Secondary battery and electronic device

Abstract

A secondary battery and an electronic device. The secondary battery comprises a first packaging portion and a second packaging portion, the first packaging portion comprises a first area and a second area which are connected, and the second packaging portion comprises a third area and a fourth area which are connected. The second area and the fourth area form a main body portion for accommodating an electrode assembly. The first area is connected to the third area to form a packaging portion for packaging the main body portion. The packaging portion includes a first packaging portion and a second packaging portion. The distance between a first metal plate and a second metal plate is less than 1.5 mm. A first insulating layer covers the surface of the first metal plate and is connected to the first area. A second insulating layer covers the surface of the second metal plate and is connected to the third area. In a first direction, a packaging film is arranged between the first insulating layer and the second insulating layer. The packaging film comprises a first surface facing the first area and a second surface facing the third area, the first surface is bonded to the first insulating layer to form the first packaging portion, and the second surface is bonded to the second insulating layer to form the second packaging portion.

Description

Secondary batteries and electronic devices Technical Field

[0001] The present application relates to the technical field of soft-pack batteries, and in particular to a secondary battery and an electronic device including the secondary battery. Background Art

[0002] Secondary batteries, especially lithium-ion batteries, are widely used in electric vehicles and consumer electronics due to their high energy density, high output power, and long cycle life. As electronic products rapidly develop towards high integration and lightweight design, the demand for smaller batteries is also increasing.

[0003] Summary of the Invention

[0004] One object of the present application is to provide a secondary battery, wherein a first metal plate and a second metal plate extend from the same side and can meet the requirements of battery miniaturization.

[0005] In a first aspect, the present application provides a secondary battery comprising an electrode assembly, a packaging bag, a first metal plate, a second metal plate, a first insulating layer, a second insulating layer, and an encapsulating film. The packaging bag comprises a first and second packaging portions arranged opposite each other. The first packaging portion comprises a first and second interconnected region, and the second packaging portion comprises a third and fourth interconnected region. The second and fourth regions, arranged along a first direction, constitute a main body portion for accommodating the electrode assembly. The first and third regions are joined to form an encapsulating portion for encapsulating the main body portion. The encapsulating portion comprises a first and second encapsulating portion located on the same side of the secondary battery. The first direction is the thickness direction of the electrode assembly. The first metal plate is electrically connected to the electrode assembly and extends out of the packaging bag through the first encapsulating portion in a second direction perpendicular to the first direction. The second metal plate is electrically connected to the electrode assembly and extends out of the packaging bag through the second encapsulating portion in a second direction. In a third direction perpendicular to the first and second directions, the distance between the first and second metal plates is less than 1.5 mm. The first insulating layer covers the surface of the first metal plate and is in contact with the first region. The second insulating layer covers the surface of the second metal plate and is in contact with the third region. The encapsulating film is disposed between the first and second insulating layers in the first direction. The packaging film includes a first surface facing the first area and a second surface facing the third area. The first surface is bonded to the first insulating layer to form a first packaging portion, and the second surface is bonded to the second insulating layer to form a second packaging portion.

[0006] In the secondary battery provided by the present application, the first metal plate and the second metal plate extend from the same side of the secondary battery and are isolated by the packaging film provided between the first insulating layer and the second insulating layer. Even when the distance between the first metal plate and the second metal plate is less than 1.5 mm, the risk of contact short circuit caused by the small distance between the first metal plate and the second metal plate can still be reduced, which can broaden the application range of the secondary battery, meet the design requirements of narrow secondary batteries, and improve energy density. The packaging film is bonded to the first insulating layer and the second insulating layer, which is conducive to improving the packaging strength.

[0007] According to some embodiments of the present application, the first surface is bonded to the first area, and the second surface is bonded to the third area, which is beneficial to improving the packaging strength.

[0008] According to some embodiments of the present application, when viewed along the first direction, the first metal plate and the second metal plate have overlapping portions, which further reduces the width of the secondary battery and facilitates miniaturization.

[0009] According to some embodiments of the present application, in the third direction, the packaging film includes opposing first and second edges, the first insulating layer includes a first end located on one side of the first edge, and the second insulating layer includes a second end located on one side of the second edge. In the third direction, the first edge extends beyond the first end by a distance W1, and the second edge extends beyond the second end by a distance W2, where W1 ≥ 1 mm and W2 ≥ 1 mm. When W1 and W2 are within the above ranges, the entire first metal plate and the entire second metal plate are completely isolated by the packaging film in the third direction, reducing the risk of short circuits between the first and second metal plates.

[0010] According to some embodiments of the present application, in the second direction, the packaging film includes a third edge and a fourth edge arranged opposite to each other along the second direction, and in the second direction, the third edge is closer to the electrode assembly than the fourth edge; the first insulating layer includes a third end and a fourth end arranged opposite to each other along the second direction, and in the second direction, the third end is closer to the electrode assembly than the fourth end.

[0011] According to some embodiments of the present application, in the second direction, the distance L1 extending from the third edge to the third end, and the distance L2 extending from the fourth edge to the fourth end, are -1.5 mm ≤ L1 ≤ 0.5 mm, and -1.5 mm ≤ L2 ≤ 0.5 mm. When L1 and L2 are within the above ranges, in the second direction, the entire first metal plate and the entire second metal plate are isolated by the packaging film, reducing the risk of short circuits caused by contact between the first and second metal plates.

[0012] According to some embodiments of the present application, in the second direction, the packaging portion includes a fifth edge and a sixth edge disposed opposite each other in the second direction. In the second direction, the fifth edge is further away from the electrode assembly than the sixth edge. In the second direction, the fourth end extends beyond the fifth edge by a distance L3, where 0.05 mm ≤ L3 ≤ 2 mm. When L3 is within the aforementioned range, the first insulating layer is partially exposed outside the packaging bag, reducing the risk of the bag's edges being compressed during packaging and facilitating sealing. Furthermore, the shorter the exposed length of the first insulating layer, the less space it occupies, which is more conducive to improving energy density.

[0013] According to some embodiments of the present application, in the third direction, the first metal plate includes a fifth end and a sixth end opposite to each other, and the first insulating layer includes a first end located on one side of the fifth end and a seventh end located on one side of the sixth end; in the third direction, the first end extends beyond the fifth end by a distance W3, and the seventh end extends beyond the sixth end by a distance W4, 0.5mm≤W3≤3mm, and 0.5mm≤W4≤3mm.

[0014] According to some embodiments of the present application, in the second direction, the electrode assembly includes a seventh edge, and the seventh edge and the third end are located on the same side of the secondary battery in the second direction. In the second direction, the third end extends beyond the seventh edge by a distance L4, where -2.5mm≤L4≤1mm. When L4 is within the above range, the risk of wrinkling of the electrode sheet of the electrode assembly due to contact between the first insulating layer and the electrode assembly, or the risk of the first insulating layer covering the electrode sheet due to excessive contact between the first insulating layer and the electrode assembly, leading to lithium deposition, can be reduced.

[0015] According to some embodiments of the present application, in the second direction, the packaging film and the electrode assembly do not overlap, so as to reduce the risk of wrinkles on the electrode sheet of the electrode assembly due to contact with the packaging film.

[0016] According to some embodiments of the present application, the packaging film includes a first layer, a second layer, and a third layer that are stacked.

[0017] According to some embodiments of the present application, the first layer and the third layer each independently include at least one of polypropylene, modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer.

[0018] According to some embodiments of the present application, the second layer includes a metal layer.

[0019] According to some embodiments of the present application, the packaging bag is an aluminum-plastic film or a steel-plastic film.

[0020] According to some embodiments of the present application, the first insulating layer and the second insulating layer each independently include at least one of polyethylene, polypropylene, polyethylene terephthalate, phenolic resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin or polyurethane.

[0021] A second aspect of the present application provides an electronic device comprising the secondary battery of any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a view of a secondary battery provided in one embodiment of the present application viewed along a first direction.

[0023] FIG2 is a schematic diagram of a packaging bag before packaging provided in one embodiment of the present application.

[0024] FIG3 is a cross-sectional view of the secondary battery shown in FIG1 along line III-III.

[0025] FIG4 is a cross-sectional view of the secondary battery shown in FIG1 along line IV-IV.

[0026] FIG5 is a cross-sectional view of a secondary battery provided in another embodiment of the present application.

[0027] Description of main component symbols

[0028] Secondary battery 100

[0029] Electrode assembly 10

[0030] Packaging bag 20

[0031] First metal plate 30

[0032] Second metal plate 40

[0033] First packaging unit 20a

[0034] Second packaging unit 20b

[0035] District 1 20a1

[0036] Second District 20a2

[0037] District 3 20b1

[0038] District 4 20b2

[0039] pit S1

[0040] Main body 21

[0041] Packaging unit 22

[0042] Packaging film 50

[0043] Encapsulation layer 201

[0044] Metal layer 202

[0045] Protective layer 203

[0046] First insulating layer 60

[0047] Second insulating layer 70

[0048] First packaging portion 221

[0049] Second packaging portion 222

[0050] First side 51

[0051] Second side 52

[0052] 501 on the first floor

[0053] Second floor 502

[0054] 503 on the third floor

[0055] First edge 50a

[0056] Second edge 50b

[0057] The third edge 50c

[0058] Fourth edge 50d

[0059] Fifth edge 22a

[0060] Sixth edge 22b

[0061] Seventh edge 10a

[0062] First end 60a

[0063] Second end 70a

[0064] The third end 60b

[0065] Fourth end 60c

[0066] Fifth end 30a

[0067] Sixth end 30b

[0068] Seventh end 60d

[0069] Eighth end 70b

[0070] Ninth end 70c

[0071] Tenth end 40a

[0072] Eleventh end 40b

[0073] 12th end 70d

[0074] First direction Z

[0075] Second direction Y

[0076] The third direction X

[0077] The following specific implementation methods will further illustrate this application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the present application are described clearly and in detail below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0079] Below, embodiments of the present application will be described in detail. However, the present application may be embodied in many different forms and should not be construed as limited to the exemplary embodiments illustrated herein. Rather, these exemplary embodiments are provided to make the present application thorough and detailed for those skilled in the art.

[0080] In addition, for the sake of brevity and clarity, the size or thickness of various components, layers may be amplified in the accompanying drawings. Throughout the text, the same numerical value refers to the same element. As used herein, the terms "and / or" and "and / or" include any and all combinations of one or more related enumerated items. In addition, it should be understood that when element A is referred to as "connecting" element B, or when element A is referred to as "connecting" to element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.

[0081] Further, when describing embodiments of the present application, the use of “may” refers to “one or more embodiments of the present application.”

[0082] The technical terms used herein are for the purpose of describing specific embodiments and are not intended to limit this application. As used herein, the singular is intended to include the plural, unless the context clearly indicates otherwise. It should be further understood that the term "comprising", when used in this specification, refers to the presence of the described features, values, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, values, steps, operations, elements, components and / or combinations thereof.

[0083] It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part without departing from the teachings of the exemplary embodiments.

[0084] In the present application, the element A and the element B are welded together, which means that the element A and the element B are heated to soften and melt them and then adhere to each other.

[0085] In the present application, the first direction Z refers to the thickness direction of the electrode assembly, the second direction Y refers to the length direction of the electrode assembly, and the third direction X refers to the width direction of the electrode assembly.

[0086] Referring to FIG. 1 , one embodiment of the present application provides a secondary battery 100 comprising an electrode assembly 10, a packaging bag 20, a first metal plate 30, and a second metal plate 40. The electrode assembly 10 is housed within the packaging bag 20. The first metal plate 30 and the second metal plate 40 are each electrically connected to the electrode assembly 10 and extend outside the packaging bag 20 in a second direction Y for connection to external components. The first metal plate 30 and the second metal plate 40 are located on the same side of the secondary battery 100 in the second direction Y.

[0087] The electrode assembly 10 includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive and negative electrode sheets. The positive electrode sheet, separator, and negative electrode sheet can be stacked in sequence to form an electrode assembly 10 having a laminated structure. The positive electrode sheet, separator, and negative electrode sheet can also be stacked and then wound to form an electrode assembly 10 having a wound structure, although this application is not limited thereto.

[0088] Referring to Figures 1 to 3 , the packaging bag 20 includes a first packaging portion 20a and a second packaging portion 20b arranged opposite each other in a first direction Z perpendicular to a second direction Y. The first packaging portion 20a and the second packaging portion 20b are integrally arranged and sealed to form the packaging bag 20. The first packaging portion 20a includes a first region 20a1 and a second region 20a2 connected to each other. The three sides of the second region 20a2 are surrounded by the first region 20a1. The second packaging portion 20b includes a third region 20b1 and a fourth region 20b2 connected to each other. The three sides of the fourth region 20b2 are surrounded by the third region 20b1. The second region 20a2 and the fourth region 20b2 are arranged along the first direction Z. The fourth region 20b2 is generally flat. The second region 20a2 is provided with a recess S1 for accommodating the electrode assembly 10. The second region 20a2 and the fourth region 20b2 constitute the main body 21 that accommodates the electrode assembly 10. The first region 20 a 1 and the third region 20 b 1 are arranged along the first direction Z and connected to form a packaging portion 22 for packaging the main body portion 21 .

[0089] Please refer to Figure 4 as well. The packaging bag 20 has a film stacking structure. Specifically, the first packaging part 20a and the second packaging part 20b each include a stacked packaging layer 201, a metal layer 202 and a protective layer 203. The packaging layer 201 is arranged close to the electrode assembly 10, and the protective layer 203 is arranged away from the electrode assembly 10 and exposed outside the secondary battery 100. The material of the protective layer 203 can be a polymer resin, which is used to protect the metal layer 202. The material of the metal layer 202 can be aluminum, steel, etc., which is used to prevent moisture from the external environment from penetrating and to increase the strength of the packaging bag 20. The material of the packaging layer 201 can be a polymer, such as polypropylene, polyamide, etc. The packaging layers 201 located in the first area 20a1 and the third area 20b1 can be directly connected by hot melting to form the packaging part 22. In other embodiments, a fusible element is disposed between the encapsulation layer 201 in the first region 20a1 and the third region 20b1, allowing the encapsulation layer 201 in the first region 20a1 and the third region 20b1 to be indirectly connected by heat-melting to form the encapsulation portion 22. In another embodiment, the encapsulation layer 201 in the first region 20a1 and the third region 20b1 are connected by gluing to form the encapsulation portion. For example, an adhesive layer is disposed between the encapsulation layer 201 in the first region 20a1 and the third region 20b1, and the encapsulation layer 201 in the first region 20a1 and the third region 20b1 are bonded together. In this embodiment, the packaging bag 20 is an aluminum-plastic film or a steel-plastic film.

[0090] Referring to Figure 4 , the secondary battery 100 further includes a first insulating layer 60 and a second insulating layer 70. The first insulating layer 60 covers the surface of the first metal plate 30, with the first metal plate 30 in contact with the first region 20a1 of the packaging bag 20 through the first insulating layer 60. The second insulating layer 70 covers the surface of the second metal plate 40, with the second metal plate 40 in contact with the third region 20b1 of the packaging bag 20 through the second insulating layer 70. Specifically, the first insulating layer 60 is integrally provided and covers both surfaces of the first metal plate 30 facing the first region 20a1 and the third region 20b1. The portion of the first insulating layer 60 covering the surface of the first metal plate 30 facing the first region 20a1 is in contact with the first region 20a1. The second insulating layer 70 is integrally provided and covers both surfaces of the second metal plate 40 facing the first region 20a1 and the third region 20b1. The portion of the second insulating layer 70 covering the surface of the second metal plate 40 facing the third region 20b1 is in contact with the third region 20b1. In this embodiment, the first insulating layer 60 and the second insulating layer 70 are spaced apart in the first direction Z.

[0091] The first insulating layer 60 and / or the second insulating layer 70 can comprise at least one of polyethylene, polypropylene, polyethylene terephthalate, phenolic resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, or polyurethane. In this embodiment, the first insulating layer 60 is welded to the packaging layer 201 of the packaging bag 20 to achieve contact between the first insulating layer 60 and the first region 20a1; the second insulating layer 70 is welded to the packaging layer 201 of the packaging bag 20 to achieve contact between the second insulating layer 70 and the third region 20b1. In other embodiments, the first insulating layer 60 or the second insulating layer 70 can be bonded to the packaging bag 20 by gluing, for example, via an adhesive layer.

[0092] 1 and 4 , the packaging portion 22 includes a first packaging portion 221 and a second packaging portion 222. The first packaging portion 221 and the second packaging portion 222 are located on the same side of the secondary battery 100. The secondary battery 100 also includes a packaging film 50 disposed between the first insulating layer 60 and the second insulating layer 70 in the first direction Z. The packaging film 50 includes a first surface 51 facing the first area 20a1 and a second surface 52 facing the third area 20b1. The first packaging portion 221 is formed by welding the first surface 51 of the packaging film 50 to the first insulating layer 60. Specifically, the first surface 51 is bonded to the portion of the first insulating layer 60 covering the surface of the first metal plate 30 facing the third area 20b1. The second packaging portion 222 is formed by bonding the second surface 52 of the packaging film 50 to the second insulating layer 70. Specifically, the second surface 52 is connected to the portion of the second insulating layer 70 covering the surface of the second metal plate 40 facing the first area 20a1. The first metal plate 30 extends out of the packaging bag 20 through the first packaging portion 221. The second metal plate 40 extends through the second packaging portion 222 and out of the packaging bag 20. The first surface 51 of the packaging film 50 is also bonded to the first area 20a1, and the second surface 52 of the packaging film 50 is also bonded to the third area 20b1, which helps to improve the packaging strength.

[0093] Referring to Figure 4 , as viewed along the first direction Z, the first metal plate 30 and the second metal plate 40 are separated in a third direction X, which is perpendicular to the second direction Y and the first direction Z. The portion of the second surface 52 corresponding to the first metal plate 30 is in contact with the third region 20b1, and the portion of the first surface 51 corresponding to the second metal plate 40 is in contact with the first region 20a1. In the third direction X, the distance W5 between the first metal plate 30 and the second metal plate 40 is less than 1.5 mm. In this application, the distance W5 between the first metal plate 30 and the second metal plate 40 refers to the distance between two adjacent edges of the first metal plate 30 and the second metal plate 40, which are spaced apart in the third direction X. The spaced-apart first metal plate 30 and the second metal plate 40 are isolated by the bonded first area 20a1, the packaging film 50 and the third area 20b1, so that even when the distance between the first metal plate 30 and the second metal plate 40 reaches less than 1.5 mm, there will still be no contact short circuit between the first metal plate 30 and the second metal plate 40 due to the small distance, thus meeting the design requirements of the narrow secondary battery.

[0094] Referring to FIG. 5 , in another embodiment, when viewed along the first direction Z, the first metal plate 30 and the second metal plate 40 have overlapping portions. At least a portion of the second surface 52 corresponding to the first metal plate 30 is in contact with the second insulating layer 70, and at least a portion of the first surface 51 corresponding to the second metal plate 40 is in contact with the first insulating layer 60. In the third direction X, the distance between the first metal plate 30 and the second metal plate 40 is 0, further reducing the width of the secondary battery 100 in the third direction X, which is conducive to miniaturization. In this case, the first metal plate 30 and the second metal plate 40 are isolated by the packaging film 50, reducing the risk of short circuit between the first metal plate 30 and the second metal plate 40.

[0095] Referring to FIG. 4 , the packaging film 50 has a laminated film structure. Specifically, the packaging film 50 includes a first layer 501, a second layer 502, and a third layer 503, which are stacked. The first layer 501 is positioned adjacent to the first region 20a1 of the first packaging portion 20a. The surface of the first layer 501 facing away from the second layer 502 serves as the first surface 51 of the packaging film 50. The third layer 503 is positioned adjacent to the third region 20b1 of the second packaging portion 20b. The surface of the third layer 503 facing away from the second layer 502 serves as the second surface 52 of the packaging film 50. The packaging film 50 is bonded to the packaging layer 201 or the insulating layer via the first layer 501 or the second layer 502. The first layer 501 and / or the third layer 503 comprise at least one of polypropylene, modified polypropylene, polyethylene, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, or an ethylene-ethyl acrylate copolymer. The second layer 502 comprises a metal layer for supporting the first layer 501 and the third layer 503 and preventing moisture from penetrating the external environment. In this embodiment, the second layer 502 is a metal layer, and the metal layer can be made of aluminum, steel, etc. In other embodiments, the second layer 502 includes multiple metal layers and polymer layers sandwiched between adjacent metal layers. In one embodiment, the packaging film 50 is an aluminum-plastic film or a steel-plastic film.

[0096] Referring to Figure 1 , in the third direction X, the packaging film 50 includes opposing first and second edges 50a, 50b. The first insulating layer 60 includes a first end 60a located on one side of the first edge 50a, and the second insulating layer 70 includes a second end 70a located on one side of the second edge 50b. In the third direction X, the first edge 50a extends beyond the first end 60a by a distance W1, and the second edge 50b extends beyond the second end 70a by a distance W2, where W1 is ≥ 1 mm and W2 is ≥ 1 mm. When W1 and W2 are within the above ranges, the entire first metal plate 30 and the entire second metal plate 40 are completely isolated by the packaging film 50 in the third direction X, reducing the risk of short circuits between the first and second metal plates 30, 40.

[0097] Referring to Figure 1 , in the second direction Y, the packaging film 50 includes a third edge 50c and a fourth edge 50d disposed opposite each other. The third edge 50c is closer to the electrode assembly 10 than the fourth edge 50d. The first insulating layer 60 includes a third end 60b and a fourth end 60c disposed opposite each other. The third end 60b is closer to the electrode assembly 10 than the fourth end 60c. In the second direction Y, the third edge 50c extends beyond the third end 60b by a distance L1, and the fourth edge 50d extends beyond the fourth end 60c by a distance L2. The range is -1.5 mm ≤ L1 ≤ 0.5 mm, and -1.5 mm ≤ L2 ≤ 0.5 mm. In the second direction Y, the second insulating layer 70 includes an eighth end 70b and a ninth end 70c disposed opposite each other. The eighth end 70b is closer to the electrode assembly 10 than the ninth end 70c. In the second direction Y, the third edge 50c extends beyond the eighth end 70b by a distance L5, and the fourth edge 50d extends beyond the ninth end 70c by a distance L6, where -1.5 mm ≤ L5 ≤ 0.5 mm, and -1.5 mm ≤ L6 ≤ 0.5 mm. When L1 / L2 / L5 / L6 are less than 0, the orthographic projection of the edge of the first insulating layer 60 / second insulating layer 70 in the second direction Y along the first direction Z falls within the packaging film 50. When L1 / L2 / L5 / L6 are equal to 0, the edge of the first insulating layer 60 / second insulating layer 70 in the second direction Y is aligned with the edge of the packaging film 50 in the second direction Y. When L1 / L2 / L5 / L6 are greater than 0, the orthographic projection of the edge of the packaging film 50 in the second direction Y along the first direction Z falls within the first insulating layer 60 / second insulating layer 70. When L1, L2, L5, and L6 are within the above ranges, in the second direction Y, the entire first metal plate 30 and the entire second metal plate 40 are completely isolated by the packaging film 50, reducing the risk of short circuit between the first metal plate 30 and the second metal plate 40.

[0098] Referring to Figure 1 , in the second direction Y, the packaging portion 22 includes a fifth edge 22a and a sixth edge 22b disposed opposite each other. The fifth edge 22a is further away from the electrode assembly 10 than the sixth edge 22b. In the second direction Y, the fourth end 60c extends beyond the fifth edge 22a by a distance L3, where 0.05 mm ≤ L3 ≤ 2 mm. In the second direction Y, the ninth end 70c extends beyond the fifth edge 22a by a distance L7, where 0.05 mm ≤ L7 ≤ 2 mm. When L3 and L7 are within the aforementioned ranges, the first and second insulating layers 60 and 70 are partially exposed outside the packaging bag 20, reducing the risk of the edges of the packaging bag 20 being compressed during packaging and facilitating sealing. Furthermore, the shorter the exposed length of the first and second insulating layers 60 and 70, the less space they occupy, which is more conducive to improving energy density.

[0099] Referring to Figure 1 , in the third direction X, the first metal plate 30 includes opposing fifth and sixth ends 30a and 30b. The first insulating layer 60 includes a first end 60a located on the side of the fifth end 30a and a seventh end 60d located opposite the first end 60a and on the side of the sixth end 30b. In the third direction X, the first end 60a extends beyond the fifth end 30a by a distance W3, and the seventh end 60d extends beyond the sixth end 30b by a distance W4, with 0.5 mm ≤ W3 ≤ 3 mm, and 0.5 mm ≤ W4 ≤ 3 mm. The second metal plate 40 includes opposing tenth and eleventh ends 40a and 40b. The second insulating layer 70 includes a second end 70a located on the side of the tenth end 40a and a twelfth end 70d located opposite the second end 70a and on the side of the eleventh end 40b. In the third direction X, the second end 70a extends beyond the tenth end 40a by 0.5 to 3 mm, and the twelfth end 70d extends beyond the eleventh end 40b by 0.5 to 3 mm. When the distance between the edges of the metal plate and the insulating layer in the third direction X meets the above range, the packaging strength is improved.

[0100] Referring to Figure 1 , in the second direction Y, the electrode assembly 10 includes a seventh edge 10a proximal to the first insulating layer 60. The seventh edge 10a, the third end 60b, and the eighth end 70b are located on the same side of the secondary battery 100 in the second direction Y. In the second direction Y, the third end 60b extends beyond the seventh edge 10a by a distance L4, and the eighth end 70b extends beyond the seventh edge 10a by a distance L8, with -2.5 mm ≤ L4 ≤ 1 mm and -2.5 mm ≤ L8 ≤ 1 mm. When L4 / L8 is less than 0, the first insulating layer 60 / second insulating layer 70 and the electrode assembly 10 are separated in the second direction Y. When L4 / L8 is 0, the edges of the first insulating layer 60 / second insulating layer 70 and the electrode assembly 10 contact each other in the second direction Y. When L4 / L8 is greater than 0, the first insulating layer 60 / second insulating layer 70 and the electrode assembly 10 overlap when viewed along the first direction Z. When L4 / L8 is within the above range, the risk of wrinkles on the electrode sheet of the electrode assembly 10 due to contact between the first insulating layer 60 / the second insulating layer 70 and the electrode assembly 10, or the risk of the first insulating layer 60 / the second insulating layer 70 covering the electrode sheet due to excessive contact between the first insulating layer 60 / the second insulating layer 70 and the electrode assembly 10, leading to problems such as lithium deposition, can be reduced.

[0101] Referring to FIG. 1 , in the second direction Y, the packaging film 50 and the electrode assembly 10 do not overlap, so as to reduce the risk of wrinkles on the electrode sheet of the electrode assembly 10 due to contact with the packaging film 50 .

[0102] In the secondary battery 100 provided herein, the first metal plate 30 and the second metal plate 40 extend from the same side of the secondary battery 100 and are separated by an encapsulation film 50 disposed between the first insulating layer 60 and the second insulating layer 70. This ensures that when the distance between the first metal plate 30 and the second metal plate 40 is less than 1.5 mm, contact short circuits will not occur between the first metal plate 30 and the second metal plate 40, thus meeting the requirements of an ultra-narrow battery. Furthermore, the encapsulation film 50 is bonded to the first insulating layer 60 and the second insulating layer 70, thereby improving the encapsulation strength.

[0103] An embodiment of the present application further provides an electronic device comprising any of the above-mentioned secondary batteries. The electronic device of the present application may be, but is not limited to, a wearable electronic product, such as a watch, glasses, smart clothing, etc.

[0104] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A secondary battery comprising: Electrode assembly; A packaging bag, comprising a first packaging part and a second packaging part arranged opposite to each other, wherein the first packaging part comprises a first area and a second area connected to each other, and the second packaging part comprises a third area and a fourth area connected to each other, wherein the second area and the fourth area arranged along a first direction constitute a main body for accommodating the electrode assembly, the first area and the third area are connected to form a packaging part for packaging the main body, the packaging part comprises a first packaging part and a second packaging part located on the same side of the secondary battery, and the first direction is a thickness direction of the electrode assembly; a first metal plate, electrically connected to the electrode assembly and extending through the first packaging portion and out of the packaging bag along a second direction perpendicular to the first direction; a second metal plate, electrically connected to the electrode assembly and extending out of the packaging bag through the second packaging portion along the second direction, wherein a distance between the first metal plate and the second metal plate in a third direction perpendicular to the first direction and the second direction is less than 1.5 mm; a first insulating layer, covering a surface of the first metal plate and contacting the first region; a second insulating layer covering a surface of the second metal plate and connected to the third region; and A packaging film is arranged between the first insulating layer and the second insulating layer along the first direction, and the packaging film includes a first surface facing the first area and a second surface facing the third area, the first surface is bonded to the first insulating layer to form the first packaging part, and the second surface is bonded to the second insulating layer to form the second packaging part.

2. The secondary battery according to claim 1, wherein: The first surface is bonded to the first area, and the second surface is bonded to the third area.

3. The secondary battery according to claim 1, wherein: When viewed along the first direction, the first metal plate and the second metal plate have overlapping portions.

4. The secondary battery according to claim 1, wherein: In the third direction, the packaging film includes a first edge and a second edge opposite to each other, the first insulating layer includes a first end located on one side of the first edge, and the second insulating layer includes a second end located on one side of the second edge; in the third direction, the first edge extends beyond the first end by a distance W1, and the second edge extends beyond the second end by a distance W2, W1≥1mm, and W2≥1mm.

5. The secondary battery according to claim 1, wherein: The packaging film includes a third edge and a fourth edge arranged opposite to each other along the second direction, and in the second direction, the third edge is closer to the electrode assembly than the fourth edge; the first insulating layer includes a third end and a fourth end arranged opposite to each other along the second direction, and in the second direction, the third end is closer to the electrode assembly than the fourth end.

6. The secondary battery according to claim 5, characterized in that: In the second direction, the third edge exceeds the third end by a distance L1, the fourth edge exceeds the fourth end by a distance L2, and -1.5 mm ≤ L1 ≤ 0.5 mm, and -1.5 mm ≤ L2 ≤ 0.5 mm.

7. The secondary battery according to claim 5, characterized in that: The packaging portion includes a fifth edge and a sixth edge arranged opposite to each other in the second direction, and in the second direction, the fifth edge is farther away from the electrode assembly than the sixth edge; in the second direction, the fourth end exceeds the fifth edge by a distance L3, 0.05mm≤L3≤2mm.

8. The secondary battery according to claim 1, wherein: In the third direction, the first metal plate includes a fifth end and a sixth end opposite to each other, and the first insulating layer includes a first end located on one side of the fifth end and a seventh end located on one side of the sixth end; in the third direction, the first end extends beyond the fifth end by a distance W3, and the seventh end extends beyond the sixth end by a distance W4, 0.5mm≤W3≤3mm, 0.5mm≤W4≤3mm.

9. The secondary battery according to claim 5, characterized in that: The electrode assembly includes a seventh edge, and the seventh edge and the third end are located on the same side of the secondary battery in the second direction; in the second direction, the third end exceeds the seventh edge by a distance L4, -2.5mm≤L4≤1mm.

10. The secondary battery according to claim 1, wherein: In the second direction, the packaging film does not overlap with the electrode assembly.

11. The secondary battery according to claim 1, wherein The packaging film includes a first layer, a second layer and a third layer which are stacked.

12. The secondary battery according to claim 11, wherein: The first layer and the third layer each independently include at least one of polypropylene, modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer.

13. The secondary battery according to claim 11, wherein: The second layer includes a metal layer.

14. The secondary battery according to claim 1, wherein: The packaging bag is an aluminum-plastic film or a steel-plastic film.

15. The secondary battery according to claim 1, wherein: The first insulating layer and the second insulating layer each independently include at least one of polyethylene, polypropylene, polyethylene terephthalate, phenolic resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin or polyurethane.

16. An electronic device, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 15.

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