldering, which is conducive to improving the connection reliability between the first connection part and the metal layer. In addition, the distance between the active material layer and the first solder mark is small, and the active material layer can be closer to the first solder mark. Therefore, when the size of the metal layer in the first direction is fixed, the active material layer can cover a larger area, which is conducive to improving the energy density of the battery cell.

[0065] In some embodiments, the current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the conductive portion.

[0066] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the metal layer while protecting the metal layer, reducing the risk of cracks in the metal layer caused by rolling the active material layer, and improving the current carrying capacity of the metal layer.

[0067] In some embodiments, along the direction from the main body to the protrusion, the conductive protective layer protrudes from the end face of the active material layer facing the protrusion.

[0068] By adopting the technical solution of this embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the conductive protective layer has better protection for the metal layer, and the first electrode has better overcurrent capacity, which is conducive to improving the fast charging performance and reliability of the battery cell.

[0069] In some embodiments, the conductive protective layer protrudes from the end face of the active material layer toward the protrusion in the direction from the main body to the protrusion by a distance ranging from 0.3 mm to 0.8 mm.

[0070] By adopting the technical solution of this embodiment, the overcurrent capacity and energy density of the battery cell can be well balanced.

[0071] In some embodiments, the current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the conductive portion, and the conductive protective layer and the first solder mark are spaced apart along a first direction.

[0072] By adopting the technical solution of this embodiment, the first connection part will not be welded to the conductive protective layer, which can reduce the risk of poor welding between the first connection part and the metal layer and improve the reliability of welding between the first connection part and the metal layer.

[0073] In some embodiments, the electrode assembly includes a second electrode with a polarity opposite to that of the first electrode. The second electrode includes a main functional portion and an electrode tab. The electrode tab protrudes from the main functional portion in a first direction. In the direction from the main portion to the protrusion, the main functional portion protrudes from the end of the transition portion toward the protrusion.

[0074] By adopting the technical solution of this embodiment, the burrs on the end face of the main functional part of the second electrode facing the tab correspond to the hollow area where the transition part does not extend into the protrusion, which can also reduce the short circuit risk of the battery cell and improve the reliability of the battery cell.

[0075] In some embodiments, the thickness of the conductive portion is at least partially smaller than the thickness of the transition portion.

[0076] By adopting the technical solution of this embodiment, the transition portion has a larger thickness and better current carrying capacity, which is beneficial to improving the current carrying capacity of the first electrode, reducing the heat generation of the battery cell, and improving the fast charging performance and reliability of the battery cell.

[0077] In some embodiments, the conductive portion includes a first sub-portion and a second sub-portion, the first sub-portion being connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion being covered with an active material layer, the thickness of the first sub-portion being greater than the thickness of the second sub-portion, and the thickness of the transition portion being greater than or equal to the thickness of the first sub-portion.

[0078] By adopting the technical solution of this embodiment, the current-carrying capacity of the first sub-part closer to the transition section is greater than that of the second sub-part farther from the transition section. This reduces the limitation on current, improves the current-carrying capacity of the first electrode, reduces the heat generation of the battery cell, and helps to improve the reliability of the battery cell.

[0079] In some embodiments, the current collector further includes a conductive protective layer, which includes a first protective portion and a second protective portion. The first protective portion is located between the first sub-part and the active material layer, and the second protective portion is located between the second sub-part and the active material layer. The thickness of the first protective portion is less than the thickness of the second protective portion.

[0080] By adopting the technical solution of this embodiment, the surface of the conductive protective layer facing away from the insulating substrate is close to a plane, which helps to reduce rolling damage and improve the current carrying capacity of the metal layer; in addition, it can also reduce the problem of current collector winding bulging.

[0081] In some embodiments, the conductive protective layer further includes a third protective portion, which covers the surface of the transition portion facing away from the insulating substrate, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

[0082] By adopting the technical aspects of this embodiment, the provision of the third protective part allows the conductive protective layer to protrude from the active material layer, thus better separating the active material layer and the metal layer. In addition, the thickness of the third protective part is not too large, which helps to reduce material waste and save on the manufacturing cost of the battery cell.

[0083] In some embodiments, the thickness of the protrusion is greater than or equal to the thickness of the transition portion.

[0084] By adopting the technical solution of this embodiment, the thickness of the protrusion is relatively large, which can improve the current carrying capacity of the protrusion, which is beneficial to improving the current carrying capacity of the first electrode, reducing the heat generation of the battery cell, and improving the fast charging performance and reliability of the battery cell.

[0085] Secondly, a battery device is provided, including the battery cell described in the above embodiments.

[0086] The battery device in this application uses the above-mentioned battery cells, which have good fast-charging performance and good reliability, which is beneficial to improving the fast-charging performance of the battery device and also to improving the reliability of the battery device.

[0087] Thirdly, an electrical device is provided, including a battery device as described in the above embodiments.

[0088] The battery device in this application embodiment uses the above-described battery device, which has good fast charging performance and good reliability, which is beneficial to improving the battery life of the device and also to improving the reliability of the device.

[0089] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0090] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0091] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0092] Figure 2 is an exploded view of a battery device provided in some embodiments of this application.

[0093] Figure 3 is an exploded view of a battery cell provided in some embodiments of this application.

[0094] Figure 4 is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application.

[0095] Figure 5 is a cross-sectional view along line AA in Figure 4.

[0096] Figure 6 is a schematic diagram of the structure of the first electrode provided in some embodiments of this application.

[0097] Figure 7 is a cross-sectional view along line BB in Figure 6.

[0098] Figure 8 is a magnified view of point C in Figure 6.

[0099] Figure 9 is a schematic diagram of the structure of the first electrode shown in Figure 6 after the conductive components are concealed.

[0100] Figure 10 is a magnified view of part D in Figure 9.

[0101] Figure 11 is a schematic diagram of the structure of the first electrode provided in some other embodiments of this application.

[0102] Figure 12 is a cross-sectional view along line EE in Figure 11.

[0103] Figure 13 is a cross-sectional view along line FF in Figure 11.

[0104] Figure 14 is a schematic diagram of the structure of the first electrode provided in some embodiments of this application.

[0105] Figure 15 is a magnified view of point G in Figure 14.

[0106] Figure 16 is a schematic diagram of the structure of the first electrode provided in some embodiments of this application.

[0107] Figure 17 is a cross-sectional view along line HH in Figure 16.

[0108] Figure 18 is a schematic diagram of the structure of the second insulating part provided in some embodiments of this application.

[0109] Figure 19 is a cross-sectional view along line II in Figure 18.

[0110] The following are the labeling elements in the figure:

[0111] 1000, Vehicle; 1100, Battery Unit; 1200, Controller; 1300, Motor; 100, Battery Cell; 101, Electrode Assembly; 1, First Electrode; 10, Current Collector; 11, Insulating Substrate; 12, Metal Layer; 121, Main Body; 1211, Transition Section; 1212, Conductive Section; 12121, First Sub-section; 12122, Second Sub-section; 122, Protrusion; 13, Conductive Protective Layer; 131, First Protective Section; 132, Second Protective Section; 133, Third Protective Section; 20, Active Material Layer; 21, First Active Material Section; 22, Second Active Material Section; 30, Conductive Component; 31, First 311. Connecting part; 312. First connecting sub-part; 32. Second connecting part; 40. Insulating component; 41. First insulating part; 42. Second insulating part; 421. First part; 422. Second part; 423. Insulating base layer; 424. Adhesive layer; 51. First solder mark; 511. Second solder mark part; 512. First solder mark part; 52. Second solder mark; 2. Second electrode plate; 210. Main functional part; 220. Electrode lug part; 3. Isolating component; 200. Outer shell; 201. End cap; 2011. Electrode lead-out part; 202. Housing; 300. Box body; 301. First box body part; 302. Second box body part. Detailed Implementation

[0112] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0113] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0114] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0115] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0116] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0117] In the description of the embodiments of this 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", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0118] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0119] In the description of the embodiments of this application, unless otherwise expressly specified and limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it may be directly connected to or indirectly connected to the other element.

[0120] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0121] Battery cells may include, but are not limited to, lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0122] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0123] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0124] In some embodiments, the battery device can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0125] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0126] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0127] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0128] A single battery cell typically consists of an electrode assembly and a casing, with the electrode assembly housed within the casing. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes.

[0129] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes, which can prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0130] The housing is used to encapsulate electrode components and electrolytes. The housing can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0131] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector. The negative electrode can be a negative electrode sheet, which may include a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector.

[0132] Current collectors (positive or negative electrode current collectors) are usually made of metal, such as aluminum foil and copper foil. However, pure metal foil is prone to producing metal burrs. These burrs can pierce the separator, causing internal short circuits and posing a significant risk of fire and explosion to individual battery cells.

[0133] To reduce the risk of short circuits within individual battery cells, a current collector has been proposed. This current collector includes an insulating substrate and a metal layer covering the surface of the insulating substrate. An active material layer covers the surface of the metal layer facing away from the insulating substrate. The thickness of the metal layer is typically small, resulting in minimal burrs generated during foreign object piercing of the electrode, making it less likely to pierce the separator. The metal layer typically includes a main body and protrusions extending beyond the main body. These protrusions connect to electrode leads on the casing for inputting or outputting electrical energy from the battery cell. However, the small thickness of the metal layer results in a small current-carrying area between the protrusions and the main body, leading to poor current-carrying capacity, increased heat generation, and hindering the improvement of the battery cell's charging efficiency.

[0134] Based on this, the present application provides a technical solution that utilizes a transition portion on the main body to connect with a conductive member, allowing current to flow directly into or out of the conductive member through the transition portion. This allows the current to bypass the root of the protrusion near the main body, or only a portion of the current to flow through the root of the protrusion near the main body, reducing the current restriction imposed by the root of the protrusion near the main body. This improves the current-carrying capacity of the first electrode, reduces heat generation in the battery cell, and enhances the fast-charging performance of the battery cell.

[0135] The battery cells described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0136] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0137] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0138] As shown in Figure 1, a battery device 1100 is installed inside the vehicle 1000. The battery device 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 1100 can be used to power the vehicle 1000; for example, the battery device 1100 can serve as the operating power source for the vehicle 1000.

[0139] The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0140] In some embodiments of this application, the battery device 1100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0141] As shown in Figure 2, the battery device 1100 includes a housing 300 and a battery cell 100, with the battery cell 100 housed within the housing 300.

[0142] The housing 300 is used to accommodate the battery cell 100, and the housing 300 can have various structures. In some embodiments, the housing 300 may include a first housing portion 301 and a second housing portion 302, which overlap each other, and together define a receiving space for accommodating the battery cell 100. The second housing portion 302 may be a hollow structure with one end open, and the first housing portion 301 may be a plate-like structure, with the first housing portion 301 covering the open side of the second housing portion 302 to form a housing 300 with a receiving space; alternatively, both the first housing portion 301 and the second housing portion 302 may be hollow structures with one side open, with the open side of the first housing portion 301 covering the open side of the second housing portion 302 to form a housing 300 with a receiving space. Of course, the first housing portion 301 and the second housing portion 302 can have various shapes, such as cylinders, cuboids, etc.

[0143] To improve the sealing performance after the first housing part 301 and the second housing part 302 are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 301 and the second housing part 302.

[0144] Assuming that the first box part 301 covers the top of the second box part 302, the first box part 301 can also be called the upper box cover, and the second box part 302 can also be called the lower box 300.

[0145] In the battery device 1100, there can be one or more battery cells 100. If there are multiple battery cells 100, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 100 are connected in both series and parallel.

[0146] Multiple battery cells 100 can be directly connected in series, parallel, or in a mixed manner, and then the whole composed of multiple battery cells 100 can be housed in the housing 300; of course, multiple battery cells 100 can also be connected in series, parallel, or in a mixed manner to form a battery module, and multiple battery modules can then be connected in series, parallel, or in a mixed manner to form a whole, and housed in the housing 300.

[0147] For example, the battery cell 100 may be the smallest unit that makes up the battery device 1100.

[0148] As shown in Figure 3, in some embodiments, the battery cell 100 includes a housing 200 and an electrode assembly 101 housed within the housing 200. The electrode assembly 101 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 100, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 101 further includes a separator 3 disposed between the positive and negative electrodes. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0149] The housing 200 is used to encapsulate the electrode assembly 101 and electrolyte components.

[0150] In some embodiments, the housing 200 includes a housing 202 and an end cap 201, the housing 202 having an opening and the end cap 201 for closing the opening.

[0151] The housing 202 is a component used to cooperate with the end cap 201 to form an internal cavity of the battery cell 100. The formed internal cavity can be used to accommodate the electrode assembly 101, electrolyte, and other components.

[0152] The housing 202 and the end cap 201 can be separate components. For example, an opening can be provided on the housing 202, and the end cap 201 can be used to close the opening to form an internal cavity of the battery cell 100.

[0153] The housing 202 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 202 can be determined according to the specific shape and size of the electrode assembly 101. The housing 202 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0154] The shape of the end cap 201 can be adapted to the shape of the housing 202 to fit the housing 202. The material of the end cap 201 can be the same as or different from the material of the housing 202. Optionally, the end cap 201 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 201 is not easily deformed when subjected to compression and impact, so that the battery cell 100 can have higher structural strength and improve reliability.

[0155] The end cap 201 is connected to the housing 202 by welding, bonding, snap-fitting or other means.

[0156] The housing 202 may be open at one end or open at both ends. In some examples, the housing 202 may be a structure with an opening on one side, with one end cap 201 covering the housing 202. In other examples, the housing 202 may be a structure with openings on both sides, with two end caps 201 covering the two openings of the housing 202 respectively.

[0157] In some embodiments, the battery cell 100 includes two electrode leads 2011, which are respectively connected to a positive electrode and a negative electrode to output or input electrical energy into the battery cell 100.

[0158] In some embodiments, the battery cell 100 further includes an electrolyte contained within the housing 200. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid.

[0159] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0160] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0161] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0162] The solvent may also be an ether solvent. Ether solvents may include one or more of the following: ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0163] In some embodiments, the gel electrolyte comprises a polymer-based backbone network coupled with an ionic liquid-lithium salt.

[0164] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0165] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0166] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0167] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0168] Referring to Figures 4 and 5, the electrode assembly 101 of this application embodiment includes a first electrode 1 and a second electrode 2 with opposite polarities.

[0169] For example, one of the first electrode 1 and the second electrode 2 is a positive electrode and the other is a negative electrode.

[0170] In some embodiments, the positive electrode sheet may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0171] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0172] As an example, the positive electrode current collector can be made of carbon, metal foil, or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, titanium, silver-treated aluminum, or stainless steel can be used. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0173] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. The positive electrode active material may 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 may be used alone or in combination of two or more. Examples of lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0174] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0175] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0176] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may be a negative electrode active material known in the art for use in battery cell 100. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of this application may also use other conventional materials that can be used as negative electrode active materials for battery device 1100. These negative electrode active materials may be used alone or in combination of two or more.

[0177] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0178] In some embodiments, the electrode assembly 101 further includes a separator 3 for separating the first electrode 1 and the second electrode 2. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0179] In some embodiments, the separator 3 includes a separator membrane. The separator membrane in this application can be any known porous structure separator membrane with good chemical and mechanical stability.

[0180] As an example, the main material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator 3 may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0181] In some embodiments, the separator 3 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, serving both to transport ions and to isolate the positive and negative electrodes.

[0182] In some embodiments, the electrode assembly 101 is a wound structure. Exemplarily, the first electrode 1 and the second electrode 2 are both strip structures, and the first electrode 1, the spacer 3, and the second electrode 2 are wound into a wound structure.

[0183] In some embodiments, the electrode assembly 101 has a stacked structure.

[0184] As an example, multiple first electrode 1 and multiple second electrode 2 can be set, and multiple first electrode 1 and multiple second electrode 2 can be stacked alternately.

[0185] As an example, multiple first electrode plates 1 can be provided, and second electrode plates 2 can be folded to form multiple stacked folded segments, with a first electrode plate 1 sandwiched between adjacent folded segments.

[0186] As an example, both the first electrode 1 and the second electrode 2 are folded to form multiple stacked folded segments.

[0187] As an example, multiple separators 3 can be provided, each disposed between any adjacent first electrode 1 or second electrode 2.

[0188] As an example, the separator 3 can be continuously arranged between any adjacent first electrode 1 or second electrode 2 by folding or rolling.

[0189] Referring to Figures 6-10, in some embodiments, the battery cell 100 includes a housing 200 and an electrode assembly 101; the housing 200 is provided with an electrode lead-out portion 2011; the electrode assembly 101 is at least partially housed within the housing 200, and the electrode assembly 101 includes a first electrode 1, which includes a conductive member 30, a current collector 10, and an active material layer 20; the conductive member 30 is connected to the electrode lead-out portion 2011; the current collector 10 includes an insulating substrate 11 and a metal layer 12, which are stacked along the thickness direction of the current collector 10, and at least part of the metal layer 12 is disposed within the current collector 10. The metal layer 12 is located between the insulating substrate 11 and the active material layer 20; the metal layer 12 includes a main body 121 and at least one protrusion 122 extending outward from the end of the main body 121 along a first direction perpendicular to the thickness direction of the current collector 10; the main body 121 includes a transition portion 1211 and a conductive portion 1212, the transition portion 1211 is connected between the conductive portion 1212 and the protrusion 122, the conductive portion 1212 is covered with the active material layer 20, and the protrusion 122 and the transition portion 1211 are not covered with the active material layer 20; the conductive member 30 is connected to the surface of the transition portion 1211 facing away from the insulating substrate 11.

[0190] A portion of the electrode assembly 101 is located inside the housing 200; another portion is located outside the housing 200; or the entire electrode assembly 101 is located inside the housing 200.

[0191] In some examples, the first electrode 1 is a positive electrode, 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 1 is a negative electrode, 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.

[0192] The conductive component 30 can refer to a component used to connect the electrode lead-out portion 2011 and the current collector 10. The conductive component 30 can be made of copper foil or aluminum foil to facilitate connection with the electrode lead-out portion 2011.

[0193] The electrode lead-out portion 2011 can refer to a conductive component used for outputting or inputting electrical energy. The electrode lead-out portion 2011 is connected to an external electronic device so that the battery cell 100 outputs or inputs electrical energy. The electrode lead-out portion 2011 can also be called a terminal post. The electrode lead-out portion 2011 can be provided on the housing 202 or on the end cover 201.

[0194] The electrode lead-out portion 2011 is connected to the conductive member 30. The electrode lead-out portion 2011 can be directly connected to the conductive member 30. For example, the electrode lead-out portion 2011 can be directly welded to the conductive member 30. Alternatively, the electrode lead-out portion 2011 can be connected to the conductive member 30 through a conductive component (e.g., an adapter plate). For example, one end of the conductive component is welded to the conductive member 30, and the other end of the conductive component is welded to the electrode lead-out portion 2011.

[0195] The current collector 10 includes a metal layer 12 and an insulating substrate 11. The current collector 10 has a multilayer structure. The insulating substrate 11 can refer to a component in the current collector 10 made of an insulating material (e.g., the aforementioned polymer substrate). The metal layer 12 can refer to a component in the current collector 10 made of the aforementioned metal material.

[0196] The surface of the insulating substrate 11 is covered with a metal layer 12, and the surface of the metal layer 12 facing away from the insulating substrate 11 is covered with an active material layer 20, so that the insulating substrate 11, the metal layer 12, and the active material layer 20 are stacked, and the stacking direction of the insulating substrate 11, the metal layer 12, and the active material layer 20 is the thickness direction of the current collector 10 (see the Y direction in Figure 7). The active material layer 20 can be directly applied to the surface of the metal layer 12, or it can be applied after other substances have been applied to the surface of the metal layer 12.

[0197] In some examples, one surface of the insulating substrate 11 is covered with a metal layer 12.

[0198] In some examples, both opposite surfaces of the insulating substrate 11 are covered with metal layers 12, and at least one of the metal layers 12 has an active material layer 20 covering the surface of the metal layer 12 facing away from the insulating substrate.

[0199] The first direction can refer to the direction perpendicular to the thickness direction of the current collector 10; the second direction can refer to the direction perpendicular to both the thickness direction of the current collector 10 and the first direction.

[0200] In some examples, the electrode assembly 101 is a wound structure. When the first electrode 1 is in the unfolded state, the first direction can be referred to as the width direction of the first electrode 1 (refer to the Z direction in Figure 6); the second direction can be referred to as the length direction of the first electrode 1 (refer to the X direction in Figure 6). When the first electrode 1 is in the wound state, the second direction can also be referred to as the winding direction of the first electrode 1 (refer to the direction indicated by arrow V in Figure 4).

[0201] In some examples, the electrode assembly 101 is a stacked structure, the first direction can be the width direction of the first electrode 1 (see the Z direction in Figure 6), and the second direction can be the length direction of the first electrode 1 (see the X direction in Figure 6).

[0202] The metal layer 12 includes a main body 121 and protrusions 122. The main body 121 is the main portion of the metal layer 12. The protrusions 122 extend outward from the end of the main body 121 along a first direction. The protrusions 122 can be protruding structures formed along the edge of the main body 121 along the first direction. Along a second direction, the size of the protrusions 122 is smaller than the size of the main body 121, such that the protrusions 122 and the main body 121 form a stepped structure. The number of protrusions 122 can be one or more, and the protrusions 122 are arranged at intervals along the second direction.

[0203] Along the first direction, the main body 121 is divided into two parts, the part near the protrusion 122 is the transition part 1211, and the part away from the protrusion 122 is the conductive part 1212. The protrusion 122 protrudes from the edge of the transition part 1211 away from the conductive part 1212 toward the conductive part 1212. The conductive part 1212 is covered with an active material layer 20, while neither the transition part 1211 nor the protrusion 122 is covered with an active material layer 20, so as to facilitate connection with the conductive member 30.

[0204] In some examples, the protrusion 122 extends outward from the side of the transition portion 1211 away from the conductive portion 1212 in a first direction. In a second direction, the size of the protrusion 122 may be equal to the size of the transition portion 1211, or, in the second direction, the sum of the sizes of all the protrusions 122 is less than or equal to the size of the transition portion 1211.

[0205] In some examples, the conductive member 30 is directly connected to the surface of the protrusion 122 facing away from the insulating substrate 11, and the conductive member 30 is not directly connected to the main body 121.

[0206] In some examples, the surface of the protrusion 122 facing away from the insulating substrate 11 and the surface of the main body 121 facing away from the insulating substrate 11 are both directly connected to the conductive member 30, thereby increasing the current-carrying area between the conductive member 30 and the metal layer 12, which is beneficial to improving the current-carrying capacity of the first electrode 1 and improving the fast-charging performance of the battery cell 100.

[0207] In some examples, the conductive component 30 can be connected to the surface of the transition portion 1211 facing away from the insulating substrate 11 by means of welding or conductive adhesive, thereby achieving the connection between the conductive component 30 and the transition portion 1211.

[0208] In some examples, the conductive component 30 and the electrode lead-out portion 2011 can be connected by welding or conductive adhesive.

[0209] In the battery cell 100 of this application embodiment, under normal use, the electrode lead-out portion 2011 is used to input or output electrical energy, realizing the charging and discharging of the battery cell 100; while the surface of the transition portion 1211 in the main body portion 121 facing away from the insulating substrate 11 is connected to the conductive member 30, so that the current can directly flow into or out of the conductive member 30 through the transition portion 1211. In this way, the current can pass through the protrusion 122 near the root of the main body portion 121 without passing through the protrusion 122 near the root of the main body portion 121, or a part of the current can pass through the protrusion 122 near the root of the main body portion 121, reducing the current restriction of the protrusion 122 near the root of the main body portion 121, which is beneficial to improving the current passing capacity of the first electrode 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance of the battery cell 100. In addition, the current collector 10 adopts a composite structure of insulating substrate 11 and metal layer 12. Compared with the pure metal current collector 10, the metal layer 12 has a smaller thickness. The burrs generated by the metal layer 12 during the manufacturing process of the current collector 10 are smaller, which reduces the risk of internal short circuit of the battery cell 100 and helps to improve the reliability of the battery cell 100. Therefore, the battery cell 100 of the present application embodiment can better balance overcurrent capacity and reliability.

[0210] In some embodiments, along the second direction, the size of the conductive portion 1212 is L1, the size of the transition portion 1211 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 10.

[0211] 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 more than 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 between the transition portion 1211 and the conductive member 30 can be set, and the better the current carrying capacity between the transition portion 1211 and the conductive member 30.

[0212] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1211 may be located in the middle of the conductive portion 1212, and the two ends of the transition portion 1211 are not flush with the conductive portion 1212.

[0213] In some examples, 0.8 ≤ L2 / L1 < 1, and along the second direction, the transition portion 1211 is disposed at one end that may also be biased towards the conductive portion 1212, such that one end of the transition portion 1211 is flush with the conductive portion 1212, while the other end is not flush, or both ends are not flush. The value of L2 / L1 can be, but is not limited to, 0.8, 1, or any value between 0.8 and 1. For example, the value of L2 / L1 can be, but is not limited to, 0.8, 0.85, 0.9, 0.95, or 1.

[0214] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion 1211 larger along the second direction, which is beneficial to increasing the connection area between the conductive member 30 and the transition portion 1211, increasing the current carrying capacity at the connection between the conductive member 30 and the transition portion 1211, increasing the current carrying capacity of the first electrode 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance of the battery cell 100.

[0215] In some embodiments, L2 = L1.

[0216] 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. The two ends of the transition portion 1211 are flush with the conductive portion 1212. The main body portion 121 has an equal length structure.

[0217] By adopting the technical solution of this embodiment, the design of L2=L1 makes the size of the transition portion 1211 along the second direction larger, which is beneficial to design the connection area between the conductive member 30 and the transition portion 1211 to be larger. The current carrying capacity at the connection between the conductive member 30 and the transition portion 1211 is the best, which can effectively improve the current carrying capacity of the first electrode 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell 100.

[0218] In some embodiments, along the second direction, the size L4 of the protrusion 122 is smaller than the size L2 of the transition portion 1211.

[0219] Along the second direction, the dimension L4 of the protrusion 122 may refer to the dimension of the protrusion 122 near the root of the transition portion 1211 along the second direction. For example, along the second direction, the dimension L4 of the protrusion 122 may refer to the length of the boundary line (see dashed line Q) between the protrusion 122 and the transition portion 1211.

[0220] "Along the second direction, the size L4 of the protrusion 122 is smaller than the size L2 of the transition portion 1211." The protrusion 122 and the transition portion 1211 form a stepped structure, such that along the second direction, the size L4 of the protrusion 122 is smaller than the size L2 of the transition portion 1211.

[0221] The dimension L4 of each protrusion 122 along the second direction may be the same or different.

[0222] In some examples, the dimensions of the protrusion 122 do not change along the second direction along the first direction, that is, the protrusion 122 is a structure of equal length.

[0223] In some examples, the size of the protrusion 122 can gradually increase or decrease in the direction from the main body 121 to the protrusion 122 in the second direction. The direction from the main body 121 to the protrusion 122 can be referred to by the direction indicated by arrow Z in Figure 6.

[0224] By adopting the technical solution of this embodiment, the size L4 of the protrusion 122 is small along the second direction. The protrusion 122 is easy to bend with the conductive member 30 and connect with the electrode lead 2011, which is convenient for processing and manufacturing. It also helps to reduce the space occupied by the conductive member 30 after bending, and helps to improve the energy density of the battery cell 100.

[0225] In some embodiments, along the second direction, the sum of the dimensions L5 of all protrusions 122 is more than 0.5 times the dimension L2 of the transition portion 1211. It is understood that 0.5 ≤ L5 / L2 ≤ 1, such that along the second direction, the sum of the dimensions L5 of all protrusions 122 is greater than or equal to more than half of the dimension L2 of the transition portion 1211, thereby increasing the total flow area between the protrusions 122 and the transition portion 1211 and improving the total flow capacity between the protrusions 122 and the transition portion 1211. For example, the sum of the dimensions L5 of all protrusions 122 along the second direction can be increased by increasing the number of protrusions 122, or the sum of the dimensions L5 of all protrusions 122 along the second direction can be increased by increasing the dimension L4 of a single protrusion 122 along the second direction.

[0226] In some examples, the value of L5 / L2 can be 0.5, 1, or any value between 0.5 and 1, for example; wherein, the value of L5 / L2 can be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, or 1. One end of the conductive member 30 is connected to the electrode lead-out, and the other end of the conductive member 30 is connected to the protrusion 122 and the transition portion 1211, thereby electrically connecting the metal layer 12 and the electrode lead-out portion 2011.

[0227] In some embodiments, as shown in FIG7, 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 to the ends of the protrusion 122, and the thickness of the first active material portion 21 is less than the thickness of the second active material portion 22.

[0228] In some examples, the first active material portion 21 is located at the edge of the active material layer 20 facing the protrusion 122. Both the first active material portion 21 and the second active material portion 22 cover the conductive portion 1212. The first active material portion 21 may have a generally equal thickness structure, and 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 may also decrease in a stepped manner, so that the first active material portion 21 has a stepped structure. Alternatively, along the direction from the main body portion 121 to the protrusion 122, the thickness of the first active material portion 21 may also decrease slowly, so that the thickness of the first active material portion 21 decreases slowly, and the shape of the first active material portion 21 is more rounded or smooth.

[0229] During the forming process of the first electrode 1, the active material layer 20 can be rolled to compress the active material layer 20; and the provision of the first active material part 21 can reduce the rolling pressure on the edge of the active material layer 20 and reduce the risk of edge cracking of the active material layer 20.

[0230] 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 a first direction and connected together. The second connecting portion 32 is connected to the electrode lead-out portion 2011. The first connecting portion 31 is soldered to the surface of the metal layer 12 facing away from the insulating substrate 11 to form a first solder mark 51. The second connecting portion 32 is located on the side of the protrusion 122 facing away from the main body portion 121. Along the first direction, the first solder mark 51 is located on the side of the active material layer 20 facing the protrusion 122.

[0231] The first connecting part 31 may be the part that guides the welding of the electrical component 30 to the metal layer 12, and the second connecting part 32 may be the part that guides the connection of the electrical component 30 to the electrode lead-out part 2011.

[0232] In some examples, the first connection portion 31 may cover the metal layer 12 and be welded to the metal layer 12, and the second connection portion 32 may be led out from the side of the first connection portion 31 away from the active material layer 20 along the first direction to protrude outside the insulating substrate 11. Along the thickness direction of the current collector 10, the projection of the first connection portion 31 is located within the projection of the metal layer 12, and the projection of the second connection portion 32 is located outside the projection range of the metal layer 12. 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 the connection and reduces the mutual influence between the two connections, which is beneficial to the connection reliability.

[0233] The first connecting part 31 is stacked on the surface of the metal layer 12 facing away from the insulating substrate 11 and welded to the surface of the metal layer 12 facing away from the insulating substrate 11. The trace formed by the welding is the first weld mark 51.

[0234] "Along the first direction, the first solder mark 51 is located on the side of the active material layer 20 facing the protrusion 122." This can be understood as follows: along the first direction, the first solder mark 51 is spaced apart from the active material layer 20, so that the part of the metal layer 12 facing the protrusion 122 that does not cover the active material layer 20 is welded to the first connection part 31. This prevents the first connection part 31 from being welded to the active material layer 20, which helps reduce the risk of problems such as cold solder joints and improves the connection reliability and current carrying capacity of the metal layer 12 and the conductive component 30. Alternatively, the edge of the first solder mark 51 is connected to the edge of the active material layer 20 facing the protrusion 122, that is, the first connection part 31 is welded to the edge of the active material layer 20, while the first solder mark 51 and the active material layer 20 only overlap at the edge, which reduces the risk of cold solder joints and helps improve the connection reliability of the first connection part 31 and the metal layer 12.

[0235] In some examples, the first connection 31 may be welded only to the transition 1211.

[0236] In some examples, the first connecting portion 31 is welded to the protrusion 122, and the first connecting portion 31 is also welded to the transition portion 1211.

[0237] In some examples, the second connecting part 32 and the electrode lead-out part 2011 can be connected by direct welding, or by welding through conductive parts (e.g., adapter pieces). Welding is a convenient connection method that is easy to manufacture. Of course, other methods can also be used to achieve the connection.

[0238] By adopting the technical solution of this embodiment, the first connecting part 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 fabrication of the first electrode 1. 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 flow area between the conductive member 30 and the metal layer 12, and improve the current flow capacity of the first electrode 1, thereby improving the fast charging performance of the battery cell 100. The second connecting part 32 protrudes from the protrusion 122, which facilitates the connection between the second connecting part 32 and the electrode lead 2011, making the processing and manufacturing more convenient. At the same time, it can also reduce the risk of problems such as poor soldering between the first connecting part 31 and the metal layer 12, which helps to improve the connection reliability between the metal layer 12 and the conductive member 30, and also helps to improve the current flow capacity of the first electrode 1, thereby improving the fast charging performance and reliability of the battery cell 100.

[0239] In some embodiments, the first solder mark 51 includes a first solder mark portion 512, and the first connecting portion 31 is soldered to the surface of the transition portion 1211 facing away from the insulating substrate 11 to form the first solder mark portion 512.

[0240] The first connecting portion 31 is welded to the surface of the transition portion 1211 facing away from the insulating substrate 11, and the trace produced by the welding of the transition portion 1211 and the first connecting portion 31 is the first solder mark 512; the first solder mark 512 is located between the protrusion 122 and the active material layer 20.

[0241] By adopting the technical solution of this embodiment, the first connecting part 31 and the transition part 1211 are connected by welding, which is simple and facilitates the production of the first electrode 1. In addition, the first connecting part 31 and the transition part 1211 can directly pass current through the first solder mark part 512, which helps to improve the current passing capacity between the first connecting part 31 and the transition part 1211 and reduce the heat generation of the battery cell 100.

[0242] In some embodiments, along the second direction, the size of the transition portion 1211 is L2, the size of the first solder mark 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.

[0243] 0.8≤L3 / L2≤1, along the second direction, the size L3 of the first solder mark 512 can be less than or equal to the size L2 of the transition part 1211, the size L3 of the first solder mark 512 is greater than or equal to more than 0.8 times the size L2 of the transition part 1211, the size L3 of the first solder mark 512 exceeds more than half of the size L2 of the transition part 1211, the longer the size L3 of the first solder mark 512, the larger the welding area between the transition part 1211 and the first connecting part 31, and the better the current carrying capacity at the connection between the transition part 1211 and the first connecting part 31.

[0244] In some examples, 0.8≤L3 / L2<1, along the second direction, the first solder mark 512 may be located in the middle of the transition portion 1211, and the two ends of the first solder mark 512 are not flush with the transition portion 1211.

[0245] In some examples, 0.8≤L2 / L1<1, along the second direction, the first solder mark 512 is disposed at one end of the transition portion 1211, such that one end of the transition portion 1211 is flush with the other end, or neither end is flush.

[0246] The value of L3 / L2 can be, but is not limited to, 0.8, 1, or any value between 0.8 and 1. For example, the value of L3 / L2 can be, but is not limited to, 0.8, 0.85, 0.9, 0.95, or 1.

[0247] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the transition portion 1211 larger along the second direction, which is beneficial to increase the connection area between the first connecting portion 31 and the transition portion 1211, increase the current carrying capacity at the connection between the first connecting portion 31 and the transition portion 1211, increase the current carrying capacity of the first electrode 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell 100.

[0248] In some embodiments, L3 = L2.

[0249] L3 / L2 = 1. Along the second direction, the size L3 of the first solder mark 512 is equal to the size L2 of the transition part 1211. Both ends of the first solder mark 512 are flush with the transition part 1211.

[0250] By adopting the technical solution of this embodiment, the design of L3 / L2=1 makes the size of the first soldering part 512 along the second direction larger, which is beneficial to design the welding area between the first connecting part 31 and the transition part 1211 to be larger. The current carrying capacity at the connection between the first connecting part 31 and the transition part 1211 is the best, which can effectively improve the current carrying capacity of the first electrode 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell 100.

[0251] In some embodiments, the first solder mark 51 further includes a second solder mark portion 511, wherein the first connecting portion 31 is welded to the protrusion 122 to form the second solder mark portion 511.

[0252] The first connecting part 31 is stacked on the surface of the protrusion 122 facing away from the insulating substrate 11 and welded to the protrusion 122. The trace formed by the welding is the second solder mark 511.

[0253] In some examples, the first connecting portion 31 may be welded to the entire protrusion 122; the first connecting portion 31 may also be welded to a portion of the protrusion 122, while another portion of the first protrusion 122 is not welded to the first connecting portion 31.

[0254] The first solder mark 51 includes a first solder mark portion 512 and a second solder mark portion 511. The first solder mark portion 512 is located between the second solder mark portion 511 and the first solder mark portion 512, that is, the first connecting portion 31 simultaneously welds the transition portion 1211 and the protrusion portion 122.

[0255] By adopting the technical solution of this embodiment, the first connecting part 31 and the protrusion 122 are connected by welding, which is simple and convenient for the fabrication of the first electrode 1. In addition, the first connecting part 31 and the protrusion 122 can directly pass through the second solder mark 511, which is beneficial to improve the current passing capacity between the first connecting part 31 and the protrusion 122.

[0256] In some examples, the protrusion 122 and the transition portion 1211 are simultaneously welded to the first connecting portion 31 to form the entire solder mark. Welding the first connecting portion 31 to the transition portion 1211 can effectively increase the welding area between the first connecting portion 31 and the metal layer 12, improve the flow area between the first connecting portion 31 and the metal layer 12, and help improve the flow capacity between the first connecting portion 31 and the metal layer 12.

[0257] During the process of cutting the conductive component 30, first, cutting is performed along the second direction on the equal-width solder mark. Then, cutting is performed along the direction away from the active material layer 20 until the equal-width solder mark is removed. Then, cutting continues along the direction away from the active material layer 20 for a certain distance. Next, cutting continues along the second direction for a certain distance. Then, cutting continues along the direction towards the active material layer 20 until the equal-width solder mark is cut for a certain distance. Finally, cutting continues along the second direction on the equal-width solder mark. This process is repeated to obtain the first solder mark 51. The first solder mark 51 is obtained by taking the cutting position along the second direction on the equal-width solder mark as a reference, along the first direction. The portion located on the side facing the active material layer 20 at the cutting position is the first solder mark 512, while the portion located on the side facing away from the active material layer 20 at the cutting position is the second solder mark 511. The second solder mark 511 can be a protruding structure of the first solder mark 512 facing away from the active material layer 20. After the cutting is completed, during the cutting process from the direction away from the active material layer 20 to the direction facing the active material layer 20, the metal layer 12 of the current collector 10 cuts out a protrusion 122. During the cutting process along the second direction, the portion located between the protrusion 122 and the active material layer 20 forms a transition portion 1211.

[0258] In some embodiments, during the fabrication of the first electrode 1, the conductive member 30 is welded to the edge of the equal-length current collector 10 to form an equal-width solder mark, and then the conductive member 30 is cut to form an electrode tab to facilitate connection with the electrode lead-out portion 2011. During the cutting process, the equal-length current collector 10 can be cut on the side facing away from the active material layer 20 without cutting the equal-length solder mark. In this case, the equal-length solder mark is the first solder mark portion 512, which is also the first solder mark 51. In this process, if the metal layer 12 is cut, a protrusion 122 can be formed. At this time, along the second direction, the size of the protrusion is smaller than the size of the transition portion 1211. If the metal layer 12 is not cut, then along the second direction, the size of the protrusion is equal to the size of the transition portion 1211 and also equal to the size of the conductive portion 1212.

[0259] In some embodiments, along the second direction, the size L6 of the second solder mark 511 is smaller than the size L3 of the first solder mark 512, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0260] By adopting the technical solution of this embodiment, along the second direction, the size L3 of the first solder mark 512 is large, and the welding area of ​​the transition part 1211 and the first connecting part 31 is large, which is beneficial to improving the overcurrent capacity of the first connecting part 31 and the transition part 1211, and is beneficial to improving the fast charging performance and reliability of the battery cell 100.

[0261] In some embodiments, along a second direction, the second solder mark 511 extends from one side of the protrusion 122 to the other side of the protrusion 122.

[0262] Along the first direction, the projection of the second solder mark 511 falls within the projection of the protrusion 122.

[0263] By adopting the technical solution of this embodiment, the size L6 of the second solder mark portion 511 is large along the second direction, which is beneficial to increasing the overcurrent area between the first connecting portion 31 and the protrusion 122, improving the overcurrent capacity between the first connecting portion 31 and the protrusion 122, reducing the risk of overheating, and improving the fast charging performance and reliability of the battery cell 100.

[0264] In some embodiments, there are multiple protrusions 122, which are spaced apart along a second direction. Each protrusion 122 is welded to the first connecting portion 31 to form a second solder mark 511. The sum of the dimensions of all the second solder marks 511 along the second direction is less than the dimension of the first solder mark 512 along the second direction. The second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0265] The number of protrusions 122 is multiple, such as two, three, four, etc.; the multiple protrusions 122 are spaced apart along the second direction.

[0266] In some examples, after the first electrode 1 is wound or stacked, multiple protrusions 122 are stacked together, and multiple second connecting portions 32 are also stacked together, thereby breaking the insulation limitation of the insulating substrate 11, which can effectively improve the conductivity of the first electrode 1, improve the fast charging performance of the battery cell 100, reduce the heat generation of the battery cell 100, and improve the reliability of the battery cell 100 in use.

[0267] Multiple protrusions 122 are spaced apart along the second direction, such that the sum of the dimensions L5 of all protrusions 122 along the second direction is less than the dimension L3 of the transition portion 1211.

[0268] Among the multiple second solder marks 511, along the second direction, some of the second solder marks 511 may have the same size, or all the second solder marks 511 may have completely different sizes, or all the second solder marks 511 may have the same size.

[0269] By adopting the technical solution of this embodiment, multiple protrusions 122 are spaced apart along the second direction, which is beneficial to divide the conductive part 1212 into multiple regions along the second direction, and each region can correspond to one protrusion 122. Electrons in each region can be transmitted to the electrode lead-out part 2011 through the corresponding protrusion 122, so that the electrons in the main body 121 are transmitted in regions, and the electron transmission path in each region to the corresponding protrusion 122 is short, which is beneficial to reduce the transmission distance of electrons, reduce the overall resistance of the first electrode 1, and improve the fast-start performance and reliability of the battery cell 100.

[0270] In some embodiments, the first connecting portion 31 includes a plurality of first connecting sub-portions 311, which are spaced apart along a second direction. The number of second connecting portions 32 is also plurality of, with each first connecting sub-portion 311 corresponding to and connected to each second connecting portion 32. Each first connecting sub-portion 311 is welded to the surface of each protrusion 122 facing away from the insulating substrate 11.

[0271] The first connecting part 311 may refer to the portion of the first connecting part 31 that covers the protrusion 122; the number of first connecting parts 311, the number of second connecting parts 32 and the number of protrusions 122 are the same, one first connecting part 311 corresponds to one protrusion 122, one first connecting part 311 is connected to one second connecting part 32, and one first connecting part 311 and one protrusion 122 are welded to form a second solder mark 511.

[0272] By adopting the technical solution of this embodiment, the plurality of first connecting sub-parts 311 of the first connecting part 31 are arranged at intervals along the second direction, and there is a gap between two adjacent first connecting sub-parts 311, which can reduce the material required for the first connecting part 31 and reduce the manufacturing cost of the battery cell 100.

[0273] In some embodiments, the first connecting portion 31 further includes a second connecting sub-portion 312. There are multiple second connecting portions 32. Along the first direction, one side of each first connecting sub-portion 311 is connected to each second connecting portion 32 in a one-to-one correspondence. The other side of each first connecting sub-portion 311 is connected to the second connecting sub-portion 312. The second connecting sub-portions 312 are continuously arranged along the second direction. The second connecting sub-portions 312 are welded to the surface of the transition portion 1211 facing away from the insulating substrate 11.

[0274] The second connecting portion 312 may refer to the portion of the first connecting portion 31 that covers the transition portion 1211; the second connecting portion 312 is continuously provided along the second direction, for example, along the second direction, the second connecting portion 312 extends from one side of the transition portion 1211 to the other side of the transition portion 1211.

[0275] The second connecting part 312 is welded to the surface of the transition part 1211 facing away from the insulating substrate 11 to form the first solder mark part 512.

[0276] By adopting the technical solution of this embodiment, the second connecting sub-part 312 is continuously arranged along the second direction, which can connect multiple first connecting sub-parts 311 into a whole. The second connecting sub-part 312 can provide good support for the first connecting sub-part 311, which can reduce the risk of the first connecting sub-part 311 being bent and inserted into the first electrode 1 and the second electrode 2, reduce the risk of short circuit, and help improve the reliability of the battery cell 100. In addition, the second connecting sub-part 312 is large in size along the second direction, which helps to increase the welding area between the second connecting sub-part 312 and the transition part 1211, which helps to improve the current carrying capacity at the connection between the first connecting part 31 and the transition part 1211, improve the current carrying capacity of the first electrode 1, and improve the fast charging performance and reliability of the battery cell 100.

[0277] In some embodiments, the first solder mark 512 and the second solder mark 511 are directly connected.

[0278] The first solder mark 512 and the second solder mark 511 form a single first solder mark 51, with no obvious dividing line between them; the single first solder mark 51 can cover the junction of the protrusion 122 and the transition 1211; in the actual manufacturing process, the first solder mark 512 and the second solder mark 511 are formed by cutting the above-mentioned equal-width solder mark.

[0279] In some examples, the first solder mark 512 and the second solder mark 511 adopt a solder joint structure, and the solder joint spacing in the first solder mark 512 is the same as the solder joint spacing in the second solder mark 511; for example, the solder joints in the first solder mark 512 and the second solder mark 511 are not welded to the boundary line between the protrusion 122 and the transition 1211, and the spacing between two adjacent solder joints in the first solder mark 512 and the second solder mark 511 is equal to the solder joint spacing in the first solder mark 512; for example, the solder joints are welded to the boundary line between the protrusion 122 and the transition 1211, thereby connecting the first solder mark 512 and the second solder mark 511 into a single solder mark.

[0280] By adopting the technical solution of this embodiment, the first solder mark 51 can cover the junction of the protrusion 122 and the transition portion 1211, and a portion of the current can flow directly through the transition portion 1211 to the first connecting portion 31, reducing the overcurrent pressure at the junction of the protrusion 122 and the transition portion 1211, which is beneficial to improving the overcurrent capacity of the first electrode 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance of the battery cell 100.

[0281] In some embodiments, the first connecting portion 31 is spaced apart from the active material layer 20 along the first direction.

[0282] The first connecting part 31 does not directly contact the active material layer 20, but there is a certain gap, so that the first connecting part 31 does not contact the active material layer 20.

[0283] In some examples, the first electrode 1 is a positive electrode, and the first connection portion 31 does not contact the active material layer 20, which can reduce the risk of lithium plating and improve the reliability of the battery cell 100. In other examples, the first electrode 1 is a negative electrode, and the first connection portion 31 may or may not contact the active material layer 20.

[0284] By adopting the technical solution of this embodiment, the first connection part 31 does not come into contact with the active species layer, which can reduce the mutual influence between the two and improve the reliability of the battery cell 100.

[0285] In some embodiments, the electrode assembly 101 further includes an insulating member 40, which includes a first insulating portion 41. The first insulating portion 41 covers the surface of the metal layer 12 facing away from the insulating substrate 11, and the entire first insulating portion 41 is located between the first solder mark 51 and the active material layer 20.

[0286] The insulating component 40 can refer to a component capable of insulation. The insulating component 40 includes a first insulating part 41, which can refer to an insulating component covering the surface of the metal layer 12 facing away from the active material layer 20. The first insulating part 41 can be, but is not limited to, an insulating coating, an insulating adhesive (e.g., hot melt adhesive) or an insulating tape.

[0287] Along the thickness direction of the current collector 10, the first insulating portion 41 does not overlap with the first solder mark 51. The first insulating portion 41 and the first solder mark 51 are spaced apart, so that the first connecting portion 31 will not be soldered to the first insulating portion 41, which helps to reduce the risk of poor soldering between the first connecting portion 31 and the metal layer 12. Alternatively, the first insulating portion 41 and the first solder mark 51 only overlap at the edge, and the edge of the first solder mark 51 overlaps with the edge of the first insulating portion 41. The overlapping area between the two is small, which can also reduce the risk of poor soldering between the first connecting portion 31 and the metal layer 12.

[0288] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of poor soldering between the first connection part 31 and the metal layer 12, improve the connection reliability between the first connection part 31 and the metal layer 12, and also improve the current carrying capacity.

[0289] In some embodiments, the first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0290] The first insulating part 41 may refer to the portion of the first insulating part 41 located between the first connecting part 31 and the active material layer 20.

[0291] In some examples, the entire first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0292] In some examples, the first insulating portion 41 covers the transition portion 1211.

[0293] By adopting the technical solution of this embodiment, the first insulating part 41 can support the portion of the metal layer 12 located between the first connecting part 31 and the active material layer 20, which can reduce damage such as cracks and breaks that occur in this part during the manufacturing process of the battery device 1100, and is conducive to improving the electron transmission capability of this part, improving the fast charging performance and reliability of the battery cell 100; in addition, the first insulating part 41 can also achieve insulation of this part, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0294] Please refer to Figures 11-13. In some embodiments, the insulating member 40 further includes a second insulating portion 42, at least a portion of which covers the first solder mark 51.

[0295] The second insulating portion 42 covers the surface of the first connecting portion 31 facing away from the metal layer 12 and covers at least a portion of the first solder mark 51. The second insulating portion 42 may cover a portion of the first solder mark 51 or the entire first solder mark 51. The second insulating portion 42 may be, but is not limited to, an insulating coating, insulating adhesive (e.g., hot melt adhesive), or insulating tape. The first insulating portion 41 and the second insulating portion 42 may be an integrally formed structure or two separate components connected together.

[0296] A portion of the second insulating portion 42 may cover the first solder mark 51, and another portion may cover the first insulating portion 41 or the active material layer 20, or the entire second insulating portion 42 may cover the first solder mark 51.

[0297] In some examples, the first solder mark 51 includes a first solder mark portion 512, and the second insulating portion 42 covers the first solder mark portion 512.

[0298] In some examples, the first solder mark 51 includes a first solder mark portion 512 and a second solder mark portion 511, and the second insulating portion 42 covers the first solder mark portion 512 and the second solder mark portion 511.

[0299] After the first connecting part 31 is welded to the metal layer 12, burrs, metal debris and other parts are easily generated on the surface of the first solder mark 51. However, the second insulating part 42 of this application embodiment covers the surface of the first solder mark 51, which can prevent the sharp protrusions, metal debris and other parts on the surface of the first solder mark 51 from piercing the separator 3 and connecting with the second electrode 2, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0300] In some embodiments, along a first direction, one side of the second insulating portion 42 covers the first solder mark 51, and the other side of the second insulating portion 42 covers at least a portion of the first insulating portion 41.

[0301] It is understood that, on one of the opposite sides of the second insulating portion 42 along the first direction, one side may cover the first solder mark 51, and the other side may cover the entire first insulating portion 41, or a part of the first insulating portion 41, or even the active material layer 20.

[0302] Along the first direction, the second insulating portion 42 extends from the first solder mark 51 onto the first insulating portion 41; or, the second insulating portion 42 extends from the first solder mark 51 to the active material layer 20, thereby completely covering the first insulating portion 41.

[0303] By adopting the technical solution of this embodiment, the second insulating part 42 and the first insulating part 41 jointly cover the extension, which can achieve double-layer insulation, which helps to reduce the short-circuit risk of the battery cell 100 and improve the reliability of the battery cell 100.

[0304] In some embodiments, the electrode assembly 101 further includes an insulating member 40, which includes a second insulating portion 42, at least a portion of which covers the first solder mark 51.

[0305] It is understood that the insulating member 40 includes a second insulating portion 42, and the insulating member 40 may not include a first insulating portion 41, or the insulating member 40 may include a first insulating portion 41 and a second insulating portion 42.

[0306] By adopting the technical solution of this embodiment, the second insulating part 42 covers the surface of the first solder mark 51, which can prevent the sharp protrusions, metal debris and other components on the surface of the first solder mark 51 from piercing the separator 3 and connecting with the second electrode 2, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0307] Please refer to Figures 14-17. In some embodiments, along the first direction, one side of the second insulating portion 42 covers the first solder mark 51, and the other side of the second insulating portion 42 covers at least a portion of the active material layer 20.

[0308] It is understood that, of the two sides of the second insulating portion 42 that are distributed opposite each other along the first direction, one side covers the first solder mark 51 and the other side covers at least a portion of the active material layer 20. The second insulating portion 42 may cover the end of the active material layer 20 facing the first connecting portion 31 or it may cover the entire active material layer 20.

[0309] Along the first direction, the second insulating portion 42 extends from the first solder mark 51 to the active material layer 20, thereby covering the portion of the metal layer 12 and the first connecting portion 31 located between the first solder mark 51 and the active material layer 20. The first insulating portion 41 may or may not be provided between the second insulating portion 42 and the metal layer 12.

[0310] In some examples, the metal layer 12 covers the first insulating portion 41, and the second insulating portion 42 completely covers the first insulating portion 41 and can also extend to the active material layer 20 to cover the active material layer 20. The metal layer 12 covers the first insulating portion 41 and the second insulating portion 42, achieving two layers of insulation with good insulation effect.

[0311] In some examples, the metal layer 12 does not cover the first insulating portion 41, and the second insulating portion 42 extends from the first solder mark 51 to the active material layer 20. This covers the portion of the metal layer 12 located between the first connection portion 31 and the active material layer 20, reducing the risk of short circuits in this part and improving the reliability of the battery cell 100. In addition, the first insulating portion 41 can be omitted, saving costs. At the same time, the active material layer 20 can be used to cover the original position of the first insulating portion 41, which increases the coverage area of ​​the active material layer 20 on the metal layer 12 and helps to improve the energy density of the battery cell 100.

[0312] By adopting the technical solution of this embodiment, the second insulating part 42 extends from the first solder mark 51 to the active material layer 20. The second insulating part 42 has a wide coverage area and good insulation effect, which is conducive to improving the reliability of the battery cell 100.

[0313] In some embodiments, along the first direction, the size of the portion of the second insulating portion 42 covering the active material layer 20 is H, wherein 0.2 mm ≤ H ≤ 1.0 mm.

[0314] In some examples, the value of H can be 0.2mm, 1mm, or any value between 0.2mm and 1.0mm. For example, the value of H can be, but is not limited to, 0.2mm, 0.3mm, 0.4mm, 0.6mm, 0.8mm, 0.9mm, or 1mm.

[0315] The design with H≥0.2mm allows the insulating member 40 to cover the end of the active material layer 20 facing the protrusion 122. The insulating member 40 can block burrs at the end of the active material layer 20 facing the protrusion 122, improving the reliability of the battery cell 100. The design with H≤1.0mm ensures that the portion of the second insulating part 42 covering the active material layer 20 is not too large, which helps to reduce the weight and volume of the insulating member 40 and improve the energy density of the battery cell 100.

[0316] By adopting the technical solution of this embodiment, the size of the portion of the second insulating part 42 covering the active material layer 20 along the first direction is reasonable, which can simultaneously address the issues of burrs at the end of the main body 121 facing the protrusion 122 and the energy density of the battery cell 100.

[0317] In some embodiments, 0.3mm ≤ H ≤ 0.8mm.

[0318] By adopting the technical solution of this embodiment, the size of the portion of the second insulating part 42 covering the active material layer 20 along the first direction is more reasonable, which can better take into account the burrs at the end of the blocking main body 121 toward the protrusion 122 and the energy density problem of the battery cell 100.

[0319] In some embodiments, there are two metal layers 12, which are disposed on opposite sides of the insulating substrate 11 along the thickness direction of the current collector 10; there are two active material layers 20, which respectively cover the two metal layers 12; there are two conductive members 30, whose first connecting portions 31 are respectively welded to the surfaces of the two metal layers 12 facing away from the insulating substrate 11 to form two first solder marks 51; there are two insulating members 40, whose second insulating portions 42 respectively cover at least a portion of the two first solder marks 51.

[0320] The number of metal layers 12, insulating elements 40, active material layers 20, and conductive elements 30 are all two. The two metal layers 12 cover opposite sides of the insulating substrate 11 along the thickness direction, and the two active material layers 20 cover the conductive portions 1212 of the two metal layers 12. The first connecting portion 31 of one conductive element 30 is welded to the surface of one of the metal layers 12 facing away from the insulating substrate 11 and forms a first solder mark 51. The first connecting portion 31 of the other conductive element 30 is welded to the other metal layer 12 and also forms a first solder mark 51. The second insulating portions 42 of the two insulating elements 40 are located on opposite sides of the insulating substrate 11 along the thickness direction and cover the two first solder marks 51 respectively.

[0321] By adopting the technical solution of this embodiment, the first connecting portions 31 of the two conductive members 30 are respectively welded to the metal layers 12 located on opposite sides of the insulating substrate 11, and the second connecting portions 32 of the two conductive members 30 are located on the side of the protrusion 122 facing away from the main body 121. In this way, the two metal layers 12 can be directly connected by the second connecting portions 32 of the two conductive members 30, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductivity of the first electrode 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the reliability of the battery cell 100.

[0322] In some embodiments, the second insulating portion 42 includes a first portion 421 and a second portion 422 connected to each other. The first portion 421 covers at least a portion of the main body portion 121 in a direction along the main body portion 121 toward the protrusion 122. The second portion 422 protrudes from the main body portion 121 and is located on the side of the protrusion 122 along a second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0323] In some examples, the insulating member 40 has a uniform width structure, and the insulating member 40 covers the conductive member 30 and the metal layer 12 along the length direction of the first electrode 1; while along the thickness direction of the current collector 10, the portion of the second insulating part 42 located within the projection range of the metal layer 12 and the conductive member 30 is the first part 421, and the portion of the second insulating part 42 located outside the projection range of the metal layer 12 and the conductive member 30 is the second part 422.

[0324] In some examples, during the process of cutting the conductive component 30, burrs are easily formed on the end face of the transition portion 1211 facing the protrusion 122. In particular, during the process of cutting the conductive component 30 at the first solder mark 51, large burrs are easily formed on the end face of the transition portion 1211 facing the protrusion 122. However, the second insulating portion 42 of the present application embodiment can prevent the burrs on the end face of the transition portion 1211 facing the protrusion 122 from piercing the separator 3 and contacting the second electrode 2, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0325] In some examples, the end of the transition portion 1211 facing the protrusion 122 is susceptible to impact, which can generate metal debris that can fall into the electrode assembly 101 and cause a short circuit in the battery cell 100.

[0326] By adopting the technical solution of this embodiment, metal debris and other components at the end of the transition portion 1211 toward the protrusion 122 can be located between the second part 422 of the two insulating members 40, which can reduce the risk of metal debris falling into the electrode assembly 101 and help reduce the risk of short circuit.

[0327] In some embodiments, the second portions 422 of the two insulating members 40 are attached to each other.

[0328] In some examples, the second portions 422 of the two insulating members 40 are located in the hollow area of ​​the transition portion 1211 where the protrusion 122 does not extend, so that the second portions 422 of the two insulating members 40 can approach each other and fit together.

[0329] The second part 422 of the two insulating parts 40 can be glued together, statically adsorbed together, or other bonding methods can be used.

[0330] By adopting the technical solution of this embodiment, after the second parts 422 of the two insulating members 40 are attached together, the metal debris and other components at the end of the transition part 1211 toward the protrusion 122 can be covered, so that the metal debris and other components are less likely to fall into the electrode assembly 101, which can better reduce the risk of short circuit in the battery cell 100.

[0331] In some embodiments, the second connection portion 32 of the two conductive members 30 is welded to form a second solder mark 52.

[0332] In some examples, along the direction from the main body 121 to the protrusion 122, the portion of the conductive member 30 protruding from the protrusion 122 forms a second connecting portion 32, allowing the second connecting portions 32 of the two conductive members 30 to directly approach each other and be welded together, leaving a weld mark known as a second weld mark 52. The second connecting portions 32 of the two conductive members 30 can be welded by methods such as ultrasonic welding or laser welding.

[0333] By adopting the technical solution of this embodiment, the second connection portion 32 of the two conductive members 30 can connect the metal layers 12 located on opposite sides of the insulating substrate 11, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductivity of the first electrode 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the reliability of the battery cell 100.

[0334] In some embodiments, the second insulating portion 42 covers the second solder mark 52, and in the direction from the main body portion 121 to the protrusion portion 122, the second insulating portion 42 protrudes from the edge of the second solder mark 52 facing away from the transition portion 1211.

[0335] Along the thickness direction of the current collector 10, the projection of the second solder mark 52 falls within the projection of the second insulating portion 42, so that the second insulating portion 42 can completely cover the second solder mark 52.

[0336] By adopting the technical solution of this embodiment, the second insulating part 42 can completely cover the second solder mark 52, which can prevent burrs, metal debris and other parts on the second solder mark 52 from piercing the separator 3 and connecting with the second electrode 2, reducing the risk of short circuit and improving the reliability of the battery cell 100.

[0337] In some embodiments, the electrode assembly 101 includes a second electrode 2 with a polarity opposite to that of the first electrode 1. The second electrode 2 includes a main functional portion 210 and an electrode tab 220. The electrode tab 220 protrudes from the main functional portion 210 in a first direction. In the direction from the main portion 121 to the protrusion 122, the main functional portion 210 protrudes from the end face of the insulating member 40 toward the active material layer 20, and the main functional portion 210 does not protrude from the end face of the insulating member 40 away from the active material layer 20.

[0338] The second electrode 2 can refer to an electrode with the opposite polarity to the first electrode 1, wherein the first electrode 1 is a positive electrode and the second electrode 2 is a negative electrode, or the first electrode 1 is a negative electrode and the second electrode 2 is a positive electrode. The first electrode 1 and the second electrode 2 can be stacked and wound to form a wound electrode assembly 101; multiple first electrodes 1 and multiple second electrodes 2 are stacked to form a stacked electrode assembly 101.

[0339] The second electrode 2 includes a main functional portion 210 and a tab portion 220. The main functional portion 210 can refer to the main body of the second electrode 2, and the tab portion 220 can refer to the portion of the second electrode 2 that protrudes from the main functional portion 210. When the second electrode 2 is a negative electrode, the tab portion 220 can refer to the protruding structure located at the edge of the negative current collector, and the main functional portion 210 can include the portion of the negative current collector excluding the protruding structure and the negative active material layer. When the second electrode 2 is a positive electrode, the tab portion 220 can refer to the protruding structure located at the edge of the positive current collector, and the main functional portion 210 can include the portion of the positive current collector excluding the protruding structure and the positive active material layer.

[0340] During the manufacturing process of the second electrode 2, the edge of the second electrode 2 is die-cut to obtain the electrode tab 220 and the main functional part 210. During the die-cutting process, burrs are easily generated on the end face of the main functional part 210 facing the electrode tab 220.

[0341] For example, along the thickness direction of the current collector 10, the projection of the end face of the main functional part 210 near the tab 220 falls within the projection of the first insulating part 41 or the projection of the second insulating part 42.

[0342] By adopting the technical solution of this embodiment, the insulating member 40 can prevent the burrs at the end face of the main functional part 210 of the second electrode 2 near the tab 220 from piercing the separator 3 and connecting with the first electrode 1, thereby reducing the risk of short circuit between the first electrode 1 and the second electrode 2 and improving the reliability of the battery cell 100.

[0343] In some embodiments, the electrode assembly 101 includes a second electrode 2 with a polarity opposite to that of the first electrode 1. The second electrode 2 includes a main functional portion 210 and an electrode tab 220. The electrode tab 220 protrudes from the main functional portion 210 in a first direction. In the direction from the main portion 121 to the protrusion 122, the main functional portion 210 protrudes from the end of the transition portion 1211 toward the protrusion 122.

[0344] Along the thickness direction of the current collector 10, the projection of the end face of the main functional part 210 toward the tab 220 does not coincide with the projection of the main part 121, so that the burrs at the end face of the main functional part 210 of the second electrode 2 toward the tab 220 correspond to the hollow area of ​​the transition part 1211 where the protrusion 122 does not extend.

[0345] In some examples, along the thickness direction of the current collector 10, the projection of the first solder mark 512 can fall into the projection of the main functional part 210, and the first solder mark 512 can be covered by the second insulating part 42, so that the second insulating part 42 can prevent burrs, metal debris and other components on the first solder mark 51 from piercing the separator 3 and connecting with the second electrode 2, reducing the risk of short circuit and improving the reliability of the battery cell 100.

[0346] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part 210 of the second electrode 2 facing the tab 220 correspond to the hollow area of ​​the transition part 1211 where the protrusion 122 does not extend out, which can also reduce the short circuit risk of the battery cell 100 and improve the reliability of the battery cell 100.

[0347] In some embodiments, the distance between the first solder mark 51 and the active material layer 20 is S1, wherein 0.3mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

[0348] In some examples, S1 is the spacing between the first solder mark 512 and the active material layer 20.

[0349] The design with S1≥0.3mm ensures that there is a gap between the first solder mark 51 and the active material layer 20, preventing the conductive component 30 from being soldered onto the active material layer 20 and reducing the risk of problems such as poor soldering. The design with S1≤5mm ensures that the gap between the first solder mark 51 and the active material layer 20 is not too large, which is beneficial to increasing the coverage area of ​​the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell 100.

[0350] The value of S1 can be 0.3mm, 5mm, or any value between 0.3mm and 5mm. For example, the value of S1 can be, but is not limited to, 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, and 5mm.

[0351] By adopting the technical solution of this embodiment, the design of 0.3mm≤S1≤5mm ensures that the first solder mark 51 will not be soldered to the active material layer 20, reducing problems such as poor soldering and improving the connection reliability between the first connection part 31 and the metal layer 12. In addition, the small distance between the active material layer 20 and the first solder mark 51 allows the active material layer 20 to be closer to the first solder mark 51. Therefore, with a fixed size of the metal layer 12 in the first direction, the active material layer 20 can cover a larger area, which is beneficial to improving the energy density of the battery cell 100.

[0352] In some embodiments, 0.5mm ≤ S1 ≤ 2.8mm.

[0353] By adopting the technical solution of this embodiment, the design of 0.5mm≤S1≤2.8mm makes the distance between the active material layer 20 and the first solder mark 51 more reasonable, which can better balance the connection reliability of the conductive component 30 and the energy density of the battery cell 100.

[0354] In some embodiments, along a first direction, the first solder mark 51 and the first connection portion 31 are spaced apart from each other at their end faces toward the active material layer 20.

[0355] In some examples, the first electrode 1 is a positive electrode, and there is a gap between the first solder mark 51 and the active material layer 20. This gap can be used to provide space between the conductive component 30 and the active material layer 20, so as to reduce the risk of lithium plating caused by contact between the conductive component 30 and the active material layer 20. In addition, it can also provide space between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, so that the first solder mark 51 will not extend to the end face of the first connection portion 31 facing the active material layer 20, reducing the risk of the end face of the first connection portion 31 facing the active material layer 20 being welded through or cracked. This is beneficial to reduce the burrs generated by welding and improve the reliability of the battery cell 100.

[0356] In some examples, the first electrode 1 is a negative electrode, and there is a gap between the first solder mark 51 and the active material layer 20. This gap provides space between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, so that the first solder mark 512 does not extend to the end face of the first connection portion 31 facing the active material layer 20. This reduces the risk of the end face of the first connection portion 31 facing the active material layer 20 being welded through or cracked, which helps to reduce burrs generated during welding and improves the reliability of the battery cell 100. The conductive component 30 may or may not be connected to the active material layer 20.

[0357] There is a gap between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, so that the first solder mark 51 will not extend to the end face of the first connection portion 31 facing the active material layer 20, reducing the risk of the end face of the first connection portion 31 facing the active material layer 20 being welded through or cracked, which is beneficial to reducing burrs generated by welding and improving the reliability of the battery cell 100.

[0358] In some embodiments, the distance between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20 along the first direction is in the range of 0.3 mm to 1.2 mm.

[0359] Along the first direction, the distance between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20 is S2, wherein 0.3mm≤S2≤1.2mm.

[0360] The design with S2≥0.3mm ensures a gap between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, preventing the first solder mark 51 from extending to the end face of the first connection portion 31 facing the active material layer 20 and reducing the risk of the end face of the first connection portion 31 facing the active material layer 20 being soldered through or cracked. The design with S2≤1.2mm ensures that the gap between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20 is not too large, which is beneficial to increasing the coverage area of ​​the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell 100.

[0361] The value of S2 can be 0.3mm, 1.2mm, or any value between 0.3mm and 1.2mm. For example, the value of S2 can be, but is not limited to, 0.3mm, 0.6mm, 0.8mm, 1mm, or 1.2mm.

[0362] By adopting the technical solution of this embodiment, the reliability and energy density of the battery cell 100 can be well balanced.

[0363] In some embodiments, the current collector 10 further includes a conductive protective layer 13, at least a portion of which is located between the active material layer 20 and the conductive portion 1212.

[0364] The conductive protective layer 13 can refer to a conductive structure disposed between the active material layer 20 and the conductive part 1212. This conductive structure is capable of conducting electricity, enabling the battery cell 100 to output or input electrical energy. The conductive protective layer 13 can be a structure of uniform thickness or a structure of unequal thickness.

[0365] For example, a portion of the conductive protective layer 13 is located between the active material layer 20 and the conductive portion 1212, and another portion covers the transition portion 1211 and protrudes beyond the active material layer 20.

[0366] For example, the entire conductive protective layer 13 is located between the active material layer 20 and the conductive portion 1212.

[0367] In some examples, the conductive protective layer 13 may contain conductive carbon black and a binder. On the one hand, it acts as a buffer and lubricant between the active material and the metal layer, which can alleviate the damage to the metal layer 12 caused by particles in the active material layer 20 during the rolling process of the first electrode 1. On the other hand, the conductive carbon black can reduce the contact resistance between the particles and the metal layer 12, which is beneficial to improving the performance of the battery cell 100.

[0368] During the rolling process of the first electrode 1, the metal layer 12 is relatively thin, and the particles in the active material layer 20 can damage the metal layer 12, which can easily lead to cracks in the metal layer 12. The conductive protective layer 13 of this embodiment can separate the active material layer 20 and the metal layer 12 and protect the metal layer 12 at the same time, reducing the risk of cracks in the metal layer 12 caused by rolling the active material layer 20, and improving the current carrying capacity of the metal layer 12.

[0369] In some embodiments, the conductive protective layer 13 protrudes from the end face of the active material layer 20 toward the protrusion 122 in the direction from the main body 121 to the protrusion 122.

[0370] The conductive protective layer 13 protrudes from the active material layer 20. The conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20. In addition, it can provide an epitaxial space for the active material layer 20 during the rolling process, which is beneficial for the subsequent conductive protective layer 13 to completely separate the metal layer 12 and the active material layer 20.

[0371] By adopting the technical solution of this embodiment, the conductive protective layer 13 can completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 13 has better protection for the metal layer 12, and the first electrode 1 has better overcurrent capacity, which is beneficial to improving the fast charging performance and reliability of the battery cell 100.

[0372] In some embodiments, the conductive protective layer 13 protrudes from the end face of the active material layer 20 toward the protrusion 122 in the direction from the main body 121 to the protrusion 122 by a distance ranging from 0.3 mm to 0.8 mm.

[0373] The conductive protective layer 13 protrudes from the end face of the active material layer 20 toward the protrusion 122 by a distance S3, wherein 0.3mm≤S3≤0.8mm, and the value of S3 can be 0.3mm, 0.8mm, or any value between 0.3mm and 0.8mm. For example, the value of S3 can be, but is not limited to, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, or 0.8mm.

[0374] The design with S3≥0.3mm allows the conductive protective layer 13 to completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 13 provides better protection for the metal layer 12, and the first electrode 1 has better overcurrent capacity, which is beneficial to improving the fast charging performance and reliability of the battery cell 100. The design with S3≤0.8mm prevents the conductive protective layer 13 from being too large and taking up too much space, which helps to save internal space in the battery cell 100 and improve the energy density of the battery cell 100.

[0375] By adopting the technical solution of this embodiment, the overcurrent capacity and energy density of the battery cell 100 can be well balanced.

[0376] In some embodiments, the current collector 10 further includes a conductive protective layer 13, at least a portion of which is located between the active material layer 20 and the conductive portion 1212, and the conductive protective layer 13 and the first solder mark 51 are spaced apart along a first direction.

[0377] In some examples, the conductive protective layer 13 is spaced apart from the first connection portion 31, and the first insulating portion 41 covers the portion of the conductive protective layer 13 located between the first connection portion 31 and the active material layer 20.

[0378] By adopting the technical solution of this embodiment, the first connecting part 31 will not be welded to the conductive protective layer 13, which can reduce the risk of poor welding between the first connecting part 31 and the metal layer 12 and improve the reliability of welding between the first connecting part 31 and the metal layer 12.

[0379] In some embodiments, the second insulating portion 42 is connected to the first electrode 1.

[0380] The second insulating part 42 can be connected to the metal layer 12, the conductive member 30, or the active material layer 20. The second insulating part 42 can be connected to the first electrode 1 by means of bonding or attaching.

[0381] By adopting the technical solution of this embodiment, the second insulating part 42 is connected to the first electrode 1, and the second insulating part 42 can be fixed, thereby stably blocking the burrs at the end of the main body 121 toward the protrusion 122, which is beneficial to improving the reliability of the battery cell 100.

[0382] Please refer to Figures 18 and 19 together. In some embodiments, the second insulating part 42 includes an insulating base layer 423 and an adhesive layer 424, which is bonded between the insulating base layer 423 and the first electrode 1.

[0383] The second insulating part 42 adopts a tape structure; the insulating base layer 423 may refer to the main body of the second insulating part 42, and the adhesive layer 424 may refer to the adhesive covering the surface of the insulating base layer 423. The material of the insulating base layer 423 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and their block copolymers. The material of the adhesive layer 424 includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0384] By adopting the technical solution of this embodiment, the tape structure is easy to fully cover, which helps to reduce the risk of missed coverage and the risk of internal short circuit in the battery cell 100; the insulating base layer 423 can improve the structural strength of the second insulating part 42, reduce the deformation of the second insulating part 42 during the bonding process, and help to improve the insulation effect; the adhesive layer 424 can stably fix the insulating base layer 423 on the first electrode 1, reducing the risk of the insulating tape falling off.

[0385] In some embodiments, the thickness of the insulating base layer 423 ranges from 6 μm to 15 μm.

[0386] The thickness of the insulating base layer 423 is T1, 6μm≤T1≤15μm. It can be understood that the value of T1 can be 6μm, 15μm, or any value between 6μm and 15μm. For example, the value of T1 can be, but is not limited to, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, and 16μm.

[0387] The design of T1≥6μm ensures that the insulating base layer 423 has a certain thickness to block burrs and achieve insulation; the design of T1≤15μm ensures that the thickness of the insulating base layer 423 is not too large, which is beneficial to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery cell 100.

[0388] By adopting the technical solution of this embodiment, both the internal insulation and energy density of the battery cell 100 can be taken into account.

[0389] In some embodiments, the thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0390] The thickness of the adhesive layer 424 is T2, 0.5μm≤T2≤3μm. It can be understood that the value of T2 can be 0.3μm, 3μm, or any value between 0.3μm and 3μm. For example, the value of T2 can be, but is not limited to, 0.3μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, and 3μm.

[0391] The design of T2≥0.5μm ensures that the adhesive layer 424 has a certain thickness, which allows the second insulating part 42 to be stably bonded to the first electrode 1, and the second insulating part 42 has good insulation reliability. The design of T2≤3μm ensures that the thickness of the adhesive layer 424 is not too large, which helps to reduce the volume occupied by the second insulating part 42 and improves the energy density of the battery cell 100.

[0392] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell 100 can be simultaneously taken into account.

[0393] In some embodiments, the thickness of the insulating base layer 423 ranges from 6 μm to 15 μm; the thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0394] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell 100 can be simultaneously taken into account.

[0395] In some embodiments, the dimension of the insulating member 40 along the first direction is W, wherein 3mm≤W≤9mm.

[0396] In some examples, the insulating element 40 includes a second insulating portion 42, where W is equal to the dimension of the second insulating portion 42 along the first direction.

[0397] In some examples, the insulating element 40 includes a second insulating portion 42 and a first insulating portion 41, where W is equal to the overall dimension of the second insulating portion 42 and the insulating coating along the first direction.

[0398] 3mm≤W≤9mm. It can be understood that the value of W can be 3mm, 9mm, or any value between 3mm and 9mm. For example, the value of W can be, but is not limited to, 3mm, 4mm, 4.5mm, 5mm, 6mm, 6.5mm, 7mm, 8mm, and 9mm.

[0399] The design with W≥3mm ensures that the insulating element 40 has a certain size along the first direction, which is beneficial to the internal insulation of the battery cell 100; the design with W≤9mm ensures that the size of the insulating element 40 along the first direction is not too large, which is beneficial to reducing the volume occupied by the insulating element 40 and improving the energy density of the battery cell 100.

[0400] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell 100 can be simultaneously taken into account.

[0401] In some embodiments, 4.5mm ≤ W ≤ 6.5mm.

[0402] By adopting the technical solution of this embodiment, the size of the insulating member 40 is more reasonable along the first direction, which can better balance the insulation reliability and energy density of the battery cell 100.

[0403] In some embodiments, the thickness of the conductive portion 1212 is at least partially smaller than the thickness of the transition portion 1211.

[0404] For example, the transition portion 1211 is a structure of equal thickness or substantially equal thickness, and the conductive portion 1212 is also a structure of equal thickness or substantially equal thickness. The thickness t1 of the transition portion 1211 is greater than the thickness of the conductive portion 1212, and the transition portion 1211 and the conductive portion 1212 form a stepped structure.

[0405] For example, the conductive portion 1212 may have an uneven thickness. Along the direction from the main body portion 121 to the protrusion portion 122, the thickness of the conductive portion 1212 is progressively increased. Specifically, it may be progressively increased in a step or gradually. The thickness of the portion of the conductive portion 1212 away from the transition portion 1211 is less than the thickness of the transition portion 1211.

[0406] By adopting the technical solution of this embodiment, the thickness t1 of the transition portion 1211 is relatively large, and the current carrying capacity of the transition portion 1211 is good, which is conducive to improving the current carrying capacity of the first electrode 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance and reliability of the battery cell 100.

[0407] In some embodiments, the conductive portion 1212 includes a first sub-portion 12121 and a second sub-portion 12122. The first sub-portion 12121 is connected between the second sub-portion 12122 and the transition portion 1211. The first sub-portion 12121 and the second sub-portion 12122 are covered with an active material layer 20. The thickness of the first sub-portion 12121 is greater than the thickness of the second sub-portion 12122, and the thickness of the transition portion 1211 is greater than or equal to the thickness of the first sub-portion 12121.

[0408] The conductive portion 1212 may have an unequal thickness structure. Along the direction from the main body portion 121 to the protrusion portion 122, the conductive portion 1212 is divided into two parts. The part closer to the transition portion 1211 is the first sub-part 12121, and the part farther away from the transition portion 1211 is the second sub-part 12122. Both the first sub-part 12121 and the second sub-part 12122 are covered with an active material layer 20.

[0409] In some examples, the first sub-part 12121 may be of equal thickness, and the second sub-part 12122 may 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, and the thickness t1 of the transition part 1211 is greater than or equal to the thickness t2 of the first sub-part 12121, such that the first sub-part 12121 and the second sub-part 12122 form a stepped structure; the thickness t1 of the transition part 1211 may be equal to the thickness t2 of the first sub-part 12121, such that the transition part 1211 and the first sub-part 12121 form a structure of equal thickness; or, the thickness t1 of the transition part 1211 may be greater than the thickness t3 of the second sub-part 12122, such that the first sub-part 12121 and the transition part 1211 form a stepped structure.

[0410] In some examples, the first sub-part 12121 may also be a multi-segment structure, with the thickness of each segment increasing sequentially along the direction from the main body 121 to the protrusion 122. For example, the first sub-part 12121 includes a first segment and a second segment, with the first segment located between the second segment and the second sub-part 12122. Along the direction from the main body 121 to the protrusion 122, the thickness of the first segment gradually increases, while the second segment is generally of uniform thickness, equal to the thickness t1 of the transition portion 1211. The thickness of the first segment gradually increases from the thickness t3 of the second sub-part 12122 to the thickness of the second segment. This arrangement allows the first segment to smoothly transition between the second segment and the second sub-part 12122, which helps reduce stress concentration and improve structural strength. The thickness of the first segment can be equal to the thickness t1 of the transition portion 1211, or the thickness t1 of the transition portion 1211 can be greater than the thickness of the first segment.

[0411] During the use of the battery cell 100, along the direction from the main body 121 to the protrusion 122, electrons and ions generated by the active material layer 20 gradually converge on the transition portion 1211 via the conductive portion 1212. The portion of the conductive portion 1212 near the transition portion 1211 receives more electrons and ions than the portion of the conductive portion 1212 far from the transition portion 1211. This requires that the current carrying capacity of the portion of the conductive portion 1212 near the transition portion 1211 be greater than that of the portion of the conductive portion 1212 far from the transition portion 1211.

[0412] In this embodiment, the first sub-part 12121 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. This makes the current-carrying capacity of the first sub-part 12121 closer to the transition part 1211 greater than the current-carrying capacity of the second sub-part 12122 farther from the transition part 1211. This reduces the limitation on current, improves the current-carrying capacity of the first electrode 1, reduces the heat generation of the battery cell 100, and helps to improve the reliability of the battery cell 100.

[0413] In some embodiments, the current collector 10 further includes a conductive protective layer 13, which includes a first protective portion 131 and a second protective portion 132. The first protective portion 131 is located between the first sub-part 12121 and the active material layer 20, and the second protective portion 132 is located between the second sub-part 12122 and the active material layer 20. The thickness of the first protective portion 131 is less than the thickness of the second protective portion 132, and the thickness of the third protective portion 133 is less than or equal to the thickness of the first protective portion 131.

[0414] In some examples, along the first direction, the portion of the conductive protective layer 13 located between the first sub-part 12121 and the active material layer 20 can be the first protective part 131, and the portion of the conductive protective layer 13 located between the second sub-part 12122 and the active material layer 20 can be the second protective part 132. The thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, while the thickness t2 of the first sub-part 12121 is greater than the thickness t3 of the second sub-part 12122. This can reduce the thickness difference between the current collector 10 at the first protective part 131 and the second protective part 132.

[0415] For example, the first sub-part 12121 is divided into a third part and a fourth part. The third part is located between the first section and the active material layer 20, and the fourth part is located between the second section and the active material layer 20. The third part is located between the fourth part and the second protective part 132. Along the direction from the main body 121 to the protrusion 122, the thickness of the third part gradually decreases, and the fourth part is generally of uniform thickness, so that the thickness t4 of the first protective part 131 can be matched with the thickness t2 of the first sub-part 12121, so that the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane.

[0416] By adopting the technical solution of this embodiment, the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane, which helps to reduce rolling damage and improve the current carrying capacity of the metal layer 12; in addition, it can also reduce the problem of winding bulging of the current collector 10.

[0417] In some embodiments, the conductive protective layer 13 further includes a third protective portion 133, which 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.

[0418] In some examples, along the first direction, the conductive protective layer 13 can be divided into three parts: a part closer to the conductive member 30 is the third protective part 133, a part farther from the conductive member 30 is the second protective part 132, and the middle part is the first protective part 131. The thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, and the thickness t2 of the first sub-part 12121 is greater than the thickness t5 of the second protective part 132. This can reduce the thickness difference between the current collector 10 at the first protective part 131 and the second protective part 132. Similarly, the thickness t6 of the third protective part 133 is less than or equal to the thickness t4 of the first protective part 131, and the thickness t1 of the transition part 1211 is greater than or equal to the thickness t2 of the first sub-part 12121. This can reduce the thickness difference between the current collector 10 at the first protective part 131 and the third protective part 133, which is beneficial for the surface of the conductive protective layer 13 facing away from the metal layer 12 to approach a plane.

[0419] For example, the second protective portion 132, the third protective portion 133, the transition portion 1211, and the second sub-portion 12122 are all of equal thickness, while the first sub-portion 12121 and the first protective portion 131 are of unequal thickness; the thickness t2 of the first sub-portion 12121 and the thickness t4 of the first protective portion 131 are matched so that the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane.

[0420] By adopting the technical aspects of this embodiment, the provision of the third protective part 133 allows the conductive protective layer 13 to protrude from the active material layer 20, thereby better separating the active material layer 20 and the metal layer 12. In addition, the thickness of the third protective part 133 is not too large, which helps to reduce material waste and save the manufacturing cost of the battery cell 100.

[0421] In some embodiments, the thickness t7 of the protrusion 122 is greater than or equal to the thickness t1 of the transition portion 1211.

[0422] For example, the thickness t7 of the protrusion 122 can be equal to the thickness t1 of the transition portion 1211, so that the protrusion 122 and the transition portion 1211 form a structure of equal thickness.

[0423] For example, the thickness t7 of the protrusion 122 may also be greater than the thickness t1 of the transition portion 1211, so that the protrusion 122 and the transition portion 1211 form a stepped structure.

[0424] By adopting the technical solution of this embodiment, the thickness t7 of the protrusion 122 is thicker, which can improve the current carrying capacity of the protrusion 122, which is beneficial to improving the current carrying capacity of the first electrode 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance and reliability of the battery cell 100.

[0425] In some embodiments, as shown in Figures 12 and 13, the thickness of the second active material portion 22 is t8, wherein 0.002≤(t1-t3) / t8≤0.08.

[0426] t1-t3 can refer to the thickness difference between the transition portion 1211 and the second sub-portion 12122.

[0427] The value of (t1-t3) / t8 can be 0.002, 0.08, or 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, and 0.08.

[0428] By adopting the technical solution of this embodiment, the setting of 0.002≤(t1-t3) / t8≤0.08 makes the thickness difference between the transition portion 1211 and the second sub-portion 12122 within the thickness error range of the active material layer 20. In this way, the thickening of the transition portion 1211 is less likely to cause the surface of the active material layer 20 to bulge, which can reduce subsequent rolling damage and subsequent squeezing damage between the first electrode 1 and other electrodes, which is beneficial to improving the reliability of the battery cell 100.

[0429] In some embodiments, as shown in Figures 12 and 13, 0.003 ≤ (t1-t3) / t8 ≤ 0.06.

[0430] By adopting the technical solution of this embodiment, the setting of 0.003≤(t1-t3) / t8≤0.06 allows the thickness difference between the transition portion 1211 and the second sub-portion 12122 to be better located within the thickness difference range of the active material layer 20. In this way, the thickening of the transition portion 1211 is less likely to cause the surface of the active material layer 20 to bulge, which can reduce subsequent rolling damage and subsequent squeezing damage between the first electrode 1 and other electrodes, thus improving the reliability of the battery cell 100.

[0431] In some embodiments, as shown in Figures 12 and 13, 60 μm ≤ t8 ≤ 250 μm.

[0432] It is understood that the value of t8 can be 60μm, 250μm, or any value between 60μm and 250μm; for example, the value of t8 can be, but is not limited to, 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, and 250μm.

[0433] The design with t8≥60μm allows the battery cell 100 to have a higher capacity; the design with t3≤250μm ensures that the distance for electrons to escape from the part of the active material layer 20 close to the metal layer 12 is not too long, and the electrons in the part of the active material layer 20 close to the metal layer 12 are easy to escape, which is beneficial to improving the capacity of the battery cell 100.

[0434] By adopting the technical solution of this embodiment, the thickness of the second active material portion 22 is within a suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and reliability of the battery cell 100. It can also reduce the risk of ion extraction difficulties in the region of the active material layer 20 near the conductive layer, thereby improving the performance of the battery cell 100.

[0435] In some embodiments, as shown in Figures 12 and 13, 80 μm ≤ t8 ≤ 180 μm.

[0436] By adopting the technical solution of this embodiment, with the setting of 80μm≤t8≤180μm, the thickness of the second active material part 22 is within a more suitable range, and the volume setting of the active material layer 20 is reasonable. This is beneficial to improving the fast charging performance and reliability of the battery cell 100, and can also reduce the risk of ion extraction difficulties in the region of the active material layer 20 near the conductive layer, thereby improving the performance of the battery cell 100.

[0437] In some embodiments, as shown in Figures 12 and 13, 0.2 μm ≤ t1 - t3 ≤ 4.5 μm.

[0438] 0.2μm≤t1-t3≤4.5μm. It can be understood that the value of t1-t3 can be 0.2μm, 4.5μm, or any value between 0.2μm and 4.5μm; for example, the value of t1-t3 can be, but is not limited to, 0.2μm, 0.3μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 1.75μm, 2μm, 3μm, 4μm, and 4.5μm.

[0439] By adopting the technical solution of this embodiment, the design of 0.2μm≤t1-t3≤4.5μm results in a reasonable thickness of the transition portion 1211. While improving the current carrying capacity, it also ensures that the thickness of the transition portion 1211 is not too large, thus avoiding excessive space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0440] In some embodiments, as shown in Figures 12 and 13, 0.3 μm ≤ t1 - t3 ≤ 1.75 μm.

[0441] By adopting the technical solution of this embodiment, the design of 0.3μm≤t1-t3≤1.75μm makes the thickness of the transition part 1211 more reasonable, the current carrying capacity better, and it is also more conducive to improving the energy density of the battery cell 100.

[0442] In some embodiments, referring to Figures 12 and 13, 1 < t1 / t3 ≤ 4, and optionally, 1.5 < t1 / t3 ≤ 2.5.

[0443] t1 / t3 can refer to the ratio of the thickness t1 of the transition portion 1211 to the thickness t3 of the second sub-part 12122, or it can characterize the degree of thickening of the transition portion 1211.

[0444] 1 < t1 / t3 ≤ 4. It can be understood that the value of t1 / t3 can be 4 or any value between 1 and 4; for example, the value of t1 / t3 can be, but is not limited to, 1.1, 1.5, 2, 2.5, 3, 3.5, and 4.

[0445] By adopting the technical solution of this embodiment, the design of 1<t1 / t3≤4 results in a reasonable thickness of the transition portion 1211. In addition to improving the current carrying capacity, the thickness of the transition portion 1211 is not too large, thus avoiding the occupation of a large amount of space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0446] In some embodiments, as shown in Figures 12 and 13, 1.5 < t1 / t3 ≤ 2.5.

[0447] By adopting the technical solution of this embodiment, the design of 1.5<t1 / t3≤2.5 results in a more reasonable thickening of the transition section 1211, better current carrying capacity, and is more conducive to improving the energy density of the battery cell 100.

[0448] In some embodiments, as shown in Figures 12 and 13, 1 μm ≤ t1 ≤ 5 μm.

[0449] 1μm≤t1≤5μm, which means that the value of t1 can be 1μm, 5μm, or any value between 1μm and 5μm; for example, the value of t1 can be, but is not limited to, 1μm, 1.1μm, 1.2μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, and 5μm.

[0450] By adopting the technical solution of this embodiment, the design of 1μm≤t1≤5μm and the thickness design of the transition part 1211 are reasonable, which is conducive to improving the current carrying capacity. In addition, the thickness of the transition part 1211 is not too large, and the generated burrs are small, which is conducive to improving the reliability of the battery cell 100.

[0451] In some embodiments, as shown in Figures 12 and 13, 1.2 μm ≤ t1 ≤ 3.5 μm.

[0452] By adopting the technical solution of this embodiment, the design of 1.2μm≤t1≤3.5μm makes the thickness design of the transition part 1211 more reasonable, the current carrying capacity better, and it is also more conducive to improving the reliability of the battery cell 100.

[0453] In some embodiments, as shown in Figures 12 and 13, 0.03 ≤ t6 / t5 ≤ 0.95.

[0454] t6 / t5 can refer to the ratio of the thickness of the third protective part 133 to the thickness of the second protective part 132, which can characterize the degree of thinning of the third protective part 133 relative to the second protective part 132.

[0455] 0.03≤t6 / t5≤0.95, which means that the value of t6 / t5 can be 0.03, 0.95, or any value between 0.03 and 0.95; for example, the value of t6 / t5 can be, but is not limited to, 0.03, 0.1, 0.125, 0.15, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.95.

[0456] By adopting the technical solution of this embodiment, the design of 0.03≤t6 / t5≤0.95 results in a reasonable degree of thinning of the conductive protective layer 13, which can be well matched with the degree of thickening of the transition portion 1211. This is beneficial for the surface of the conductive protective layer 13 facing away from the metal layer 12 to approach a plane, which helps to reduce rolling damage and improve the flow capacity of the metal layer 12.

[0457] In some embodiments, as shown in Figures 12 and 13, 0.125 ≤ t6 / t5 ≤ 0.8.

[0458] By adopting the technical solution of this embodiment, the design of 0.03≤t6 / t5≤0.95 makes the thinning degree of the conductive protective layer 13 more reasonable and better matches the thickening degree of the transition portion 1211. This is beneficial for the surface of the conductive protective layer 13 facing away from the metal layer 12 to approach the plane, which helps to reduce rolling damage and improve the flow capacity of the metal layer 12.

[0459] In some embodiments, as shown in Figures 12 and 13, 0.5 μm ≤ t6 ≤ 4 μm.

[0460] 0.5μm≤t6≤4μm, which means that the value of t6 can be 0.5μm, 4μm, or any value between 0.5μm and 4μm; for example, the value of t6 can be, but is not limited to, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 4μm, and 5μm.

[0461] By adopting the technical solution 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 metal layer 12 into the second protective part 132 due to excessive thickness, and the material accumulation can also be reduced, thus reducing the manufacturing cost.

[0462] In some embodiments, 1μm≤t6≤2μm.

[0463] By adopting the technical solution 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 the manufacturing cost.

[0464] In some embodiments, referring to Figures 12 and 13, along a first direction, the size of the first sub-part 12121 is W1, and the size of the second sub-part 12122 is W2, wherein W1 / (W1+W2)≤0.45.

[0465] For example, the dimension W1 of the first sub-part 12121 can refer to the width of the first sub-part 12121, and the dimension W2 of the second sub-part 12122 can refer to the width of the second sub-part 12122. W1 + W2 can be the width of the conductor part 1212.

[0466] W1 / (W1+W2) can refer to the proportion of the first sub-part 12121 occupying the conductive part 1212 in the width direction of the first electrode 1.

[0467] W1 / (W1+W2)≤0.45, which means that the value of W1 / (W1+W2) can be 0.45 or 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, and 0.45.

[0468] During the manufacturing process of the first electrode 1, the electrode raw material is slit to form multiple first electrode 1s. The thicker the metal layer 12 of the first electrode 1, the larger the burrs generated at the slit (i.e., at the end face of the first electrode 1 along the length direction). Furthermore, the wider the first sub-part 12121 of the metal layer 12, the more areas with large burrs are generated at the slit, which makes it easier for the battery cell 100 to have an internal short circuit. In addition, in the puncture test of the battery cell 100, the wider the first sub-part 12121, the easier it is for the needle to puncture the first sub-part 12121, which makes it easier to generate large burrs and cause an internal short circuit, which is not conducive to improving the reliability of the battery cell 100.

[0469] By adopting the technical solution of this embodiment, the design of W1 / (W1+W2)≤0.45 allows the active material layer 20 to cover the first sub-part 12121, thereby improving the overcurrent capacity and reducing the heat generation of the battery cell 100. In addition, along the second direction, the first sub-part 12121 does not occupy too much area, which is beneficial to reducing the space occupied and weight of the first sub-part 12121 and improving the energy density of the battery cell 100.

[0470] In some embodiments, as shown in Figures 12 and 13, the size of the first sub-part 12121 along the first direction is W2, wherein 10mm ≤ W2 ≤ 100mm.

[0471] It is understood that the value of W2 can be 10mm, 100mm, or 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, or 100mm.

[0472] By adopting the technical solution of this embodiment, the design of 10mm≤W2≤100mm allows the active material layer 20 to cover the first sub-part 12121, thereby improving the overcurrent capacity and reducing the heat generation of the battery cell 100. In addition, along the second direction, the first sub-part 12121 does not occupy too much area, which is beneficial to reducing the space occupied and weight of the first sub-part 12121 and improving the energy density of the battery cell 100.

[0473] The battery cell 100 of this application will be described below with reference to some embodiments.

[0474] Example 1

[0475] Referring to Figures 3-10, in this embodiment, the battery cell 100 includes an end cap 201, a housing 202, and an electrode assembly 101. The electrode assembly 101 is installed at the housing 202, and the end cap 201 covers the opening of the housing 202 to seal the housing 202. The end cap 201 is provided with an electrode lead-out portion 2011.

[0476] In this embodiment, the electrode assembly 101 includes a first electrode 1, a second electrode 2 and an insulating member 3 wound together. The insulating member 3 is located between the first electrode 1 and the second electrode 2. The first electrode 1 and the second electrode 2 have opposite polarities. The first electrode 1 can be a positive electrode and the second electrode 2 can be a negative electrode.

[0477] In this embodiment, the first electrode 1 includes a current collector 10, an active material layer 20, and a conductive member 30. The current collector 10 includes an insulating substrate 11, a metal layer 12, and a conductive protective layer 13. The two opposing surfaces of the insulating substrate 11 along the thickness direction are covered with the metal layer 12. The surface of the metal layer 12 facing away from the insulating substrate is covered with the conductive protective layer 13. The surface of the conductive protective layer 13 facing away from the insulating substrate is covered with the active material layer 20.

[0478] In this embodiment, conductive components 30 are welded to both metal layers 12. Each conductive component 30 includes a first connecting portion 31 and a second connecting portion 32 connected to each other. The first connecting portion 31 is welded to the metal layer 12 to form a first solder mark 51, and the second connecting portions 32 of the two conductive components 30 are welded to form a second solder mark 52.

[0479] In this embodiment, the electrode assembly 101 further includes an insulating member 40, which includes a first insulating portion 41 located between the first connecting portion 31 and the active material layer 20.

[0480] In this embodiment, the metal layer 12 includes a main body 121 and at least one protrusion 122. The main body 121 includes a transition portion 1211 and a conductive portion 1212. The transition portion 1211 is connected between the conductive portion 1212 and the protrusion 122. The protrusion 122 protrudes from the transition portion 1211 along a first direction. The active material layer 20 covers the metal layer 12. The protrusion 122 and the transition portion 1211 are not covered by the active material layer 20. The first direction is perpendicular to the thickness direction of the current collector 10.

[0481] In this embodiment, there are multiple protrusions 122, which are arranged at intervals along a second direction, which is perpendicular to the first direction and the thickness direction of the current collector 10.

[0482] The first connecting part 31 is welded to the protrusion 122 and the transition part 1211 to form the first solder mark 51.

[0483] Example 2

[0484] Referring to Figures 11-13, the difference between this embodiment and Embodiment 1 is that the insulating member 40 further includes a second insulating portion 42, one side of which covers the first solder mark 51 and the second solder mark 52, and the other side covers the first insulating portion 41.

[0485] Example 3

[0486] Referring to Figures 14-17, the difference between this embodiment and Embodiment 1 is that, as shown in Figures 14-17, the insulating member 40 includes a second insulating portion 42 but does not include a first insulating portion 41. One side of the second insulating portion 42 covers the first solder mark 51, and the other side of the second insulating portion 42 covers the active material layer 20.

[0487] In some embodiments, referring to FIG2, a battery device 1100 is provided, including the battery cell 100 of the above embodiment.

[0488] The battery device 1100 of this application embodiment adopts the above-mentioned battery cell 100. The battery cell 100 has a large fast charging performance and good reliability, which is beneficial to improving the fast charging performance of the battery device 1100 and also beneficial to improving the reliability of the battery device 1100.

[0489] In some embodiments, referring to FIG1, an electrical device is provided, including a battery device 1100 as described in the above embodiments.

[0490] The battery device 1100 of this application embodiment adopts the above-described battery device 1100. The battery device 1100 has a large fast charging performance and good reliability, which is conducive to improving the battery life of the power device and also conducive to improving the reliability of the power device.

[0491] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0492] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This 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, comprising: a housing provided with an electrode lead-out portion; an electrode assembly at least partially accommodated in the housing, the electrode assembly comprising a first electrode tab, the first electrode tab comprising a conductive member, a current collector and an active material layer; the conductive member is connected to the electrode lead-out portion; the current collector comprises an insulating base body and a metal layer, the insulating base body, the metal layer and the active material layer are 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 comprises a main body portion and at least one protruding portion extending outward from the end portion of the main body portion along a first direction, and the first direction is perpendicular to the thickness direction of the current collector; the main body portion comprises a transition portion and a conductive portion, the transition portion is connected between the conductive portion and the protruding portion, the conductive portion is covered with the active material layer, and the protruding portion and the transition portion are not covered with the active material layer; and the conductive member is connected to the surface of the transition portion away from the insulating base body.

2. The battery cell of claim 1, wherein, In a 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.

3. The battery cell of claim 2, wherein, L2=L1.

4. The battery cell according to any one of claims 1 to 3, wherein, In the second direction, the size of the protruding portion is smaller than the size of the transition portion.

5. The battery cell according to any one of claims 1 to 4, wherein, The conductive member comprises a first connecting portion and at least one second connecting portion, the first connecting portion and the second connecting portion are arranged along the first direction, the first connecting portion and the second connecting portion are connected, the second connecting portion is connected to the electrode lead-out portion, the first connecting portion is welded to the surface of the metal layer away from the insulating base body to form a first welding mark, and the second connecting portion is located on the side of the protruding portion away from the main body portion; In the first direction, the first welding mark is located on the side of the active material layer toward the protruding portion.

6. The battery cell of claim 5, wherein: The first welding mark comprises a first welding mark portion, and the first connecting portion is welded to the surface of the transition portion away from the insulating base body to form the first welding mark portion.

7. The battery cell of claim 6, wherein, In a second direction, the size of the transition portion is L2, the size of the first 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.

8. The battery cell of claim 7, wherein, L3=L2.

9. The battery cell of any one of claims 6-8, wherein, The first welding mark further comprises a second welding mark portion, and the first connecting portion is welded to the protruding portion to form the second welding mark portion.

10. The battery cell of claim 9, wherein, In a second direction, the size of the second welding mark portion is smaller than the size of the first welding mark portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

11. The battery cell of claim 9 or 10, wherein, In a second direction, the second welding mark portion extends from one side edge of the protruding portion to the other side edge of the protruding portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

12. The battery cell of any one of claims 9-11, wherein, The number of the protrusions is multiple, the multiple protrusions are arranged at intervals along a second direction, each of the protrusions is welded with the first connecting part, along the second direction, the sum of the sizes of all the second welding parts is less than the size of the first welding part, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

13. The battery cell of claim 12, wherein, The first connecting part includes multiple first connecting sub-parts arranged at intervals along the second direction, and the number of the second connecting parts is multiple, each of the first connecting sub-parts is connected with each of the second connecting parts one by one. Each of the first connecting sub-parts is welded on the surface of each of the protrusions away from the insulating base one by one.

14. The battery cell of claim 13, wherein, The first connecting part further includes a second connecting sub-part, the number of the second connecting parts is multiple, along the first direction, one side of each of the first connecting sub-parts is connected with each of the second connecting parts one by one, the other side of each of the first connecting sub-parts is connected with the second connecting sub-part, and the second connecting sub-part is arranged continuously along the second direction; the second connecting sub-part is welded on the surface of the transition part away from the insulating base.

15. The battery cell of any one of claims 9-14, wherein, The first welding part and the second welding part are directly connected.

16. The battery cell of any one of claims 5-15, wherein, Along the first direction, the first connecting part is arranged at intervals with the active material layer.

17. The battery cell of any one of claims 5-16, wherein: The electrode assembly further includes an insulating member, the insulating member includes a first insulating part, the first insulating part covers the surface of the metal layer away from the insulating base, and the entire first insulating part is located between the first welding part and the active material layer.

18. The battery cell of claim 17, wherein: The first insulating part is located between the first connecting part and the active material layer.

19. The battery cell of claim 18, wherein: The insulating member further includes a second insulating part, at least part of the second insulating part covers the first welding part.

20. The battery cell of claim 19, wherein: Along the first direction, one side of the second insulating part covers the first welding part, and the other side of the second insulating part covers at least part of the first insulating part.

21. The battery cell of any one of claims 5-20, wherein: The electrode assembly further includes an insulating member, the insulating member includes a second insulating part, at least part of the second insulating part covers the first welding part.

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

23. The battery cell of any one of claims 19-21, wherein: The number of the 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, and the number of the active material layers is two, the two active material layers cover the two metal layers respectively; The number of the conductive members is two, the first connecting parts of the two conductive members are welded on the surfaces of the two metal layers away from the insulating base respectively and form the two first welding parts; The number of the insulating members is two, the second insulating parts of the two insulating members cover at least part of the two first welding parts respectively.

24. The battery cell of claim 23, wherein: The second insulating part includes a first portion and a second portion connected to each other, the first portion covers at least part of the main body part in a direction of the main body part toward the protruding part, and the second portion protrudes from the main body part, and the second portion is located at a side of the protruding part in a second direction perpendicular to the first direction and a thickness direction of the current collector.

25. The battery cell of claim 24, wherein: The second portions of the two insulating parts are in contact with each other.

26. The battery cell of any one of claims 23-25, wherein: In the first direction, the second connecting parts of the two conductive members are welded to form a second welding mark at a side of the protruding part away from the main body part.

27. The battery cell of claim 26, wherein: The second insulating part covers the second welding mark in a direction of the main body part toward the protruding part, and the second insulating part protrudes from an edge of the second welding mark away from the transition part.

28. The battery cell of any one of claims 17-27, wherein: The electrode assembly includes a second tab opposite to the first tab in polarity, and the second tab includes a main functional part and a tab part protruding from the main functional part in the first direction. In a direction of the main body part toward the protruding part, the main functional part protrudes from an end surface of the insulating part toward the active material layer, and the main functional part does not protrude from an end surface of the insulating part away from the active material layer.

29. The battery cell of any one of claims 5-28, wherein: The first welding mark is spaced apart from the active material layer by a distance S1, where 0.3 mm ≤ S1 ≤ 5 mm, and optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

30. The battery cell of any one of claims 5-29, wherein: The current collector further includes a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the conductive part, and in the first direction, the conductive protective layer and the first welding mark are spaced apart.

31. The battery cell of any one of claims 1-30, wherein: The current collector further includes a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the conductive part.

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

33. The battery cell of claim 32, wherein: In a direction of the main body part toward the protruding part, a protruding distance of the conductive protective layer from an end surface of the active material layer toward the protruding part is in a range of 0.3 mm to 0.8 mm.

34. The battery cell of any one of claims 1-33, wherein: The electrode assembly includes a second tab opposite to the first tab in polarity, and the second tab includes a main functional part and a tab part protruding from the main functional part in the first direction. In a direction of the main body part toward the protruding part, the main functional part protrudes from an end part of the transition part toward the protruding part.

35. The battery cell of any one of claims 1-34, wherein: The conductive part has a thickness less than a thickness of the transition part.

36. The battery cell of claim 35, wherein: The conductive part includes a first sub-part and a second sub-part, the first sub-part is connected between the second sub-part and the transition part, the first sub-part and the second sub-part are covered with the active material layer, the first sub-part has a thickness greater than a thickness of the second sub-part, and the transition part has a thickness greater than or equal to the thickness of the first sub-part.

37. The battery cell of claim 36, wherein: The current collector further comprises a conductive protective layer, the conductive protective layer comprises a first protective part and a second protective part, the first protective part is located between the first subpart and the active material layer, and the second protective part is located between the second subpart and the active material layer; wherein the thickness of the first protective part is less than the thickness of the second protective part.

38. The battery cell of claim 37, wherein: The conductive protective layer further comprises a third protective part, the third protective part covers the surface of the transition part away from the insulating base, and the thickness of the third protective part is less than or equal to the thickness of the first protective part.

39. The battery cell of any one of claims 1-38, wherein: The thickness of the convex part is greater than or equal to the thickness of the transition part.

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

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

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