Secondary battery and electronic device

Abstract

A secondary battery and an electronic device. The secondary battery comprises an electrode assembly, a packaging pouch and an encapsulation film. The packaging pouch comprises a first packaging part and a second packaging part which are oppositely arranged in a first direction, wherein the first packaging part comprises a first area and a second area which are connected, and the second packaging part comprises a third area and a fourth area which are connected. The second area and the fourth area arranged in the first direction constitute a main body part for accommodating the electrode assembly. The second area and the fourth area arranged in the first direction constitute a main body part for accommodating the electrode assembly. In the first direction, the encapsulation film is arranged between the first area and the third area; and at least part of the first portion is connected to the first area to form a first encapsulation part, and at least part of the second portion is connected to the third area to form a second encapsulation part. The encapsulation film is recessed toward the electrode assembly to form a recess.

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, particularly soft-pack lithium batteries, are widely used in electric vehicles and consumer electronics due to their light weight, flexible form factors, high energy density, high output power, and long cycle life. Soft-pack lithium batteries use bags to enclose the electrode assembly and electrolyte, which are then sealed at the edges to create a seal. When the battery is subjected to impact, such as a drop, the seal may break, causing the bag to break and leak, impacting its lifespan and safety.

[0003] Summary of the Invention

[0004] One object of the present application is to provide a secondary battery that can reduce the risk of a sealing portion of a packaging bag being broken during a drop process.

[0005] In a first aspect, the present application provides a secondary battery comprising an electrode assembly, a packaging bag and a packaging film. The packaging bag comprises a first packaging portion and a second packaging portion arranged opposite to each other in a first direction, the first packaging portion comprising a first area and a second area connected thereto, and the second packaging portion comprising a third area and a fourth area connected thereto. The second area and the fourth area arranged along the first direction constitute a main body portion for accommodating the electrode assembly, and the first direction is the thickness direction of the electrode assembly. The packaging film comprises a first portion and a second portion connected thereto. In the first direction, the packaging film is arranged between the first area and the third area; at least a portion of the first portion is connected to the first area to form a first packaging portion, and at least a portion of the second portion is connected to the third area to form a second packaging portion. The packaging film is recessed toward the electrode assembly to form a recess.

[0006] In the secondary battery provided in the embodiment of the present application, the packaging bag and the packaging film are connected to form a first packaging part and a second packaging part, and the packaging film is formed with a recessed part located between the first packaging part and the second packaging part and exposed outside the secondary battery. When the secondary battery is subjected to impact such as falling and collision, the recessed part can open and deform, increasing the angle of the recessed part to absorb the impact load, reduce the risk of the first packaging part and the second packaging part being broken open, and improve the drop performance.

[0007] According to some embodiments of the present application, the secondary battery further includes a first metal plate, a second metal plate, a first insulating layer and a second insulating layer. The first metal plate is electrically connected to the electrode assembly and extends out of the packaging bag along 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 along the second direction. The first insulating layer covers the surface of the first metal plate and includes a first surface and a second surface opposite in the first direction, and the first surface is bonded to the first area. The second insulating layer covers the surface of the second metal plate and includes a third surface and a fourth surface opposite in the first direction, and the third surface is bonded to the third area. By arranging the first insulating layer / second insulating layer between the first metal plate / second and the packaging bag, the phenomenon of reduced airtightness of the packaging bag due to the configuration of the first metal plate and the second metal plate can be reduced, thereby improving the sealing performance.

[0008] According to some embodiments of the present application, when viewed along a first direction, the first metal plate overlaps with the first packaging portion, and the second metal plate overlaps with the second packaging portion. The first and second metal plates are separated by the first and second packaging portions, reducing the risk of a short circuit between the first and second metal plates. Furthermore, the first and second metal plates extend from the same side of the secondary battery, thereby increasing energy density.

[0009] According to some embodiments of the present application, the second surface of the first insulating layer is bonded to the first portion, and the fourth surface of the second insulating layer is bonded to the second portion.

[0010] According to some embodiments of the present application, the distance between the first metal plate and the second metal plate along a third direction perpendicular to the first and second directions is less than 1.5 mm. The first metal plate and the second metal plate extending from the same side of the secondary battery are isolated by the first packaging portion and the second packaging portion, so that even when the distance between the first metal plate and the second metal plate reaches the above range, the first metal plate and the second metal plate will not cause a short circuit due to the excessive distance. When the distance between the first metal plate and the second metal plate meets the above range, it is beneficial to reduce the width of the secondary battery in the third direction, broaden the application range of the secondary battery, meet the design requirements of narrow secondary batteries, and improve energy density.

[0011] According to some embodiments of the present application, in the first direction, the projection of the first insulating layer and the projection of the second insulating layer are located within the projection of the packaging film, so that the entire first metal plate and the entire second metal plate are completely isolated as a whole by the packaging film, reducing the risk of contact short circuit between the first metal plate and the second metal plate due to the small distance.

[0012] 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 aforementioned ranges, good sealing performance can be maintained. Furthermore, in the third direction, the entire first metal plate and the entire second metal plate are completely isolated by the first packaging portion and the second packaging portion, reducing the risk of short circuits between the first and second metal plates.

[0013] According to some embodiments of the present application, in the second direction, the packaging film and the electrode assembly do not overlap, thereby reducing the risk of the packaging film contacting the electrode assembly and causing wrinkles in the electrode piece.

[0014] According to some embodiments of the present application, in the second direction, the packaging film includes a third edge and a fourth edge disposed opposite each other, the third edge being closer to the electrode assembly than the fourth edge, and the first insulating layer includes a third end and a fourth end disposed opposite each other, the third end being closer to the electrode assembly than the fourth end; in the second direction, the third edge extends beyond the third end by a distance D1, and the fourth edge extends beyond the fourth end by a distance D2, with -1.5mm≤D1≤0.5mm, and -1.5mm≤D2≤0.5mm. When D1 and D2 are within the above ranges, good sealing performance can be maintained; and in the second direction, the entire first metal plate and the entire second metal plate are completely isolated by the first packaging portion and the second packaging portion, reducing the risk of short circuiting between the first and second metal plates.

[0015] According to some embodiments of the present application, in a third direction perpendicular to the first and second directions, the width of the packaging bag is W3, the width of the packaging film is W4, and W4≤W3, thereby reducing the occurrence of the phenomenon that the energy density is affected by the excessive width of the packaging film.

[0016] 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.

[0017] According to some embodiments of the present application, the packaging film includes a packaging layer, a metal layer, and a protective layer that are stacked, and the packaging film is connected to the first region and the third region through the packaging layer.

[0018] According to some embodiments of the present application, the encapsulation layer includes at least one of polypropylene, modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, or ethylene-ethyl acrylate copolymer.

[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, along a direction extending from the first portion to the second portion, the total length of the packaging film is L, the length of the first portion is L1, and 1 / 4≤L1 / L≤3 / 4.

[0021] According to some embodiments of the present application, the angle at which the recess is recessed toward the electrode assembly is α, satisfying 0°<α<180°.

[0022] 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

[0023] FIG1 is a view of a secondary battery provided in one embodiment of the present application viewed along a first direction.

[0024] FIG2 is a schematic diagram of a packaging bag before packaging provided in one embodiment of the present application.

[0025] FIG3 is a view of a secondary battery provided by one embodiment of the present application observed along a third direction.

[0026] FIG4 is a cross-sectional view of the secondary battery shown in FIG3 along line IV-IV.

[0027] FIG5 is a view of a secondary battery provided by another embodiment of the present application viewed along a first direction.

[0028] : Description of Main Component Symbols Secondary battery 100 Electrode assembly 10 Packaging bag 20 First metal plate 30 Second metal plate 40 First packaging portion 20a Second packaging portion 20b First region 20a1 Second region 20a2 Third region 20b1 Fourth region 20b2 Recess S1 Main body 21 Packaging portion 22 Packaging film 50 First portion 51 Second portion 52 First packaging portion 22a Second packaging portion 22b Third packaging portion 22c Recess 53 Packaging layer 201, 501 Metal layer 202, 502 Protective layer 203, 503 Extension direction R First insulating layer 60 Second insulating layer 70 First surface 61 Second surface 62 Third surface 71 Fourth surface 72 First edge 50a Second edge 50b Third edge 50c Fourth edge 50d Fifth edge 25 Sixth edge 26 Seventh edge 10a Eighth edge 10bFirst end 60a Second end 70a Third end 60b Fourth end 60c Fifth end 70b Sixth end 70c Seventh end 60d Eighth end 70d First side 30a Second side 30b Third side 40a Fourth side 40b First direction Z Second direction X Third direction Y

[0029] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] In addition, for the sake of brevity and clarity, the size or thickness of various components, layers may be exaggerated 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, 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.

[0033] Further, when describing embodiments of the present application, the use of “may” refers to “one or more embodiments of the present application.”

[0034] 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.

[0035] 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.

[0036] In the present application, the first direction Z refers to the thickness direction of the electrode assembly, the second direction X refers to the length direction of the electrode assembly, and the third direction Y refers to the width direction of the secondary battery.

[0037] Referring to Figure 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 in the packaging bag 20. The first metal plate 30 and the second metal plate 40 are respectively electrically connected to the electrode assembly 10 and extend out of the packaging bag 20 along the second direction X to connect to external components. In this embodiment, 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 X. In other embodiments, the first metal plate 30 and the second metal plate 40 may be located on different sides of the secondary battery 100 in the second direction X.

[0038] 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.

[0039] Referring to Figures 1 and 2, the packaging bag 20 includes a first packaging portion 20a and a second packaging portion 20b, which are arranged opposite each other in a first direction Z perpendicular to a second direction X. The first packaging portion 20a and the second packaging portion 20b are integrally formed and sealed to form the packaging bag 20. The first packaging portion 20a includes a first region 20a1 and a second region 20a2, which are interconnected. The third region 20a2 surrounds three sides of the second region 20a2. The second packaging portion 20b includes a third region 20b1 and a fourth region 20b2, which are interconnected. The third region 20b1 surrounds three sides of the fourth region 20b2. The second and fourth regions 20a2 and 20b2 are arranged along the first direction Z. The fourth region 20b2 is generally flat, with the second region 20a2 having a recess S1. The second and fourth regions 20a2 and 20b2 form a main body 21 for accommodating the electrode assembly 10. The first and third regions 20a1 and 20b1 are arranged along the first direction Z and form a sealing portion 22 that encapsulates the main body 21. In some embodiments, the first packaging portion 20 a and the second packaging portion 20 b are each independent and packaged to form a packaging bag 20 .

[0040] In some embodiments, bonding element A and element B means heating element A and element B to soften and melt them and bond them together.

[0041] Referring to Figures 1 and 3 , the secondary battery 100 further includes a packaging film 50 disposed between the first packaging portion 20a and the second packaging portion 20b. The packaging film 50 includes a first portion 51 and a second portion 52 connected to each other. The packaging portion 22 includes a first packaging portion 22a, a second packaging portion 22b, and a third packaging portion 22c. The first packaging portion 22a is formed by at least a portion of the first portion 51 connecting to the first region 20a1 of the first packaging portion 20a. The second packaging portion 22b is formed by at least a portion of the second portion 52 connecting to the third region 20b1 of the second packaging portion 20b. The third packaging portion 22c is formed by connecting portions of the first region 20a1 and the third region 20b1 that are separated from the packaging film 50. The first and second packaging portions 22a and 22b are located on the same side of the secondary battery 100. The packaging film 50 is recessed toward the electrode assembly 10 to form a recess 53. In this embodiment, the connected first and second portions 51 and 52 surround the recess 53. The recess 53 is located between the first packaging portion 22a and the second packaging portion 22b and is exposed outside the secondary battery 100. When the secondary battery 100 is subjected to impact such as a drop, the recess 53 can expand and deform, increasing the angle α of the recess 53 to absorb the impact load, reduce the risk of the packaging portion 22 being broken open, and improve drop resistance.

[0042] In some embodiments, the angle of the recess 53 toward the electrode assembly 10 is α, satisfying 0°≤α<180°. When the angle α is within the above range, the recess 53 is conducive to deformation when impacted, thereby improving drop performance.

[0043] 3 , along the extending direction R extending from the first portion 51 to the second portion 52 , the total length of the packaging film 50 is L, the length of the first portion 51 is L1 , and 1 / 4≤L1 / L≤3 / 4.

[0044] Please refer to Figures 3 and 4. The packaging bag 20 has a film stacking structure. Specifically, the packaging bag 20 includes 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 packaging layer 201 can be a polymer, such as polypropylene, polyamide, etc. The packaging layers 201 of the first packaging part 20a and the second packaging part 20b are connected to encapsulate the packaging bag 20. 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 protective layer 203 can be a polymer resin, which is used to protect the metal layer 202. In this embodiment, the packaging bag 20 is an aluminum-plastic film or a steel-plastic film.

[0045] The packaging film 50 has a stacked structure. Specifically, the packaging film 50 includes a packaging layer 501, a metal layer 502 and a protective layer 503 that are stacked. The packaging layer 501 is arranged close to the electrode assembly 10, and the protective layer 503 is arranged away from the electrode assembly 10 and exposed outside the secondary battery 100. The packaging layer 501 may include at least one of polypropylene, modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer. The packaging film 50 is connected to the packaging layer 201 of the first area 20a1 and the third area 20b1 through the packaging layer 501 for packaging. The material of the metal layer 505 can be aluminum, steel, etc., which is used to prevent moisture from penetrating the external environment and to increase the strength of the packaging film 50. The material of the protective layer 503 can be a polymer resin, which is used to protect the metal layer 505. In this embodiment, the packaging film 50 is an aluminum-plastic film or a steel-plastic film, which is beneficial to improving the weight density of the secondary battery.

[0046] Referring to Figure 3 , the first metal plate 30 extends through the first packaging portion 22a and out of the packaging bag 20, while the second metal plate 40 extends through the second packaging portion 22b and out of the packaging bag 20. When viewed along the first direction Z, the first metal plate 30 and the first packaging portion 22a overlap, and the second metal plate 40 and the second packaging portion 22b overlap. Referring to Figure 1 , when viewed along the first direction Z, the first metal plate 30 is positioned away from the second metal plate 40, and along a third direction Y perpendicular to the first direction Z and the second direction X, the distance between the first metal plate 30 and the second metal plate 40 is W6, where W4>W6 and W6<1.5 mm. In this application, the distance W6 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 that are spaced apart in the third direction Y. In other embodiments, the first metal plate 30 and the second metal plate 40 have overlapping portions when viewed along the first direction Z. In this case, the distance between the first metal plate 30 and the second metal plate 40 in the third direction Y is zero. The first metal plate 30 and the second metal plate 40 extending from the same side of the secondary battery 100 are separated by the first encapsulation portion 22a and the second encapsulation portion 22b. This reduces the risk of short circuits caused by contact between the first metal plate 30 and the second metal plate 40 due to excessive spacing, even when the distance between the first metal plate 30 and the second metal plate 40 falls within the aforementioned range. Furthermore, when the distance between the first metal plate 30 and the second metal plate 40 falls within the aforementioned range, the width of the secondary battery 100 in the third direction Y can be reduced, facilitating miniaturization.

[0047] Referring to Figures 1 and 3, 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, and the first metal plate 30 is connected to the packaging bag 20 through the first insulating layer 60. The second insulating layer 70 covers the surface of the second metal plate 40, and the second metal plate 40 is connected to the packaging bag 20 through the second insulating layer 70. Specifically, the first insulating layer 60 includes a first surface 61 and a second surface 62 opposite to each other in the first direction Z. The first surface 61 is connected to the first region 20a1, and the second surface 62 is connected to the first portion 51 of the packaging film 50 to seal the first packaging portion 22a. The second insulating layer 70 includes a third surface 71 and a fourth surface 72 opposite to each other in the first direction Z. The third surface 71 is connected to the third region, and the fourth surface 72 is connected to the second portion 52 of the packaging film 50 to seal the second packaging portion 22b. In other embodiments, the first metal plate 30 is disposed away from the first packaging portion 22a, and / or the second metal plate 40 is disposed away from the second packaging portion 22b, as viewed along the first direction Z. In such cases, the first surface 61 and the second surface 62 of the first insulating layer 60 are in contact with the first region 20a1 and the third region 20b1 of the packaging bag 20, respectively, and / or the third surface 71 and the fourth surface 72 of the second insulating layer 70 are in contact with the first region 20a1 and the third region 20b1 of the packaging bag 20, respectively, to seal the third packaging portion 22c.

[0048] The first insulating layer 60 and / or the second insulating layer 70 can include 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 bonded to the packaging layer 201 of the packaging bag 20 to ensure that the first insulating layer 60 is in contact with the first region 20a1 and / or the third region 20b1, and is bonded to the packaging layer 501 of the packaging film 50 to ensure that the first insulating layer 60 is in contact with the first portion 51. The second insulating layer 70 is bonded to the packaging layer 201 of the packaging bag 20 to ensure that the second insulating layer 70 is in contact with the first region 20a1 and / or the third region 20b1, and is bonded to the packaging layer 501 of the packaging film 50 to ensure that the second insulating layer 70 is in contact with the first portion 51. In other embodiments, the first insulating layer 60 or the second insulating layer 70 can be bonded to the packaging bag 20 and the packaging film 50 by bonding, for example, using an adhesive layer.

[0049] The first insulating layer 60 / second insulating layer 70 adheres more closely to the metal plate than the packaging bag 20 / encapsulation film 50. Because the metal plate undergoes only a brief heating and pressurization period during the packaging process, if the first insulating layer 60 / second insulating layer 70 is not placed between the packaging bag 20 / encapsulation film 50 and the metal plate, gaps may exist between the metal plate and the packaging bag 20 / encapsulation film 50, or there is a high probability of separation during the subsequent lifecycle, seriously affecting the sealing performance. Furthermore, the materials of the first insulating layer 60 / second insulating layer 70 and the packaging layer of the packaging bag 20 / encapsulation film 50 can both be polymers, which have similar melting points. This allows for better bonding under high-temperature and pressurized conditions, thus improving sealing performance.

[0050] Referring to Figure 1 , as viewed along the first direction Z, in the third direction Y, 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 Y, 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, with W1 ≥ 1 mm and W2 ≥ 1 mm. When W1 and W2 are within the above ranges, the first packaging portion 22a and the second packaging portion 22b maintain good sealing performance in the third direction Y. Furthermore, in the third direction, 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 circuits between the first and second metal plates 30, 40.

[0051] When viewed along the first direction Z, in the third direction Y, the width of the packaging bag 20 is W3, and the width of the packaging film 50 is W4, where W4 ≤ W3. When the width of the packaging film 50 is less than or equal to the width of the packaging bag 20, the energy density can be reduced due to the packaging film 50 being too wide.

[0052] As viewed along the first direction Z, in the third direction Y, the first insulating layer 60 further includes a seventh end 60d located opposite the first end 60a. The second insulating layer 70 further includes an eighth end 70d located opposite the second end 70a. The first metal plate 30 includes a first edge 30a located on the side of the first end 60a and a second edge 30b located on the side of the seventh end 60d. The second metal plate 40 includes a third edge 40a located on the side of the second end 70a and a fourth edge 40b located on the side of the eighth end 70d. In the third direction Y, the distance W5 by which the first end 60a extends beyond the first edge 30a is 0.05 mm ≤ W5 ≤ 2 mm. In some embodiments, in the third direction Y, the distance by which the seventh end 60d extends beyond the second edge 30b, the distance by which the second end 70a extends beyond the third edge 40a, and the distance by which the eighth end 70d extends beyond the fourth edge 40b are all within a range of 0.05 mm to 2 mm, thereby facilitating a balance between sealing reliability and energy density.

[0053] Please refer to Figure 1. When observed along the first direction Z, in the second direction X, the packaging film 50 includes a third edge 50c and a fourth edge 50d arranged opposite to each other, and 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 arranged opposite to each other, and the third end 60b is closer to the electrode assembly 10 than the fourth end 60c. The second insulating layer 70 includes a fifth end 70b and a sixth end 70c arranged opposite to each other, and the fifth end 70b is closer to the electrode assembly 10 than the sixth end 70c. In the second direction X, the third edge 50c extends beyond the third end 60b by a distance D1, the fourth edge 50d extends beyond the fourth end 60c by a distance D2, the third edge 50c extends beyond the fifth end 70b by a distance D3, and the fourth edge 50d extends beyond the sixth end 70c by a distance D4. The values ​​of -1.5 mm ≤ D1 ≤ 0.5 mm, -1.5 mm ≤ D2 ≤ 0.5 mm, -1.5 mm ≤ D3 ≤ 0.5 mm, and -1.5 mm ≤ D4 ≤ 0.5 mm are specified. When D1, D2, D3, and D4 are within the aforementioned ranges, the first and second packaging portions 22a and 22b maintain a good seal in the second direction X. Furthermore, in the second direction X, 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 circuits between the first and second metal plates 30 and 40.

[0054] When viewed along the first direction Z, in the second direction X, the packaging bag 20 includes a fifth edge 25 and a sixth edge 26 that are opposed to each other. The fifth edge 25 is farther from the electrode assembly 10 than the sixth edge 26. The first metal plate 30 and the second metal plate 40 are protruding from the fifth edge 25. In the second direction X, the fourth end 60c of the first insulating layer 60 extends beyond the fifth edge 25 by a distance D5, and the sixth end 70c of the second insulating layer 70 extends beyond the fifth edge 25 by a distance D6. The values ​​are 0.5 mm ≤ D5 ≤ 3 mm, and 0.5 mm ≤ D6 ≤ 3 mm.

[0055] In the second direction X, the electrode assembly 10 includes a seventh edge 10a and an eighth edge 10b that are relatively arranged. The seventh edge 10a is closer to the first insulating layer 60 than the eighth edge 10b. The distance from the third end 60b to the seventh edge 10a is D7, and the distance from the fifth end 70b to the seventh edge 10a is D8, -1mm≤D7≤2.5mm, -1mm≤D8≤2.5mm.

[0056] When viewed along the first direction Z, the packaging film 50 and the electrode assembly 10 do not overlap in the second direction X, thereby reducing the risk of wrinkles on the electrode sheet of the electrode assembly 10 due to contact with the packaging film 50 .

[0057] Please refer to Figure 1. In some embodiments, in the first direction Z, the projection of the first insulating layer 60 and the projection of the second insulating layer 70 are located within the projection of the packaging film 50, so that the entire first insulating layer 60 can be bonded to the first part 51 of the packaging film 50, and the entire second insulating layer 70 can be bonded to the second part 52 of the packaging film 50, thereby improving the sealing reliability of the first packaging part 22a and the second packaging part 22b; and 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.

[0058] 5 , in some embodiments, viewed along the first direction Z, the packaging film 50 is located between the first metal plate 30 and the second metal plate 40 , and the width of the packaging film 50 is less than or equal to the distance W6 between the first metal plate 30 and the second metal plate 40 .

[0059] In the secondary battery 100 provided in the present application, the packaging bag 20 and the packaging film 50 are connected to form a first packaging part 22a and a second packaging part 22b, and the packaging film 50 is formed with a recessed portion 53 located between the first packaging part 22a and the second packaging part 22b and exposed outside the secondary battery 100. When the secondary battery 100 is subjected to impact such as falling and collision, the recessed portion 53 can open and deform, increasing the angle α of the recessed portion 53 to absorb the impact load, reduce the risk of the first packaging part 22a and the second packaging part 22b being broken open, and improve the drop performance. In addition, the first metal plate 30 and the second metal plate 40 extend from the same side of the secondary battery 100 and are isolated by the first packaging portion 22a and the second packaging portion 22b, so that even when the distance between the first metal plate 30 and the second metal plate 40 is too small (less than 1.5 mm), the risk of contact short circuit between the first metal plate 30 and the second metal plate 40 can still be reduced; and when the distance between the first metal plate 30 and the second metal plate 40 is less than 1.5 mm, it is beneficial to reduce the width of the secondary battery 100 in the third direction Y, which is beneficial to miniaturization.

[0060] One embodiment of the present application further provides an electronic device comprising any of the above-described secondary batteries. The electronic device of the present application may include, but is not limited to, a laptop computer, a pen-type computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a power-assisted bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor.

[0061] 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 portion and a second packaging portion arranged opposite to each other in a first direction, wherein the first packaging portion comprises a first area and a second area connected to each other, and the second packaging portion comprises a third area and a fourth area connected to each other, wherein the second area and the fourth area arranged along the first direction constitute a main body for accommodating the electrode assembly, and the first direction is a thickness direction of the electrode assembly; and A packaging film comprises a first part and a second part connected to each other. In the first direction, the packaging film is arranged between the first area and the third area; at least part of the first part is connected to the first area to form a first packaging part, and at least part of the second part is connected to the third area to form a second packaging part; the packaging film is recessed toward the electrode assembly to form a recess.

2. The secondary battery according to claim 1, wherein: The secondary battery further comprises: a first metal plate, electrically connected to the electrode assembly and extending 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 along the second direction; a first insulating layer covering a surface of the first metal plate, the first insulating layer comprising a first surface and a second surface opposite to each other in the first direction, the first surface being bonded to the first region; and The second insulating layer covers the surface of the second metal plate, and the second insulating layer includes a third surface and a fourth surface opposite to each other in the first direction, and the third surface is bonded to the third region.

3. The secondary battery according to claim 2, characterized in that: Viewed along the first direction, the first metal plate and the first packaging portion have overlapping portions, and the second metal plate and the second packaging portion have overlapping portions.

4. The secondary battery according to claim 3, characterized in that: The second surface is bonded to the first portion, and the fourth surface is bonded to the second portion.

5. The secondary battery according to claim 3, characterized in that: Along a third direction perpendicular to the first direction and the second direction, a distance between the first metal plate and the second metal plate is less than 1.5 mm.

6. The secondary battery according to claim 5, characterized in that: In the first direction, a projection of the first insulating layer and a projection of the second insulating layer are located within a projection of the packaging film.

7. The secondary battery according to claim 5, characterized in that: 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.

8. The secondary battery according to claim 2, wherein: In the second direction, the packaging film does not overlap with the electrode assembly.

9. The secondary battery according to claim 8, characterized in that In the second direction, the packaging film includes a third edge and a fourth edge arranged opposite to each other, the third edge is closer to the electrode assembly than the fourth edge, and the first insulating layer includes a third end and a fourth end arranged opposite to each other, the third end is closer to the electrode assembly than the fourth end; in the second direction, the third edge exceeds the third end by a distance D1, and the fourth edge exceeds the fourth end by a distance D2, -1.5mm≤D1≤0.5mm, -1.5mm≤D2≤0.5mm.

10. The secondary battery according to claim 2, wherein: In a third direction perpendicular to the first direction and the second direction, the width of the packaging bag is W3, the width of the packaging film is W4, and W4≤W3.

11. The secondary battery according to claim 2, characterized in that: 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.

12. The secondary battery according to claim 1, wherein: The packaging film includes a packaging layer, a metal layer and a protective layer which are stacked, and the packaging film is connected to the first area and the third area through the packaging layer.

13. The secondary battery according to claim 12, characterized in that: The encapsulation layer includes at least one of polypropylene, modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer.

14. The secondary battery according to claim 12, wherein: The packaging bag is an aluminum-plastic film or a steel-plastic film.

15. The secondary battery according to claim 1, wherein: Along the direction extending from the first portion to the second portion, the total length of the packaging film is L, the length of the first portion is L1, and 1 / 4≤L1 / L≤3 / 4.

16. The secondary battery according to claim 1, wherein: The angle of the recessed portion toward the electrode assembly is α, and 0°<α<180°.

17. An electronic device, characterized in that: Comprising the secondary battery according to any one of claims 1 to 16.

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