Secondary battery and electric device

Abstract

The invention discloses a secondary battery and electric equipment. The secondary battery comprises a shell, an electrode assembly, a first tab bundle, a first adapter tab and a first bonding piece, the first tab bundle is accommodated in the shell, the first tab bundle is bent into a U shape, and the first tab bundle comprises a first part, a second part and a third part which are arranged in sequence. The first transfer tab comprises a first connecting part and a second connecting part, the first connecting part is connected with the first tab bundle, and the second connecting part is connected with the first connecting part; the second connecting portion has a first surface. The first adhesive layer is arranged on the first surface, the first adhesive layer extends in the direction that the second connecting part extends out of the shell, the first adhesive layer comprises a connecting part and an extending part which are arranged in sequence, and the connecting part adheres to the shell and the first adapter tab. The first adhesive adheres the extension and the electrode assembly. In the secondary battery, the possibility that the first tab bundle is torn can be reduced.

Description

Technical Field

[0001] This application belongs to the technical field of energy storage, and particularly relates to a secondary battery and an electrical device. Background Art

[0002] Currently, the ears of a multi-tab secondary battery are usually gathered into an ear bundle, and the ear bundle is connected to a transfer ear. The transfer ear extends out of the housing to facilitate the connection of the secondary battery to an external device. To reduce the occupation of the head space of the secondary battery by the ear bundle, the ear bundle is usually bent into a U shape, and the part of the transfer ear extending out of the housing is located on one side of the bending position of the ear bundle. For such a secondary battery, when it falls, the electrode assembly moves around in the housing, while the transfer ear is relatively stationary with respect to the housing, causing the ear bundle to be repeatedly pulled, and the ear bundle is prone to tearing, affecting the performance of the secondary battery. Summary of the Invention

[0003] In view of the above situation, it is necessary to provide a secondary battery that is conducive to reducing the possibility of the ear being torn.

[0004] In a first aspect of an embodiment of the present application, a secondary battery is provided. The secondary battery includes a housing, an electrode assembly, a first ear bundle, a first transfer ear, and a first bonding member. The housing is a packaging bag, and the electrode assembly is received in the housing. The first ear bundle is received in the housing. The first ear bundle includes a plurality of first ears, and all the plurality of first ears are electrically connected to the electrode assembly. The plurality of first ears are stacked to form the first ear bundle. The first ear bundle is bent into a U shape. The first ear bundle includes a first part, a second part, and a third part arranged in sequence. The first part is connected to the electrode assembly. The second part connects the first part and the third part. The first ear bundle is located on one side of the electrode assembly along a first direction, and the first direction is perpendicular to the thickness direction of the electrode assembly. The first transfer ear includes a first connection portion and a second connection portion. The first connection portion includes a first end. The second connection portion is connected to the first end. The first connection portion is connected to the third part. The second connection portion is connected to the first connection portion, and a part of the second connection portion extends out of the housing. The second connection portion and the second part are located on the same side of the electrode assembly along the thickness direction of the electrode assembly. The second connection portion has a first surface and a second surface oppositely arranged along its thickness direction. A first glue layer is provided on the first surface. The first glue layer includes a connecting portion and an extending portion connected to each other. The connecting portion bonds the housing and the first transfer ear and forms a sealing portion. The extending portion is located in the housing. Along the direction in which the second connection portion extends out of the housing, the length of the extending portion is L 1 , the first part has a third surface, the third surface faces the third part along the first direction, and along the first direction, the distance from the sealing portion to the third surface is A, L 1≥0.3 A; The bending point of the second part is the highest point of the second part in the thickness direction of the electrode assembly. The first adhesive secures the extension part and the electrode assembly. Along the direction in which the second connecting part extends out of the housing, the length of the overlapping part of the first adhesive and the extension part is L 2 , 0.5L 1 ≤L 2 ≤L 1 ; Along the direction perpendicular to the second connecting part extending out of the housing, the width of the extension part is W 1 , the width of the overlapping part of the first adhesive and the extension part is W 2 , 0.8W 1 ≤W 2 ≤W 1 .

[0005] In this secondary battery, by arranging the first adhesive to bond the electrode assembly and the first adhesive layer, and the first adhesive layer is in turn bonded to the housing, it is beneficial to improve the stability of the position of the electrode assembly relative to the housing. When the secondary battery drops, it is beneficial to reduce the amplitude of the electrode assembly moving relative to the housing. Thus, it is beneficial to reduce the degree of the first tab bundle being pulled, thereby reducing the possibility of the first tab bundle being torn. And, setting 0.5L 1 ≤L 2 ≤L 1 , 0.8W 1 ≤W 2 ≤W 1 , is beneficial to improve the bonding stability of the first adhesive and the first adhesive layer, reducing the possibility of the first adhesive being disconnected from the first adhesive layer due to being pulled by the electrode assembly, so as to facilitate the first adhesive to maintain the connection state of the first adhesive layer and the electrode assembly when the secondary battery drops.

[0006] In one or more embodiments of the present application, the length of the part of the first adhesive bonding the electrode assembly in the first direction is D, D≥2 mm. Setting D≥2 mm, the part of the first adhesive bonding the electrode assembly will not be too short, which is beneficial to improve the bonding stability of the first adhesive and the electrode assembly.

[0007] In one or more embodiments of the present application, the length of the electrode assembly in the first direction is L 3 , D≤0.5L 3 . Setting D≤0.5L 3 , the part of the first adhesive bonding the electrode assembly will not be too short, which is beneficial to save materials.

[0008] In one or more embodiments of the present application, along the first direction, the distance from the connecting part to the electrode assembly is L 4 , 1.5 mm≤L 4 ≤2 mm. Setting L 4≥1.5 mm. The distance from the connecting part to the electrode assembly is not too short, which is beneficial to leaving space for arranging the extending part between the connecting part and the electrode assembly; set L 4 ≤2 mm. The distance between the connecting part and the electrode assembly is not too large, which is beneficial to improving the energy density of the secondary battery.

[0009] In one or more embodiments of the present application, among the plurality of first tab ears, there is a first outer tab ear. The first outer tab ear and the first adhesive layer are on the same side of the electrode assembly along the thickness direction of the electrode assembly. The first outer tab ear includes a fourth surface, and the fourth surface is the surface of the first outer tab ear along its thickness direction. A part of the fourth surface faces the outside of the electrode assembly; the first adhesive is bonded to the fourth surface and the extending part. Bonding the first adhesive to the first outer tab ear is beneficial to reducing the possibility of the first outer tab ear being torn; and, bonding the first adhesive to the fourth surface is convenient for bonding.

[0010] In one or more embodiments of the present application, L 1 ≤A. Set L 1 ≤A. Along the direction in which the second connecting part extends out of the housing, the extending part of the first adhesive layer does not cross the third surface, which is beneficial to reducing the possibility that the first adhesive layer squeezes the first tab ear bundle when the electrode assembly moves, and thus is beneficial to reducing the possibility of the first tab ear being torn.

[0011] In one or more embodiments of the present application, along the thickness direction of the electrode assembly, the extending part and the electrode assembly overlap. In this way, it is beneficial to reducing the possibility that the first adhesive layer squeezes the first tab ear bundle when the electrode assembly moves, and thus is beneficial to reducing the possibility of the first tab ear being torn.

[0012] In one or more embodiments of the present application, the thickness of the first adhesive is T 1 , 11.2 μm ≤ T 1 . Set the thickness T of the first adhesive 1 ≥11.2 μm. The thickness of the first adhesive is not too thin, which is beneficial to reducing the possibility that the first adhesive is broken by the pulling of the electrode assembly.

[0013] In one or more embodiments of the present application, T 1 ≤20.8 μm. Set T 1 ≤20.8 μm. The thickness of the first adhesive is not too thick, which is beneficial to reducing the influence of the first adhesive on the thickness of the secondary battery.

[0014] In one or more embodiments of the present application, the secondary battery includes a second adhesive layer, and a part of the second adhesive layer is disposed on the second surface and connects the housing and the second connecting portion. Along the first direction, a part of the second adhesive layer is located between the housing and the first connecting portion. Thus, when the electrode assembly moves axially in the housing along the first direction, the second adhesive layer can provide buffering for the electrode assembly to reduce the possibility of damage to the electrode assembly.

[0015] In one or more embodiments of the present application, the first connecting portion is welded to the third part to form a welding mark. The secondary battery further includes a second bonding member, and the second bonding member is bonded to the first part. Along the direction in which the second connecting portion extends out of the housing, at least a part of the second bonding member is located between the first part and the third part. In the thickness direction of the third part, the second bonding member covers the welding mark. The provision of the second bonding member is beneficial to reducing the risk that the burrs formed during the welding process pierce the separator in the electrode assembly and reducing the risk of short circuit of the secondary battery.

[0016] In one or more embodiments of the present application, the thickness of the first adhesive layer is T 2 , 56μm ≤ T 2 ≤ 104μm. By setting T 2 ≥ 56μm, the thickness of the first adhesive layer is not too small, which is beneficial to improving the encapsulation strength of the first adhesive layer and further reducing the possibility of separation between the first adhesive layer and the housing; by setting T 2 ≤ 104μm, the thickness of the first adhesive layer is not too large, which is beneficial to reducing the influence of the setting of the first adhesive layer on the thickness of the secondary battery.

[0017] In one or more embodiments of the present application, the first bonding member includes a base material layer and an adhesive layer. The material of the base material layer includes one of polyethylene terephthalate, coextruded polypropylene, oriented polystyrene, thermoplastic polyurethane, polylactic acid, polyolefin, and polyimide; the adhesive layer is made of one or a combination of natural rubber, styrene-butadiene rubber, isoprene rubber, styrene-polybutadiene-styrene block copolymer, hydrogenated styrene-polybutadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-polyisoprene-styrene block copolymer, polyisobutene, amorphous α-olefin copolymer, petroleum resin, terpene resin, and rosin resin.

[0018] The second aspect of the present application provides an electrical device, and the electrical device includes the secondary battery as described in any one of the foregoing embodiments. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a secondary battery in an embodiment of the present application.

[0020] Figure 2 is Figure 1Schematic cross-sectional structure diagram at II-II.

[0021] Figure 3 It is a schematic cross-sectional structure diagram of a secondary battery in an embodiment of the present application.

[0022] Figure 4 It is a schematic partial structure diagram of a secondary battery in an embodiment of the present application.

[0023] Figure 5 It is a schematic cross-sectional structure diagram of a secondary battery in an embodiment of the present application.

[0024] Figure 6 It is a schematic cross-sectional structure diagram of a secondary battery in an embodiment of the present application.

[0025] Figure 7 It is Figure 1 Schematic cross-sectional structure diagram at IV-IV.

[0026] Figure 8 It is a schematic structure diagram of an electrical device in an embodiment of the present application.

[0027] Description of main component symbols 100, secondary battery; 10, housing; 11, sealing part; 20, electrode assembly; 21, positive electrode plate; 211, positive current collector; 212, positive active material layer; 22, negative electrode plate; 221, negative current collector; 222, negative active material layer; 23, separator; 31, first tab bundle; 3101, first tab; 31011, first outer tab; 31012, fourth surface; 311, first part; 3111, third surface; 312, second part; 313, third part; 32, second tab bundle; 3201, second tab; 41, first transfer tab; 411, first connection part; 4111, first end; 412, second connection part; 4121, first surface; 4122, second surface; 42, second transfer tab; 51, first adhesive layer; 511, connection part; 512, extension part; 52, second adhesive layer; 53, third adhesive layer; 61, first bonding member; 62, second bonding member; 63, third bonding member; 1000, electrical device; X, first direction.

[0028] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific embodiments

[0029] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0030] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be intervening elements. When an element is considered to be "disposed" on another element, it can be directly disposed on the other element or there may be intervening elements.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, "a plurality of" means more than two unless otherwise specifically defined.

[0033] In the description of the embodiments of this application, the term "vertical" is used to describe the ideal state between two components. In the actual production or use state, there may be a state approximately vertical between the two components. The two components described as "vertical" may not be absolutely straight lines or planes, and may also be approximately straight lines or planes. From a macroscopic perspective, as long as the overall extension direction is a straight line or a plane, the components can be considered "straight lines" or "planes".

[0034] Referring to "embodiments" herein means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Without conflict, the various embodiments in this application can be combined with each other.

[0035] A first aspect of an embodiment of the present application provides a secondary battery, which includes a housing, an electrode assembly, a first tab bundle, a first transfer tab, and a first adhesive member. The housing is a packaging bag, and the electrode assembly is received in the housing. The first tab bundle is received in the housing. The first tab bundle includes a plurality of first tabs, and all the plurality of first tabs are electrically connected to the electrode assembly. The plurality of first tabs are stacked to form the first tab bundle; the first tab bundle is bent into a U shape. The first tab bundle includes a first portion, a second portion, and a third portion arranged in sequence. The first portion is connected to the electrode assembly, the second portion connects the first portion and the third portion. The first tab bundle is located on one side of the electrode assembly along a first direction, and the first direction is perpendicular to the thickness direction of the electrode assembly. The first transfer tab includes a first connection portion and a second connection portion. The first connection portion includes a first end, and the second connection portion is connected to the first end. The first connection portion is connected to the third portion, the second connection portion is connected to the first connection portion, and a part of the second connection portion extends out of the housing; the second connection portion and the second portion are on the same side of the electrode assembly along the thickness direction of the electrode assembly; the second connection portion has a first surface and a second surface oppositely arranged along its thickness direction. The first adhesive layer is provided on the first surface. The first adhesive layer includes a connection portion and an extension portion connected to each other. The connection portion bonds the housing and the first transfer tab. The connection portion and the first transfer tab and the housing form a sealing portion by hot pressing. The extension portion is located in the housing. Along the direction in which the second connection portion extends out of the housing, the length of the extension portion is L 1 , the first portion has a third surface, and the third surface faces the third portion along the first direction. Along the first direction, the distance from the sealing portion to the third surface is A, L 1 ≥0.3A; the bending point of the second portion is the highest point of the second portion along the thickness direction of the electrode assembly. The first adhesive member bonds the extension portion and the electrode assembly. Along the direction in which the second connection portion extends out of the housing, the length of the part of the first adhesive member overlapping with the extension portion is L 2 , 0.5L 1 ≤L 2 ≤L 1 ; the width of the extension portion is W 1 , the width of the part of the first adhesive member overlapping with the extension portion is W 2 , 0.8W 1 ≤W 2 ≤W 1 .

[0036] In this secondary battery, by providing the first adhesive member to bond the electrode assembly and the first adhesive layer, and the first adhesive layer is bonded to the housing, it is beneficial to improve the stability of the position of the electrode assembly relative to the housing. When the secondary battery drops, it is beneficial to reduce the amplitude of the electrode assembly moving relative to the housing. Thus, it is beneficial to reduce the degree of the first tab bundle being pulled, thereby reducing the possibility of the first tab bundle being torn. And, setting 0.5L 1 ≤L 2 ≤L 1, 0.8W 1 ≤W 2 ≤W 1 , which is conducive to improving the bonding stability between the first bonding member and the first adhesive layer, reducing the possibility that the first bonding member is detached from the first adhesive layer due to the pulling of the electrode assembly, so as to facilitate the first bonding member to maintain the connection state between the first adhesive layer and the electrode assembly when the secondary battery drops.

[0037] The following will further illustrate the embodiments of the present application with reference to the accompanying drawings.

[0038] As Figure 1 and Figure 2 shown, an embodiment of the present application provides a secondary battery 100, including a housing 10 and an electrode assembly 20, and the electrode assembly 20 is received in the housing 10.

[0039] In some embodiments, the housing 10 is a flexible packaging bag, such as an aluminum-plastic film.

[0040] In some embodiments, as Figure 2 shown, the electrode assembly 20 includes a positive electrode sheet 21, a negative electrode sheet 22, and a separator 23 stacked, and the separator 23 is located between the positive electrode sheet 21 and the negative electrode sheet 22 to insulate the positive electrode sheet 21 and the negative electrode sheet 22.

[0041] In some embodiments, the positive electrode sheet 21, the separator 23, and the negative electrode sheet 22 are stacked and wound in sequence to form a wound structure.

[0042] In some embodiments, a plurality of positive electrode sheets 21, separators 23, and a plurality of negative electrode sheets 22 are alternately stacked to form a stacked structure.

[0043] In some embodiments, as Figure 2 shown, the positive electrode sheet 21 includes a positive electrode current collector 211 and a positive electrode active material layer 212 stacked.

[0044] In some embodiments, the positive electrode current collector 211 is a metal foil. As an exemplary example, the positive electrode current collector 211 may be a metal foil including at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil.

[0045] In some embodiments, the positive electrode current collector 211 is a composite current collector.

[0046] In some embodiments, the positive electrode active material layer 212 includes a positive electrode active material. As an exemplary example, the positive electrode active material includes at least one of lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganate.

[0047] In some embodiments, as Figure 2As shown, the negative electrode sheet 22 includes a negative electrode current collector 221 and a negative electrode active material layer 222 which are stacked.

[0048] In some embodiments, the negative electrode current collector 221 is a metal foil. As an exemplary example, the negative electrode current collector 221 may be a metal foil including at least one of copper, nickel, tantalum, and titanium, such as a copper foil.

[0049] In some embodiments, the negative electrode current collector 221 is a composite current collector.

[0050] In some embodiments, the negative electrode active material layer 222 includes a negative electrode active material. As an exemplary example, the negative electrode active material includes at least one of graphite, hard carbon, soft carbon, silicon, silicon oxide material, and silicon carbon material.

[0051] In some embodiments, the separator 23 is one of a polyethylene film, a polypropylene film, a polyester film, or a polyimide film.

[0052] In some embodiments, the secondary battery 100 includes an electrolyte, and the electrolyte is housed in the housing 10.

[0053] In some embodiments, the electrolyte includes an electrolyte salt. The electrolyte salt includes at least one of an organic lithium salt or an inorganic lithium salt.

[0054] In some embodiments, the electrolyte salt includes, but is not limited to, lithium hexafluorophosphate (LiPF 6 ), lithium bis(trifluoromethanesulfonyl)imide LiN(CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium hexafluorocesate (LiCsF 6 ), lithium perchlorate (LiClO 4 ), or lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) or at least one of them.

[0055] In some embodiments, as Figure 2 shown, the secondary battery 100 further includes a first tab bundle 31. The first tab bundle 31 is housed in the housing 10. The first tab bundle 31 includes a plurality of first tabs 3101. The plurality of first tabs 3101 are all electrically connected to the electrode assembly 20. The plurality of first tabs 3101 are stacked to form the first tab bundle 31.

[0056] In some embodiments, the first pole tab 3101 is formed by die-cutting the current collector of the pole piece. In the embodiments of the present application, to avoid conceptual confusion, the first pole tab 3101 is considered to be a structure different from the current collector after die-cutting.

[0057] In some embodiments, Figure 2 As shown, the first tab bundle 31 is bent into a U shape, and the first tab bundle 31 includes a first portion 311, a second portion 312, and a third portion 313 arranged in sequence, the first portion 311 is connected to the electrode assembly 20, the second portion 312 is connected to the first portion 311 and the third portion 313, and the first tab bundle 31 is located on one side of the electrode assembly 20 along the first direction X, and the first direction X is perpendicular to the thickness direction of the electrode assembly 20. In this way, it is beneficial to reduce the occupation of the head space of the secondary battery 100 by the first tab bundle 31. It should be noted that the U-shape is a description of the overall structure of the first pole tab bundle 31, and this shape is formed by the first pole tab bundle 31 undergoing bending during the preparation process. Specifically, during the preparation process of the secondary battery 100, a plurality of first pole tabs 3101 are arranged along the thickness direction of the electrode assembly 20, and the plurality of first pole tabs 3101 are gathered along the thickness direction of the electrode assembly 20 by a pressing tool so that the plurality of first pole tabs 3101 are stacked, and then the plurality of first pole tabs 3101 are connected (for example, welded) and then bent to obtain the U-shaped structure of the first pole tab bundle 31.

[0058] In some embodiments, Figure 2 As shown, the secondary battery 100 includes a first adapter tab 41, the first adapter tab 41 includes a first connection portion 411 and a second connection portion 412, the first connection portion 411 includes a first end 4111, the second connection portion 412 is connected to the first end 4111, the first connection portion 411 is connected to the first tab bundle 31, the second connection portion 412 is connected to the first connection portion 411, and part of the second connection portion 412 extends out of the shell 10; the second connection portion 412 and the second portion 312 are located on the same side of the electrode assembly 20 along the thickness direction of the electrode assembly 20. Here, the "same side" is determined by the center line of the electrode assembly 20. In other words, the second connection portion 412 and the second portion 312 are located on the same side of the center line of the electrode assembly 20. Figure 2 The position of the center line of the electrode assembly 20 is shown by a dot-dash line.

[0059] In some embodiments, Figure 2 and Figure 3As shown, the secondary battery 100 includes a first adhesive layer 51. The second connecting portion 412 has a first surface 4121 and a second surface 4122 that are oppositely disposed along its thickness direction, and the first adhesive layer 51 is disposed on the first surface 4121. The first adhesive layer 51 includes a connecting portion 511 and an extending portion 512 that are connected to each other. The connecting portion 511 bonds the housing 10 and the first transfer tab 41, and a sealing portion 11 is formed by hot pressing the connecting portion 411, the first transfer tab 41, and the housing 10. The extending portion 512 is located inside the housing 10, and along the direction in which the first transfer tab 41 extends out of the housing 10, the length of the extending portion 512 is L 1 , the first portion 311 has a third surface 3111, the third surface 3111 faces the third portion 313 along the first direction X, and along the first direction X, the distance from the sealing portion 11 to the third surface 3111 is A, L 1 ≥0.3A; the bending point of the second portion 312 is the highest point of the second portion 312 along the thickness direction of the electrode assembly 20. It should be noted that the connecting portion 511 and the extending portion 512 are different parts of the first adhesive layer 51. When distinguishing the connecting portion 511 and the extending portion 512, it is distinguished by whether it is connected to the housing 10. The part connected to the housing 10 is the connecting portion 511, and the part not connected to the housing 10 is the extending portion 512

[0060] In some embodiments, as Figure 2 shown, the secondary battery 100 further includes a second adhesive layer 52. The second adhesive layer 52 is bonded to the second surface 4122, the second adhesive layer 52 bonds the first adhesive layer 51, and the second adhesive layer 52 bonds the housing 10

[0061] In some embodiments, as Figure 2 shown, along the thickness direction of the second connecting portion 412, the second adhesive layer 52 overlaps with the connecting portion 511

[0062] In some embodiments, as Figures 2 to 4 shown, the secondary battery 100 includes a first bonding member 61. The first bonding member 61 bonds the extending portion 512 and the electrode assembly 20, and along the direction in which the second connecting portion 412 extends out of the housing 10, the length of the overlapping portion of the first bonding member 61 and the extending portion 512 is L 2 , 0.5L 1 ≤L 2 ≤L 1 . Along the direction perpendicular to the direction in which the second connecting portion 412 extends out of the housing 10, the width of the extending portion 512 is W 1 , the width of the overlapping portion of the first bonding member 61 and the extending portion 512 is W 2 , 0.8W 1 ≤W 2 ≤W 1 . Among them, L 1 、L 2 、W1 and W 2 can be obtained in the following way: by disassembling the secondary battery 100 to obtain the first adhesive layer 51 and the first bonding member 61, and after leveling treatment, measuring with a laser rangefinder.

[0063] In this secondary battery 100, by arranging the first bonding member 61 to bond the electrode assembly 20 and the first adhesive layer 51, and the first adhesive layer 51 is further bonded to the housing 10, it is beneficial to improve the stability of the position of the electrode assembly 20 relative to the housing 10. When the secondary battery 100 drops, it is beneficial to reduce the amplitude of the electrode assembly 20 moving relative to the housing 10. Thus, it is beneficial to reduce the degree of the first ear bundle 31 being pulled, thereby reducing the possibility of the first ear bundle 31 being torn. And, setting 0.5L 1 ≤L 2 ≤L 1 ,0.8W 1 ≤W 2 ≤W 1 ,is beneficial to improve the bonding stability of the first bonding member 61 and the first adhesive layer 51, reduce the possibility of the first bonding member 61 being pulled by the electrode assembly 20 and disconnecting from the first adhesive layer 51, so as to facilitate the first bonding member 61 to maintain the connection state of the first adhesive layer 51 and the electrode assembly 20 when the secondary battery 100 drops.

[0064] In some embodiments, the first bonding member 61 includes a base material layer and an adhesive layer.

[0065] In some embodiments, the material of the base material layer includes one of polyethylene terephthalate, coextruded polypropylene, oriented polystyrene, thermoplastic polyurethane, polylactic acid, polyolefin, polyimide.

[0066] In some embodiments, the adhesive layer is made of a combination of one or more of natural rubber, styrene-butadiene rubber, isoprene rubber, styrene-polybutadiene-styrene block copolymer, hydrogenated styrene-polybutadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-polyisoprene-styrene block copolymer, polyisobutylene, amorphous α-olefin copolymer, petroleum resin, terpene resin, rosin resin.

[0067] In some embodiments, as Figure 2 and Figure 3 shown, the length of the part of the first bonding member 61 bonding the electrode assembly 20 along the first direction X is D, and D≥2mm. Setting D≥2mm, the part of the first bonding member 61 bonding the electrode assembly 20 is not too short, which is beneficial to improve the bonding stability of the first bonding member 61 and the electrode assembly 20.

[0068] In some embodiments, as Figure 3As shown, the length of the electrode assembly 20 in the first direction X is L 3 , D ≤ 0.5L 3 . Setting D ≤ 0.5L 3 , the portion of the first bonding member 61 bonding the electrode assembly 20 will not be too short, which is beneficial to saving materials.

[0069] In some embodiments, such as Figure 2 and Figure 3 shown, the first tab bundle 31 is located on one side of the electrode assembly 20 in the first direction X, and the first direction X is perpendicular to the thickness direction of the electrode assembly 20. Along the first direction X, the distance from the connecting portion 511 to the electrode assembly 20 is L 4 , 1.5 mm ≤ L 4 ≤ 2 mm. Setting L 4 ≥ 1.5 mm, the distance from the connecting portion 511 to the electrode assembly 20 will not be too short, which is beneficial to leaving a space for arranging the extension portion 512 between the connecting portion 511 and the electrode assembly 20; setting L 4 ≤ 2 mm, the distance between the connecting portion 511 and the electrode assembly 20 will not be too large, which is beneficial to improving the energy density of the secondary battery 100.

[0070] In some embodiments, such as Figure 2 shown, among the plurality of first tabs 3101, there is a first outer tab 31011. The first outer tab 31011 and the first adhesive layer 51 are on the same side of the electrode assembly 20 along the thickness direction of the electrode assembly 20. The first outer tab 31011 includes a fourth surface 31012, and the fourth surface 31012 is the surface of the first outer tab 31011 along its thickness direction. A part of the fourth surface 31012 faces the outside of the electrode assembly 20; the first bonding member 61 is bonded to the fourth surface 31012 and the extension portion 512. When the electrode assembly 20 moves erratically, the first outer tab 31011 is subjected to a greater force and is more likely to be torn compared to other first tabs 3101. Bonding the first bonding member 61 to the first outer tab 31011 is beneficial to reducing the possibility of the first outer tab 31011 being torn; moreover, bonding the first bonding member 61 to the fourth surface 31012 facilitates bonding.

[0071] In some embodiments, L 1 ≤ A. Setting L 1 ≤ A, along the direction in which the second connecting portion 412 extends out of the housing 10, the extension portion 512 of the first adhesive layer 51 does not cross the third surface 3111, which is beneficial to reducing the possibility that the first adhesive layer 51 squeezes the first tab bundle 31 when the electrode assembly 20 moves erratically, and thus is beneficial to reducing the possibility of the first tab 3101 being torn.

[0072] In some embodiments, such as Figure 5As shown, along the thickness direction of the electrode assembly 20, the extending portion 512 overlaps with the electrode assembly 20. In this way, it is beneficial to reduce the possibility that the first adhesive layer 51 squeezes the first tab bundle 31 when the electrode assembly 20 moves erratically, thereby reducing the possibility of the first tab 3101 being torn.

[0073] In some embodiments, as Figure 3 shown, the thickness of the first bonding member 61 is T 1 , 11.2 μm ≤ T 1 . By setting the thickness T 1 of the first bonding member 61 to be ≥ 11.2 μm, the thickness of the first bonding member 61 is not too thin, which is beneficial to reducing the possibility of the first bonding member 61 being broken due to the pulling of the electrode assembly 20.

[0074] In some embodiments, T 1 ≤ 20.8 μm. By setting T 1 ≤ 20.8 μm, the thickness of the first bonding member 61 is not too thick, which is beneficial to reducing the influence of the first bonding member 61 on the thickness of the secondary battery 100.

[0075] In some embodiments, as Figure 6 shown, a part of the second adhesive layer 52 is disposed on the second surface 4122 and connects the housing 10 and the second connecting portion 412. Along the first direction X, a part of the second adhesive layer 52 is located between the housing 10 and the first connecting portion 411. In this way, when the electrode assembly 20 moves erratically in the housing 10 along the first direction X, the second adhesive layer 52 can provide buffering for the electrode assembly 20 to reduce the possibility of the electrode assembly 20 being damaged.

[0076] In some embodiments, as Figure 2 shown, the first connecting portion 411 is welded to the third part 313 to form a welding mark. The secondary battery 100 further includes a second bonding member 62. The second bonding member 62 is bonded to the first part 311. Along the direction in which the second connecting portion 412 extends out of the housing 10, at least a part of the second bonding member 62 is located between the first part 311 and the third part 313. In the thickness direction of the third part 313, the second bonding member 62 covers the welding mark. By providing the second bonding member 62, it is beneficial to reduce the risk that the burrs formed during the welding process pierce the separator 23 in the electrode assembly 20 and reduce the risk of the secondary battery 100 short-circuiting.

[0077] In some embodiments, as Figure 2 shown, the thickness of the first adhesive layer 51 is T 2 , 56 μm ≤ T 2 ≤ 104 μm. By setting T 2≥56 μm, the thickness of the first adhesive layer 51 is not too small, which is beneficial to improving the strength of the first adhesive layer 51, enhancing the encapsulation strength of the first adhesive layer 51, and thus reducing the possibility of separation between the first adhesive layer 51 and the housing 10; set T 2 ≤104 μm, the thickness of the first adhesive layer 51 is not too large, which is beneficial to reducing the influence of the setting of the first adhesive layer on the thickness of the secondary battery 100.

[0078] In some embodiments, such as Figure 7 shown, the secondary battery 100 includes a second tab bundle 32, the second tab bundle 32 is received in the housing 10, the second tab bundle 32 includes a plurality of second tabs 3201, and the plurality of second tabs 3201 are all electrically connected to the electrode assembly 20, and the plurality of second tabs 3201 are stacked to form the second tab bundle 32.

[0079] In some embodiments, such as Figure 7 shown, the secondary battery 100 includes a second transfer tab 42, the second transfer tab 42 is connected to the second tab bundle 32, and a part of the second transfer tab 42 extends out of the housing 10.

[0080] In some embodiments, such as Figure 7 shown, the secondary battery 100 includes a third adhesive layer 53 and a third bonding member 63, and the third bonding member 63 bonds the third adhesive layer 53 and the electrode assembly 20. The specific setting method of the third adhesive layer 53 and the third bonding member 63 can refer to the setting method of the first adhesive layer 51 and the first bonding member 61, which will not be elaborated here.

[0081] Such as Figure 8 shown, an embodiment of the present application further provides an electrical device 1000, and the secondary battery 100 includes the secondary battery 100 involved in any of the foregoing embodiments.

[0082] To verify the effects of the solutions in the embodiments of the present application, the inventors conducted the following experiments. The experiment included 13 experimental groups, specifically 4 comparative groups and 9 experimental groups, and each experimental group included 100 secondary batteries 100.

[0083] The preparation process of the secondary battery 100 in Example 1 included the following steps: (1) Preparation of the positive electrode sheet 21: The active material lithium cobalt oxide (LiCoO 2) Super P (conductive carbon black), CNT (carbon nanotube), and PVDF (polyvinylidene fluoride) are mixed in a weight ratio of 97.5:0.5:0.5:1.5. N-methylpyrrolidone (NMP) is added as a solvent to prepare a cathode active material with a solid content of 75 wt%, and the mixture is stirred evenly for later use. Aluminum foil with a thickness of 10 μm is used as the cathode current collector 211. The above active material is evenly coated on one side of the cathode current collector 211 using a slot coater, and then dried at 90 °C to obtain a cathode plate 21 with the cathode active material coated on one side. At this time, the thickness of the cathode active material layer 212 is 50 μm. Then, the above coating steps are repeated on the other side of the cathode current collector 211. Then, the coated cathode plate 21 is cold-pressed. After cold pressing, the thickness of the cathode active material layer 212 is 35 μm. The area of the cathode current collector 211 not covered by the cathode active material layer 212 is the cathode empty foil area, and multiple cathode tabs are obtained by die-cutting the cathode empty foil area.

[0084] (2) Preparation of the anode plate 22: Artificial graphite as the active material, Super P (conductive carbon black), SBR (styrene-butadiene rubber), and CMC (sodium carboxymethyl cellulose) are mixed in a weight ratio of 97:0.5:1.3:1.2. Deionized water is added as a solvent to prepare an anode active material with a weight percentage of 50 wt%, and the mixture is stirred evenly for later use. Copper foil with a thickness of 10 μm is used as the anode current collector 221. The above anode active material is evenly coated on one side of the anode current collector 221 using a slot coater, and then dried at 110 °C to obtain an anode plate 22 with the anode active material layer 222 coated on one side. At this time, the thickness of the anode active material layer 222 is 55 μm. Then, the above steps are repeated on the other side of the anode current collector 221 to obtain an anode plate 22 with the anode active material layer 222 coated on both sides. Then, the coated anode plate 22 is cold-pressed. After cold pressing, the thickness of the anode active material layer 222 is 45 μm. The area of the anode current collector 221 not covered by the anode active material layer 222 is the anode empty foil area, and multiple anode tabs are obtained by die-cutting the anode empty foil area.

[0085] (3) Preparation of the electrolyte: In a dry argon atmosphere, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are first mixed in a mass ratio of EC:EMC:DEC = 30:50:20 to form a basic organic solvent, and then lithium salt lithium hexafluorophosphate (LiPF 6 ) is added to the basic organic solvent and dissolved and mixed evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0086] (4) Preparation of the separator 23: A 7-μm-thick polyethylene porous polymer film is used as the separator 23.

[0087] (5) Preparation of the electrode assembly 20: The positive electrode sheet 21, the separator 23, and the negative electrode sheet 22 are stacked and then wound. A plurality of positive electrode sheets 21 are stacked in the thickness direction of the electrode assembly 20 to form a positive electrode tab bundle (in this embodiment, the positive electrode tab bundle is the first tab bundle 31), and a plurality of negative electrode sheets 22 are stacked in the thickness direction of the electrode assembly 20 to form a negative electrode tab bundle (equivalent to the second tab bundle 32). The positive transfer tab (equivalent to the first transfer tab 41) is welded to the positive electrode tab bundle, and the negative transfer tab (equivalent to the second transfer tab 42) is welded to the negative electrode tab bundle. During the welding process, both the positive electrode tab bundle and the negative electrode tab bundle are bent into a U shape. The positive transfer tab is adhered with a first adhesive layer 51 and a second adhesive layer 52, and the first adhesive member 61 is used to adhere the first adhesive layer 51 and the electrode assembly 20.

[0088] (6) Assembly of the secondary battery 100: The formed aluminum plastic film with a pit is placed in the assembly fixture with the pit surface facing up, and the electrode assembly 20 is placed in the pit and pressed tightly with an external force. Then, another formed aluminum plastic film with a pit is covered on the electrode assembly 20 with the pit surface facing down, and three edges of the two aluminum plastic films are heat-sealed by means of hot pressing. The unheat-sealed edge is the side where the positive transfer tab and the negative transfer tab extend out of the housing 10. Then, the electrolyte is injected through the unheat-sealed edge, and then the two aluminum plastic films and the first adhesive layer 51 and the second adhesive layer 52 are encapsulated. The part of the first adhesive layer 51 connected to the aluminum plastic film forms a connection part 511, and the part located inside the aluminum plastic film packaging bag is an extension part 512. Through processes such as standing, hot pressing formation, and shaping, the secondary battery 100 is obtained.

[0089] (7) In the obtained secondary battery 100, A = 2 mm, W 1 = 6 mm. Along the direction in which the second connection part 412 extends out of the housing 10, the distance from the connection part 511 to the electrode assembly 20 is 4.2 mm. The data related to the experiment of the secondary battery 100 in Example 1 are recorded in Table 1.

[0090] The preparation process of the secondary battery 100 in Comparative Example 1 is basically the same as that in Example 1, and the difference is that the first adhesive member 61 is not provided in the secondary battery 100 in Comparative Example 1.

[0091] The preparation processes of the secondary batteries 100 in Comparative Example 2, Comparative Example 3, and Examples 2 to 9 are basically the same as that in Example 1, and the difference is that some parameters are different. The relevant parameters are recorded in Table 1. It should be added that in Example 9, L 1 > 4.2 mm, and the first adhesive layer 51 and the electrode assembly 20 overlap in the thickness direction of the electrode assembly 20.

[0092] After the secondary batteries 100 in the experimental group are prepared, a drop test is carried out on each secondary battery 100 in the experimental group. The process of the drop test is as follows: Fix the secondary battery 100 in the drop test fixture with double-sided tape. Number the six faces of the fixture as 1, 2, 3, 4, 5, and 6 in sequence, and number the four corners of the fixture as C1, C2, C3, and C4 in sequence.

[0093] At 25 °C, place the fixture on a test bench 1.5 m high, and drop the secondary battery 100 in sequence according to the numbers from 1 to 6, and then drop the secondary battery 100 in sequence according to the numbers from C1 to C4. After completing the drop test, let it stand for 1 h. After disassembling the lithium-ion secondary battery 100, observe whether there are cracks in the tabs in the positive tab bundle and the negative tab bundle through SEM. The secondary battery 100 without cracks in the positive tab bundle and the negative tab bundle is regarded as passing the drop test. Count the number of secondary batteries 100 passing the drop test in each experimental group, and record the experimental results in Table 1.

[0094] Table 1 Note: In Table 1, " / " indicates no such data.

[0095] As can be seen from Table 1, compared with Comparative Examples 1 to 4, the passing rates of the secondary batteries 100 in Examples 1 to 6 in the drop test are higher. The reason is that compared with Comparative Example 1, the secondary batteries 100 in Examples 1 to 6 are provided with a first bonding member 61, which is beneficial to reducing the crosstalk amplitude of the electrode assembly 20 relative to the housing 10, thereby reducing the possibility of tearing of the positive tab bundle and the negative tab bundle; compared with Comparative Example 2, the secondary batteries 100 in Examples 1 to 6 satisfy L 1 ≥0.3A, and the length of the first adhesive layer 51 available for bonding the first bonding member 61 is longer. When the secondary battery 100 drops, the first bonding member 61 is not easily separated from the first adhesive layer 51, so it is more likely to take effect; compared with Comparative Examples 3 and 4, the secondary batteries 100 in Examples 1 to 6 satisfy 0.5L 1 ≤L 2 ≤L 1 and W 2 ≥0.5W 1 , the bonding between the first bonding member 61 and the first adhesive layer 51 is more stable. When the secondary battery 100 drops, the first bonding member 61 is not easily separated from the first adhesive layer 51, so it is more likely to take effect. It can be seen that setting L 1 ≥0.3A, 0.5L 1 ≤L 2 ≤L 1 and W 2 ≥0.5W 1, which is conducive to improving the bonding stability between the first bonding member 61 and the first adhesive layer 51, reducing the possibility that the first bonding member 61 is detached from the first adhesive layer 51 due to the pulling of the electrode assembly 20, so as to facilitate the first bonding member 61 to maintain the connection state between the first adhesive layer 51 and the electrode assembly 20 when the secondary battery 100 drops. And the first bonding member 61 can reduce the crosstalk amplitude of the electrode assembly 20 relative to the housing 10, thereby reducing the possibility of tearing of the positive electrode ear bundle and the negative electrode ear bundle.

[0096] In Embodiment 2 and Embodiment 3, the secondary battery 100 satisfies D≥2 mm. Compared with Embodiment 1, the passing rate of the secondary battery 100 in the drop test in Embodiment 2 and Embodiment 3 is higher. The reason is that the bonding length between the first bonding member 61 and the electrode assembly 20 in Embodiment 2 and Embodiment 3 is longer, and the bonding between the first bonding member 61 and the electrode assembly 20 is more stable. When the secondary battery 100 drops, the first bonding member 61 is not easily detached from the electrode assembly 20, so it is more likely to take effect. It can be seen that setting D≥2 mm makes the part of the first bonding member 61 bonding the electrode assembly 20 not too short, which is conducive to improving the bonding stability between the first bonding member 61 and the electrode assembly 20.

[0097] In Embodiment 3, Embodiment 5 and Embodiment 6, the secondary battery 100 satisfies T 1 ≥11.2 μm. Compared with Embodiment 4, the passing rate of the secondary battery 100 in the drop test in Embodiment 3, Embodiment 5 and Embodiment 6 is higher. It can be seen that setting the thickness T 1 of the first bonding member 61 ≥11.2 μm makes the thickness of the first bonding member 61 not too thin, which is conducive to reducing the possibility that the first bonding member 61 is broken due to the pulling of the electrode assembly 20. On this basis, setting T 1 ≤20.8 μm makes the thickness of the first bonding member 61 not too thick, which is conducive to reducing the influence of the first bonding member 61 on the thickness of the secondary battery 100.

[0098] In Embodiment 3 and Embodiment 7, the secondary battery 100 satisfies L 1 ≤A. Compared with Embodiment 8, the passing rate of the secondary battery 100 in the drop test in Embodiment 3 and Embodiment 7 is higher. It can be seen that setting L 1 ≤A, along the direction in which the second connecting portion 412 extends out of the housing 10, the extending portion 512 of the first adhesive layer 51 does not cross the third surface 3111, which is conducive to reducing the possibility that the first adhesive layer 51 squeezes the first pole ear bundle 31 when the electrode assembly 20 crosstalks, thereby being conducive to reducing the possibility that the first pole ear 3101 is torn.

[0099] In Embodiment 9, the secondary battery 100 satisfies that the extension portion 512 extends along the direction in which the second connection portion 412 extends out of the housing 10 and extends beyond the third surface 3111. Compared with Embodiment 8, the passing rate of the secondary battery 100 in the drop test in Embodiment 9 is higher. It can be seen that arranging the extension portion 512 to be stacked with the electrode assembly 20 is beneficial to reducing the possibility that the first adhesive layer 51 squeezes the first tab bundle 31 when the electrode assembly 20 moves out of place, thereby being beneficial to reducing the possibility that the first tab 3101 is torn.

[0100] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the substantial spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope of the disclosure of the present application.

Claims

1. A secondary battery, characterized in that: include: A shell, wherein the shell is a packaging bag; An electrode assembly, housed in the housing; A first pole tab bundle is accommodated in the shell, the first pole tab bundle includes a plurality of first pole tabs, the plurality of first pole tabs are electrically connected to the electrode assembly, and the plurality of first pole tabs are stacked to form the first pole tab bundle; the first pole tab bundle is bent into a U shape, the first pole tab bundle includes a first part, a second part and a third part which are arranged in sequence, the first part is connected to the electrode assembly, and the second part is connected to the first part and the third part; the first pole tab bundle is located at one side of the electrode assembly along a first direction, and the first direction is perpendicular to the thickness direction of the electrode assembly; a first adapter tab, the first adapter tab comprising a first connection portion and a second connection portion, the first connection portion comprising a first end, the second connection portion being connected to the first end, the first connection portion being connected to the third portion, and a portion of the second connection portion extending from the shell; the second connection portion and the second portion being located on the same side of the electrode assembly along the thickness direction of the electrode assembly; the second connection portion having a first surface and a second surface disposed opposite to each other along the thickness direction thereof; A first adhesive layer is provided on the first surface, the first adhesive layer comprises a connecting portion and an extending portion connected to each other, the connecting portion is bonded to the shell and the first transfer tab and forms a sealing portion, the extending portion is located in the shell, and extends out of the shell along the direction of the second connecting portion, the length of the extending portion is L1, the first part has a third surface, the third surface faces the third part along the first direction, and the distance from the sealing portion to the third surface along the first direction is A, L1≥0.3A; A first adhesive member, the first adhesive member bonds the extension portion and the electrode assembly, and along the direction in which the second connection portion extends out of the shell, the length of the portion in which the first adhesive member overlaps with the extension portion is L2, 0.5L1≤L2≤L1; along the direction perpendicular to the second connection portion extending out of the shell, the width of the extension portion is W1, and the width of the portion in which the first adhesive member overlaps with the extension portion is W2, 0.8W1≤W2≤W1.

2. The secondary battery according to claim 1, wherein: The length of the portion of the first adhesive member bonded to the electrode assembly along the first direction is D, and D≥2 mm.

3. The secondary battery according to claim 2, characterized in that: The length of the electrode assembly along the first direction is L3, D≤0.5L3.

4. The secondary battery according to claim 1, wherein: Along the first direction, the distance from the connecting portion to the electrode assembly is L4, 1.5 mm ≤ L4 ≤ 2 mm.

5. The secondary battery according to any one of claims 1 to 4, characterized in that: The plurality of first electrode tabs include a first outer electrode tab, wherein the first outer electrode tab and the first glue layer are located on the same side of the electrode assembly along the thickness direction of the electrode assembly; The first outer layer electrode tab includes a fourth surface, which is a surface of the first outer layer electrode tab along a thickness direction thereof; the first adhesive is bonded to the fourth surface and the extension portion.

6. The secondary battery according to claim 5, characterized in that: L1≤A.

7. The secondary battery according to claim 5, characterized in that: Along the thickness direction of the electrode assembly, the extension portion overlaps with the electrode assembly.

8. The secondary battery according to claim 5, characterized in that: The thickness of the first adhesive member is T1, 11.2 μm≤T1.

9. The secondary battery according to claim 8, characterized in that T1≤20.8μm.

10. The secondary battery according to claim 1, wherein: The secondary battery includes a second adhesive layer, part of which is disposed on the second surface and connects the shell and the second connection portion, and part of which is located between the shell and the first connection portion along the first direction.

11. The secondary battery according to claim 1, wherein The first connecting portion is welded to the third portion to form a weld mark; The secondary battery also includes a second adhesive, which is adhered to the first part and extends out of the shell along the second connecting portion. At least part of the second adhesive is located between the first part and the third part. In the thickness direction of the third part, the second adhesive covers the weld mark.

12. The secondary battery according to claim 1, wherein: The thickness of the first adhesive layer is T2, 56 μm≤T2≤104 μm.

13. The secondary battery according to claim 1, wherein: The first adhesive member includes a substrate layer and an adhesive layer; The material of the substrate layer includes one of polyethylene terephthalate, coextruded polypropylene, oriented polystyrene, thermoplastic polyurethane, polylactic acid, polyolefin, and polyimide; The adhesive layer is made of one or a combination of natural rubber, styrene-butadiene rubber, isoprene rubber, styrene-polybutadiene-styrene block copolymer, hydrogenated styrene-polybutadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-polyisoprene-styrene block copolymer, polyisobutylene, amorphous α-olefin copolymer, petroleum resin, terpene resin, and rosin resin.

14. An electrical device, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 13.

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