Secondary battery and electronic device

Abstract

The invention relates to the technical field of batteries, and discloses a secondary battery and electronic equipment, and the secondary battery comprises a shell, an electrode assembly and a conductive terminal. A first pole piece of the electrode assembly comprises a first sub-pole piece, the first sub-pole piece is located on the outermost side of the electrode assembly in the thickness direction, the surface, away from a second pole piece, of the first sub-pole piece is provided with an empty foil area, and the empty foil area is electrically connected with the shell. The conductive terminal is arranged on the shell in an insulating mode, and the second pole piece of the electrode assembly comprises a pole lug electrically connected with the conductive terminal. The first pole piece comprises a first main body part and a first extension part, and the projection of the first extension part in the thickness direction does not coincide with the tab and the conductive terminal. According to the secondary battery, the empty foil area is arranged on the surface of the first pole piece, the empty foil area is in contact with the shell to form electric connection, the connection stability of the first pole piece and the shell can be improved, the number of the conductive terminals is reduced, the first extension part is additionally arranged on the first pole piece to increase the coating space of the active material layer, and then the energy density of the secondary battery is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and particularly to a secondary battery and an electronic device. Background Art

[0002] At present, existing secondary batteries have problems such as unstable internal structure and low energy density. With the rapid development of new energy technologies, secondary batteries have been widely used in fields such as mobile phones, tablets, laptop computers, and electric vehicles. The requirements for the quality and safety of secondary batteries and the energy density are also getting higher and higher. Summary of the Invention

[0003] The embodiments of the present application provide a secondary battery and an electronic device, which can improve the structural stability inside the secondary battery and the energy density of the secondary battery.

[0004] One technical solution adopted in the embodiments of the present application is: providing a secondary battery, including a housing, an electrode assembly, and a conductive terminal. The housing is provided with a receiving cavity. The electrode assembly includes a first electrode tab, a second electrode tab, and a separator. The first electrode tab and the second electrode tab are alternately arranged in sequence, and the separator is arranged between the adjacent first electrode tab and second electrode tab. The first electrode tab includes a first sub-electrode tab. Along the thickness direction of the electrode assembly, the first sub-electrode tab is located on the outermost side in the thickness direction of the electrode assembly, and an empty foil area is provided on the surface of the first sub-electrode tab away from the second electrode tab. The empty foil area is electrically connected to the housing. The conductive terminal is insulatingly arranged on the housing, part of the conductive terminal extends out of the housing, and part of the conductive terminal is located in the receiving cavity. The second electrode tab includes an ear tab, and the ear tab is electrically connected to the conductive terminal. Along the length direction of the electrode assembly, the first electrode tab includes a first main body portion and a first extension portion. Along the thickness direction of the electrode assembly, the projection of the first extension portion does not overlap with the ear tab and the conductive terminal. The length direction of the electrode assembly is perpendicular to the thickness direction of the electrode assembly. The conductive terminal extending out of the housing means that the conductive terminal exposes the housing to facilitate electrical connection with an external circuit. In terms of height, the conductive terminal can extend beyond the outer surface of the housing or not, such as being flush with the outer surface of the housing or lower than the outer surface of the housing. In the secondary battery of the present application, an empty foil area is provided on the surface of the first electrode tab, and the empty foil area is in contact with the housing to form an electrical connection, which can improve the connection stability between the first electrode tab and the housing, reduce the number of conductive terminals, so as to release more space in the receiving cavity. The first electrode tab is increased with a first extension portion to increase the coating space of the active material layer, thereby improving the energy density of the secondary battery.

[0005] In some embodiments, the first electrode tab further includes at least one second sub-electrode tab. The first sub-electrode tab and the second sub-electrode tab are independent of each other, and are electrically connected after being stacked in the thickness direction of the electrode assembly, or the first electrode tab is integrally formed and continuously folded to form the first sub-electrode tab and the second sub-electrode tab.

[0006] In some embodiments, the surface of the first sub-pole piece away from the second pole piece is a hollow foil area to increase the contact area between the first pole piece and the shell, increase the current transmission path, and further reduce the impedance to reduce energy consumption.

[0007] In some embodiments, the secondary battery includes a conductive glue disposed between the hollow foil area and the shell, and electrically connecting the hollow foil area and the shell. The conductive glue helps fill the small gap between the hollow foil area and the shell to enhance the stability and conductivity of the connection between the two.

[0008] In some embodiments, a conductive protrusion is disposed on the hollow foil area, and the conductive protrusion electrically connects the hollow foil area and the shell. The conductive protrusion helps to improve the conductivity between the first electrode sheet and the shell.

[0009] In some embodiments, along the length direction of the electrode assembly, the second pole piece further includes a second main body and a second extension, and the pole ear is connected to the second main body. Along the thickness direction of the electrode assembly, the projection of the first extension covers the projection of the second extension. The first pole piece is directly electrically connected to the shell, and does not need to be connected through a transfer terminal, releasing more space in the receiving cavity. The first pole piece can add a first extension to increase the space for coating the active material layer of the first pole piece, and the second pole piece can add a second extension to increase the space for coating the active material layer of the second pole piece, thereby improving the energy density of the secondary battery.

[0010] In some embodiments, the first pole piece includes two first sub-pole pieces. Along the thickness direction of the electrode assembly, the two first sub-pole pieces are respectively arranged at the two outermost sides in the thickness direction of the electrode assembly. This can increase the contact area between the first pole piece and the shell, increase the current transmission path, further reduce the impedance to reduce energy consumption, and also reduce the insulation requirements between the second pole piece and the shell.

[0011] In some embodiments, the empty foil area includes a first area and a second area, the first area is located on a surface of one of the first sub-electrode sheets away from the second electrode sheet, and the second area is located on a surface of another first sub-electrode sheet away from the second electrode sheet, so that the first area and the second area are respectively located at the two outermost sides in the thickness direction of the electrode assembly. The electrode assembly also includes a conductive member, the conductive member includes a first conductive layer and a second conductive layer, the first conductive layer is disposed between the first area and the shell, and electrically connects the first area and the shell, and the second conductive layer is disposed between the second area and the shell, and electrically connects the second area and the shell.

[0012] In some embodiments, the electrode assembly includes a first side portion, a second side portion, a third side portion and a fourth side portion, the first side portion and the second side portion are relatively arranged in the length direction of the electrode assembly, the electrode ear extends from the first side portion, the third side portion and the fourth side portion are relatively arranged in the width direction of the electrode assembly, and the width direction of the electrode assembly, the length direction of the electrode assembly and the thickness direction of the electrode assembly are perpendicular to each other.

[0013] In some embodiments, the conductive member is wound around the first region, the first side portion, and the second region along the length direction of the electrode assembly. The conductive member further includes a third conductive layer, and the third conductive layer is located at the first side portion and is respectively connected to a first conductive layer and a second conductive layer. The first conductive layer, the second conductive layer, and the third conductive layer form a U-shaped structure to form a binding and fixing effect on the first electrode sheet, the second electrode sheet, and the separator in the thickness direction of the electrode assembly.

[0014] And / or, the conductive member is wound around the first region, the second side portion, and the second region along the length direction of the electrode assembly. The conductive member further includes a fourth conductive layer, and the fourth conductive layer is located at the second side portion and is respectively connected to a first conductive layer and a second conductive layer. The first conductive layer, the second conductive layer, and the fourth conductive layer form a U-shaped structure to form a binding and fixing effect on the first electrode sheet, the second electrode sheet, and the separator in the thickness direction of the electrode assembly.

[0015] In some embodiments, the length L1 of the first conductive layer satisfies: 0 mm < L1 ≤ 100 mm, and the width K1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - K1 ≤ 100 mm. And / or, the length L2 of the second conductive layer satisfies: 0 mm < L2 ≤ 100 mm, and the width K2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - K2 ≤ 100 mm. By setting the length of the first conductive layer and / or the length of the second conductive layer within the above range, it is possible to effectively electrically connect the first electrode sheet and the housing without excessively increasing the overall weight of the secondary battery while enabling the conductive member to effectively bind and fix the electrode assembly. Preferably, 1 mm ≤ L1 ≤ 5 mm, 1 mm ≤ K3 - K1 ≤ 3 mm; and / or, 1 mm ≤ L2 ≤ 5 mm, 1 mm ≤ K3 - K2 ≤ 3 mm.

[0016] In some embodiments, the conductive member is wound around the first region, the third side portion, and the second region along the width direction of the electrode assembly. The conductive member further includes a fifth conductive layer, and the fifth conductive layer is located at the third side portion and is respectively connected to a first conductive layer and a second conductive layer. The first conductive layer, the second conductive layer, and the fifth conductive layer form a U-shaped structure to form a binding and fixing effect on the first electrode sheet, the second electrode sheet, and the separator in the thickness direction of the electrode assembly

[0017] And / or, the conductive member is wound around the first region, the fourth side portion, and the second region along the width direction of the electrode assembly. The conductive member further includes a sixth conductive layer, and the sixth conductive layer is located at the fourth side portion and is respectively connected to a first conductive layer and a second conductive layer. The first conductive layer, the second conductive layer, and the sixth conductive layer form a U-shaped structure to form a binding and fixing effect on the first electrode sheet, the second electrode sheet, and the separator in the thickness direction of the electrode assembly.

[0018] In some embodiments, the length L1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - L1 ≤ 100 mm, and the width K1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - 2*K1 ≤ 100 mm. And / or, the length L2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - L2 ≤ 100 mm, and the width K2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - 2*K2 ≤ 100 mm. The above settings can enable the first conductive layer and / or the second conductive layer to cover the surface of the electrode assembly as much as possible in the width direction, increasing the binding and fixing effect on the electrode assembly, and at the same time making the area of the first conductive layer and / or the second conductive layer larger, which is beneficial to enhancing the electrical conductivity between the housing and the first pole piece. Preferably, 1 mm ≤ K3 - L1 ≤ 10 mm, 1 mm ≤ K3 - 2*K1 ≤ 5 mm; and / or, 1 mm ≤ K3 - L2 ≤ 10 mm, 1 mm ≤ K3 - 2*K2 ≤ 5 mm.

[0019] In some embodiments, the conductive member includes a conductive agent and a binder; the conductive agent includes at least one of silver powder, copper powder, nickel powder, carbon black, and graphene; the binder includes at least one of epoxy resin, polyurethane, and acrylate. By mixing the conductive agent and the binder to form the conductive member, the conductive member has both good adhesion performance and good electrical conductivity.

[0020] In some embodiments, the thickness H of the conductive member satisfies: 0 μm < H ≤ 500 μm. By setting the thickness of the conductive member within the above range, the conductive member can not only have good electrical conductivity, but also effectively fix the electrode assembly, reduce the space occupied by the accommodation cavity inside the housing, and improve the energy density of the secondary battery. In some embodiments, the thickness H of the conductive member satisfies: 5 μm ≤ H ≤ 30 μm. Setting H ≥ 5 μm can further improve the electrical conductivity of the conductive member; setting H ≤ 30 μm can further improve the energy density of the secondary battery while ensuring that the conductive member has good electrical conductivity.

[0021] In some embodiments, the first pole piece is an anode pole piece and the second pole piece is a cathode pole piece. By connecting the anode pole piece to the housing, the housing corresponds to a hard steel shell, which has higher strength and better wear resistance and impact resistance.

[0022] Another technical solution adopted in the embodiments of the present application is: to provide an electronic device including a secondary battery.

[0023] The beneficial effects of the embodiments of the present application are as follows: the secondary battery of the embodiments of the present application sets a first zone on the surface of the first sub-pole sheet away from the second sub-pole sheet in the first pole sheet, and makes the first zone contact with the shell to form an electrical connection. Compared with the structure of the prior art using the adapter terminal, the structure of the embodiments of the present application can improve the stability of the connection between the first sub-pole sheet and the shell, and the contact area between the first zone and the shell is larger, which reduces the impedance and reduces the energy consumption. In addition, the first pole sheet is directly electrically connected to the shell without the need for connection through the adapter terminal. The first pole sheet can add a first extension portion to increase the space for coating the active material layer on the first pole sheet, thereby improving the energy density of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the following is a brief introduction to the drawings required for describing the specific embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0025] Figure 1 is a partial cross-sectional view of a secondary battery in the prior art.

[0026] Figure 2 It is a cross-sectional view of a secondary battery according to an embodiment of the present application.

[0027] Figure 3 The electrode assembly of the secondary battery of the present application embodiment is Figure 2 Sectional view of AA.

[0028] Figure 4 The first electrode of the electrode assembly of the secondary battery of the present application embodiment is along the Figure 2 Sectional view of AA.

[0029] Figure 5 It is a schematic diagram of the first current collector of the secondary battery of the embodiment of the present application.

[0030] Figure 6 The second pole piece of the electrode assembly of the secondary battery of the embodiment of the present application is Figure 2 Sectional view of AA.

[0031] Figure 7 It is a schematic diagram of the second current collector of the secondary battery of the embodiment of the present application.

[0032] Figure 8 It is a cross-sectional view of a secondary battery having a conductive member according to an embodiment of the present application.

[0033] Figure 9 The secondary battery of the present application embodiment is Figure 8 Cross-sectional view of BB.

[0034] Figure 10 It is a schematic diagram of the electrode assembly of the secondary battery according to the embodiment of the present application winding a conductive member along the length direction.

[0035] Figure 11 It is another schematic diagram of the electrode assembly of the secondary battery according to the embodiment of the present application winding a conductive member along the length direction.

[0036] Figure 12 It is the secondary battery according to the embodiment of the present application along Figure 10 The cross-sectional view taken along C-C in

[0037] Figure 13 It is a schematic diagram of the electrode assembly of the secondary battery according to the embodiment of the present application winding a conductive member along the width direction.

[0038] Figure 14 It is another schematic diagram of the electrode assembly of the secondary battery according to the embodiment of the present application winding a conductive member along the width direction.

[0039] Figure 15 It is the secondary battery according to the embodiment of the present application along Figure 13 The cross-sectional view taken along D-D in

[0040] The reference numerals in the specific embodiments are as follows:

[0041] 100, secondary battery;

[0042] 10, housing; 11, receiving cavity;

[0043] 20, electrode assembly; 21, first electrode tab; 211, first sub-electrode tab; 212, second sub-electrode tab; 213, empty foil area; 2131, first area; 2132, second area; 214, first current collector; 2141, first main body; 2142, first extension; 215, first active material layer; 22, second electrode tab; 221, tab; 222, second current collector; 2221, second main body; 2222, second extension; 223, second active material layer; 23, separator; 24, first side; 25, second side; 26, third side; 27, fourth side;

[0044] 30, conductive terminal; X, length direction; Y, width direction; Z, thickness direction;

[0045] 40, conductive member; 41, first conductive layer; 42, second conductive layer; 43, third conductive layer; 44, fourth conductive layer; 45, fifth conductive layer; 46, sixth conductive layer. Specific embodiments

[0046] For ease of understanding of the present application, the present application will be described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is expressed as "fixed to" another element, it can be directly on the other element, or there can be one or more intermediate elements therebetween. When an element is expressed as "connected to" another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "vertical", "horizontal", etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0047] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not used to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0048] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0049] Please refer to Figure 1 , in the prior art, the secondary battery 100A includes a housing 10A and an electrode assembly 20A. The electrode assembly 20A includes a positive electrode tab, a separator, and a negative electrode tab that are stacked or wound. The positive electrode tab is provided with a positive electrode ear, and the negative electrode tab is provided with a negative electrode ear. A plurality of positive electrode ears are gathered and welded to the positive electrode adapter terminal 30A, and a plurality of negative electrode ears are gathered and welded to the negative electrode adapter terminal 40A. The positive electrode adapter terminal 30A and the negative electrode adapter terminal 40A extend out of the housing 10A to form the positive and negative electrodes of the secondary battery 100A respectively. The above structure of the secondary battery 100A in the prior art has at least the following problems. On the one hand, the welding of the tabs to the adapter terminals easily causes cracking at the welding points and tab breakage. On the other hand, the positive electrode adapter terminal and the negative electrode adapter terminal occupy a relatively large amount of space inside the housing. A space 11A needs to be reserved between the electrode assembly 20A and the housing 10A to accommodate the positive electrode adapter terminal and the negative electrode adapter terminal, resulting in waste of internal space and low energy density of the secondary battery 100A.

[0050] In view of the above problems, the present application provides an embodiment of a secondary battery 100. By changing the connection manner between the electrode assembly 20 and the housing 10, specifically, one of the electrode plates in the electrode assembly 20 extends out of the housing 10 through a conductive terminal 30 to form an electrode of the secondary battery 100, such as the negative electrode (positive electrode), and the other electrode plate in the electrode assembly 20 is directly electrically connected to the housing 10, so that the housing 10 forms the other electrode of the secondary battery 100, such as the positive electrode (negative electrode). In this way, the number of conductive terminals 30 is reduced, and more space inside the housing 10 can be released to accommodate the electrode plates, so as to improve the energy density of the secondary battery 100. In addition, the electrode plate is directly electrically connected to the housing 10 without welding, effectively reducing the risk of poor contact between the electrode plate and the housing 10 caused by the fracture of the electrode plate, thereby improving the stability of the internal structure of the secondary battery 100 and enhancing its anti-drop and anti-impact capabilities.

[0051] In some embodiments, referring to Figures 1 to 4 , the secondary battery 100 includes a housing 10, an electrode assembly 20, and a conductive terminal 30. The housing 10 is provided with a receiving cavity 11, and the electrode assembly 20 is disposed in the receiving cavity 11. An electrolyte is provided in the receiving cavity 11 so that the electrode assembly 20 can perform an electrochemical reaction. The electrode assembly 20 has a length direction X, a width direction Y, and a thickness direction Z that are perpendicular to each other. The electrode assembly 20 includes a first electrode plate 21, a second electrode plate 22, and a separator 23. The first electrode plate 21 and the second electrode plate 22 are alternately arranged in sequence, and the separator 23 is disposed between the adjacent first electrode plate 21 and second electrode plate 22 to isolate the first electrode plate 21 and the second electrode plate 22 and prevent them from directly contacting and short-circuiting. Among them, the polarities of the first electrode plate 21 and the second electrode plate 22 are opposite, one of them is an anode electrode plate, and the other is a cathode electrode plate.

[0052] The first electrode plate 21 includes a first sub-electrode plate 211. Along the thickness direction Z of the electrode assembly 20, the first sub-electrode plate 211 is located on the outermost side of the electrode assembly 20 in its thickness direction Z, and an empty foil area 213 is provided on the surface of the first sub-electrode plate 211 away from the second sub-electrode plate 212. The empty foil area 213 is electrically connected to the housing 10. For example, the empty foil area 213 is directly in contact with the housing 10, or the empty foil area 213 is indirectly connected to the housing 10 through other structures with conductive properties, so that the first electrode plate 21 is electrically connected to the housing 10, and the housing 10 forms an electrode of the secondary battery 100. It can be understood that the number of the first sub-electrode plates 211 in the first electrode plate 21 can be one or two.

[0053] The conductive terminals 30 are insulated and disposed in the housing 10. Part of the conductive terminals 30 protrude from the housing 10, and part of the conductive terminals 30 are located in the receiving cavity 11. The second pole piece 22 includes a tab 221. The tab 221 is electrically connected to the conductive terminal 30, and the conductive terminal 30 constitutes another electrode of the secondary battery 100. In some embodiments, the conductive terminal 30 can be a pole post, or a transition piece with a thickness greater than that of the tab, or the tab directly protrudes from the housing 10 and the tab constitutes the conductive terminal 30, or any two or more combinations of the pole post, the transition piece, and the tab constitute the conductive terminal 30 in this application.

[0054] Please refer to Figure 4 and Figure 5 , along the length direction X of the electrode assembly 20, the first pole piece 21 includes a first main body portion 2141 and a first extension portion 2142. Along the thickness direction Z of the electrode assembly 20, the projection of the first extension portion 2142 does not overlap with the tab 221 and the conductive terminal 30. The length direction X of the electrode assembly 20 is perpendicular to the thickness direction Z of the electrode assembly 20.

[0055] In the secondary battery 100 according to the embodiment of the present application, by providing an empty foil area 213 on the surface of the first sub-pole piece 211 away from the second pole piece 22 and making the empty foil area 213 form an electrical connection with the housing 10, compared with the structure using two conductive terminals in the prior art, the above structure of the secondary battery 100 in the embodiment of the present application can improve the connection stability between the first pole piece 21 and the housing 10, and the contact area between the empty foil area 213 and the housing 10 is larger, reducing the impedance to lower the energy consumption. In addition, the first pole piece 21 is directly electrically connected to the housing 10 without the need to be connected through a transition terminal, releasing more space in the receiving cavity 11. The first pole piece 21 can increase the first extension portion 2142 to increase the space for coating the active material layer of the first pole piece 21, thereby improving the energy density of the secondary battery 100.

[0056] In some embodiments, the first pole piece 21 further includes at least one second sub-pole piece 212. Among them, the polarity of the second sub-pole piece 212 is the same as that of the first sub-pole piece 211, that is, both are anode pole pieces or both are cathode pole pieces. As an example, the first sub-pole piece 211 and the second sub-pole piece 212 are independent sub-pole pieces, which are stacked and electrically connected in the thickness direction Z of the electrode assembly 20 to jointly form the above-mentioned first pole piece 21. As another example, the first pole piece 21 is a long strip-shaped integrally formed structure, and the first pole piece 21 is connected and folded to form the first sub-pole piece 211 and the second sub-pole piece 212.

[0057] Please refer to Figure 4, when the first electrode tab 21 has a continuously folded structure, the first electrode tab 21 includes a strip-shaped first current collector 214 and a first active material layer 215 coated thereon at intervals. The first electrode tab 21 is continuously folded at the intervals of the first active material layer 215 to form a first sub-electrode tab 211 and a plurality of second sub-electrode tabs 212. Wherein, the first sub-electrode tab 211 and the plurality of second sub-electrode tabs 212 both have a first main body portion 2141 and a first extension portion 2142, and in the thickness direction Z of the first electrode tab 21, there is a space between the first sub-electrode tab 211 and the plurality of second sub-electrode tabs 212 for stacking the second electrode tab 22.

[0058] In some embodiments, the surfaces of the first sub-electrode tab 211 away from the second electrode tab 22 are all empty foil areas 213, that is, the surfaces of the first sub-electrode tab 211 away from the second electrode tab 22 are not coated with an active material layer, so as to increase the contact area between the first electrode tab 21 and the housing 10, increase the current transmission path, and further reduce the impedance to reduce the energy consumption.

[0059] In some embodiments, the secondary battery 100 includes a conductive adhesive disposed between the empty foil area 213 and the housing 10, and the conductive adhesive electrically connects the empty foil area 213 and the housing 10. The conductive adhesive helps to fill the tiny gap between the empty foil area 213 and the housing 10 to enhance the connection stability and conductivity between the two.

[0060] In some embodiments, conductive protrusions are provided on the empty foil area 213, and the conductive protrusions electrically connect the empty foil area 213 and the housing 10. The forming method of the conductive protrusions on the first sub-electrode tab 211 includes but is not limited to laser texturing, so that burrs are generated on the surface of the current collector of the first sub-electrode tab 211, and the surface roughness of the conductive protrusion area is greater than that of the remaining areas; or, by stamping the current collector of the first sub-electrode tab 211 to make it locally protrude. Of course, in other embodiments, both conductive protrusions and a conductive adhesive can be provided on the empty foil area 213.

[0061] In some embodiments, please refer to Figure 3 and Figure 4 , the first electrode tab 21 includes two first sub-electrode tabs 211. Along the thickness direction Z of the electrode assembly 20, the two first sub-electrode tabs 211 are respectively disposed oppositely on the two outermost sides of the electrode assembly 20 in its thickness direction Z. By setting the two outermost sides in the thickness direction Z of the electrode assembly 20 as the first sub-electrode tabs 211 and both being electrically connected to the housing 10, on the one hand, the contact area between the first electrode tab 21 and the housing 10 can be increased, the current transmission path can be increased, and the impedance can be further reduced to reduce the energy consumption. On the other hand, the insulation requirement between the outside of the electrode assembly 20 and the housing 10 can be reduced. If the outermost sides of the electrode assembly 20 are the first electrode tab 21 and the second electrode tab 22 respectively, insulation measures need to be added between the second electrode tab 22 and the housing 10.

[0062] It is understandable that the number of the second sub - electrode sheets 212 in the first electrode sheet 21 can be 0, 1, 2,... Both side surfaces of the second sub - electrode sheet 212 are coated with the first active material layer 215. The first active material layer 215 is coated on the surface of the first sub - electrode sheet 211 facing the second sub - electrode sheet 212, and the surface of the first sub - electrode sheet 211 facing away from the second sub - electrode sheet 212 may be partially provided with the first active material layer 215 or may not be provided with the first active material layer 215.

[0063] For the above - mentioned second electrode sheet 22, please refer to Figure 6 and Figure 7 , the second electrode sheet 22 includes a tab 221, a second current collector 222 and a second active material layer 223. The second active material layer 223 is coated on both side surfaces of the second current collector 222. The tab 221 is welded to the second current collector 222, or in other embodiments, the second current collector 222 is formed into a tab 221 by cutting. Along the length direction X of the electrode assembly 20, the second electrode sheet 22 includes a second main body portion 2221 and a second extension portion 2222, and the tab 221 is connected to the second main body portion 2221. When the number of the second electrode sheets 22 is multiple, the multiple tabs 221 are gathered and electrically connected to the conductive terminal 30.

[0064] Please also refer to Figure 3 , along the thickness direction Z of the electrode assembly 20, the first main body portion 2141 and the second main body portion 2221 are stacked. The projection of the first extension portion 2142 covers the projection of the second extension portion 2222. In the prior art, since the first electrode sheet 21 needs to be provided with a transfer terminal to be connected to the housing 10, there is a space between the electrode assembly 20 and the housing 10 to accommodate the transfer terminal. In the present application, the first electrode sheet 21 is provided with an empty foil area 213 to be electrically connected to the housing 10, and there is no need to reserve a space to accommodate the transfer terminal. Then, the first electrode sheet 21 can be provided with the first extension portion 2142 on the basis of the existing structure, and the second electrode sheet 22 can correspondingly be provided with the second extension portion 2222. The first extension portion 2142 and the second extension portion 2222 are correspondingly arranged, so that the first active material layer 215 on the first extension portion 2142 and the second active material layer 223 on the second extension portion 2222 can undergo an electrochemical reaction, improving the energy density of the secondary battery 100.

[0065] In some embodiments, the first electrode sheet 21 is an anode electrode sheet, and the second electrode sheet 22 is a cathode electrode sheet. By connecting the anode electrode sheet to the housing 10, the housing 10 correspondingly is a hard steel shell, which has higher strength and better wear - resistance and impact - resistance capabilities.

[0066] In some embodiments, please refer to Figure 8 and Figure 9, the secondary battery 100 includes a conductive member 40 disposed between the first electrode sheet 21 and the housing 10 to electrically connect the first electrode sheet 21 and the housing 10. The empty foil area 213 includes a first area 2131 and a second area 2132. The first area 2131 is located on the surface of one of the first sub-electrode sheets 211 away from the second electrode sheet 22, and the second area 2132 is located on the surface of the other first sub-electrode sheet 211 away from the second electrode sheet 22, such that the first area 2131 and the second area 2132 are respectively located on two outermost sides in the thickness direction Z of the electrode assembly 20.

[0067] The conductive member 40 includes a first conductive layer 41 disposed between the housing 10 and the first area 2131. The first conductive member 40 bonds the first area 2131 and the inner wall of the housing 10 to electrically connect the two. The first conductive layer 41 helps to fill the minute gap between the first area 2131 and the housing 10 to increase the connection stability therebetween, and to reduce the contact interface impedance between the first area 2131 and the inner wall of the housing 10. The conductive member 40 has good electrical conductivity to enhance the electrical conductivity between the two.

[0068] In some embodiments, the conductive member 40 further includes a second conductive layer 42 disposed between the housing 10 and the second area 2132. The second conductive member 40 bonds the second area 2132 and the inner wall of the housing 10 to electrically connect the two. The second conductive layer 42 helps to fill the minute gap between the second area 2132 and the housing 10 to increase the connection stability therebetween, and to reduce the contact interface impedance between the second area 2132 and the inner wall of the housing 10. The conductive member 40 has good electrical conductivity to enhance the electrical conductivity between the two.

[0069] In some embodiments, please refer to Figure 10 , after the stacking of the electrode assembly 20 is completed, it is generally in a cuboid structure. The electrode assembly 20 includes a first side 24, a second side 25, a third side 26, and a fourth side 27. The first side 24 and the second side 25 are oppositely disposed in the length direction X of the electrode assembly 20, and the tab 221 extends from the first side 24. The third side 26 and the fourth side 27 are oppositely disposed in the width direction Y of the electrode assembly 20. The conductive member 40 can be wound around the electrode assembly 20 in the length direction X to bundle and fix the electrode assembly 20 in the length direction X, and / or the conductive member 40 can be wound around the electrode assembly 20 in the width direction Y to bundle and fix the electrode assembly 20 in the width direction Y to enhance the structural strength of the electrode assembly 20.

[0070] In some embodiments, please refer to Figures 10 to 12, the conductive member 40 is wound around the first region 2131, the first side portion 24, and the second region 2132 along the length direction X of the electrode assembly 20. Specifically, the conductive member 40 further includes a third conductive layer 43, and the third conductive layer 43 is located at the first side portion 24 and is respectively connected to a first conductive layer 41 and a second conductive layer 42. The first conductive layer 41, the second conductive layer 42, and the third conductive layer 43 form a U-shaped structure to form a binding and fixing effect on the first electrode sheet 21, the second electrode sheet 22, and the separator 23 in the thickness direction Z of the electrode assembly 20. In some embodiments, the conductive member 40 is wound around the first region 2131, the second side portion 25, and the second region 2132 along the length direction X of the electrode assembly 20. The conductive member 40 further includes a fourth conductive layer 44, and the fourth conductive layer 44 is located at the second side portion 25 and is respectively connected to a first conductive layer 41 and a second conductive layer 42. The first conductive layer 41, the second conductive layer 42, and the fourth conductive layer 44 form a U-shaped structure to form a binding and fixing effect on the first electrode sheet 21, the second electrode sheet 22, and the separator 23 in the thickness direction Z of the electrode assembly 20.

[0071] It should be noted that in the embodiment where the third conductive layer 43 is provided at the first side portion 24 of the electrode assembly 20 and the fourth conductive layer 44 is provided at the second side portion 25, one first conductive layer 41 may be provided on the first region 2131, and one first conductive layer 41 is respectively connected to the third conductive layer 43 and the fourth conductive layer 44. Alternatively, two first conductive layers 41 spaced apart in the length direction X may be provided on the first region 2131, where one first conductive layer 41 is connected to the third conductive layer 43 and the other first conductive layer 41 is connected to the fourth conductive layer 44. Similarly, one second conductive layer 42 may be provided on the second region 2132, and one second conductive layer 42 is respectively connected to the third conductive layer 43 and the fourth conductive layer 44. The first conductive layer 41, the second conductive layer 42, the third conductive layer 43, and the fourth conductive layer 44 form a closed ring structure to bind the electrode assembly 20 in the length direction X. Alternatively, two second conductive layers 42 spaced apart in the length direction X may be provided on the second region 2132, where one second conductive layer 42 is connected to the third conductive layer 43 and the other second conductive layer 42 is connected to the fourth conductive layer 44. Of course, in other embodiments, as Figure 1 shown, the number of the first conductive layers 41 on the first region 2131 may be three or more. Correspondingly, the number of the second conductive layers 42 and the number of the fourth conductive layers 44 on the second region 2132 correspond to the number of the first conductive layers 41.

[0072] In some embodiments, please refer to Figure 10 and Figure 11, when the conductive member 40 is wound around the electrode assembly 20 in the length direction X of the electrode assembly 20, along the length direction X of the electrode assembly 20, the length L1 of the first conductive layer 41 satisfies: 0 mm < L1 ≤ 100 mm, and / or, the length L2 of the second conductive layer 42 satisfies: 0 mm < L2 ≤ 100 mm. Setting the length L1 of the first conductive layer 41 and / or the length L2 of the second conductive layer 42 within the above range can enable the conductive member 40 to effectively bind and fix the electrode assembly 20, and at the same time, can effectively electrically connect the first pole piece 21 and the housing 10, and will not excessively increase the overall weight of the secondary battery 100. In some embodiments, the length L1 of the first conductive layer 41 satisfies: 1 mm ≤ L1 ≤ 5 mm, and / or, the length L2 of the second conductive layer 42 satisfies: 1 mm ≤ L2 ≤ 5 mm.

[0073] Along the width direction Y of the electrode assembly 20, the width K1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - K1 ≤ 100 mm; and / or, the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - K2 ≤ 100 mm. Establishing a relationship between the width K1 of the first conductive layer 41 and / or the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20, such that the difference between the two is within the range of 0 mm to 100 mm, can enable the first conductive layer 41 and / or the second conductive layer 42 to cover the surface of the electrode assembly 20 as much as possible in the width direction Y, increasing the binding and fixing effect on the electrode assembly 20, and at the same time making the area of the first conductive layer 41 and / or the second conductive layer 42 larger, which is beneficial to enhancing the electrical conductivity between the housing 10 and the first pole piece 21. In some embodiments, the width K1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - K1 ≤ 3 mm; the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - K2 ≤ 3 mm.

[0074] In some embodiments, please refer to Figures 13 to 15, the conductive member 40 is wound around the first region 2131, the third side portion 26, and the second region 2132 along the width direction Y of the electrode assembly 20. Specifically, the conductive member 40 further includes a fifth conductive layer 45, and the fifth conductive layer 45 is located at the third side portion 26 and is respectively connected to a first conductive layer 41 and a second conductive layer 42. The first conductive layer 41, the second conductive layer 42, and the fifth conductive layer 45 form a U-shaped structure to form a binding and fixing effect on the first electrode sheet 21, the second electrode sheet 22, and the separator 23 in the thickness direction Z of the electrode assembly 20. In some embodiments, the conductive member 40 is wound around the first region 2131, the fourth side portion 27, and the second region 2132 along the width direction Y of the electrode assembly 20, and the conductive member 40 further includes a sixth conductive layer 46, and the sixth conductive layer 46 is located at the fourth side portion 27 and is respectively connected to a first conductive layer 41 and a second conductive layer 42. The first conductive layer 41, the second conductive layer 42, and the sixth conductive layer 46 form a U-shaped structure to form a binding and fixing effect on the first electrode sheet 21, the second electrode sheet 22, and the separator 23 in the thickness direction Z of the electrode assembly 20.

[0075] It should be noted that in the embodiment where the fifth conductive layer 45 is provided on the third side portion 26 of the electrode assembly 20 and the sixth conductive layer 46 is provided on the fourth side portion 27, one first conductive layer 41 may be provided on the first region 2131, and one first conductive layer 41 is respectively connected to the fifth conductive layer 45 and the sixth conductive layer 46. Alternatively, two first conductive layers 41 spaced apart in the width direction Y may be provided on the first region 2131, where one first conductive layer 41 is connected to the fifth conductive layer 45 and the other first conductive layer 41 is connected to the sixth conductive layer 46. Similarly, one second conductive layer 42 may be provided on the second region 2132, and one second conductive layer 42 is respectively connected to the fifth conductive layer 45 and the sixth conductive layer 46. The first conductive layer 41, the second conductive layer 42, the fifth conductive layer 45, and the sixth conductive layer 46 form a closed ring structure to bind the electrode assembly 20 in the width direction Y. Alternatively, two second conductive layers 42 spaced apart in the length direction X may be provided on the second region 2132, where one second conductive layer 42 is connected to the fifth conductive layer 45 and the other second conductive layer 42 is connected to the sixth conductive layer 46.

[0076] In some embodiments, please refer to Figure 13 and Figure 14, when the conductive member 40 is wound around the electrode assembly 20 in the width direction Y, along the length direction X of the electrode assembly 20, the length L1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - L1 ≤ 100 mm, and / or, the length L2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - L2 ≤ 100 mm. When the first electrode tab 21 is continuously folded in the length direction X to form an integral body, the first electrode tab 21 is continuous at the first side portion 24 and the second side portion 25 of the electrode assembly 20, and it is not easy for the electrolyte to enter the interior from the first side portion 24 and the second side portion 25 of the electrode assembly 20 to wet the first active material layer 215 and the second active material layer 223. The first electrode tab 21 is discontinuous at the third side portion 26 and the fourth side portion 27 of the electrode assembly 20, and it is easier for the electrolyte to enter the interior from the third side portion 26 and the fourth side portion 27 of the electrode assembly 20 to wet the first active material layer 215 and the second active material layer 223. Therefore, the length L1 of the first conductive layer 41 should not be too long. A relationship is established between the length L1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 such that the length L1 of the first conductive layer 41 is 0 mm to about 100 mm smaller than the width K3 of the electrode assembly 20. A relationship is established between the length L2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 such that the length L2 of the second conductive layer 42 is 0 mm to about 100 mm smaller than the width K3 of the electrode assembly 20, thereby leaving sufficient space at the third side portion 26 and the fourth side portion 27 of the electrode assembly 20 for the electrolyte to enter the interior of the electrode assembly 20. In some embodiments, the length L1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - L1 ≤ 10 mm, and / or, the length L2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - L2 ≤ 10 mm.

[0077] Along the width direction Y of the electrode assembly 20, the width K1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - 2 * K1 ≤ 100 mm; and / or, the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 0 mm ≤ K3 - 2 * K2 ≤ 100 mm. When K3 - 2 * K1 is 0 mm, the first conductive layer 41 on the first region 2131 covers the first region 2131 in the width direction Y of the electrode assembly 20. Similarly, when K3 - 2 * K2 is 0 mm, the second conductive layer 42 on the second region 2132 covers the second region 2132 in the width direction Y of the electrode assembly 20. Establishing the relationship between the width K1 of the first conductive layer 41 and / or the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 and meeting the above range requirements can enable the conductive member 40 to effectively bind the electrode assembly 20 in the width direction Y and enhance the structural stability of the electrode assembly 20. In some embodiments, the width K1 of the first conductive layer 41 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - 2 * K1 ≤ 5 mm; and / or, the width K2 of the second conductive layer 42 and the width K3 of the electrode assembly 20 satisfy: 1 mm ≤ K3 - 2 * K2 ≤ 5 mm.

[0078] In some embodiments, referring to Figure 12 and Figure 15 , the thickness H of the conductive member 40 satisfies: 0 um < H ≤ 500 um. By setting the thickness of the conductive member 40 within the above range, the conductive member 40 can not only have good electrical conductivity but also effectively fix the electrode assembly 20, reduce the space occupied by the accommodation cavity 11 inside the housing 10, and improve the energy density of the secondary battery 100. Preferably, the thickness H of the conductive member 40 satisfies: 5 um ≤ H ≤ 30 um. Setting H ≥ 5 um can further improve the electrical conductivity of the conductive member 40; setting H ≤ 30 um can further improve the energy density of the secondary battery 100 while ensuring that the conductive member 40 has good electrical conductivity.

[0079] In some embodiments, the conductive member 40 can be a conductive coating, such as the above-mentioned conductive adhesive, that is, a conductive member 40 is formed by coating and curing a molten conductive material on the surface and side of the electrode assembly 20. In other embodiments, the conductive member 40 can also be a conductive tape, that is, a conductive member 40 is formed by directly pasting a solid thin film tape with electrical conductivity on the surface of the electrode assembly 20.

[0080] In some embodiments, the conductive member 40 includes a conductive agent and a binder; the conductive agent includes at least one of silver powder, copper powder, nickel powder, carbon black, and graphene; the binder includes at least one of epoxy resin, polyurethane, and acrylate. By mixing the conductive agent and the binder to form the conductive member 40, the conductive member 40 has both good adhesion performance and good electrical conductivity.

[0081] The present application also provides an embodiment of an electronic device. The electronic device includes a secondary battery 100, and the secondary battery 100 is used for storing and releasing electrical energy. For the structure and function of the secondary battery 100, reference may be made to the above embodiments, and details are not described herein again.

[0082] In the secondary battery 100 according to the embodiment of the present application, an empty foil area 213 is provided on the surface of the first sub-pole piece 211 of the first pole piece 21 away from the second pole piece 22, and the empty foil area 213 is in contact with the housing 10 to form an electrical connection. Compared with the structure using two adapter terminals in the prior art, the structure of the secondary battery 100 in the embodiment of the present application can improve the connection stability between the first sub-pole piece 211 and the housing 10. The contact area between the first area 2131 and the housing 10 is larger, reducing the impedance to lower the energy consumption. In addition, the first pole piece 21 is directly electrically connected to the housing 10 without the need to be connected through an adapter terminal, increasing the available space in the receiving cavity 11. The first pole piece 21 can increase the first extension portion 2142 to increase the space for coating the active material layer on the first pole piece 21, thereby improving the energy density of the secondary battery 100.

[0083] The above are only the embodiments of the present application, and do not limit the patent scope of the present application accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A secondary battery, characterized in that, Comprising: A housing having a receiving cavity; An electrode assembly including a first pole piece, a second pole piece, and a separator. The first pole piece and the second pole piece are alternately arranged in sequence. The separator is disposed between the adjacent first pole piece and the second pole piece. The first pole piece includes a first sub-pole piece. Along the thickness direction of the electrode assembly, the first sub-pole piece is located at the outermost side in the thickness direction of the electrode assembly, and an empty foil area is provided on the surface of the first sub-pole piece away from the second pole piece. The empty foil area is electrically connected to the housing; A conductive terminal, insulatedly disposed on the housing, and part of the conductive terminal extends out of the housing, and part of the conductive terminal is located in the receiving cavity. The second pole piece includes a tab, and the tab is electrically connected to the conductive terminal; Along the length direction of the electrode assembly, the first pole piece includes a first main body portion and a first extension portion. Along the thickness direction of the electrode assembly, the projection of the first extension portion does not overlap with the tab and the conductive terminal. The length direction of the electrode assembly is perpendicular to the thickness direction of the electrode assembly.

2. The secondary battery according to claim 1, wherein The first pole piece further includes at least one second sub-pole piece; The first sub-pole piece and the second sub-pole piece are independent of each other and are electrically connected after being stacked in the thickness direction of the electrode assembly, or the first pole piece is integrally formed and continuously folded to form the first sub-pole piece and the second sub-pole piece.

3. The secondary battery according to claim 1, wherein The surface of the first sub-pole piece away from the second pole piece is all the empty foil area.

4. The secondary battery according to claim 1, wherein The secondary battery includes a conductive adhesive, and the conductive adhesive is disposed between the empty foil area and the housing, and the conductive adhesive electrically connects the empty foil area and the housing.

5. The secondary battery according to claim 1, wherein A conductive protrusion is provided on the empty foil area, and the conductive protrusion electrically connects the empty foil area and the housing.

6. The secondary battery according to claim 1, wherein Along the length direction of the electrode assembly, the second pole piece further includes a second main body portion and a second extension portion, and the tab is connected to the second main body portion; Along the thickness direction of the electrode assembly, the projection of the first extension portion covers the projection of the second extension portion.

7. The secondary battery according to any one of claims 1-6, wherein The first pole piece includes two of the first sub-pole pieces. Along the thickness direction of the electrode assembly, the two first sub-pole pieces are respectively oppositely disposed at the two outermost sides in the thickness direction of the electrode assembly.

8. The secondary battery according to claim 7, wherein The empty foil area includes a first area and a second area. The first area is located on the surface of one of the first sub-pole pieces away from the second pole piece, and the second area is located on the surface of the other first sub-pole piece away from the second pole piece, so that the first area and the second area are respectively located at the two outermost sides in the thickness direction of the electrode assembly; The electrode assembly further includes a conductive member, which includes a first conductive layer and a second conductive layer. The first conductive layer is disposed between the first region and the housing and electrically connects the first region and the housing. The second conductive layer is disposed between the second region and the housing and electrically connects the second region and the housing.

9. The secondary battery according to claim 8, wherein the electrode assembly includes a first side portion, a second side portion, a third side portion, and a fourth side portion. The first side portion and the second side portion are oppositely disposed in the length direction of the electrode assembly, and the tab extends from the first side portion. The third side portion and the fourth side portion are oppositely disposed in the width direction of the electrode assembly. The width direction of the electrode assembly, the length direction of the electrode assembly, and the thickness direction of the electrode assembly are perpendicular to each other in pairs.

10. The secondary battery according to claim 9, wherein the conductive member is wound around the first region, the first side portion, and the second region along the length direction of the electrode assembly. The conductive member further includes a third conductive layer, and the third conductive layer is located at the first side portion and connects one of the first conductive layer and one of the second conductive layers respectively; and / or the conductive member is wound around the first region, the second side portion, and the second region along the length direction of the electrode assembly. The conductive member further includes a fourth conductive layer, and the fourth conductive layer is located at the second side portion and connects one of the first conductive layer and one of the second conductive layers respectively.

11. The secondary battery according to claim 10, wherein the length L1 of the first conductive layer satisfies: 0 mm < L1 ≤ 100 mm, and the width K1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - K1 ≤ 100 mm; and / or the length L2 of the second conductive layer satisfies: 0 mm < L2 ≤ 100 mm, and the width K2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - K2 ≤ 100 mm.

12. The secondary battery according to claim 11, wherein 1 mm ≤ L1 ≤ 5 mm, 1 mm ≤ K3 - K1 ≤ 3 mm; and / or 1 mm ≤ L2 ≤ 5 mm, 1 mm ≤ K3 - K2 ≤ 3 mm.

13. The secondary battery according to claim 9, wherein the conductive member is wound around the first region, the third side portion, and the second region along the width direction of the electrode assembly. The conductive member further includes a fifth conductive layer, and the fifth conductive layer is located at the third side portion and connects one of the first conductive layer and one of the second conductive layers respectively; and / or the conductive member is wound around the first region, the fourth side portion, and the second region along the width direction of the electrode assembly. The conductive member further includes a sixth conductive layer, and the sixth conductive layer is located at the fourth side portion and connects one of the first conductive layer and one of the second conductive layers respectively.

14. The secondary battery according to claim 13, wherein The length L1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - L1 ≤ 100 mm, and the width K1 of the first conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - 2*K1 ≤ 100 mm; and / or The length L2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - L2 ≤ 100 mm, and the width K2 of the second conductive layer and the width K3 of the electrode assembly satisfy: 0 mm ≤ K3 - 2*K2 ≤ 100 mm.

15. The secondary battery according to claim 14, wherein 1 mm ≤ K3 - L1 ≤ 10 mm, 1 mm ≤ K3 - 2*K1 ≤ 5 mm; and / or 1 mm ≤ K3 - L2 ≤ 10 mm, 1 mm ≤ K3 - 2*K2 ≤ 5 mm.

16. The secondary battery according to claim 8, wherein the conductive member includes a conductive agent and a binder; the conductive agent includes at least one of silver powder, copper powder, nickel powder, carbon black, and graphene; the binder includes at least one of epoxy resin, polyurethane, and acrylate.

17. The secondary battery according to claim 8, wherein the thickness H of the conductive member satisfies: 0 μm < H ≤ 500 μm.

18. The secondary battery according to claim 17, wherein the thickness H of the conductive member satisfies: 5 μm ≤ H ≤ 30 μm.

19. The secondary battery according to claim 1, wherein the first electrode sheet is an anode electrode sheet, and the second electrode sheet is a cathode electrode sheet.

20. An electronic device, characterized in that, including the secondary battery according to any one of claims 1-19.

Images