WO2025002220A1 - 二次电池及电子装置 - Google Patents

二次电池及电子装置 Download PDF

Info

Publication number
WO2025002220A1
WO2025002220A1 PCT/CN2024/101861 CN2024101861W WO2025002220A1 WO 2025002220 A1 WO2025002220 A1 WO 2025002220A1 CN 2024101861 W CN2024101861 W CN 2024101861W WO 2025002220 A1 WO2025002220 A1 WO 2025002220A1
Authority
WO
WIPO (PCT)
Prior art keywords
adhesive
section
secondary battery
sub
pole piece
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2024/101861
Other languages
English (en)
French (fr)
Other versions
WO2025002220A9 (zh
Inventor
谭康
唐徐情
黎胜
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to EP24830854.6A priority Critical patent/EP4738495A1/en
Publication of WO2025002220A1 publication Critical patent/WO2025002220A1/zh
Publication of WO2025002220A9 publication Critical patent/WO2025002220A9/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the embodiments of the present application relate to the field of electrochemical technology, and in particular to a secondary battery and an electronic device.
  • Lithium-ion batteries generally include a shell and an electrode assembly.
  • a commonly used method is to bond the electrode assembly to the shell with adhesive to reduce the relative movement between the electrode assembly and the shell, thereby reducing the collision failure of the electrode assembly and the shell.
  • the embodiments of the present application aim to provide a secondary battery and an electronic device to improve the problem of easy tearing of the outermost electrode sheet, thereby reducing the failure risk of the lithium-ion battery.
  • the present application proposes a secondary battery, including a housing, an electrode assembly, a first adhesive, and a second adhesive.
  • the electrode assembly is disposed in the housing, and the electrode assembly includes a first pole piece, a second pole piece, and a separator between the first pole piece and the second pole piece.
  • the first pole piece, the second pole piece, and the separator are stacked and wound, and the winding center axis direction of the electrode assembly is a first direction;
  • the first pole piece includes a first section, the first section constitutes the outermost part of the electrode assembly, and the first section has a first surface facing the winding center axis and a first surface facing away from the winding center axis.
  • the first section includes a tail section along the winding direction of the first section, and the first and second surfaces of the tail section are both empty foil areas.
  • the first adhesive is at least partially bonded to the first surface of the tail section.
  • the second adhesive is arranged on the second surface of the tail section and bonds the second surface of the tail section and the housing, and the second adhesive partially overlaps the first adhesive along a direction perpendicular to the first surface.
  • the first adhesive is at least partially bonded to the first surface of the tail section, which can improve the tensile strength of the tail section, thereby reducing the risk of the tail section tearing;
  • the second adhesive is arranged on the second surface of the tail section and bonds the tail section and the shell, thereby reducing the relative movement between the electrode assembly and the shell, and can again improve the tensile strength of the tail section, thereby further reducing the risk of the tail section tearing.
  • the projection of the second adhesive partially overlaps with the projection of the first adhesive, so that when the secondary battery falls or collides, part of the shear force on the second adhesive can be transmitted to the first adhesive, thereby reducing the shear force concentration, so as to further reduce the risk of the tail section tearing.
  • the portion of the second adhesive that overlaps the first adhesive is the first portion.
  • the projection of the first portion falls within the projection range of the first adhesive. The shear force transmission between the first adhesive and the second adhesive can effectively reduce the risk of tearing of the tail section.
  • the area of the first part is S1
  • the area of the second adhesive is S2, and 15% ⁇ S1/S2 ⁇ 50%.
  • Sufficient adhesive area of the second adhesive can improve the tensile strength of the tail section on the one hand, and ensure sufficient overlapping area between the second adhesive and the first adhesive for shear force transmission on the other hand, thereby reducing the risk of tail tearing.
  • the distance between the first adhesive and the end of the tail section is a first distance, and the first distance is greater than or equal to 2 mm.
  • the first distance is reserved so that the first adhesive can be fully bonded to the tail section, thereby effectively reducing the curling of the first adhesive.
  • the first section further includes a coating section connected to the finishing section.
  • one end of the first adhesive is bonded to the coating section, and the other end is bonded to the tail section, and the first adhesive covers the connection between the coating section and the tail section.
  • the length of the first adhesive is L1 mm
  • the length of the first section is L2 mm
  • the first direction is parallel to the winding center axis direction of the electrode assembly. It can reduce the puncture of the isolation film by protruding structures such as burrs, thereby reducing the risk of short circuits, and can reduce the powdering and shedding of the active material layer at the junction.
  • the first adhesive member includes a first sub-adhesive member and a second sub-adhesive member.
  • the first sub-adhesive member is disposed on the first surface.
  • the second sub-adhesive member is disposed on the first surface, and the second sub-adhesive member is bonded to the first sub-adhesive member at the end section.
  • the second sub-adhesive member is bonded to the second sub-adhesive member in a direction perpendicular to the first surface. The projection on the surface partially overlaps with the second adhesive member.
  • one end of the first sub-adhesive is bonded to the coating section, and the other end is bonded to the tail section, and the first sub-adhesive covers the connection between the coating section and the tail section.
  • the length of the first sub-adhesive is L3 mm
  • the length of the first section is L2 mm
  • the first sub-adhesive completely covers the junction in the first direction X to further reduce the puncture of the isolation film by protruding structures such as burrs, thereby reducing the risk of short circuits and reducing the powdering and shedding of the active material layer at the junction.
  • the first adhesive includes a plurality of second sub-adhesives.
  • the plurality of second sub-adhesives are arranged in sequence on the first surface along the winding direction of the first section, and two adjacent second sub-adhesives are bonded to each other.
  • the second sub-adhesive at the starting end of the arrangement is bonded to the first sub-adhesive on the ending section, and along the direction perpendicular to the first surface, the projection of the second sub-adhesive at the end of the arrangement partially overlaps with the projection of the second adhesive.
  • the structural arrangement of the plurality of sub-adhesives can further reduce the occurrence of bubbles during bonding, and can further reduce the concentration of shear force, thereby reducing the risk of tearing of the ending section.
  • the first adhesive member and the second adhesive member are adhesive tapes to facilitate the gluing process of the first adhesive member and the second adhesive member and improve production efficiency.
  • the first section includes a first straight section, a first curved section, a second straight section and a second curved section connected to each other.
  • the first straight section and the second straight section are arranged opposite to each other in the second direction
  • the first curved section and the second curved section are connected between the first straight section and the second straight section
  • the first curved section and the second curved section are arranged opposite to each other in the third direction.
  • the second adhesive component is partially arranged on the first straight section or the second straight section, and the first direction, the second direction and the third direction are mutually perpendicular.
  • the straight section is easier for the second adhesive component to be bonded to the tail, which can facilitate bonding and improve the bonding effect, thereby facilitating the improvement of the tensile strength of the first section and reducing the risk of tearing of the first section.
  • the peel strength between the isolation film and the first electrode sheet or the second electrode sheet is 8 N/m to 12 N/m, thereby effectively improving the bonding strength of the entire electrode assembly.
  • the first adhesive member is a single-sided adhesive having adhesiveness on only one side, and the single-sided adhesive comprises a first substrate layer and a first adhesive layer coated on one side of the first substrate layer.
  • the second adhesive member is a double-sided adhesive having adhesiveness on both sides
  • the double-sided adhesive comprises a second substrate layer and a second adhesive layer and/or hot melt adhesive layer coated on both sides of the second substrate layer.
  • the housing is a packaging bag.
  • the first electrode piece is a cathode electrode piece
  • the second electrode piece is an anode electrode piece
  • the first section is provided with an active material layer only on the first side, and the active material layer is provided on the first side of the coating section.
  • the second adhesive is used to fix the end section.
  • the second adhesive is used to fix the end section.
  • the present application further proposes an electronic device, comprising the secondary battery described in any one of the above embodiments.
  • FIG1 is an exploded view of a secondary battery according to some embodiments of the present application.
  • FIG2 is a schematic diagram of a winding structure of an electrode assembly according to some embodiments of the present application.
  • FIG3 a is a schematic diagram of a stacked structure of a first pole piece, an isolation film, and a second pole piece in some embodiments of the present application;
  • FIG3 b is a schematic diagram of the structure of an isolation membrane in some embodiments of the present application.
  • FIG4 is a schematic diagram of the bonding structure of the first section and the first adhesive member and the second adhesive member in some embodiments of the present application (viewed along the X direction);
  • FIG5a is a schematic diagram of the bonding structure of the first section and the first adhesive member and the second adhesive member in some embodiments of the present application (observed along the M direction);
  • FIG5 b is a schematic structural diagram of a first adhesive member and a second adhesive member in some embodiments of the present application;
  • FIG6 is a schematic diagram of the bonding structure of the first section and the first adhesive member and the second adhesive member in some embodiments of the present application (viewed along the X direction);
  • FIG. 7 is a schematic diagram of the bonding structure of the first section and the first adhesive member and the second adhesive member in some embodiments of the present application (viewed along the M direction);
  • FIG. 8 is a diagram showing a bonding structure of a first sub-adhesive member and a plurality of second sub-adhesive members in some embodiments of the present application. intention.
  • electrode assembly 20a, winding center; 21, first pole piece; 211, first current collector; 212, first active material layer; 213, first section; 213a, first surface; 213b, second surface; 2131, finishing section; 2132, coating section; 22, second pole piece; 221, second current collector; 222, second active material layer; 23, isolation film; 231, base layer; 232, ceramic bonding layer; 24, first straight section; 25, first curved section; 26, second straight section; 27, second curved section;
  • first adhesive member 30a, first substrate layer; 30b, first adhesive layer; 31, first sub-adhesive member; 32, second sub-adhesive member;
  • N winding direction
  • X first direction
  • Y second direction
  • Z third direction
  • M direction perpendicular to the first surface
  • the term "and/or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships.
  • a and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone.
  • the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.
  • the present application proposes a secondary battery 100, referring to FIG. 1 and FIG. 2, the secondary battery 100 comprises a housing 10, an electrode assembly 20, a first adhesive 30 and a second adhesive 40.
  • the electrode assembly 20 is accommodated in the housing 10, and the second adhesive 40 can be used to close the electrode assembly 20 to connect the electrode assembly 20 into a structurally stable whole; the second adhesive 40 can also be used to bond the electrode assembly 20 to the housing 10 to reduce the relative movement between the electrode assembly 20 and the housing 10.
  • the shell 10 encloses a containing cavity (not shown in the figure), and the containing cavity can accommodate the above-mentioned electrode assembly 20 and electrolyte (not shown in the figure).
  • the shell 10 can be a packaging bag, for example, the shell 10 can be a multi-layer composite film packaging bag including a metal layer.
  • the above-mentioned packaging bag can be an aluminum-plastic film packaging bag including a PP (polypropylene) layer and an aluminum layer, and a PP layer can be provided on both surfaces of the aluminum layer in the thickness direction to facilitate the insulation sealing of the packaging bag.
  • the shell 10 includes a first shell 11 and a second shell 12, and the first shell 11 and/or the second shell 12 are punched with a pit cavity (not shown in the figure), and the electrode assembly 20 can be arranged in the pit cavity, and then the first shell 11 and the second shell 12 are packaged by heat pressing to form a complete shell 10, wherein the above-mentioned pit cavity forms a accommodating cavity.
  • the electrode assembly 20 is disposed in the housing cavity of the housing 10.
  • the electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22 and a separator 23.
  • the first electrode sheet 21, the second electrode sheet 22 and the separator 23 are stacked and wound to form a wound electrode assembly 20.
  • the separator 23 is disposed between the first electrode sheet 21 and the second electrode sheet 22 to separate the two (FIG. 2 shows the winding structure of the electrode assembly 20).
  • the polarity of the first electrode sheet 21 and the second electrode sheet 22 are opposite, for example, the first electrode sheet 21 is a cathode electrode sheet and the second electrode sheet 22 is an anode electrode sheet; the first electrode sheet 21 includes a first current collector 211 and a first active material layer 212, and the first active material layer 212 is coated on at least one surface of the first current collector 211; the second electrode sheet 22 includes a second current collector 221 and a second active material layer 222, and the second active material layer 222 is coated on at least one surface of the first current collector 211.
  • the first pole piece 21 is an anode pole piece
  • the second pole piece 22 is a cathode pole piece.
  • the isolation film 23 of the electrode assembly 20 can be bonded between the first pole piece 21 and the second pole piece 22 so as to improve the overall bonding strength of the electrode assembly 20 and improve the flatness of the interface between the first pole piece 21 and the second pole piece 22, thereby reducing the risk of tail tearing and enhancing the cycle performance of the secondary battery.
  • the isolation film 23 includes a base layer and an adhesive layer 232 arranged on at least one surface of the base layer 231.
  • the adhesive layer 232 is arranged on both surfaces of the base layer 231 in the thickness direction.
  • the material of the base layer 231 includes one or more of high molecular weight polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyparaphenylene, polynaphthalene, polyimide, polyamide, aramid, polyparaphenylene benzodithiazole.
  • the material of the adhesive layer 232 may include at least one of polyvinylidene fluoride or vinyl-polysilsesquioxane.
  • the peel strength between the isolation film 23 and the first pole piece 21 or the second pole piece 22 is 8N/m to 12N/m, thereby effectively improving the overall bonding strength of the electrode assembly 20.
  • the peel strength can be controlled by the content of the adhesive in the adhesive layer 232. When the peel strength is too large, too much adhesive will block the pores on the surface of the first pole piece 21 and the second pole piece 22, causing problems such as lithium deposition black spots; while too little adhesive will result in low bonding strength of the electrode assembly 20 and low interface flatness between the first pole piece 21 and the second pole piece 22. When falling, the electrode assembly 20 is more likely to move between the shell 10, increasing the risk of tearing at the end.
  • the first pole piece 21 is a cathode pole piece
  • the second pole piece 22 is an anode pole piece
  • the electrode assembly 20 is a winding type.
  • the first pole piece 21 includes a first section 213, and the first section 213 constitutes the outermost part of the electrode assembly 20.
  • the first section 213 has a first surface 213a facing the winding center 20a of the electrode assembly 20 and a second surface 213b away from the winding center 20a.
  • the first section 213 has a tail section 2131
  • the tail section 2131 is also the winding end section of the first section 213.
  • the first surface 213a and the second surface 213b of the tail section 2131 are both empty foil areas, and the empty foil area in this embodiment is also the section without the active material layer coated.
  • the first surface 213a is the surface of the first active material layer 212 facing the winding center 20a; when the first current collector 211 is not coated with the first active material layer 212, the surface of the first current collector 211 facing the winding center 20a is the first surface 213a, and the same is true for the second surface 213b, and the same is true for the second pole piece 22.
  • the first section 213 further includes a coating section 2132 connected to the above-mentioned finishing section 2131, and the coating section 2132 is also the section of the first section 213 coated with the active material layer.
  • the first surface 213a of the first section 213 is provided with the first active material layer 212, and the first active material layer 212 is provided in the coating section.
  • the first side 213a of 2132 is the single-sided cathode plate used in the first section 213.
  • the outermost layer uses a single-sided cathode plate, and there is no corresponding anode plate outside the single-sided cathode plate, which can reduce one active material layer to improve the energy density of the secondary battery 100.
  • the first adhesive component 30 is at least partially bonded to the first surface 213a of the tail section 2131.
  • the first surface 213a of the tail section 2131 is a hollow foil area. The shear force exerted on the hollow foil area can be transmitted to the first adhesive component 30, thereby improving the tensile strength of the tail section 2131 and reducing the risk of tearing of the tail section 2131.
  • one end of the first adhesive 30 is bonded to the coating section 2132, that is, the first adhesive 30 is bonded to the first active material layer 212 of the coating section 2132, and the other end is bonded to the tail section 2131, and the first adhesive 30 covers the connection between the coating section 2132 and the tail section 2131.
  • the first active material layer 212 is coated on the first surface 213a, at the junction of the coating section 2132 and the tail section 2131, the first active material layer 212 is prone to have convex structures such as tailing burrs, which are prone to interfere with the isolation film 23 and cause the part of the first active material layer 212 to shed powder.
  • the probability of burrs and other convex structures piercing the isolation film 23 can be reduced, thereby reducing the risk of short circuits and reducing the powdering and shedding of the active material layer at the junction.
  • the first adhesive 30 can be used to completely cover the junction in the first direction X.
  • the length of the first adhesive 30 is L1 mm
  • the length of the first section 213 is L2 mm, 0 ⁇ L1-L2 ⁇ 3
  • the first direction X is parallel to the winding center axis direction of the electrode assembly 20, and the first adhesive 30 completely covers the junction in the first direction X, so as to further reduce the burrs and other protruding structures at the junction from piercing the separator 23 to cause a short circuit and reduce the powdering and shedding of the active material at the junction.
  • the distance between the first adhesive 30 and the end of the tail section 2131 is a first distance W, and the first distance W is greater than or equal to 2 mm, so as to reserve cutting space at the end of the first section 213.
  • first distance W is greater than or equal to 2 mm, so as to reserve cutting space at the end of the first section 213.
  • the above curling will affect the energy density of the secondary battery 100 and easily interfere with the isolation film 23.
  • reserving the first distance can make the first adhesive 30 fully bonded to the tail section 2131, thereby effectively reducing the curling of the first adhesive 30.
  • the first adhesive member 30 may be adhesive tape, and when in use, the adhesive tape may be directly bonded to the first surface 213a of the tail section 2131 and to the first active material layer 212 of the coating section 2132.
  • the first adhesive member 30 is a single-sided adhesive tape having adhesiveness on only one side, and the single-sided adhesive tape includes a first substrate layer 30a and a first adhesive layer 30b coated on one side of the first substrate layer 30a (see FIG. 5b ).
  • the first adhesive layer 30b may be directly bonded to the first active material layer 212 and the tail section 2131, and the shear force on the empty foil area of the tail section 2131 may be transferred to the single-sided adhesive tape, thereby reducing the tearing of the tail section 2131; and the single-sided adhesive tape directly covers the junction between the coating section 2132 and the tail section 2131, thereby reducing the piercing of the isolation film 23 by protruding structures such as burrs.
  • the material of the first substrate layer 30a includes at least one of polyethylene terephthalate (PET), polyimide or polypropylene.
  • PET polyethylene terephthalate
  • Polyethylene terephthalate has excellent physical and mechanical properties, and its long-term use temperature can reach 120°C. It has excellent electrical insulation. Even at high temperature and high frequency, its electrical properties are still good, and it has better creep resistance, fatigue resistance, friction resistance and dimensional stability.
  • the first adhesive member 30 made of polyethylene terephthalate can fully improve the tensile strength of the tail section 2131 to reduce the risk of tearing the tail section 2131.
  • the material of the first adhesive layer 30b includes at least one of polyacrylic acid (PAA), polymethyl methacrylate, polypropylene, polyethylene, polyamide, styrene-butadiene rubber, nitrile rubber, butadiene rubber, isoprene rubber, ethylene-propylene rubber or chloroprene rubber.
  • PAA polyacrylic acid
  • polymethyl methacrylate polypropylene
  • polyethylene polyethylene
  • polyamide polyamide
  • styrene-butadiene rubber nitrile rubber
  • butadiene rubber isoprene rubber
  • ethylene-propylene rubber or chloroprene rubber isoprene rubber.
  • the second adhesive 40 is bonded between the electrode assembly 20 and the shell 10.
  • the second adhesive 40 is arranged on the second surface 213b of the tail section 2131 to further improve the tensile strength of the tail section 2131; and the second adhesive 40 is bonded between the second surface 213b of the tail section 2131 and the shell 10, which can reduce the relative movement between the electrode assembly 20 and the shell 10.
  • the collision between the electrode assembly 20 and the shell 10 can be effectively reduced, thereby reducing the failure risk of the secondary battery 100.
  • the second adhesive member 40 may also be made of adhesive tape, for example, a double-sided adhesive tape having adhesiveness on both sides, the double-sided adhesive tape comprising a second substrate layer 41 and a second adhesive layer 42 and/or a hot melt adhesive layer coated on both sides of the second substrate layer 41.
  • the second adhesive member 40 is bonded to the electrode assembly 20 on one side and to the shell 10 on the other side, thereby reducing the relative movement between the electrode assembly 20 and the shell 10.
  • the material of the second substrate layer 41 includes one or more of polyester resin, cellulose derivatives, polyvinyl chloride, polyolefin, polystyrene, polyester, polyimide, polyamide, polycarbonate or polyphenylene sulfide, polyethylene terephthalate.
  • the material includes one or more of rubber resin, acrylic resin or silicone resin.
  • the second adhesive layer 42 is a hot melt adhesive layer
  • the material includes one or more of styrene-isoprene-styrene block copolymer, ethylene-vinyl acetate copolymer, polyurethane elastomer, polyurethane acrylate, polyisobutylene or polybutadiene.
  • the second adhesive 40 partially overlaps with the first adhesive 30; that is, along the direction M perpendicular to the first surface 213a, the projection of the second adhesive 40 partially overlaps with the projection of the first adhesive 30.
  • the second adhesive 40 adheres to the electrode assembly 20 and the shell 10, which can reduce the relative movement between the electrode assembly 20 and the shell 10, but the second adhesive 40 will be subjected to a large shear force, which can easily cause the end section 2131 adhered by the second adhesive 40 to tear.
  • the portion of the second adhesive 40 that overlaps with the projection of the first adhesive 30 is the first portion 40a, and along the direction M perpendicular to the first surface 213a, the projection of the first portion 40a falls within the projection range of the first adhesive 30.
  • the shear force transmission between the first adhesive 30 and the second adhesive 40 can effectively reduce the risk of tearing of the tail section 2131.
  • the area of the first portion 40a is S1
  • the area of the second adhesive member 40 is S2, and 15% ⁇ S1/S2 ⁇ 50%.
  • Sufficient adhesive area of the second adhesive member 40 can improve the tensile strength of the tail section 2131 on the one hand, and ensure sufficient overlapping area between the second adhesive member 40 and the first adhesive member 30 for shear force transmission, thereby reducing the risk of tail tearing.
  • the actual bonding area between the second adhesive member 40 and the first section 213 is S3
  • the effective bonding area between the second adhesive member 40 and the first section 213 is S4, where S3>S4. Sufficient actual bonding area can reduce the risk of the first section 213 being torn.
  • the first adhesive 30 includes a first sub-adhesive 31 and a second sub-adhesive 32.
  • the first sub-adhesive 31 is disposed on the first surface 213a
  • the second sub-adhesive 32 is also disposed on the first surface 213a
  • the second sub-adhesive 32 is bonded to the first sub-adhesive 31 at the end section 2131.
  • the length of the first adhesive 30 is too long (30 mm)
  • bubbles may appear when bonding the first section 213, which not only affects the energy density of the secondary battery 100, but also causes the first adhesive 30 to have a poor bonding effect, so that the second adhesive 40 and The shear force transmission effect between the first adhesive 30 is not obvious.
  • the first adhesive 30 as a two-way sub-adhesive structure, that is, the first adhesive 30 includes a first sub-adhesive 31 and a second sub-adhesive 32 that are bonded to each other, the first adhesive 30 and the second adhesive 40 are both relatively short, which can effectively reduce the occurrence of bubbles during the bonding process.
  • the projection of the second sub-adhesive 32 on the second surface 213b partially overlaps with the second adhesive 40, and all the shear force of the second adhesive 40 can be transmitted to the second sub-adhesive 32, and then to the first sub-adhesive 31, thereby reducing the shear force concentration.
  • the first sub-adhesive 31 is bonded to the coating section 2132, and the other end is bonded to the tail section 2131, and the first sub-adhesive 31 covers the connection between the coating section 2132 and the tail section 2131. Since a shorter first sub-adhesive 31 is used, the first sub-adhesive 31 can reduce bubbles in the bonding of the first sub-adhesive 31, and can cover the protruding structures such as the trailing burrs at the connection, which can reduce the piercing of the isolation film 23 by the protruding structures such as the burrs, thereby reducing the risk of short circuits, and can reduce the powdering and shedding of the active material layer at the junction.
  • the length of the first sub-adhesive member 31 is L3 mm
  • the length of the first section 213 is L2 mm
  • the first sub-adhesive member 31 completely covers the junction in the first direction X to further reduce the possibility of protruding structures such as burrs piercing the isolation film 23, thereby reducing the risk of short circuit.
  • the first adhesive component 30 may also be composed of a plurality of sub-adhesive components.
  • the first adhesive component 30 includes a plurality of second sub-adhesive components 32 .
  • a plurality of second sub-adhesives 32 are arranged in sequence on the first surface 213a along the winding direction N of the first section 213, and two adjacent second sub-adhesives 32 are bonded to each other.
  • the second sub-adhesive 32 at the beginning of the arrangement is bonded to the first sub-adhesive 31 on the end section 2131, and along the direction M perpendicular to the first surface 213a, the projection of the second sub-adhesive 32 at the end of the arrangement partially overlaps with the projection of the second adhesive 40.
  • the structural arrangement of the plurality of sub-adhesives can further reduce the occurrence of bubbles during bonding, and can further reduce the concentration of shear force, thereby reducing the risk of tearing of the end section 2131.
  • the length of the first sub-adhesive 31 is L4 mm, L4 ⁇ 30.
  • the length of the first sub-adhesive 31 is preferably less than 30 mm.
  • the second sub-adhesive 32 can also be configured in the same manner, that is, along the winding direction N of the first section 213, the length of the second sub-adhesive 32 is L5 mm, L5 ⁇ 30, thereby reducing the bubbles generated during bonding of the second sub-adhesive 32.
  • FIG. 2 shows the winding structure of the electrode assembly 20 .
  • the first section 213 includes The first straight section 24, the first curved section 25, the second straight section 26 and the second curved section 27 are connected.
  • the first straight section 24 and the second straight section 26 are arranged opposite to each other in the second direction Y
  • the first curved section 25 and the second curved section 27 are connected between the first straight section 24 and the second straight section 26, and the first curved section 25 and the second curved section 27 are arranged opposite to each other in the third direction Z.
  • the first section 213 is firstly wound to form the first curved section 25, then straightened to form the second straight section 26, the second straight section 26 is extended and wound to form the second curved section 27, and finally straightened to form the first straight section 24.
  • the second adhesive 40 is partially disposed on the first straight section 24 or partially disposed on the second straight section 26.
  • the second adhesive 40 may be partially bonded to the first straight section 24; or as shown in FIG2 , when the winding end of the first section 213 is close to the second straight section, the second adhesive 40 may be partially bonded to the second straight section 26.
  • Partially disposing the second adhesive 40 on the flat first straight section 24 or the second straight section 26 can facilitate bonding and improve the bonding effect, thereby facilitating the improvement of the tensile strength of the first section 213 and reducing the risk of tearing of the first section 213.
  • the thickness of the electrode assembly 20 when the thickness of the electrode assembly 20 is greater than or equal to 6.95 mm (the thickness of the electrode assembly 20 along the second direction Y in FIG. 2), the length of the first adhesive 30 should be greater than or equal to 30 mm (at this time, up to the first sub-adhesive 31 can be used).
  • the thickness of the electrode assembly 20 satisfies: L+H+W ⁇ 25 ⁇ 30 mm.
  • H is the length of the second active material layer 222 exceeding the first active material layer 212 along the winding direction N of the first section 213, that is, the dimension H in FIG. 2;
  • W is the distance between the first adhesive 30 and the end of the tail section 2131 (that is, the above-mentioned first distance W).
  • the first adhesive 30 is at least partially bonded to the first surface 213a of the tail section 2131, which can improve the tensile strength of the tail section 2131, thereby reducing the risk of tearing of the tail section 2131;
  • the second adhesive 40 is arranged on the second surface 213b of the tail section 2131 and bonds the tail section 2131 and the shell 10, thereby reducing the relative movement of the electrode assembly 20 and the shell 10, and can further improve the tensile strength of the tail section 2131, thereby further reducing the risk of tearing of the tail section 2131.
  • the projection of the second adhesive 40 partially overlaps with the projection of the first adhesive 30, so that when the secondary battery 100 falls or collides, part of the shear force on the second adhesive 40 can be transmitted to the first adhesive 30, thereby reducing the concentration of shear force, so as to further reduce the risk of tearing of the tail section 2131.
  • the positive electrode active material lithium cobalt oxide (LiCoO 2 ), the conductive agent conductive carbon black, and the binder polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1:1.5, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and stirred evenly.
  • NMP N-methylpyrrolidone
  • the slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 9 ⁇ m, and dried at 90°C to obtain a positive electrode sheet with a positive electrode active material layer thickness of 110 ⁇ m. After the above steps are completed, the single-sided coating of the positive electrode sheet is completed.
  • the above steps are repeated on the other surface of the positive electrode sheet to obtain a positive electrode sheet with a double-sided coating of the positive electrode active material layer.
  • the coating is completed, after cold pressing, cutting, and slitting, it is dried under vacuum conditions at 85°C for 4h to obtain a positive electrode sheet with a specification of 74mm ⁇ 867mm.
  • the negative electrode active material graphite powder, conductive agent conductive carbon black (Super P), and binder styrene butadiene rubber (SBR) are mixed in a weight ratio of 96:1.5:2.5, and then deionized water is added as a solvent to prepare a slurry with a solid content of 70wt%, and stirred evenly.
  • the slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 5 ⁇ m, and dried at 110°C to obtain a single-sided negative electrode sheet with a negative electrode active material layer thickness of 130 ⁇ m. After the above steps are completed, the single-sided coating of the negative electrode sheet has been completed.
  • the above steps are repeated on the other surface of the negative electrode sheet to obtain a negative electrode sheet with a double-sided coating of the negative electrode active material layer.
  • the coating is completed, after cold pressing, cutting, and slitting, it is dried under vacuum conditions at 120°C for 12h to obtain a negative electrode sheet with a specification of 76.6mm ⁇ 875mm.
  • Polyvinylidene fluoride (binder) and alumina ceramics were mixed in a mass ratio of 9:1, deionized water was added as a solvent, and a slurry with a solid content of 25wt% was prepared. The slurry was uniformly stirred. The slurry is evenly coated on one surface of a 5 ⁇ m thick polyethylene porous polymer film, dried, and then coated on the other surface of the polyethylene porous polymer film to obtain an isolation membrane coated with a 2 ⁇ m alumina ceramic layer on both sides.
  • organic solvents ethylene carbonate, ethyl methyl carbonate and diethyl carbonate were mixed at a mass ratio of 30:50:20 to obtain an organic solution, and then lithium salt lithium hexafluorophosphate (LiPF 6 ) was added to the organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol/L.
  • LiPF 6 lithium salt lithium hexafluorophosphate
  • Polyacrylic acid was coated on one surface of a first substrate layer of polyethylene terephthalate film (PET) having a thickness of 8 ⁇ m, and dried at 80° C. to form a first adhesive layer having a thickness of 4 ⁇ m, thereby obtaining a first adhesive member.
  • PET polyethylene terephthalate film
  • the styrene-isoprene-styrene block copolymer is heated to 150°C for hot melting, and then coated on one surface of a second substrate layer polyethylene terephthalate film (PET) with a thickness of 8 ⁇ m, and then dried at 120°C to form a second adhesive layer with a thickness of 8 ⁇ m.
  • PET polyethylene terephthalate film
  • Polyacrylic acid (PAA) was coated on the other surface of the second substrate layer and dried at 80°C to form a second adhesive layer with a thickness of 4 ⁇ m, thereby obtaining a second adhesive member including a second adhesive layer, a second substrate layer and a second adhesive layer stacked in sequence.
  • the positive electrode sheet, the separator, and the negative electrode sheet prepared above are stacked in order, the separator is placed between the positive electrode sheet and the negative electrode sheet to play a role of isolation, and they are wound to obtain a wound structure electrode assembly, wherein the outermost layer is the positive electrode sheet coated with an active material layer on one side, and the first adhesive member of modified polypropylene is used to bond The coated section and the empty foil section of the outermost positive electrode sheet.
  • the second adhesive member prepared above is pasted on the outer surface of the electrode assembly through the second adhesive layer, and then the electrode assembly is placed in an aluminum-plastic film packaging bag, and the first adhesive layer is adhered to the inner surface of the shell. Then, after the top and side sealing, vacuum drying, liquid injection, formation (temperature 85°C, pressure 1.05MPa, 3.5V), capacity, and exhaust, a lithium-ion battery is obtained.
  • the mass of the lithium-ion battery is 61.5g
  • the liquid retention coefficient is 1.75g/Ah.
  • the size of the first adhesive layer is 20mm ⁇ 30mm
  • L1-L2 3 mm.
  • the lithium-ion battery was pre-treated at 25°C, and after standing at room temperature for 60 minutes, the voltage of the lithium-ion battery before the drop test was tested; the lithium-ion battery was placed in a fixture, and the drop device was used to drop it freely from a position 1.5m above the ground in the following order: head-tail-head right corner-tail right corner-head left corner-tail left corner (angle: 45 ⁇ 15°), and repeated 6 rounds. After the drop, the battery cell was disassembled to observe whether the aluminum foil was torn.
  • the lithium-ion battery was pre-treated at 25°C, and after standing at room temperature for 60 minutes, the voltage of the lithium-ion battery before the drop test was tested; the lithium-ion battery was placed in a fixture and the drop device was used as follows The battery is dropped freely from a height of 1.5m above the ground in the following order: head-tail-right corner of head-right corner of tail-left corner of head-left corner of tail (angle: 45 ⁇ 15°), and repeated for 6 rounds. After the drop, the voltage of the lithium-ion battery is measured and recorded. The appearance of the lithium-ion battery is checked and photographed before and after the test. The pass criteria of the drop test: no smoke, no leakage, and voltage drop ⁇ 30mV.
  • a high-speed rail tensile machine is used to test the peel strength between the isolation membrane and the positive electrode sheet or the negative electrode sheet (the peel strength between the isolation membrane and the positive electrode sheet is tested as an example in the embodiment of the present application).
  • the test process is as follows: discharge the lithium-ion battery to 0V, then disassemble the lithium-ion battery, remove the isolation membrane and the electrode sheet bonded to it as a whole, and wipe the electrolyte on the surface with dust-free paper. Then cut into 20mm ⁇ 60mm strip specimens.
  • the side of the electrode assembly in the specimen is adhered to the steel plate with double-sided tape (Nitto 5000NS), and the adhesion length is not less than 40mm.
  • Fix the steel plate at the corresponding position of the high-speed rail tensile testing machine pull up the other end of the electrode that is not adhered to the diaphragm, and clamp the sample in the chuck, where the angle between the pulled-up sample part and the steel plate in space is 180°.
  • the chuck pulls the sample at a speed of 5 ⁇ 0.2mm/s, and the average tensile force in the stable area is finally measured and recorded as the peel strength between the isolation membrane and the electrode, recorded as F, in N/m.
  • the length of the first adhesive member in the width direction of the electrode piece should not be too large or too small. If it is too large, it will easily curl in the width direction of the electrode piece, enter the top seal area and affect the energy density of the lithium-ion battery. If it is too small, it will be difficult to cover the burrs on the edge of the active material layer, and it will easily pierce the diaphragm and cause a short circuit.
  • the first distance W ⁇ 2mm can better reduce the curling of the first adhesive in the length direction of the pole piece when it is cut.
  • the peel strength between the isolation membrane and the positive electrode piece is 7N/m, the bonding strength of the electrode assembly is not high, so that there is still a risk of aluminum foil tearing; in combination with Example 14, when the peel strength between the isolation membrane and the positive electrode piece is 13N/m, the peel strength is too large, and too much adhesive will clog the pores on the surface of the positive electrode piece and the negative electrode piece, causing problems such as lithium deposition black spots, thereby causing the lithium-ion battery to still have a risk of falling failure.
  • the preferred peel strength of the isolation membrane is 8N/m to 12N/m, and its falling aluminum foil tearing rate and falling failure risk are low.
  • the present application further proposes an electronic device, which includes the secondary battery described in any embodiment of the first aspect.
  • the electronic device can be a portable consumer electronic device, a power tool, a drone, a wearable electronic device, an electric car, etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Cell Separators (AREA)
  • Secondary Cells (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

本申请公开了一种二次电池及电子装置，包括壳体、电极组件、第一粘接件以及第二粘接件。电极组件设置于壳体内，电极组件包括层叠并卷绕设置的第一极片、隔离膜以及第二极片，第一极片包括第一段，第一段构成电极组件最外圈的部分，第一段具有朝向卷绕中心轴的第一面和背离卷绕中心轴的第二面；沿第一段的卷绕方向，第一段包括收尾段，收尾段的第一面与第二面为空箔区。第一粘接件至少部分第一粘接件粘接于收尾段的第一面。第二粘接件设置于收尾段的第二面并粘接收尾段的第二面与壳体，沿垂直于第一面的方向，第二粘接件的投影与第一粘接件的投影部分重叠。本申请的二次电池，其跌落或碰撞失效风险降低。

Description

二次电池及电子装置
相关申请的交叉参考
本申请要求于2023年6月30日提交中国专利局，申请号为202310796380.3，发明名称为“二次电池及电子装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及电化学技术领域，尤其涉及一种二次电池及电子装置。
背景技术
随着科技的发展，手机、笔记本电脑等消费类电子产品深受广大群众青睐，而二次电池(锂离子电池)作为电子产品的核心部件，凭借高工作电压和长使用寿命等优势，成为决定电子产品发展的重要部件。
锂离子电池通常包括壳体以及电极组件，为了降低锂离子电池的跌落失效风险，目前普遍采用的方法是将电极组件与壳体通过粘胶粘接起来，以减少电极组件与壳体的相对运动，从而减少电极组件与壳体的碰撞失效。
然而，对于电极组件的最外层极片而言，覆盖粘胶与不覆盖粘胶的交界处仍存在极片撕裂风险；并且，对于粘胶收尾的情况，极片的收尾处仍处于半束缚状态，在锂离子电池跌落时，易导致极片撕裂，以致于锂离子电池失效。
发明内容
本申请实施例旨在提供一种二次电池及电子装置，以改善最外层极片易撕裂的问题，从而降低锂离子电池的失效风险。
本申请实施例为了解决其技术问题，采用以下技术方案：
本申请提出了一种二次电池，包括壳体、电极组件、第一粘接件以及第二粘接件。电极组件设置于壳体内，电极组件包括第一极片、第二极片以及位于第一极片和第二极片之间的隔离膜，第一极片、第二极片以及隔离膜层叠并卷绕设置，电极组件的卷绕中心轴方向为第一方向；第一极片包括第一段，第一段构成电极组件最外圈的部分，第一段具有朝向卷绕中心轴的第一面和背离卷 绕中心轴的第二面；沿第一段的卷绕方向，第一段包括收尾段，收尾段的第一面和第二面均为空箔区。第一粘接件至少部分粘接于收尾段的第一面。第二粘接件设置于收尾段的第二面并粘接收尾段的第二面与壳体，沿垂直于第一面的方向，第二粘接件与第一粘接件部分重叠。
上述技术方案中，第一粘接件至少部分粘接于收尾段的第一面，可提高收尾段的抗拉强度，从而降低收尾段撕裂的风险；第二粘接件设置于收尾段的第二面并粘接收尾段与壳体，从而可减少电极组件与壳体的相对运动，并可再次提高收尾段的抗拉强度，从而进一步降低收尾段撕裂的风险。同时，沿垂直于第一面的方向，第二粘接件的投影与第一粘接件的投影部分重叠，在二次电池跌落或发生碰撞时，可使得第二粘接件所受的部分剪切力传导至第一粘接件，从而减少剪切力集中，以进一步降低收尾段撕裂的风险。
在一些优选的实施方式中，第二粘接件的与第一粘接件重叠的部分为第一部分。沿垂直于第一面的方向，第一部分的投影落入第一粘接件的投影范围内。第一粘接件与第二粘接件之间的剪切力传导，可有效降低收尾段撕裂的风险。
在一些优选的实施方式中，第一部分的面积为S1，第二粘接件的面积为S2，15％≤S1/S2≤50％。第二粘接件足够的贴胶面积，一方面可提高收尾段的抗拉强度，另一方面可保证第二粘接件与第一粘接件之间具有足够的重叠面积以供剪切力传递，从而降低收尾撕裂的风险。
在一些优选的实施方式中，沿第一段的卷绕方向，第一粘接件与收尾段末端的距离为第一距离，第一距离大于等于2mm。预留出第一距离，可使得第一粘接件充分粘接于收尾段，从而有效减少第一粘接件出现卷曲。
在一些优选的实施方式中，第一段还包括与收尾段相连接的涂覆段。
在一些优选的实施方式中，第一粘接件一端粘接于涂覆段，另一端粘接于收尾段，并且第一粘接件覆盖涂覆段与收尾段的连接处。沿第一方向，第一粘接件的长度为L1 mm，第一段的长度为L2 mm，0≤L1-L2≤3。其中，第一方向平行于电极组件的卷绕中心轴方向。可减少毛刺等凸起结构刺穿隔离膜，从而降低短路风险，并可减少交界处活性物质层的掉粉脱落。
在一些优选的实施方式中，第一粘接件包括第一子粘接件以及第二子粘接件。第一子粘接件设置于第一面。第二子粘接件设置于第一面，第二子粘接件于收尾段与第一子粘接件粘接，沿垂直于第一面的方向，第二子粘接件在第二 面上的投影与第二粘接件部分重叠。
在一些优选的实施方式中，第一子粘接件一端粘接于涂覆段，另一端粘接于收尾段，并且第一子粘接件覆盖涂覆段与收尾段的连接处。沿第一方向，第一子粘接件的长度为L3 mm，第一段的长度为L2 mm，0≤L3-L2≤3。第一子粘接件在第一方向X上全部覆盖交界处，以进一步减少毛刺等凸起结构刺穿隔离膜，从而降低短路风险，并可减少交界处活性物质层的掉粉脱落。
在一些优选的实施方式中，第一粘接件包括多个第二子粘接件。多个第二子粘接件于第一面沿第一段的卷绕方向依次排列设置，相邻两第二子粘接件相互粘接。沿第一段的卷绕方向，排列起始端的第二子粘接件在收尾段上粘接第一子粘接件，沿垂直于第一面的方向，排列末端的第二子粘接件的投影与第二粘接件的投影部分重叠。多个子粘接件的结构设置，可进一步减少粘接时出现气泡，并可进一步减少剪切力集中，从而降低收尾段撕裂的风险。
在一些优选的实施方式中，第一粘接件和第二粘接件为胶纸，以便于第一粘接件和第二粘接件的贴胶工序，提高生产效率。
在一些优选的实施方式中，第一段包括相连接的第一平直段、第一弯曲段、第二平直段以及第二弯曲段。第一平直段与第二平直段在第二方向上相对设置，第一弯曲段与第二弯曲段均连接于第一平直段与第二平直段之间，并且第一弯曲段与第二弯曲段在第三方向上相对设置。第二粘接件部分设置于第一平直段或第二平直段，第一方向、第二方向以及第三方向两两相互垂直。平直段更易第二粘接件的粘接收尾，可方便粘接并可提高粘接效果，从而便于提高第一段的抗拉强度，降低第一段撕裂的风险。
在一些优选的实施方式中，隔离膜与第一极片或第二极片之间的剥离强度为8N/m至12N/m，从而有效电极组件整体的结合强度。
在一些优选的实施方式中，第一粘接件为仅单面具有粘性的单面胶，所述单面胶包括第一基材层和涂覆于所述第一基材层一侧的第一胶粘剂层。
在一些优选的实施方式中，第二粘接件为双面都具有粘性的双面胶，双面胶包括第二基材层和涂覆于所述第二基材层两侧的第二粘接层和/或热熔胶层。
在一些优选的实施方式中，壳体为包装袋。
在一些优选的实施方式中，第一极片为阴极极片，第二极片为阳极极片；第一段仅第一面设置有活性物质层，活性物质层设置于涂覆段的第一面。单面 阴极极片的外侧无对应的阳极极片，因此可减少一层活性物质层，，以便于提高二次电池的能量密度。
在一些优选的实施方式中，第二粘接件用于固定所述收尾段。通过第二粘接件直接固定收尾段，可减少一道收尾胶及贴胶收尾工序，可在减少收尾段撕裂的同时，达到降本增效的目的。
第二方面，本申请还提出了一种电子装置，包括上述任一实施例所述的二次电池。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
一个或多个实施例通过与之对应的附图进行示例性说明，这些示例性说明并不构成对实施例的限定，附图中具有相同参考数字标号的元件表示为类似的元件，除非有特别申明，附图中的图不构成比例限制。
图1为本申请一些实施例的二次电池的爆炸视图；
图2为本申请一些实施例的电极组件的卷绕结构示意图；
图3a为本申请一些实施例的第一极片、隔离膜以及第二极片的层叠结构示意图；
图3b为本申请一些实施例的隔离膜的结构示意图；
图4为本申请一些实施例的第一段与第一粘接件和第二粘接件的粘接结构示意图(沿X方向观察)；
图5a为本申请一些实施例的第一段与第一粘接件和第二粘接件的粘接结构示意图(沿M方向观察)；
图5b为本申请一些实施例的第一粘接件以及第二粘接件的结构示意图；
图6为本申请一些实施例的第一段与第一粘接件和第二粘接件的粘接结构示意图(沿X方向观察)；
图7为本申请一些实施例的第一段与第一粘接件和第二粘接件的粘接结构示意图(沿M方向观察)；
图8为本申请一些实施例的第一子粘接件与多个第二子粘接的粘接结构示 意图。
附图标记说明：
100、二次电池；
10、壳体；11、第一壳体；12、第二壳体；
20、电极组件；20a、卷绕中心；21、第一极片；211、第一集流体；212、第一活性物质层；213、第一段；213a、第一面；213b、第二面；2131、收尾段；2132、涂覆段；22、第二极片；221、第二集流体；222、第二活性物质层；23、隔离膜；231、基层；232、陶瓷粘接层；24、第一平直段；25、第一弯曲段；26、第二平直段；27、第二弯曲段；
30、第一粘接件；30a、第一基材层；30b、第一胶粘剂层；31、第一子粘接件；32、第二子粘接件；
40、第二粘接件；40a、第一部分；41、第二基材层；42、第二粘接层；
N、卷绕方向；X、第一方向；Y、第二方向；Z、第三方向；M、垂直于第一面的方向。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
在本申请实施例的描述中，技术术语“第一”、“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施 例。此外，下面所描述的本申请不同实施例中所涉及的技术特征只要彼此之间未构成冲突就可以相互结合。
第一方面，本申请提出了一种二次电池100，请参照图1和图2，该二次电池100包括壳体10、电极组件20、第一粘接件30以及第二粘接件40。其中，电极组件20收容于壳体10内，第二粘接件40可用于电极组件20收尾，以将电极组件20连接为一个结构稳定的整体；第二粘接件40还可用于将电极组件20与壳体10粘接，以减少电极组件20与壳体10的相对运动。
对于上述壳体10，请参照图1，壳体10围合有容置腔(图中未标示)，容置腔可收容上述电极组件20及电解液(图中未标示)。本申请的实施例中，壳体10可采用包装袋，例如壳体10可采用包含金属层的多层复合膜包装袋。上述包装袋可为包括PP(聚丙烯)层和铝层的铝塑膜包装袋，铝层厚度方向的两个表面均可设置PP层，以便于包装袋的绝缘封合。
可选的，壳体10包括第一壳体11以及第二壳体12，第一壳体11和/或第二壳体12冲设有坑腔(图中未标示)，电极组件20可设置于坑腔，再通过热压封装第一壳体11与第二壳体12以形成完整的壳体10，其中上述坑腔则形成容置腔。
对于上述电极组件20，请参照图1至图3a，电极组件20设置于上述壳体10的容置腔。电极组件20包括第一极片21、第二极片22以及隔离膜23，第一极片21、第二极片22以及隔离膜23层叠并卷绕设置以形成卷绕型电极组件20，隔离膜23设置于第一极片21与第二极片22之间以分隔二者(图2示出了电极组件20的卷绕结构)。第一极片21与第二极片22的极性相反，例如第一极片21为阴极极片，第二极片22为阳极极片；第一极片21包括第一集流体211以及第一活性物质层212，第一活性物质层212涂覆于第一集流体211的至少一个表面；第二极片22包括第二集流体221以及第二活性物质层222，第二活性物质层222涂覆于第一集流体211的至少一个表面。或者，在其他一些实施例中，第一极片21为阳极极片，第二极片22为阴极极片。
对于电极组件20的隔离膜23，隔离膜23可粘接于第一极片21与第二极片22之间，以便于提高电极组件20整体的结合强度以及提高第一极片21以及第二极片22之间界面的平整度，从而减少收尾撕裂的风险并增强二次电池的循环性能。
请参照图3a和图3b，隔离膜23包括基层以及设置于基层231至少一个表面的粘接层232，例如在基层231厚度方向的两个表面均设置有粘接层232，当隔离膜23设置在第一极片21与第二极片22之间时，即可同时粘接第一极片21和第二极片22。
基层231的材质包括高分子聚乙烯、聚丙烯、聚对苯二甲酸乙二酯、聚对苯二甲酸丁二酯、聚苯乙烯、聚对苯撑、聚萘、聚酰亚胺、聚酰胺、芳纶、聚对苯撑苯并二噻唑中的一种或多种。粘接层232的材质可包括聚偏二氟乙烯或乙烯基-聚倍半硅氧烷中的至少一种。
在一些实施例中，隔离膜23与第一极片21或第二极片22之间的剥离强度为8N/m至12N/m，从而有效提高电极组件20整体的结合强度。剥离强度的大小可通过粘接层232内粘接剂的含量控制，当剥离强度过大时，过多的粘接剂会将第一极片21与第二极片22表面孔隙堵塞，造成析锂黑斑等问题；而过少的粘接剂会导致电极组件20的结合强度不高以及第一极片21和第二极片22之间界面平整度不高，在跌落时，电极组件20更易在壳体10之间窜动，增加收尾撕裂的风险。
本申请的实施例中，以第一极片21为阴极极片，第二极片22为阳极极片，并且电极组件20采用卷绕型为例。第一极片21包括第一段213，第一段213构成电极组件20最外圈的部分。请参照图2和图4，第一段213具有朝向电极组件20卷绕中心20a的第一面213a以及背离卷绕中心20a的第二面213b，沿第一段213的卷绕方向N(沿第一极片21的长度方向卷绕)，第一段213具有收尾段2131，收尾段2131也即第一段213的卷绕末段。收尾段2131的第一面213a以及第二面213b均为空箔区，本实施例中的空箔区也即未涂覆活性物质层的区段。
需要说明的时，当第一极片21的第一集流体211涂覆有第一活性物质层212时，则第一面213a为第一活性物质层212面向卷绕中心20a的表面，当第一集流体211未涂覆第一活性物质层212时，则第一集流体211面向卷绕中心20a的表面为第一面213a，第二面213b如此，第二极片22同理。
可选的，第一段213还包括与上述收尾段2131相连接的涂覆段2132，该涂覆段2132也即第一段213涂覆有活性物质层的区段。优选的，第一段213仅第一面213a设置有第一活性物质层212，该第一活性物质层212设置于涂覆段 2132的第一面213a，也即第一段213采用的单面阴极极片。本实施例中，最外层采用的单面阴极极片，单面阴极极片的外侧无对应的阳极极片，可减少一层活性物质层，以便于提高二次电池100的能量密度。
对于上述第一粘接件30，请参照图4，第一粘接件30至少部分粘接于收尾段2131的第一面213a，该收尾段2131的第一面213a为空箔区，空箔区所受到的剪切力可传递至第一粘接件30，从而提高收尾段2131的抗拉强度，降低收尾段2131撕裂的风险。
可选的，第一粘接件30一端粘接于涂覆段2132，也即第一粘接件30粘接于涂覆段2132的第一活性物质层212，另一端则粘接于收尾段2131，并且第一粘接件30覆盖涂覆段2132与收尾段2131的连接处。第一活性物质层212在涂覆于第一面213a时，在涂覆段2132与收尾段2131的交界处，第一活性物质层212易出现拖尾毛刺等凸起结构，该凸起结构易对隔离膜23造成干涉，并且易导致该部分第一活性物质层212掉粉脱落。本实施例中，通过第一粘接件30粘接覆盖，可减少毛刺等凸起结构刺穿隔离膜23的机率，从而降低短路风险，并可减少交界处活性物质层的掉粉脱落。
当第一粘接件30覆盖涂覆段2132与收尾段2131的交界处时，可采用第一粘接件30在第一方向X上全部覆盖交界处。例如，请进一步参照图5a，沿第一方向X，第一粘接件30的长度为L1 mm，第一段213的长度为L2 mm，0≤L1-L2≤3；其中第一方向X平行于电极组件20的卷绕中心轴方向，第一粘接件30在第一方向X上全部覆盖交界处，以进一步减少交界处的毛刺等凸出结构刺穿隔离膜23而引起短路以及减少交界处活性物质的掉粉脱落。
请继续参照图4和图5a，沿第一段213的卷绕方向N，第一粘接件30与收尾段2131末端的距离为第一距离W，第一距离W大于等于2mm，以预留第一段213末端的裁剪空间。需要说明的是，当第一粘接件30覆盖收尾段2131的末端时，末端之后再无部件供第一粘接件30粘接，也即第一粘接件30易出现粘接不充分的情况，这就使得第一粘接件30可能会在末端存在卷曲；并且，在裁剪第一段213时同样存在极大的风险裁剪到第一粘接件30，这同样会造成第一粘接件30在末端卷曲，上述卷曲会影响二次电池100的能量密度，也易对隔离膜23造成干涉。本实施例中，预留出第一距离，可使得第一粘接件30充分粘接于收尾段2131，从而有效减少第一粘接件30出现卷曲。
可选的，第一粘接件30可采用胶纸，使用时，可直接将胶纸粘接于收尾段2131的第一面213a，以及粘接于涂覆段2132的第一活性物质层212。例如，第一粘接件30为仅单面具有粘性的单面胶，单面胶包括第一基材层30a和涂覆于第一基材层30a一侧的第一胶粘剂层30b(可参照图5b)。第一胶粘剂层30b可直接粘接第一活性物质层212以及收尾段2131，收尾段2131空箔区所受的剪切力可传递至单面胶，从而减少收尾段2131的撕裂；并且，单面胶直接覆盖涂覆段2132与收尾段2131的交界处，从而减少毛刺等凸起结构刺穿隔离膜23。
第一基材层30a的材质包括聚对苯二甲酸乙二醇酯(PET)、聚酰亚胺或聚丙烯中的至少一种。聚对苯二甲酸乙二醇酯具有优良的物理机械性能，长期使用温度可达120℃，电绝缘性优良，甚至在高温高频下，其电性能仍较好，并且具有较佳的抗蠕变性、耐疲劳性、耐摩擦性以及尺寸稳定性。采用聚对苯二甲酸乙二醇酯的第一粘接件30，可充分提高收尾段2131的抗拉强度，以减少收尾段2131撕裂的风险。第一胶粘剂层30b的材质包括聚丙烯酸(PAA)、聚甲基丙烯酸甲酯、聚丙烯、聚乙烯、聚酰胺、丁苯橡胶、丁腈橡胶、顺丁橡胶、异戊橡胶、乙丙橡胶或氯丁橡胶中的至少一种。
对于上述第二粘接件40，第二粘接件40粘接于电极组件20与壳体10之间，例如，请一并参照图1以及图4和图5a，第二粘接件40设置于收尾段2131的第二面213b，以进一步提高收尾段2131的抗拉强度；并且，第二粘接件40粘接于收尾段2131的第二面213b与壳体10之间，可减少电极组件20与壳体10的相对运动，在二次电池100跌落或发生碰撞时，由于第二粘接件40的粘接作用，可有效减少电极组件20与壳体10的碰撞，从而减少二次电池100的失效风险。
第二粘接件40也可采用胶纸，例如采用双面都具有粘性的双面胶，该双面胶包括第二基材层41和涂覆于第二基材层41两侧的第二粘接层42和/或热熔胶层，第二粘接件40一面粘接电极组件20，另一面粘接壳体10，可减少电极组件20与壳体10的相对运动。其中，第二基材层41的材质包括涤纶树脂、纤维素衍生物、聚氯乙烯、聚烯烃、聚苯乙烯、聚酯、聚酰亚胺、聚酰胺、聚碳酸酯或聚苯硫醚、聚对苯二甲酸乙二醇酯中一种或多种。第二粘接层42为胶粘剂层时，材质包括橡胶系树脂、丙烯酸系树脂或硅酮系树脂中的一种或多 种。第二粘接层42为热熔胶层时，材质包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物、乙烯-乙酸乙烯共聚物、聚氨酯弹性体、聚氨酯丙烯酸酯、聚异丁烯或聚丁二烯中的一种或多种。在电极组件20卷绕后，可通过第二粘接件40收尾固定，可减少一道收尾胶及贴胶收尾工序，可在减少收尾段撕裂的同时，提升二次电池100的能量密度。
沿垂直于第一面213a的方向M，第二粘接件40与第一粘接件30部分重叠；也即在沿垂直于第一面213a的方向M，第二粘接件40的投影与第一粘接件30的投影存在部分重叠。在二次电池100跌落或发生碰撞时，第二粘接件40粘接电极组件20及壳体10，可减少电极组件20与壳体10之间的相对运动，但第二粘接件40会受到较大的剪切力，易导致第二粘接件40粘接的收尾段2131撕裂。本实施例中，由于上述第一粘接件30投影与第二粘接件40的投影重叠，可使得第二粘接件40所受的部分剪切力传导至第一粘接件30，从而减少剪切力集中，可进一步降低收尾段2131撕裂的风险。
在一些实施例中，第二粘接件40的与第一粘接件30投影重叠的部分为第一部分40a，沿垂直于第一面213a的方向M，第一部分40a的投影落入第一粘接件30的投影范围内。第一粘接件30与第二粘接件40之间的剪切力传导，可有效降低收尾段2131撕裂的风险。
优选的，第一部分40a的面积为S1，第二粘接件40的面积为S2，15％≤S1/S2≤50％。第二粘接件40足够的贴胶面积，一方面可提高收尾段2131的抗拉强度，另一方面可保证第二粘接件40与第一粘接件30之间具有足够的重叠面积以供剪切力传递，从而降低收尾撕裂的风险。
进一步的，第二粘接件40与第一段213的实际贴胶面积为S3，第二粘接件40与第一段213的有效贴胶面积为S4，S3＞S4。足够的实际贴胶面积可减少第一段213撕裂的风险。
在一些实施例中，请参照图6和图7，第一粘接件30包括第一子粘接件31以及第二子粘接件32。第一子粘接件31设置于第一面213a，第二子粘接件32也设置于第一面213a，并且，第二子粘接件32于收尾段2131与第一子粘接件31粘接。沿第一段213的卷绕方向N，若第一粘接件30的长度过长(30mm)，在粘接第一段213时，则可能会出现气泡，该气泡不仅影响二次电池100的能量密度，并且也会导致第一粘接件30粘接效果不佳，以致于第二粘接件40与 第一粘接件30之间的剪切力传导效果不明显。对此，本申请的实施例中，通过将第一粘接件30设置为两道子粘接件的结构，也即第一粘接件30包括相互粘接的第一子粘接件31以及第二子粘接件32，第一粘接件30和第二粘接件40均较短，可有效减少在粘接过程中出现气泡。其中，第二子粘接件32在第二面213b上的投影与第二粘接件40部分重叠，第二粘接件40所有的剪切力可传递至第二子粘接件32，再传递至第一子粘接件31，从而减少剪切力集中。
可选的，第一子粘接件31一端粘接于涂覆段2132，另一端粘接于收尾段2131，并且第一子粘接件31覆盖涂覆段2132与收尾段2131的连接处。由于采用的是较短的第一子粘接件31，通过第一子粘接件31的粘接，可减少第一子粘接件31粘接出现气泡，并可并覆盖连接处的拖尾毛刺等凸起结构，可减少毛刺等凸起结构刺穿隔离膜23，从而降低短路风险，并可减少交界处活性物质层的掉粉脱落。
进一步的，沿第一方向X，第一子粘接件31的长度为L3 mm，第一段213的长度为L2 mm，0≤L3-L2≤3。第一子粘接件31在第一方向X上全部覆盖交界处，以进一步减少毛刺等凸起结构刺穿隔离膜23，从而降低短路风险。
上述第一粘接件30还可采用多个子粘接件，例如，请进一步参照图8，第一粘接件30包括多个第二子粘接件32。
多个第二子粘接件32于第一面213a沿第一段213的卷绕方向N依次排列设置，相邻两第二子粘接件32相互粘接。沿第一段213的卷绕方向N，排列起始端的第二子粘接件32在收尾段2131上粘接第一子粘接件31，沿垂直于第一面213a的方向M，排列末端的第二子粘接件32的投影与第二粘接件40的投影部分重叠。多个子粘接件的结构设置，可进一步减少粘接时出现气泡，并可进一步减少剪切力集中，从而降低收尾段2131撕裂的风险。
在一些实施例中，请参照图7，沿第一段213的卷绕方向N，第一子粘接件31长度为L4 mm，L4≤30，当第一子粘接件31的长度超过30mm时，第一子粘接件31在粘接时则易出现气泡，由此，本申请的实施例中，优先采用第一子粘接件31的长度小于30mm。第二子粘接件32也可同样设置，也即沿第一段213的卷绕方向N，第二子粘接件32长度为L5 mm，L5≤30，从而减少第二子粘接件32在粘接时出现气泡。
请参照图2和图4，图2示出了电极组件20的卷绕结构，第一段213包括 相连接的第一平直段24、第一弯曲段25、第二平直段26以及第二弯曲段27。第一平直段24与第二平直段26在第二方向Y上相对设置，第一弯曲段25与第二弯曲段27均连接于第一平直段24与第二平直段26之间，并且第一弯曲段25与第二弯曲段27在第三方向Z上相对设置。例如，第一段213首先卷绕以形成第一弯曲段25，再平直设置以形成第二平直段26，第二平直段26延伸并卷绕以形成第二弯曲段27，最后平直收尾以形成第一平直段24。
其中，第二粘接件40部分设置于第一平直段24或部分设置于第二平直段26，例如，当第一段213的卷绕末端靠近第一平直段24时，可将第二粘接件40部分粘接于第一平直段24；或者如图2中，当第一段213的卷绕末端靠近第二平直段时，则可将第二粘接件40部分粘接于第二平直段26。将第二粘接件40部分设置于平整的第一平直段24或第二平直段26，可方便粘接并可提高粘接效果，从而便于提高第一段213的抗拉强度，降低第一段213撕裂的风险。
对于电极组件20的厚度，当电极组件20的厚度大于或等于6.95mm(沿图2中第二方向Y，电极组件20的厚度)时，第一粘接件30的长度应大于或等于30mm(此时可采用多到第一子粘接件31)。电极组件20的厚度与最外层第一段213的拐角(第一弯曲段25或第二弯曲段27)长度L的关系为L＝(π*T)/2。本申请中，为实现防碰撞撕裂效果以及同时防止贴胶产生气泡，电极组件20厚度满足：L+H+W≤25～30mm。H为沿第一段213的卷绕方向N，第二活性物质层222超出第一活性物质层212的长度，也即图2中尺寸H；W为第一粘接件30与收尾段2131末端的距离(也即上述第一距离W)。
本申请的实施例中，第一粘接件30至少部分粘接于收尾段2131的第一面213a，可提高收尾段2131的抗拉强度，从而降低收尾段2131撕裂的风险；第二粘接件40设置于收尾段2131的第二面213b并粘接收尾段2131与壳体10，从而可减少电极组件20与壳体10的相对运动，并可再次提高收尾段2131的抗拉强度，从而进一步降低收尾段2131撕裂的风险。同时，沿垂直于第一面213a的方向，第二粘接件40的投影与第一粘接件30的投影部分重叠，在二次电池100跌落或发生碰撞时，可使得第二粘接件40所受的部分剪切力传导至第一粘接件30，从而减少剪切力集中，以进一步降低收尾段2131撕裂的风险。
实施例
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各 种的试验及评价按照下述的方法进行。
实施例1
正极极片(阴极)的制备
将正极活性材料钴酸锂(LiCoO2)、导电剂导电炭黑、粘结剂聚偏氟乙烯(PVDF)按照重量比97.5:1:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成固含量为75wt％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为9μm的正极集流体铝箔的一个表面上，90℃条件下烘干，得到正极活性物质层厚度为110μm的正极极片。以上步骤完成后，即完成正极极片的单面涂布。之后，在该正极极片的另一个表面上重复以上步骤，即得到双面涂布正极活性物质层的正极极片。涂布完成后，经过冷压、裁片、分切后，在85℃的真空条件下干燥4h，得到正极极片，规格为74mm×867mm。
负极极片(阳极)的制备
将负极活性材料石墨粉末、导电剂导电炭黑(Super P)、粘结剂丁苯橡胶(SBR)按照重量比96:1.5:2.5进行混合，然后加入去离子水作为溶剂，调配成固含量为70wt％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为5μm的负极集流体铜箔的一个表面上，110℃条件下烘干，得到负极活性物质层厚度为130μm的单面负极极片。以上步骤完成后，即已完成负极极片的单面涂布。之后，在该负极极片的另一个表面上重复以上步骤，即得到双面涂布负极活性物质层的负极极片。涂布完成后，经过冷压、裁片、分切后，在120℃的真空条件下干燥12h，得到负极极片，规格为76.6mm×875mm。
隔离膜的制备
将聚偏二氟乙烯(粘接剂)和氧化铝陶瓷按照质量比9:1进行混合，加入去离子水作为溶剂，调配成固含量为25wt％的浆料，并搅拌均匀，将浆料均匀 的涂覆在5μm厚的聚乙烯多孔聚合物薄膜的一个表面，烘干，然后将浆料均匀的涂覆在聚乙烯多孔聚合物薄膜的另一个表面上，得到双面涂覆2μm氧化铝陶瓷层的隔离膜。
电解液的制备
在干燥氩气环境中，将有机溶剂碳酸乙烯酯、碳酸甲乙酯和碳酸二乙酯以质量比30:50:20混合得到有机溶液，然后向有机溶剂中加入锂盐六氟磷酸锂(LiPF6，)溶解并混合均匀，得到锂盐的浓度为1.15mol/L的电解液。
第一粘接件的制备
在8μm的第一基材层聚对苯二甲酸乙二醇酯薄膜(PET)的一个表面上涂布聚丙烯酸(PAA)，80℃下烘干形成厚度为4μm的第一胶粘剂层，得到第一粘接件。
第二粘接件的制备
将苯乙烯-异戊二烯-苯乙烯嵌段共聚物、加热至150℃热熔，然后涂布在厚度为8μm的第二基材层聚对苯二甲酸乙二醇酯薄膜(PET)的一个表面上，然后在120℃下烘干形成厚度为8μm第二胶粘剂层。
在第二基材层的另一个表面涂布聚丙烯酸(PAA)，80℃下烘干形成厚度为4μm的第二胶粘剂层，得到含有依次层叠设置的第二胶粘剂层、第二基材层和第二胶粘剂层的第二粘接件。
锂离子电池的制备
将上述制备的正极极片、隔离膜、负极极片按顺序叠好，隔离膜处于正极极片和负极极片中间起到隔离的作用，并卷绕得到卷绕结构的电极组件，其中，最外层为单面涂布活性物质层的正极极片，采用改性聚丙烯的第一粘接件粘接 于最外层正极极片的涂覆段与空箔段。
将上述制得的第二粘接件通过第二胶层粘贴在电极组件的外表面，然后将电极组件置于铝塑膜包装袋中，第一胶层则粘接于壳体的内表面。然后经过顶侧封、真空干燥、注液、化成(温度85℃、压力1.05MPa、3.5V)、容量、抽气等工序，得到锂离子电池。
其中，锂离子电池的质量为61.5g，保液系数为1.75g/Ah。第一胶层的尺寸为20mm×30mm，电极组件沿电极组件、粘接件和壳体的层叠方向的正投影尺寸为30mm×40mm，即S5＝600mm2，S6＝1200mm2；实际贴胶面积为S＝S5＝600mm2。沿正极极片的厚度方向，第二粘接件的与第一粘接件投影重叠区域的面积为100mm2(S1＝100mm2)，第一粘接件与正极极片末端的距离为3.2mm(W＝3.2mm)，第一粘接件与外层单面正极极片(包括空箔区)的长度差(沿电极组件中心轴方向的长度)为0.8mm(L1-L2＝0.8mm)，隔离膜剥离强度10N/m。
实施例2
与实施例1不同的是：S1＝60mm2。
实施例3
与实施例1不同的是：S1＝90mm2。
实施例4
与实施例1不同的是：S1＝150mm2。
实施例5
与实施例1不同的是：S1＝240mm2。
实施例6
与实施例1不同的是：S1＝300mm2。
实施例7
与实施例1不同的是：S1＝360mm2。
实施例8
与实施例1不同的是：W＝2mm。
实施例9
与实施例1不同的是：L1-L2＝3mm。
实施例10
与实施例1不同的是：L1-L2＝0mm。
实施例11
与实施例1不同的是：S1＝150mm2，聚偏二氟乙烯与氧化铝陶瓷质量比为6:4，隔离膜与正极极片的剥离强度7N/m。
实施例12
与实施例1不同的是：S1＝150mm2，聚偏二氟乙烯与氧化铝陶瓷质量比为8:2，隔离膜与正极极片的剥离强度8N/m。
实施例13
与实施例1不同的是：S1＝150mm2，聚偏二氟乙烯与氧化铝陶瓷质量比为9.5:0.5，隔离膜与正极极片的剥离强度12N/m。
实施例14
与实施例1不同的是：S1＝150mm2，聚偏二氟乙烯与氧化铝陶瓷质量比为9.8:0.2，隔离膜与正极极片的剥离强度13N/m。
对比例1
与实施例1不同的是，第一粘接件未覆盖空箔段，第一粘接件与第二粘接件在正极极片厚度方向上的投影不重叠，S1＝0。
测试方法和设备：
跌落铝箔撕裂率测试：
将锂离子电池在25℃下进行预处理，常温环境中静置60min后，测试跌落测试前锂离子电池的电压；将锂离子电池装入夹具中，采用跌落设备按照如下顺序从距离地面1.5m的位置自由跌落：头-尾-头右角-尾右角-头左角-尾左角(角度：45±15°)，重复6轮。跌落结束拆解电芯，观察铝箔是否被撕裂。
跌落失效率测试：
将锂离子电池在25℃下进行预处理，常温环境中静置60min后，测试跌落测试前锂离子电池的电压；将锂离子电池装入夹具中，采用跌落设备按照如下 顺序从距离地面1.5m的位置自由跌落：头-尾-头右角-尾右角-头左角-尾左角(角度：45±15°)，重复6轮。跌落结束测量记录锂离子电池的电压，测试前后均检查锂离子电池的外观并拍照。跌落测试通过判断标准：不冒烟，不漏液，电压降<30mV。
剥离强度测试：
根据GB/T 2792-2014《胶粘带剥离强度的测试方法》使用高铁拉力机测试隔离膜和正极极片或负极极片之间的剥离强度(本申请实施例中以测试隔离膜与正极极片之间的剥离强度为例)。测试过程如下：将锂离子电池放电至0V，然后拆解锂离子电池，将隔离膜以及与之粘接的极片作为一个整体取下来，用无尘纸擦拭表面的电解液。然后裁切为20mm×60mm的条状试样。沿试样长度方向，将试样中电极组件的那一面通过双面胶(日东5000NS)粘附在钢板上，其中粘附长度不低于40mm。将钢板固定在高铁拉力机的相应位置，拉起试样未被粘附在隔膜上的极片的另一端，将试样放入夹头内夹紧，其中被拉起的试样部分与钢板在空间上夹角为180°，夹头以5±0.2mm/s的速度拉动试样，最终测得平稳区域的拉力平均值记为隔离膜和极片之间的剥离强度，记为F，单位为N/m。
各实施例及对比例的相关制备参数及性能测试如表1所示：
表1

根据上述表1，结合上述对比例1以及实施例1至14可知，当采用第一粘接件覆盖空箔段，并且第一粘接件与第二粘接件在正极极片厚度方向的投影重叠时，其跌落铝箔撕裂率以及跌落失效率明显降低，这是因为第二粘接件所受的部分剪切力可传导至第一粘接件，从而减少剪切力集中，进而减少铝箔撕裂。并且，由于第一粘接件自涂覆段粘接至空箔段，可覆盖活性物质层的边缘毛刺，可减少毛刺刺穿隔离膜的风险，以降低跌落失效率。
上述实施例2中，S1/S2＝10％，第一部分所占面积较小，此时铝箔撕裂风险以及跌落失效风险均较大；实施例7中，S1/S2＝60％，第一部分过大的面积占比，又易导致裁剪时剪到第一粘接件，以致于第一粘接件边缘卷曲，因此实施例7中也存在较低的铝箔撕裂率以及跌落失效风险。而实施例3中S1/S2＝15％，实施例6中S1/S2＝50％，其铝箔撕裂率以及跌落失效风险均较低，本申请中，优选，15％≤S1/S2≤50％。
第一粘接件的在极片宽度方向上的长度不宜过大也不宜过小，过大易导致在极片宽度方向上卷曲，进入顶封区域并影响锂离子电池的能量密度，过小则难以覆盖活性物质层边缘的毛刺，易刺穿隔膜等导致短路。本申请中，优选0≤L1-L2≤3。
并且，第一距离W≥2mm可更好的减少第一粘接件裁剪时，在极片长度方向上的卷曲。结合实施例11，当隔离膜与正极极片之间的剥离强度为7N/m时，电极组件的结合强度不高，以致于仍存在铝箔撕裂风险；结合实施例14，当隔离膜与正极极片之间的剥离强度为13N/m时，剥离强度过大，过多的粘接剂会将正极极片以及负极极片表面孔隙堵塞，造成析锂黑斑等问题，从而导致锂离子电池仍存在跌落失效风险。结合实施例11至14，本申请中，优选隔离膜的剥离强度为8N/m至12N/m，其跌落铝箔撕裂率以及跌落失效风险较低。
第二方面，本申请还提出了一种电子装置，该电子装置包括上述第一方面任一实施例所述的二次电池。电子装置可以为便携式消费电子设备、电动工具、无人机、可穿戴式电子设备、电动汽车等。
最后应说明的是：以上实施例仅用以说明本申请的技术方案，而非对其限制；在本申请的思路下，以上实施例或者不同实施例中的技术特征之间也可以进行组合，步骤可以以任意顺序实现，并存在如上所述的本申请的不同方面的许多其它变化，为了简明，它们没有在细节中提供；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (17)

  1. 一种二次电池，其特征在于，包括：
    壳体；
    电极组件，设置于所述壳体内，所述电极组件包括第一极片、第二极片以及位于所述第一极片和所述第二极片之间的隔离膜，所述第一极片、所述第二极片以及所述隔离膜层叠并卷绕设置，所述电极组件的卷绕中心轴方向为第一方向；所述第一极片包括第一段，所述第一段构成所述电极组件最外圈的部分，所述第一段具有朝向所述卷绕中心轴的第一面和背离所述卷绕中心轴的第二面；沿所述第一段的卷绕方向，所述第一段包括收尾段，所述收尾段的第一面和第二面均为空箔区；
    第一粘接件，至少部分粘接于所述收尾段的第一面；
    第二粘接件，设置于所述收尾段的第二面并粘接所述收尾段的第二面与所述壳体，沿垂直于所述第一面的方向，所述第二粘接件与所述第一粘接件部分重叠。
  2. 根据权利要求1所述的二次电池，其特征在于，所述第二粘接件与所述第一粘接件重叠的部分为第一部分，所述第一部分的面积为S1，所述第二粘接件的面积为S2，15％≤S1/S2≤50％。
  3. 根据权利要求1或2所述的二次电池，其特征在于，沿所述第一段的卷绕方向，所述第一粘接件与所述收尾段末端的距离为第一距离，所述第一距离大于等于2mm。
  4. 根据权利要求1至3中任一项所述的二次电池，其特征在于，所述第一段还包括与所述收尾段相连接的涂覆段。
  5. 根据权利要求4所述的二次电池，其特征在于，所述第一粘接件一端粘接于所述涂覆段，另一端粘接于所述收尾段，并且所述第一粘接件覆盖所述涂覆段与所述收尾段的连接处；
    沿所述第一方向，所述第一粘接件的长度为L1mm，所述第一段的长度为 L2mm，0≤L1-L2≤3。
  6. 根据权利要求4或5所述的二次电池，其特征在于，所述第一粘接件包括：
    第一子粘接件，设置于所述第一面；
    第二子粘接件，设置于所述第一面，所述第二子粘接件于所述收尾段与所述第一子粘接件粘接，沿垂直于所述第一面的方向，所述第二子粘接件在所述第二面上的投影与所述第二粘接件部分重叠。
  7. 根据权利要求6所述的二次电池，其特征在于，所述第一子粘接件一端粘接于所述涂覆段，另一端粘接于所述收尾段，并且所述第一子粘接件覆盖所述涂覆段与所述收尾段的连接处；
    沿所述第一方向，所述第一子粘接件的长度为L3mm，所述第一段的长度为L2mm，0≤L3-L2≤3。
  8. 根据权利要求6或7所述的二次电池，其特征在于，所述第一粘接件包括多个第二子粘接件；
    所述多个第二子粘接件于所述第一面沿所述第一段的卷绕方向依次排列设置，相邻两所述第二子粘接件相互粘接；
    沿所述第一段的卷绕方向，排列起始端的第二子粘接件在所述收尾段上粘接所述第一子粘接件，沿垂直于所述第一面的方向，排列末端的第二子粘接件的投影与所述第二粘接件的投影部分重叠。
  9. 根据权利要求1至8中任一项所述的二次电池，其特征在于，所述第一粘接件和所述第二粘接件为胶纸。
  10. 根据权利要求1至9中任一项所述的二次电池，其特征在于，所述第一段包括相连接的第一平直段、第一弯曲段、第二平直段以及第二弯曲段；
    所述第一平直段与所述第二平直段在第二方向上相对设置，所述第一弯曲 段与所述第二弯曲段均连接于所述第一平直段与所述第二平直段之间，并且所述第一弯曲段与所述第二弯曲段在第三方向上相对设置；
    所述第二粘接件设置于所述第一平直段或所述第二平直段，所述第一方向、所述第二方向以及所述第三方向两两相互垂直。
  11. 根据权利要求1至10中任一项所述的二次电池，其特征在于，所述隔离膜与所述第一极片或所述第二极片之间的剥离强度为8N/m至12N/m。
  12. 根据权利要求1至11中任一项所述的二次电池，其特征在于，所述第一粘接件为仅单面具有粘性的单面胶，所述单面胶包括第一基材层和涂覆于所述第一基材层一侧的第一胶粘剂层。
  13. 根据权利要求1至11中任一项所述的二次电池，其特征在于，所述第二粘接件为双面都具有粘性的双面胶，所述双面胶包括第二基材层和涂覆于所述第二基材层两侧的第二粘接层，所述第二粘接层为胶粘剂层和/或热熔胶层。
  14. 根据权利要求1至13中任一项所述的二次电池，其特征在于，所述壳体为包装袋。
  15. 根据权利要求1至14中任一项所述的二次电池，其特征在于，所述第一极片为阴极极片，所述第二极片为阳极极片；所述第一段仅所述第一面设置有活性物质层，所述活性物质层设置于所述涂覆段的所述第一面。
  16. 根据权利要求1至15中任一项所述的二次电池，其特征在于，所述第二粘接件用于固定所述收尾段。
  17. 一种电子装置，其特征在于，包括如权利要求1至16中任一项所述的二次电池。
PCT/CN2024/101861 2023-06-30 2024-06-27 二次电池及电子装置 Ceased WO2025002220A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP24830854.6A EP4738495A1 (en) 2023-06-30 2024-06-27 Secondary battery and electronic device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202310796380.3 2023-06-30
CN202310796380.3A CN116722196A (zh) 2023-06-30 2023-06-30 二次电池及电子装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US19/435,963 Continuation US20260128487A1 (en) 2023-06-30 2025-12-30 Secondary battery and electronic device

Publications (2)

Publication Number Publication Date
WO2025002220A1 true WO2025002220A1 (zh) 2025-01-02
WO2025002220A9 WO2025002220A9 (zh) 2025-10-02

Family

ID=87866104

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/101861 Ceased WO2025002220A1 (zh) 2023-06-30 2024-06-27 二次电池及电子装置

Country Status (3)

Country Link
EP (1) EP4738495A1 (zh)
CN (1) CN116722196A (zh)
WO (1) WO2025002220A1 (zh)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116722196A (zh) * 2023-06-30 2023-09-08 宁德新能源科技有限公司 二次电池及电子装置
CN120858475A (zh) * 2023-12-29 2025-10-28 宁德新能源科技有限公司 二次电池及电子装置
CN120814059A (zh) * 2023-12-29 2025-10-17 东莞新能源科技有限公司 二次电池以及电子装置
CN118336146A (zh) * 2024-04-28 2024-07-12 宁德新能源科技有限公司 二次电池及电子装置
WO2025231628A1 (zh) * 2024-05-08 2025-11-13 宁德新能源科技有限公司 二次电池、电极组件的制造方法以及电子装置
WO2025245711A1 (zh) * 2024-05-29 2025-12-04 宁德新能源科技有限公司 电化学装置以及用电设备
CN120092352A (zh) * 2024-10-11 2025-06-03 宁德新能源科技有限公司 二次电池和电子装置
WO2026076679A1 (zh) * 2024-10-11 2026-04-16 宁德新能源科技有限公司 二次电池和电子装置
CN119381514B (zh) * 2024-10-31 2025-11-11 宁德新能源科技有限公司 电池及用电设备

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN211670286U (zh) * 2020-04-29 2020-10-13 北京小米移动软件有限公司 电池和电子设备
CN215988908U (zh) * 2021-09-30 2022-03-08 珠海冠宇电池股份有限公司 电池
CN216120431U (zh) * 2021-08-05 2022-03-22 湖南立方新能源科技有限责任公司 一种电芯、二次电池及用电装置
CN115642294A (zh) * 2022-11-14 2023-01-24 珠海冠宇电池股份有限公司 一种电芯及电池
CN116722196A (zh) * 2023-06-30 2023-09-08 宁德新能源科技有限公司 二次电池及电子装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN211670286U (zh) * 2020-04-29 2020-10-13 北京小米移动软件有限公司 电池和电子设备
CN216120431U (zh) * 2021-08-05 2022-03-22 湖南立方新能源科技有限责任公司 一种电芯、二次电池及用电装置
CN215988908U (zh) * 2021-09-30 2022-03-08 珠海冠宇电池股份有限公司 电池
CN115642294A (zh) * 2022-11-14 2023-01-24 珠海冠宇电池股份有限公司 一种电芯及电池
CN116722196A (zh) * 2023-06-30 2023-09-08 宁德新能源科技有限公司 二次电池及电子装置

Also Published As

Publication number Publication date
WO2025002220A9 (zh) 2025-10-02
EP4738495A1 (en) 2026-05-06
CN116722196A (zh) 2023-09-08

Similar Documents

Publication Publication Date Title
WO2025002220A1 (zh) 二次电池及电子装置
CN112768784B (zh) 一种电化学装置和电子装置
CN111785925B (zh) 极片及应用、含有该极片的低温升高安全性锂离子电池
CN106797055B (zh) 使用双面胶带固定电极构成体的方法以及二次电池
CN113728493B (zh) 电化学装置和电子装置
KR20190024707A (ko) 탭과 집전체 연결이 개선된 전극조립체, 여기에 이용되는 점착 탭 및 그 제조 방법
WO2023082036A1 (zh) 集流体及其制备方法、二次电池、电池模块、电池包和用电装置
CN111710804A (zh) 一种保护膜及其制备方法和使用该保护膜的锂离子电池
WO2025148724A1 (zh) 极片及二次电池
CN111682165A (zh) 正极极片、电化学装置和电子装置
CN111564634A (zh) 导电胶、圆柱锂离子二次电池及其制备方法
CN116632166A (zh) 正极极片及其制备方法、电池单体、电池、用电装置
WO2025246884A1 (zh) 电极组件及二次电池
CN119650867A (zh) 一种电化学装置及电子装置
WO2021243611A1 (zh) 绝缘胶带、极片和电化学装置
CN118263540A (zh) 二次电池及电子装置
CN115863540A (zh) 一种电极片和卷绕式二次电池
WO2026066663A1 (zh) 二次电池及电子设备
WO2025209088A1 (zh) 一种电化学装置和电子装置
CN205680731U (zh) 一种高安全型锂离子电池
WO2025124227A1 (zh) 电极组件、二次电池及电子设备
CN119230967A (zh) 二次电池、用电设备及二次电池的制备方法
CN117059908A (zh) 电化学装置以及电子装置
CN115732857A (zh) 一种复合隔膜及其制备方法和二次电池
CN116073004A (zh) 一种隔离膜、二次电池、电池模块、电池包及用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24830854

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2024830854

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2024830854

Country of ref document: EP

Effective date: 20260130