WO2024197940A1 - 一种二次电池和电子装置 - Google Patents

一种二次电池和电子装置 Download PDF

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Publication number
WO2024197940A1
WO2024197940A1 PCT/CN2023/085782 CN2023085782W WO2024197940A1 WO 2024197940 A1 WO2024197940 A1 WO 2024197940A1 CN 2023085782 W CN2023085782 W CN 2023085782W WO 2024197940 A1 WO2024197940 A1 WO 2024197940A1
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WO
WIPO (PCT)
Prior art keywords
secondary battery
adhesive layer
adhesive
present application
shell
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/CN2023/085782
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English (en)
French (fr)
Other versions
WO2024197940A9 (zh
Inventor
胡克文
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 PCT/CN2023/085782 priority Critical patent/WO2024197940A1/zh
Priority to CN202380017163.8A priority patent/CN118613942A/zh
Publication of WO2024197940A1 publication Critical patent/WO2024197940A1/zh
Publication of WO2024197940A9 publication Critical patent/WO2024197940A9/zh
Priority to US19/342,961 priority patent/US20260031515A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • H01M50/595—Tapes
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/117—Inorganic material
    • H01M50/119—Metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/121—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
    • 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

Definitions

  • the present application relates to the field of electrochemistry, and in particular to a secondary battery and an electronic device.
  • an adhesive such as adhesive tape
  • insulate and fix the lithium-ion battery there is a certain gap between the electrode assembly and the packaging shell, and the electrode assembly will move relative to the shell. Therefore, an adhesive (such as adhesive tape) is required to insulate and fix the lithium-ion battery.
  • SIS tapes such as styrene-isoprene-styrene block copolymer (SIS) tapes
  • SIS styrene-isoprene-styrene block copolymer
  • the purpose of this application is to provide a secondary battery and an electronic device to improve the safety performance of the secondary battery.
  • the specific technical solution is as follows:
  • a secondary battery comprising an electrode assembly, an electrolyte, a shell and an adhesive, wherein the adhesive is arranged between the electrode assembly and the shell, and the adhesive comprises a first adhesive layer and a second adhesive layer stacked, wherein the first adhesive layer is bonded to the inner surface of the shell, and the second adhesive layer is bonded to the outer surface of the electrode assembly;
  • the first adhesive layer comprises a styrene-isoprene-styrene block copolymer and a first resin, and the first resin comprises at least one of acrylonitrile-butadiene-styrene copolymer, polyurethane or polystyrene.
  • the first adhesive layer comprises the above-mentioned substance, which can increase the friction coefficient between the first adhesive layer and the inner surface of the shell, which is beneficial to reduce the stress at the edge of the adhesive, reduce the possibility of damage to the bonding interface between the adhesive and the electrode assembly, and thus reduce the possibility of tearing the outer surface of the electrode assembly; on the other hand, it is also beneficial to delay the relative movement between the electrode assembly and the shell, thereby reducing the risk of the secondary battery top seal being broken and leaking, thereby improving the safety performance of the secondary battery.
  • the mass percentage of the styrene-isoprene-styrene block copolymer is 32.5% to 75%, and the mass percentage of the first resin is 15% to 45%.
  • the friction coefficient between the first adhesive layer and the inner surface of the shell can be increased, which is beneficial to reduce the stress at the edge of the adhesive and reduce the possibility of damage to the bonding interface between the adhesive and the electrode assembly, thereby reducing the possibility of tearing the outer surface of the electrode assembly; on the other hand, This is beneficial to delaying the relative movement between the electrode assembly and the shell, thereby reducing the risk of the top seal of the secondary battery being broken and leaking, and further improving the safety performance of the secondary battery.
  • the mass percentage of the first resin is 20% to 40%.
  • the mass percentage of the first resin is 25% to 35%.
  • the first adhesive layer further comprises a functional resin, and the mass percentage of the functional resin is 5% to 25% based on the mass of the first adhesive layer;
  • the functional resin comprises at least one of ethylene-vinyl acetate copolymer, polyurethane elastomer, polyurethane acrylate, polyisobutylene or polybutadiene.
  • the first adhesive layer further includes an additive and an antioxidant; based on the mass of the first adhesive layer, the mass percentage of the additive is 1% to 5%, and the mass percentage of the antioxidant is 1% to 5%.
  • the first adhesive layer includes additives and antioxidants and regulates their contents within the above range, which can improve the heat resistance of the first adhesive layer and its antioxidant ability in the electrolyte, thereby improving the bonding performance of the first adhesive layer and improving the safety performance of the secondary battery.
  • the adhesive member further includes a substrate layer, which is located between the first adhesive layer and the second adhesive layer; the substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene. The adhesive member includes a substrate layer and selects the above materials, which can increase the friction between the adhesive member and the shell, thereby improving the safety performance of the secondary battery.
  • the area of the first adhesive layer is S 1
  • the orthographic projection area of the electrode assembly along the stacking direction of the electrode assembly, the adhesive and the housing is S 2
  • S 1 /S 2 satisfies 10% ⁇ S 1 /S 2 ⁇ 95%, and by regulating the value of S 1 /S 2 within the above range, it is beneficial to improve the safety performance of the secondary battery.
  • the shell is a packaging bag.
  • the adhesive of the present application is applied to a secondary battery whose shell is a packaging bag, the secondary battery has high energy density and good safety performance.
  • the thickness of the first adhesive layer is 2 ⁇ m to 20 ⁇ m.
  • the peel strength between the adhesive and the shell is 10N/m to 500N/m.
  • the liquid retention coefficient of the secondary battery is 1 g/Ah to 2.5 g/Ah.
  • the liquid retention coefficient of the secondary battery within the above range is conducive to the first resin in the first glue layer swelling in the electrolyte, further increasing the friction coefficient between the first glue layer and the inner surface of the shell, improving the problems of convex points and swelling of the secondary battery, thereby improving the safety performance of the secondary battery.
  • the second aspect of the present application provides an electronic device, which includes the secondary battery provided by the first aspect of the present application.
  • the secondary battery of the present application has good safety performance, so that the electronic device provided by the second aspect of the present application has a long service life.
  • FIG1 is a schematic diagram of a stacked structure of an adhesive member in one embodiment of the present application.
  • FIG2 is a schematic diagram of the positions of the molecules of the first resin before and after swelling in the electrolyte
  • FIG3 is a schematic diagram of a stacked structure of an adhesive member in another embodiment of the present application.
  • FIG. 4 is a schematic diagram of an adhesive member bonded to the outer surface of an electrode assembly in one embodiment of the present application.
  • adhesive member 10 first adhesive layer 11 , second adhesive layer 12 , substrate layer 13 , electrode assembly 20 , first resin 30 before swelling, first resin 31 after swelling.
  • the present application is explained by taking a lithium-ion battery as an example of a secondary battery, but the secondary battery of the present application is not limited to a lithium-ion battery.
  • a secondary battery including an electrode assembly, an electrolyte, a shell and an adhesive, wherein the adhesive is disposed between the electrode assembly and the shell.
  • the adhesive 10 includes a first adhesive layer 11 and a second adhesive layer 12 stacked together, wherein the first adhesive layer 11 is bonded to the inner surface of the shell, and the second adhesive layer 12 is bonded to the outer surface of the electrode assembly.
  • the first adhesive layer 11 includes a styrene-isoprene-styrene block copolymer and a first resin, wherein the first resin includes at least one of acrylonitrile-butadiene-styrene copolymer, polyurethane or polystyrene.
  • the first adhesive layer includes a first resin, wherein the molecular chain of the first resin has good flexibility and low cohesion, so that the first adhesive layer quickly exerts viscosity at low temperatures, has good flexibility at high temperatures, and has stable bonding properties.
  • the first glue layer includes the above-mentioned substance and regulates its content within the scope of the present application.
  • the first resin in the first glue layer swells in the electrolyte. As shown in FIG2 , the position between the molecules of the first resin 30 before swelling is relatively fixed. After swelling in the electrolyte, the relatively fixed position between the molecules of the first resin 31 after swelling is squeezed and amplified by the small molecules of the electrolyte. The swelling of the first resin can increase the friction force, which can increase the friction coefficient between the first glue layer and the inner surface of the shell.
  • the first glue layer includes the first resin, which can take into account the friction coefficient between the first glue layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the mass percentage of the styrene-isoprene-styrene block copolymer is 32.5% to 75%, and the mass percentage of the first resin is 15% to 45%.
  • the mass percentage of the first resin is 20% to 40%, and more preferably, the mass percentage of the first resin is 25% to 35%.
  • the mass percentage of the styrene-isoprene-styrene block copolymer can be 32.5%, 35%, 45%, 50%, 55%, 65%, 75% or a range consisting of any two of the values
  • the mass percentage of the first resin can be 15%, 20%, 25%, 27%, 30%, 33%, 35%, 40%, 45% or a range consisting of any two of the values.
  • the The friction coefficient between the first adhesive layer and the inner surface of the shell is large, which is beneficial to reduce the stress at the edge of the adhesive, reduce the possibility of damage to the bonding interface between the adhesive and the electrode assembly, and thus reduce the possibility of tearing the outer surface of the electrode assembly; on the other hand, it is also beneficial to delay the relative movement between the electrode assembly and the shell, thereby reducing the risk of the secondary battery top seal being broken and leaking, thereby improving the safety performance of the secondary battery.
  • the first resin includes two or more of acrylonitrile-butadiene-styrene copolymer, polyurethane or polystyrene, there is no particular restriction on the content of each substance, as long as the purpose of this application can be achieved.
  • the monomers of the acrylonitrile-butadiene-styrene copolymer include acrylonitrile, butadiene and styrene. Based on the mass of the acrylonitrile-butadiene-styrene copolymer, the mass percentage of acrylonitrile is 5% to 35%, the mass percentage of butadiene is 20% to 55%, and the mass percentage of styrene is 10% to 45%.
  • the first resin has good chemical resistance and thermal stability, high elasticity and good toughness, high hardness and good processability, wherein acrylonitrile provides chemical resistance and thermal stability, butadiene provides high elasticity and toughness, and styrene provides hardness and processability, thereby improving the bonding performance of the first adhesive layer, improving the problem of swelling of the electrode assembly surface and its four corners, increasing the friction coefficient between the first adhesive layer and the inner surface of the shell, reducing the possibility of tearing the outer surface of the electrode assembly and the risk of the secondary battery top seal being broken and leaking, and improving the safety of the secondary battery.
  • the friction coefficient between the first adhesive layer and the inner surface of the shell is 0.3 to 0.9. This indicates that the friction coefficient between the first adhesive layer and the inner surface of the shell is relatively large.
  • it is beneficial to reduce the stress at the edge of the adhesive reduce the possibility of damage to the bonding interface between the adhesive and the electrode assembly, and thus reduce the possibility of tearing the outer surface of the electrode assembly; on the other hand, it is also beneficial to delay the relative movement between the electrode assembly and the shell, thereby reducing the risk of the secondary battery top seal being broken and leaking, thereby improving the safety performance of the secondary battery.
  • the first adhesive layer further includes a functional resin, and based on the mass of the first adhesive layer, the mass percentage of the functional resin is 5% to 25%, for example, the mass percentage of the functional resin can be 5%, 10%, 12%, 15%, 18%, 20%, 25% or a range consisting of any two values therein; the functional resin includes at least one of ethylene-vinyl acetate copolymer, polyurethane elastomer, polyurethane acrylate, polyisobutylene or polybutadiene.
  • the morphological stability of the first adhesive layer after long-term high-temperature immersion in the electrolyte can be improved, the bonding performance of the first adhesive layer can be improved, and thus the safety performance of the secondary battery can be improved.
  • the above high temperature refers to 80°C to 90°C.
  • the first adhesive layer further comprises an additive and an antioxidant; based on the mass of the first adhesive layer, the mass percentage of the additive is 1% to 5%, the mass percentage of the antioxidant is 1% to 5%, and the mass percentage of the additive is 1% to 5%.
  • the content of the additives and antioxidants can be 1%, 2%, 3%, 4%, 5% or a range consisting of any two of the values, and the mass percentage of the antioxidant can be 1%, 2%, 3%, 4%, 5% or a range consisting of any two of the values.
  • the present application has no particular restrictions on the types of additives and oxidants, as long as the purpose of the present application can be achieved.
  • the additives may include but are not limited to at least one of titanium dioxide, talc, white carbon black or calcium carbonate; the antioxidant may include but is not limited to at least one of diphenylamine, triester phosphite or distearyl thiodipropionate.
  • the first adhesive layer includes additives and antioxidants and regulates their content within the above range, which can improve the heat resistance of the first adhesive layer and its antioxidant ability in the electrolyte, thereby improving the bonding performance of the first adhesive layer, improving the stability of the first adhesive layer, and improving the safety performance of the secondary battery.
  • the adhesive 10 further includes a substrate layer 13, the substrate layer 13 is located between the first adhesive layer 11 and the second adhesive layer 12; the substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene.
  • the present application has no particular restrictions on the content of the above-mentioned substances in the substrate layer, and those skilled in the art can adjust it according to actual needs, as long as the purpose of the present application can be achieved.
  • the present application has no particular restrictions on the weight average molecular weight of the above-mentioned substances in the substrate layer, and those skilled in the art can select it according to actual needs, as long as the purpose of the present application can be achieved, for example, its weight average molecular weight can be 10,000 to 500,000.
  • the substrate layer contains a plurality of the above-mentioned substances, the content of each substance is not particularly limited, as long as the purpose of the present application can be achieved.
  • the adhesive includes a substrate layer and selects the above-mentioned materials, so that the adhesive has a certain hardness, improves the wrinkling and bubble problems during bonding, broadens the process window of the adhesive, can be surface pressed or rolled, and effectively prevents foreign matter such as burrs and debris, protects the electrode assembly, and thus improves the safety performance of the secondary battery.
  • the substrate layer of the present application may also include colorants such as cobalt green, cobalt blue, Prussian blue, indigo, phthalocyanine blue, etc., so that the substrate has color, so that it can be identified by an electronic device of an inductively coupled device (CCD) or an active pixel sensor (CMOS) during the production process, so as to perform adhesive positioning, adhesive application, missed detection, etc.
  • CCD inductively coupled device
  • CMOS active pixel sensor
  • the present application has no particular limitation on the content of the colorant in the substrate layer, and those skilled in the art can adjust it according to actual needs, as long as the purpose of the present application can be achieved.
  • the adhesive 10 is bonded to the outer surface of the electrode assembly 20, the area of the first adhesive layer 11 is S 1 , the orthographic projection area of the electrode assembly 20 along the stacking direction of the electrode assembly 20, the adhesive 10 and the shell is S 2 , and S 1 /S 2 satisfies 10% ⁇ S 1 /S 2 ⁇ 95%, for example, the value of S 1 /S 2 can be 10%, 15%, 25%, 35%, 40%, 45%, 55%, 65%, 75%, 85%, 95% or a range consisting of any two of the values.
  • the adhesive and the shell can have a higher peel strength, and the packaging will not be affected by the adhesive being too large, which is beneficial to improving the safety performance and processing performance of the secondary battery.
  • the shell is a packaging bag
  • the packaging bag can be an aluminum-plastic film packaging bag.
  • the adhesive member of the present application is applied to a secondary battery whose shell is a packaging bag, the secondary battery has high energy density and good safety. able.
  • the thickness of the first adhesive layer is 2 ⁇ m to 20 ⁇ m, for example, the thickness of the first adhesive layer can be 2 ⁇ m, 4 ⁇ m, 7 ⁇ m, 10 ⁇ m, 14 ⁇ m, 18 ⁇ m, 20 ⁇ m or a range consisting of any two of these values.
  • the present application has no particular limitation on the thickness of the second adhesive layer and the thickness of the substrate layer, as long as the purpose of the present application can be achieved.
  • the thickness of the second adhesive layer is 2 ⁇ m to 10 ⁇ m
  • the thickness of the substrate layer is 4 ⁇ m to 30 ⁇ m.
  • the peel strength between the adhesive and the shell is 10N/m to 500N/m, for example, the peel strength between the adhesive and the shell can be 10N/m, 30N/m, 50N/m, 70N/m, 100N/m, 150N/m, 200N/m, 250N/m, 300N/m, 400N/m, 500N/m or a range consisting of any two of these values.
  • the peel strength between the adhesive and the shell can be 10N/m, 30N/m, 50N/m, 70N/m, 100N/m, 150N/m, 200N/m, 250N/m, 300N/m, 400N/m, 500N/m or a range consisting of any two of these values.
  • the liquid retention coefficient of the secondary battery is 1g/Ah to 2.5g/Ah, for example, the liquid retention coefficient of the secondary battery can be 1g/Ah, 1.2g/Ah, 1.5g/Ah, 1.7g/Ah, 2g/Ah, 2.3g/Ah, 2.5g/Ah or a range consisting of any two of these values.
  • the liquid retention coefficient of the secondary battery within the above range is conducive to the first resin in the first glue layer swelling in the electrolyte, and is conducive to further increasing the friction coefficient between the first glue layer and the inner surface of the shell, improving the problems of convex points and swelling of the secondary battery, thereby improving the safety performance of the secondary battery.
  • the present application has no particular restrictions on the preparation method of the adhesive, as long as the purpose of the present application can be achieved.
  • the present application can be prepared by the following method: styrene-isoprene-styrene block copolymer, the first resin, the functional resin, the additive, and the antioxidant are mixed evenly, hot-melted at 100°C to 150°C, and then coated on one surface of the substrate layer, and dried to form a first adhesive layer; the material of the second adhesive layer is coated on the other surface of the substrate layer, and dried to form a second adhesive layer to obtain an adhesive.
  • the present application does not particularly limit the weight average molecular weight of styrene-isoprene-styrene block copolymer, the first resin, and the functional resin, and those skilled in the art can select according to actual needs, as long as the purpose of the present application can be achieved.
  • the weight average molecular weight of styrene-isoprene-styrene block copolymer can be 50,000 to 150,000
  • the weight average molecular weight of the first resin can be 10,000 to 500,000
  • the weight average molecular weight of the functional resin can be 100,000 to 300,000.
  • the present application does not particularly limit the material of the second adhesive layer, as long as the purpose of the present application can be achieved.
  • the material of the second adhesive layer can include at least one of polymethyl methacrylate (PMMA, commonly known as acrylic), polypropylene (PP), polyethylene (PE) or polyamide.
  • the secondary battery of the present application includes an electrode assembly, an electrolyte, a housing, and an adhesive, and the electrode assembly and the electrolyte are contained in the housing.
  • the present application has no particular restrictions on the structure of the electrode assembly, as long as the purpose of the present application can be achieved.
  • the structure of the electrode assembly is a laminated structure or a winding structure.
  • the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a diaphragm, and the diaphragm is arranged between the positive electrode sheet and the negative electrode sheet.
  • the diaphragm is used to separate the positive electrode sheet and the negative electrode sheet to prevent internal short circuits in the secondary battery. It allows electrolyte ions to pass freely without affecting the electrochemical charge and discharge process.
  • the present application has no particular restrictions on the positive electrode sheet, as long as the purpose of the present application can be achieved.
  • the positive electrode sheet includes a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector.
  • the present application has no particular restrictions on the positive current collector, as long as the purpose of the present application can be achieved.
  • the positive current collector may include aluminum foil or aluminum alloy foil, etc.
  • the positive active material layer of the present application includes positive active materials.
  • the present application has no particular restrictions on the type of positive active material, as long as the purpose of the present application can be achieved.
  • the positive active material may include lithium nickel cobalt manganese oxide (NCM811, NCM622, NCM523, NCM111), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide (LiCoO 2 ), lithium manganese oxide, lithium iron manganese phosphate or lithium titanate, etc.
  • the thickness of the positive current collector and the positive active material layer there is no particular restriction on the thickness of the positive current collector and the positive active material layer, as long as the purpose of the present application can be achieved.
  • the thickness of the positive electrode collector is 4 ⁇ m to 20 ⁇ m, preferably 4 ⁇ m to 18 ⁇ m.
  • the thickness of the single-sided positive electrode active material layer is 30 ⁇ m to 120 ⁇ m.
  • the positive electrode active material layer can be arranged on one surface in the thickness direction of the positive electrode collector, or on two surfaces in the thickness direction of the positive electrode collector. It should be noted that the "surface” here can be the entire area of the positive electrode collector or a partial area of the positive electrode collector. This application is not particularly limited as long as the purpose of this application can be achieved.
  • the positive electrode active material layer of the present application may also include a conductive agent and a binder.
  • the above-mentioned conductive agent and binder are not particularly limited as long as the purpose of this application can be achieved.
  • the conductive agent may include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon nanofibers, flake graphite, carbon dots or graphene.
  • the binder may include at least one of polypropylene alcohol, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyamide-imide, styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin, lithium carboxymethyl cellulose (CMC-Li) or sodium carboxymethyl cellulose (CMC-Na), etc.
  • polypropylene alcohol sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyamide-imide, styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin, lithium carboxymethyl cellulose (CMC-Li) or sodium carboxy
  • the present application has no special restrictions on the negative electrode plate, as long as the purpose of the present application can be achieved.
  • the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector.
  • the present application has no special restrictions on the negative electrode current collector, as long as the purpose of the present application can be achieved.
  • the negative electrode current collector may include copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam or copper foam, etc.
  • the negative electrode active material layer of the present application contains negative electrode active materials.
  • the present application has no special restrictions on the type of negative electrode active materials, as long as the purpose of the present application can be achieved.
  • the negative electrode active material may include natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, At least one of silicon, silicon-carbon composite, SiO x (0 ⁇ x ⁇ 2), Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithium titanate Li 4 Ti 5 O 12 , Li-Al alloy or metallic lithium.
  • the thickness of the negative electrode current collector is 4 ⁇ m to 10 ⁇ m
  • the thickness of the negative electrode active material layer is 30 ⁇ m to 130 ⁇ m.
  • the negative electrode active material layer can be arranged on one surface in the thickness direction of the negative electrode current collector, or on two surfaces in the thickness direction of the negative electrode current collector. It should be noted that the "surface" here can be the entire area of the negative electrode current collector or a partial area of the negative electrode current collector. There is no particular restriction in the present application, as long as the purpose of the present application can be achieved.
  • the negative electrode active material layer may also include a conductive agent and a binder.
  • the present application has no particular restrictions on the types of the conductive agent and the binder in the negative electrode active material layer, as long as the purpose of the present application can be achieved.
  • the negative electrode active material layer of the present application may include the above conductive agent and the binder.
  • the present application has no particular restrictions on the mass ratio of the negative electrode active material, the conductive agent and the binder in the negative electrode active material layer, as long as the purpose of the present application can be achieved.
  • the material of the diaphragm may include but is not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene-based polyolefin (PO) diaphragms, polyester films (such as polyethylene terephthalate (PET) films), cellulose films, polyimide films (PI), polyamide films (PA), spandex or aramid films, etc.
  • the type of diaphragm may include but is not limited to at least one of woven films, non-woven films (non-woven fabrics), microporous films, composite films, rolled films or spun films, etc.
  • the diaphragm of the present application may have a porous structure, and the porous layer is arranged on at least one surface of the diaphragm, and the porous layer includes inorganic particles and a binder.
  • the inorganic particles may include at least one of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate.
  • the binder may include at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethylcellulose, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the present application does not particularly limit the size of the pore size of the porous structure, as long as the purpose of the present application can be achieved, for example, the size of the pore size can be 0.01 ⁇ m to 1 ⁇ m.
  • the thickness of the diaphragm is not particularly limited, as long as the purpose of the present application can be achieved, for example, the thickness can be 5 ⁇ m to 500 ⁇ m.
  • the electrolyte includes a lithium salt and a non-aqueous solvent.
  • the lithium salt may include at least one of LiPF 6 , LiBF 4 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , Li 2 SiF 6 , lithium bis(oxalatoborate) (LiBOB) or lithium difluoroborate.
  • LiPF 6 LiBF 4 , LiClO 4 , LiB(C 6 H 5 ) 4
  • LiCH 3 SO 3 LiCF 3 SO 3
  • LiN(SO 2 CF 3 ) 2 LiC(SO 2 CF 3 ) 3
  • Li 2 SiF 6 lithium bis(oxalatoborate) (LiBOB) or lithium difluoroborate.
  • LiBOB lithium bis(oxalatoborate)
  • the present application has no particular restriction on the non-aqueous solvent, as long as the purpose of the present application can be achieved.
  • it may include but is not limited to at least one of carbonate compounds, carboxylate compounds, ether compounds or other organic solvents.
  • the above-mentioned carbonate compounds may include but are not limited to at least one of linear carbonate compounds, cyclic carbonate compounds or fluorocarbonate compounds.
  • the above-mentioned linear carbonate compounds may include but are not limited to at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC) or methyl ethyl carbonate (MEC).
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • MPC methyl propyl carbonate
  • EPC ethyl propyl carbonate
  • MEC methyl
  • the above-mentioned cyclic carbonate may include but is not limited to at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) or vinyl ethylene carbonate (VEC).
  • the fluorinated carbonate compound may include, but is not limited to, at least one of fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, or trifluoromethylethylene carbonate.
  • FEC fluoroethylene carbonate
  • 1,2-difluoroethylene carbonate 1,1-difluoroethylene carbonate
  • 1,1,2-trifluoroethylene carbonate 1,1,2,2-tetrafluoroethylene carbon
  • the above-mentioned carboxylate compound may include, but is not limited to, at least one of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, decalactone, valerolactone, or caprolactone.
  • the above-mentioned ether compound may include but is not limited to at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1-ethoxy-1-methoxyethane, 2-methyltetrahydrofuran or tetrahydrofuran.
  • the above-mentioned other organic solvents may include but are not limited to at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate or trioctyl phosphate.
  • the present application does not particularly limit the type of secondary battery, which may include any device that undergoes an electrochemical reaction.
  • the secondary battery may include, but is not limited to: a lithium metal secondary battery, a lithium ion battery, a sodium ion battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.
  • the present application does not particularly limit the shape of the secondary battery, as long as it can achieve the purpose of the present application.
  • the preparation process of the secondary battery is well known to those skilled in the art, and there is no particular limitation in the present application.
  • it may include but is not limited to the following steps: stacking the positive electrode sheet, the separator and the negative electrode sheet in order, and winding, folding and other operations as needed to obtain an electrode assembly of a winding structure, placing the electrode assembly in a packaging bag, injecting the electrolyte into the packaging bag and sealing it to obtain a secondary battery; or stacking the positive electrode sheet, the separator and the negative electrode sheet in order, and then fixing the four corners of the entire stacked structure with tape to obtain an electrode assembly of a stacked structure, placing the electrode assembly in a packaging bag, injecting the electrolyte into the packaging bag and sealing it to obtain a secondary battery.
  • overcurrent protection elements, guide plates, etc. may also be placed in the packaging bag as needed to prevent the pressure inside the secondary battery from rising and overcharging and discharging.
  • the second aspect of the present application provides an electronic device, which includes the secondary battery provided by the first aspect of the present application.
  • the secondary battery of the present application has good safety performance, so the electronic device provided by the second aspect of the present application has a long service life. Use life.
  • the electronic device of the present application is not particularly limited, and it can be any electronic device known in the prior art.
  • the electronic device can include, but is not limited to: a laptop computer, a pen-input computer, a mobile computer, an electronic 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, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor.
  • the lithium-ion battery was disassembled, the first glue layer was taken out, and then the components and proportions of the components in the first glue layer were tested by Fourier transform infrared spectroscopy (FTIR) and pyrolysis-gas chromatography-mass spectrometry (PY-GCMS) mass spectrometer (GCMS).
  • FTIR Fourier transform infrared spectroscopy
  • PY-GCMS pyrolysis-gas chromatography-mass spectrometry
  • GCMS mass spectrometer
  • the peel strength between the adhesive and the shell (packaging bag) is tested using a high-speed rail tensile machine.
  • the test process is as follows: discharge the lithium-ion battery to 0V, then disassemble the lithium-ion battery, remove the adhesive and the electrode assembly and packaging bag attached to it as a whole, and wipe the electrolyte on the surface with dust-free paper. Then cut into 20mm ⁇ 60mm strip specimens. Along the length direction of the specimen, the electrode assembly side of the specimen is adhered to the steel plate with double-sided tape (Nito 5000NS), and the adhesion length is not less than 40mm.
  • Lithium-ion batteries were prepared according to the method of Example 1-1, and the formation temperatures of the lithium-ion batteries were set to 65°C, 75°C, 80°C, 85°C, and 90°C, respectively, which were recorded as five samples. Samples were then prepared according to the above peel strength test method. The strength test method measures the peel strength between the adhesive and the shell of the above five samples, with the unit of N/m.
  • the friction coefficient of the first adhesive layer and the inner surface of the shell is tested using the MXD-02 friction coefficient meter.
  • the test process is as follows: Place the test plate on a horizontal operating table, bond the adhesive to the aluminum foil through the second adhesive layer, cut into 50mm ⁇ 50mm samples, soak the above sample in an electrolyte at 85°C for 4h, wipe the electrolyte on the surface with dust-free paper after soaking, and fix the above sample on the test plate with double-sided tape (Nitto 5000NS) at room temperature, which is recorded as the first sample. Cut the packaging bag into 100mm ⁇ 100mm as the second sample and fix it on a slider with a gravity of 65g.
  • the static friction divided by the gravity of the slider is the static friction coefficient, that is, the friction coefficient x of the first adhesive layer and the inner surface of the shell.
  • the preparation method of the above electrolyte is the same as that of the electrolyte in Example 1-1.
  • the lithium-ion battery is left to stand for 60 minutes at room temperature and then tested for voltage.
  • the voltage of the lithium-ion battery before the roller test is tested; the lithium-ion battery is placed in a fixture and tested with a roller device in a test environment of 20 ⁇ 5°C.
  • the lithium-ion battery is placed 1m above the ground and is freely dropped at a speed of 12 circles/min for 250 circles (two drops count as one circle).
  • the voltage of the lithium-ion battery is measured and recorded.
  • the appearance of the lithium-ion battery is inspected and photographed before and after the test.
  • the roller test passing criteria no smoke, no leakage, voltage drop ⁇ 50mV.
  • 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 freely drop 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 voltage of the lithium-ion battery was measured and recorded, and the appearance of the lithium-ion battery was checked and photographed before and after the test. The pass criteria for the drop test: no smoke, no leakage, and voltage drop ⁇ 30mV.
  • the preparation method of the above electrolyte is the same as that of the electrolyte in Example 1-1.
  • the positive electrode active material 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 coating thickness of 110 ⁇ m. After the above steps are completed, the single-sided coating of the positive electrode sheet is completed.
  • PVDF and alumina ceramics are mixed in a mass ratio of 9:1, deionized water is added as a solvent, and a slurry with a solid content of 25wt% is prepared and stirred evenly.
  • the slurry is evenly coated on one surface of a 5 ⁇ m thick polyethylene porous polymer film (provided by Celgard), dried, and then the slurry is evenly coated on the other surface of the polyethylene porous polymer film to obtain a diaphragm 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 LiPF 6 was added to the organic solvent, dissolved and mixed uniformly to obtain lithium
  • the salt concentration of the electrolyte is 1.15 mol/L.
  • Styrene-isoprene-styrene block copolymer (SIS, weight average molecular weight 100,000), first resin acrylonitrile-butadiene-styrene copolymer (ABS, weight average molecular weight 300,000), functional resin ethylene-vinyl acetate copolymer (EVA, weight average molecular weight 120,000), additive titanium dioxide, and antioxidant diphenylamine are mixed evenly, heated to 150°C for hot melting, and then coated on one surface of a substrate layer polyethylene terephthalate film (PET) with a thickness of 8 ⁇ m, and then dried at 120°C to form a first adhesive layer with a thickness of 8 ⁇ m.
  • PET polyethylene terephthalate film
  • Polyacrylic acid is coated on the other surface of the substrate layer and dried at 80°C to form a second adhesive layer with a thickness of 4 ⁇ m, thereby obtaining an adhesive component comprising a first adhesive layer, a substrate layer, and a second adhesive layer stacked in sequence.
  • the mass percentage of SIS is 45%
  • the mass percentage of the first resin ABS is 30%
  • the mass percentage of the functional resin EVA is 15%
  • the mass percentage of the additive titanium dioxide is 5%
  • the mass percentage of the antioxidant diphenylamine is 5%.
  • the mass ratio of the three monomers forming ABS is 20:35:45 for acrylonitrile:butadiene:styrene.
  • the positive electrode sheet, separator and 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 the electrode assembly with a wound structure is obtained by winding.
  • the adhesive 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 then the lithium-ion battery is obtained through the processes of top and side sealing, vacuum drying, liquid injection, formation (temperature 85°C, pressure 1.05MPa, 3.5V), capacity, and exhaust.
  • the liquid retention coefficient of the lithium-ion battery is 1.75g/Ah.
  • Example 1-1 Except for adjusting the preparation parameters according to Table 1, the rest is the same as Example 1-1.
  • Example 1-1 Except for adjusting the thickness of the first adhesive layer according to Table 2, the rest is the same as Example 1-1.
  • Example 1-1 The same as Example 1-1 except that the area S 1 of the first adhesive layer is adjusted according to Table 2 and the area S 2 of the electrode assembly remains unchanged. As the area S 1 of the first adhesive layer changes, the length and width of the first adhesive layer are proportionally scaled.
  • Example 1-1 Except for adjusting the liquid retention coefficient y according to Table 2, the rest is the same as Example 1-1.
  • x is the friction coefficient between the first adhesive layer and the inner surface of the shell
  • F is the peel strength between the adhesive and the shell
  • the weight average molecular weight of the above polyurethane is 800000
  • the weight average molecular weight of the above polystyrene is 200000.
  • the first adhesive layer includes SIS and the first resin, which can take into account both the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is smaller, indicating that the lithium-ion battery has better safety performance.
  • the mass percentage of SIS and the first resin affects the safety performance of the lithium-ion battery. From Examples 1-1 to 1-10, and 1-17 to 1-18, it can be seen that by adjusting the mass percentage of SIS and the first resin within the scope of the present application, the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell can be taken into account, the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is smaller, indicating that the lithium-ion battery has better safety performance.
  • the type of the first resin affects the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 1-11 to 1-16 that the type of the first resin is within the scope of the present application, and can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the mass percentage of the monomers forming the acrylonitrile-butadiene-styrene copolymer will affect the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 1-11 to 1-14 that the mass percentage of the monomers of the acrylonitrile-butadiene-styrene copolymer is within the scope of the present application, which can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, which can improve the bonding performance of the first adhesive layer and improve the problem of swelling of the electrode assembly surface and its four corners. The ratio of the number of failures/total number in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the change in the mass percentage of the functional resin will affect the friction coefficient x between the first adhesive layer and the inner surface of the shell, the peel strength F between the adhesive and the shell, and thus affect the safety performance of the lithium-ion battery.
  • the mass percentage of the functional resin is within the scope of the present application, which can take into account both the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, and the ratio of the number of failures/total number in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the change in the mass percentage of the additive and antioxidant will affect the friction coefficient x between the first adhesive layer and the inner surface of the shell, the peel strength F between the adhesive and the shell, and thus affect the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 1-7 to 1-9 that the mass percentage of the additive and antioxidant is within the scope of the present application, which can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell, and the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the peel strength-temperature variation between the adhesive and the packaging bag of Examples 1-7 is as follows: When the formation temperature of the lithium-ion battery is 65°C, 75°C, 80°C, 85°C, and 90°C, the peel strength between the adhesive and the packaging bag of Examples 1-7 of the present application is 376N/m, 379N/m, 383N/m, 384N/m, and 387N/m, respectively. It can be seen that the peel strength between the adhesive and the packaging bag of Examples 1-7 remains at the same level at 65°C to 90°C, which broadens the process window (65°C to 90°C) of the lithium-ion battery formation process.
  • the peel strength-temperature variation between the adhesive and the packaging bag of Comparative Example 1 is as follows: when the formation temperatures of the lithium-ion battery are 65°C, 75°C, 80°C, 85°C, and 90°C, respectively, the peel strengths between the adhesive and the packaging bag of Comparative Example 1 are 37N/m, 142N/m, 417N/m, 423N/m, and 434N/m, respectively. It can be seen that the peel strength gradually increases and then remains constant, resulting in a narrow process window (80°C to 90°C) for the lithium-ion battery formation process.
  • Example 1-1 and Comparative Example 1 of the present application were cut into cuboids weighing 5 g. After being immersed in an electrolyte at 85°C for 24 hours, the adhesives in Example 1-1 of the present application swelled to 5.720 g, with a swelling rate of 14.4%. The adhesives in Comparative Example 1 swelled to 6.805 g, with a swelling rate of 36.1% and no shape. This indicates that the adhesives of the present application can swell in the electrolyte and have a stable shape.
  • y is the liquid retention coefficient
  • x is the friction coefficient between the first adhesive layer and the inner surface of the shell
  • F is the peel strength between the adhesive and the shell.
  • the thickness of the first adhesive layer will affect the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 2-1 and 2-3 that the thickness of the first adhesive layer is within the scope of the present application, and can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the value of S 1 /S 2 will affect the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 2-4 to 2-7 that the value of S 1 /S 2 is within the scope of the present application, which can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive member and the shell, the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.
  • the liquid retention coefficient of the secondary battery will affect the safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 2-8 and 2-9 that the liquid retention coefficient of the secondary battery is within the scope of this application, which can take into account the friction coefficient between the first adhesive layer and the inner surface of the shell and the peel strength between the adhesive and the shell.
  • the values of x and F are both large, and the ratio of the number of failures/total in the roller test and drop test of the lithium-ion battery is small, indicating that the lithium-ion battery has good safety performance.

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Abstract

本申请提供了一种二次电池和电子装置。其中，二次电池包括电极组件、电解液、壳体以及粘接件，粘接件设置于电极组件与壳体之间，粘接件包括层叠的第一胶层和第二胶层，第一胶层粘接壳体的内表面，第二胶层粘接电极组件的外表面；第一胶层包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂，第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的至少一种。本申请提供的二次电池包括粘接件，有利于降低电极组件外表面撕裂的可能性以及二次电池顶封冲开、漏液的风险，改善二次电池的安全性能。

Description

一种二次电池和电子装置 技术领域
本申请涉及电化学领域，具体涉及一种二次电池和电子装置。
背景技术
在二次电池，例如锂离子电池中，由于电极组件和包装壳之间存在一定的间隙，电极组件会与壳体发生相对运动，需要使用粘接件(例如胶纸)对锂离子电池进行绝缘保护和固定。
常用的胶纸例如苯乙烯-异戊二烯-苯乙烯嵌段共聚物(SIS)胶纸，存在对电极组件束缚效果差的问题，在锂离子电池跌落过程中，例如以头部跌落、尾部跌落或侧边跌落等方式跌落时胶纸边缘受到的应力大，SIS胶纸和电极组件之间的粘结界面易被破坏，导致锂离子电池电压失效、短路等，影响锂离子电池的安全性能。
发明内容
本申请的目的在于提供一种二次电池和电子装置，以改善二次电池的安全性能。具体技术方案如下：
本申请第一方面提供了一种二次电池，包括电极组件、电解液、壳体以及粘接件，粘接件设置于电极组件与壳体之间，粘接件包括层叠的第一胶层和第二胶层，第一胶层粘接壳体的内表面，第二胶层粘接电极组件的外表面；第一胶层包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂，第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的至少一种。本申请提供的二次电池中，第一胶层包括上述物质，能够增大第一胶层和壳体内表面的摩擦系数，一方面有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，从而降低电极组件外表面撕裂的可能性；另一方面还有利于延缓电极组件和壳体之间的相对运动，从而降低二次电池顶封冲开、漏液的风险，进而改善二次电池的安全性能。
在本申请的一些实施方案中，基于第一胶层的质量，苯乙烯-异戊二烯-苯乙烯嵌段共聚物的质量百分含量为32.5％至75％，第一树脂的质量百分含量为15％至45％。通过调控苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂的含量在本申请范围内，能够增大第一胶层和壳体内表面的摩擦系数，一方面有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，从而降低电极组件外表面撕裂的可能性；另一方面还 有利于延缓电极组件和壳体之间的相对运动，从而降低二次电池顶封冲开、漏液的风险，进而改善二次电池的安全性能。
在本申请的一些实施方案中，基于第一胶层的质量，第一树脂的质量百分含量为20％至40％。通过调控第一树脂的质量百分含量在上述范围内，可以进一步提高二次电池的安全性能。
在本申请的一些实施方案中，基于第一胶层的质量，第一树脂的质量百分含量为25％至35％。通过调控第一树脂的质量百分含量在上述范围内，可以进一步提高二次电池的安全性能。
在本申请的一些实施方案中，第一胶层还包括功能树脂，基于第一胶层的质量，功能树脂的质量百分含量为5％至25％；功能树脂包括乙烯-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至少一种。调控功能树脂的质量百分含量在上述范围内并选择上述材料，可以提高第一胶层长期高温浸泡电解液的粘结稳定性，从而提高二次电池的安全性能。
在本申请的一些实施方案中，第一胶层还包括添加剂和抗氧剂；基于第一胶层的质量，添加剂的质量百分含量为1％至5％，抗氧剂的质量百分含量为1％至5％。第一胶层包括添加剂和抗氧剂并调控其含量在上述范围内，可以提高第一胶层的耐热性及其在电解液中的抗氧化能力，从而改善第一胶层的粘结性能，提高二次电池的安全性能。在本申请的一些实施方案中，粘接件还包括基材层，基材层位于第一胶层和第二胶层之间；基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。粘接件包括基材层并选择上述材料，可以增大粘接件和壳体之间的摩擦力，从而提高二次电池的安全性能。
在本申请的一些实施方案中，第一胶层的面积为S1，电极组件沿电极组件、粘接件和壳体的层叠方向的正投影面积为S2，S1/S2满足10％≤S1/S2≤95％，通过调控S1/S2的值在上述范围内，有利于提高二次电池的安全性能。
在本申请的一些实施方案中，壳体为包装袋，本申请的粘接件应用于壳体为包装袋的二次电池时，二次电池具有高能量密度和良好的安全性能。
在本申请的一些实施方案中，第一胶层的厚度为2μm至20μm。通过调控第一胶层的厚度在上述范围内，可以减少二次电池能量密度的损失，同时提高二次电池的安全性能。
在本申请的一些实施方案中，粘接件与壳体之间的剥离强度为10N/m至500N/m。通过调控粘接件与壳体之间的剥离强度在上述范围内，可以降低粘接件和电极组件之间的粘结 界面被破坏的可能性，从而改善二次电池的安全性能。
在本申请的一些实施方案中，二次电池的保液系数为1g/Ah至2.5g/Ah。二次电池的保液系数在上述范围内，有利于第一胶层中的第一树脂在电解液中发生溶胀，进一步增大第一胶层和壳体内表面的摩擦系数，改善二次电池的凸点、胀液等问题，从而提高二次电池的安全性能。
本申请的第二方面提供了一种电子装置，其包括本申请第一方面提供的二次电池。本申请的二次电池具有良好的安全性能，从而本申请第二方面提供的电子装置具有较长的使用寿命。
本申请提供了一种二次电池和电子装置，其中，二次电池包括电极组件、电解液、壳体以及粘接件，粘接件设置于电极组件与壳体之间，粘接件包括层叠的第一胶层和第二胶层，第一胶层粘接壳体的内表面，第二胶层粘接电极组件的外表面；第一胶层包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂，第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的至少一种。第一胶层中包括第一树脂，第一树脂的分子链柔顺性好、内聚力低，使得第一胶层在低温下能够快速发挥粘性，在高温下柔顺性好，粘结性能稳定。本申请提供的二次电池中，第一胶层中的第一树脂在电解液中发生溶胀，能够增大第一胶层和壳体内表面之间的摩擦系数，一方面有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，从而降低电极组件外表面撕裂的可能性；另一方面还有利于延缓电极组件和壳体之间的相对运动，从而降低二次电池顶封冲开、漏液的风险，进而提高二次电池的安全性能。
附图说明
此处所说明的附图用来提供对本申请的进一步理解，构成本申请的一部分，本申请的示意性实施例及其说明用于解释本申请，并不构成对本申请的不当限定。
图1为本申请的一种实施方式中的粘接件的层叠结构示意图；
图2为第一树脂在电解液中溶胀前后的分子间的位置的示意图；
图3为本申请的另一种实施方式中的粘接件的层叠结构示意图；
图4为本申请的一种实施方式中粘接件粘结在电极组件外表面的示意图。
附图标记：粘接件10、第一胶层11、第二胶层12、基材层13、电极组件20、溶胀前的第一树脂30、溶胀后第一树脂31。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照附图并举实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他实施例，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方式中，以锂离子电池作为二次电池的例子来解释本申请，但是本申请的二次电池并不仅限于锂离子电池。
本申请第一方面提供了一种二次电池，包括电极组件、电解液、壳体以及粘接件，粘接件设置于电极组件与壳体之间，如图1所示，粘接件10包括层叠的第一胶层11和第二胶层12，第一胶层11粘接壳体的内表面，第二胶层12粘接电极组件的外表面。第一胶层11包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂，第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的至少一种。第一胶层中包括第一树脂，第一树脂的分子链柔顺性好、内聚力低，使得第一胶层在低温下快速发挥粘性，在高温下柔顺性好，粘结性能稳定。本申请提供的二次电池中，第一胶层包括上述物质并调控其含量在本申请范围内，第一胶层中的第一树脂在电解液中发生溶胀，如图2所示，溶胀前的第一树脂30其分子间的位置相对固定，在电解液中溶胀后，溶胀后第一树脂31分子间相对固定位置被电解液的小分子挤兑放大。第一树脂发生溶胀可以增大摩擦力，则能够增大第一胶层和壳体内表面的摩擦系数。本申请提供的二次电池中，第一胶层中包括第一树脂，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，一方面，有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，降低电极组件外表面撕裂的可能性；另一方面，还有利于延缓电极组件和壳体之间的相对运动，降低二次电池顶封冲开、漏液的风险，进而提高二次电池的安全性能。
在本申请的一些实施方案中，基于第一胶层的质量，苯乙烯-异戊二烯-苯乙烯嵌段共聚物的质量百分含量为32.5％至75％，第一树脂的质量百分含量为15％至45％，优选地，第一树脂的质量百分含量为20％至40％，进一步优选，第一树脂的质量百分含量为25％至35％。例如苯乙烯-异戊二烯-苯乙烯嵌段共聚物的质量百分含量可以为32.5％、35％、45％、50％、55％、65％、75％或其中任意两个数值组成的范围，第一树脂的质量百分含量可以为15％、20％、25％、27％、30％、33％、35％、40％、45％或其中任意两个数值组成的范围，通过调控苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂的含量在本申请范围内，能够增 大第一胶层和壳体内表面的摩擦系数，一方面有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，从而降低电极组件外表面撕裂的可能性；另一方面还有利于延缓电极组件和壳体之间的相对运动，从而降低二次电池顶封冲开、漏液的风险，进而改善二次电池的安全性能。当第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的两种或两种以上时，对各物质的含量没有特别限制，只要能实现本申请的目的即可。
在本申请中，丙烯腈-丁二烯-苯乙烯共聚物的单体包括丙烯腈、丁二烯和苯乙烯，基于丙烯腈-丁二烯-苯乙烯共聚物的质量，丙烯腈的质量百分含量为5％至35％，丁二烯的质量百分含量为20％至55％，苯乙烯的质量百分含量为10％至45％。通过调控丙烯腈-丁二烯-苯乙烯共聚物的单体丙烯腈、丁二烯和苯乙烯的质量百分含量在上述范围内，有利于提高第一树脂的综合性能，例如第一树脂具有良好的耐化学性和热稳定性、高弹性和良好的韧性、较高的硬度和良好的可加工性，其中丙烯腈提供耐化学性和热稳定性，丁二烯提供高弹性和韧性，苯乙烯提供硬度和可加工性，从而可以改善第一胶层的粘结性能，改善电极组件表面及其四角胀液的问题，增大第一胶层和壳体内表面的摩擦系数，降低电极组件外表面撕裂的可能性和二次电池顶封冲开、漏液的风险，改善二次电池的安全问题。
在本申请中，第一胶层与壳体内表面的摩擦系数为0.3至0.9。说明第一胶层与壳体内表面的摩擦系数较大，一方面，有利于降低粘接件边缘的应力，降低粘接件和电极组件之间的粘结界面被破坏的可能性，从而降低电极组件外表面撕裂的可能性；另一方面，还有利于延缓电极组件和壳体之间的相对运动，从而降低二次电池顶封冲开、漏液的风险，进而提高二次电池的安全性能。
在本申请的一些实施方案中，第一胶层还包括功能树脂，基于第一胶层的质量，功能树脂的质量百分含量为5％至25％，例如功能树脂的质量百分含量可以为5％、10％、12％、15％、18％、20％、25％或其中任意两个数值组成的范围；功能树脂包括乙烯-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至少一种。调控功能树脂的质量百分含量在上述范围内并选择上述材料，可以提高第一胶层长期高温浸泡电解液的形态稳定性，改善第一胶层的粘结性能，从而改善二次电池的安全性能。本申请中，上述高温指80℃至90℃。
在本申请的一些实施方案中，第一胶层还包括添加剂和抗氧剂；基于第一胶层的质量，添加剂的质量百分含量为1％至5％，抗氧剂的质量百分含量为1％至5％，添加剂的质量百 分含量可以为1％、2％、3％、4％、5％或为其中任意两个数值组成的范围，抗氧剂的质量百分含量可以为1％、2％、3％、4％、5％或为其中任意两个数值组成的范围。本申请对添加剂和氧化剂的种类没有特别限制，只要能实现本申请的目的即可。添加剂可以包括但不限于钛白粉、滑石粉、白炭黑或碳酸钙中的至少一种；抗氧剂可以包括但不限于二苯胺、亚磷酸三酯或硫代二丙酸双十八醇酯中的至少一种。第一胶层包括添加剂和抗氧剂并调控其含量在上述范围内，可以提高第一胶层的耐热性及其在电解液中的抗氧化能力，从而改善第一胶层的粘结性能，提高第一胶层的稳定性，提高二次电池的安全性能。
在本申请的一些实施方案中，如图3所示，粘接件10还包括基材层13，基材层13位于第一胶层11和第二胶层12之间；基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。本申请对基材层中上述物质的含量没有特别限制，本领域技术人员可以根据实际需要进行调整，只要能实现本申请的目的即可。本申请对基材层中上述物质的重均分子量没有特别限制，本领域技术人员可以根据实际需要进行选择，只要能实现本申请的目的即可，例如其重均分子量可以为10000至500000。当基材层中包含多种上述物质时，各物质的含量没有特别限制，只要能实现本申请的目的即可。粘接件包括基材层并选择上述材料，使粘接件具有一定硬度，在粘接时改善打皱与气泡问题，拓宽粘接件的制程加工窗口，既可以面压加工或者辊压加工，同时有效防止毛刺及碎屑等异物，保护电极组件，从而提高二次电池的安全性能。
本申请的基材层还可以包括钴绿、钴蓝、普鲁士蓝、靛蓝、酞青蓝等着色剂，使得基材具有颜色，以便在生产过程中电感耦合器件(CCD)或有源像素传感器的电子设备(CMOS)识别，以便进行贴胶定位、贴胶、漏检等。本申请对基材层中的着色剂的含量没有特别限制，本领域技术人员可以根据实际需要进行调整，只要能实现本申请的目的即可。
在本申请的一些实施方案中，如图4所示，粘接件10粘接在电极组件20的外表面，第一胶层11的面积为S1，电极组件20沿电极组件20、粘接件10和壳体的层叠方向的正投影面积为S2，S1/S2满足10％≤S1/S2≤95％，例如S1/S2的值可以为10％、15％、25％、35％、40％、45％、55％、65％、75％、85％、95％或为其中任意两个数值组成的范围。通过调控S1/S2的值在上述范围内，能够使得粘接件和壳体之间具有较高的剥离强度，还不会因粘接件过大而影响封装，有利于改善二次电池的安全性能和加工性能。
在本申请的一些实施方案中，壳体为包装袋，例如包装袋可以为铝塑膜包装袋。本申请的粘接件应用于壳体为包装袋的二次电池时，二次电池具有高能量密度和良好的安全性 能。
在本申请的一些实施方案中，第一胶层的厚度为2μm至20μm，例如第一胶层的厚度可以为2μm、4μm、7μm、10μm、14μm、18μm、20μm或为其中任意两个数值组成的范围。通过调控第一胶层的厚度在上述范围内，可以减少二次电池能量密度的损失，同时提高二次电池的安全性能。
本申请对第二胶层的厚度和基材层的厚度没有特别限制，只要能实现本申请的目的即可，例如第二胶层的厚度的厚度为2μm至10μm，基材层的厚度为4μm至30μm。
在本申请的一些实施方案中，粘接件与壳体之间的剥离强度为10N/m至500N/m，例如粘接件与壳体之间的剥离强度可以为10N/m、30N/m、50N/m、70N/m、100N/m、150N/m、200N/m、250N/m、300N/m、400N/m、500N/m或为其中任意两个数值组成的范围。通过调控粘接件与壳体之间的剥离强度在上述范围内，可以改善粘接件边缘的电极极片表面撕裂的问题，从而提高二次电池的安全性能。
在本申请的一些实施方案中，二次电池的保液系数为1g/Ah至2.5g/Ah，例如二次电池的保液系数可以为1g/Ah、1.2g/Ah、1.5g/Ah、1.7g/Ah、2g/Ah、2.3g/Ah、2.5g/Ah或为其中任意两个数值组成的范围。二次电池的保液系数在上述范围内，有利于第一胶层中的第一树脂在电解液中发生溶胀，有利于进一步增大第一胶层和壳体内表面的摩擦系数，改善二次电池的凸点、胀液等问题，从而改善二次电池的安全性能。
本申请对于粘接件的制备方法没有特别限制，只要能够实现本申请的目的即可。例如，本申请可以采用如下方法制备：将苯乙烯-异戊二烯-苯乙烯嵌段共聚物、第一树脂、功能树脂、添加剂、抗氧剂混合均匀，在100℃至150℃热熔然后涂布在基材层的一个表面上，烘干形成第一胶层；在基材层的另一个表面涂布第二胶层的材料，烘干形成第二胶层，得到粘接件。
本申请对苯乙烯-异戊二烯-苯乙烯嵌段共聚物、第一树脂、功能树脂的重均分子量没有特别限定，本领域技术人员可以根据实际需要进行选择，只要能实现本申请的目的即可。例如，苯乙烯-异戊二烯-苯乙烯嵌段共聚物的重均分子量可以为50000至150000，第一树脂的重均分子量可以为10000至500000，功能树脂的重均分子量可以为100000至300000。本申请对于第二胶层的材料没有特别限制，只要能够实现本申请的目的即可。例如第二胶层的材料可以包括聚甲基丙烯酸甲酯(PMMA，俗称亚克力)、聚丙烯(PP)、聚乙烯(PE)或聚酰胺中的至少一种。
本申请的二次电池包括电极组件、电解液、壳体以及粘接件，电极组件和电解液容纳于壳体中。本申请对电极组件的结构没有特别限制，只要能够实现本申请目的即可。例如，电极组件的结构为叠片结构或卷绕结构。电极组件包括正极极片、负极极片和隔膜，隔膜设置于正极极片和负极极片之间。隔膜用以分隔正极极片和负极极片，以防止二次电池内部短路，其允许电解质离子自由通过，且不影响电化学充放电过程的进行。
本申请对正极极片没有特别限制，只要能够实现本申请目的即可。例如，正极极片包含正极集流体和设置在正极集流体至少一个表上的正极活性材料层。本申请对正极集流体没有特别限制，只要能够实现本申请目的即可。例如，正极集流体可以包含铝箔或铝合金箔等。本申请的正极活性材料层包含正极活性材料。本申请对正极活性材料的种类没有特别限制，只要能够实现本申请目的即可。例如，正极活性材料可以包含镍钴锰酸锂(NCM811、NCM622、NCM523、NCM111)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂(LiCoO2)、锰酸锂、磷酸锰铁锂或钛酸锂等中的至少一种。在本申请中，对正极集流体和正极活性材料层的厚度没有特别限制，只要能够实现本申请目的即可。例如，正极集流体的厚度为4μm至20μm，优选为4μm至18μm。单面正极活性材料层的厚度为30μm至120μm。在本申请中，正极活性材料层可以设置于正极集流体厚度方向上的一个表面上，也可以设置于正极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是正极集流体的全部区域，也可以是正极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。本申请的正极活性材料层还可以包含导电剂和粘结剂。上述导电剂和粘结剂没有特别限制，只要能够实现本申请目的即可。例如，导电剂可以包括导电炭黑(Super P)、碳纳米管(CNTs)、碳纳米纤维、鳞片石墨、碳点或石墨烯等中的至少一种。粘结剂可以包括聚丙烯醇、聚丙烯酸钠、聚丙烯酸钾、聚丙烯酸锂、聚酰亚胺、聚酰胺酰亚胺、丁苯橡胶(SBR)、聚乙烯醇(PVA)、聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、水性丙烯酸树脂、羧甲基纤维素锂(CMC-Li)或羧甲基纤维素钠(CMC-Na)等中的至少一种。
本申请对负极极片没有特别限制，只要能够实现本申请目的即可。例如，负极极片包含负极集流体和设置在负极集流体至少一个表面上的负极活性材料层。本申请对负极集流体没有特别限制，只要能够实现本申请目的即可。例如，负极集流体可以包含铜箔、铜合金箔、镍箔、不锈钢箔、钛箔、泡沫镍或泡沫铜等。本申请的负极活性材料层包含负极活性材料。本申请对负极活性材料的种类没有特别限制，只要能够实现本申请目的即可。例如，负极活性材料可以包含天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、 硅、硅-碳复合物、SiOx(0<x≤2)、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO2、尖晶石结构的钛酸锂Li4Ti5O12、Li-Al合金或金属锂中的至少一种。在本申请中，对负极集流体、负极活性材料层的厚度没有特别限制，只要能够实现本申请目的即可。例如，负极集流体的厚度为4μm至10μm，负极活性材料层的厚度为30μm至130μm。在本申请中，负极活性材料层可以设置于负极集流体厚度方向上的一个表面上，也可以设置于负极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是负极集流体的全部区域，也可以是负极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。任选地，负极活性材料层还可以包括导电剂和粘结剂。本申请对负极活性材料层中的导电剂和粘结剂的种类没有特别限制，只要能够实现本申请目的即可，例如本申请的负极活性材料层可以包括上述导电剂和粘结剂。本申请对负极活性材料层中负极活性材料、导电剂和粘结剂的质量比没有特别限制，只要能够实现本申请目的即可。
本申请对隔膜没有特别限制，只要能够实现本申请目的即可，例如隔膜的材料可以包括但不限于聚乙烯(PE)、聚丙烯(PP)、聚四氟乙烯为主的聚烯烃(PO)类隔膜、聚酯膜(例如聚对苯二甲酸二乙酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)、氨纶或芳纶膜等中的至少一种。隔膜的类型可以包括但不限于织造膜、非织造膜(无纺布)、微孔膜、复合膜、碾压膜或纺丝膜等中的至少一种。本申请的隔膜可以具有多孔结构，多孔层设置在隔膜的至少一个表面上，多孔层包括无机颗粒和粘结剂，无机颗粒可以包括氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡中的至少一种。粘结剂可以包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素纳、聚乙烯吡咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。本申请对多孔结构的孔径的尺寸没有特别限制，只要能实现本申请的目的即可，例如，孔径的尺寸可以为0.01μm至1μm。在本申请中，隔膜的厚度没有特别限制，只要能实现本申请的目的即可，例如厚度可以为5μm至500μm。
在本申请中，电解液包括锂盐和非水溶剂。锂盐可以包括LiPF6、LiBF4、LiClO4、LiB(C6H5)4、LiCH3SO3、LiCF3SO3、LiN(SO2CF3)2、LiC(SO2CF3)3、Li2SiF6、双草酸硼酸锂(LiBOB)或二氟硼酸锂中的至少一种。本申请对锂盐在电解液中的浓度没有特别限制，只要能实现本申请的目的即可。本申请对非水溶剂没有特别限制，只要能实现本申请的目 的即可，例如可以包括但不限于碳酸酯化合物、羧酸酯化合物、醚化合物或其它有机溶剂中的至少一种。上述碳酸酯化合物可以包括但不限于链状碳酸酯化合物、环状碳酸酯化合物或氟代碳酸酯化合物中的至少一种。上述链状碳酸酯化合物可以包括但不限于碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)或碳酸甲乙酯(MEC)中的至少一种。上述环状碳酸酯可以包括但不限于碳酸乙烯酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)或碳酸乙烯基亚乙酯(VEC)中的至少一种。氟代碳酸酯化合物可以包括但不限于氟代碳酸乙烯酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯或碳酸三氟甲基亚乙酯中的至少一种。上述羧酸酯化合物可以包括但不限于甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯或己内酯中的至少一种。上述醚化合物可以包括但不限于二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、1-乙氧基-1-甲氧基乙烷、2-甲基四氢呋喃或四氢呋喃中的至少一种。上述其它有机溶剂可以包括但不限于二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯或磷酸三辛酯中的至少一种。
本申请对二次电池的种类没有特别限制，其可以包括发生电化学反应的任何装置。例如，二次电池可以包括但不限于：锂金属二次电池、锂离子电池、钠离子电池、锂聚合物二次电池、锂离子聚合物二次电池。本申请对二次电池的形状没有特别限制，只要能够实现本申请目的即可。
二次电池的制备过程为本领域技术人员所熟知的，本申请没有特别的限制，例如，可以包括但不限于以下步骤：将正极极片、隔离膜和负极极片按顺序堆叠，并根据需要将其进行卷绕、折叠等操作得到卷绕结构的电极组件，将电极组件放入包装袋内，将电解液注入包装袋并封口，得到二次电池；或者，将正极极片、隔离膜和负极极片按顺序堆叠，然后用胶带将整个叠片结构的四个角固定好得到叠片结构的电极组件，将电极组件置入包装袋内，将电解液注入包装袋并封口，得到二次电池。此外，也可以根据需要将防过电流元件、导板等置于包装袋中，从而防止二次电池内部的压力上升、过充放电。
本申请的第二方面提供了一种电子装置，其包括本申请第一方面提供的二次电池。本申请的二次电池具有良好的安全性能，从而本申请第二方面提供的电子装置具有较长的使 用寿命。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。例如，电子装置可以包括但不限于：笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器。
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。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
第一胶层组成测试：
拆解锂离子电池，取出第一胶层，然后通过傅里叶红外光谱(FTIR)测试和热裂解-气相色谱-质谱联用技术(PY-GCMS)质谱分析仪(GCMS)测试第一胶层中的组分和各组分的比例。
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粘接件和壳体(包装袋)之间的剥离强度。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，将粘接件以及与之粘接的电极组件的部分和包装袋部分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粘接件上的包装袋的另一端，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粘接件和壳体之间的剥离强度，记为F，单位为N/m。
剥离强度-温度变化测试：
按照实施例1-1的方法制备锂离子电池，将锂离子电池化成温度分别设置为65℃、75℃、80℃、85℃、90℃，记为五种样品，再按照上述剥离强度测试的方法制样，按照上述剥离 强度的测试方法测得上述五种样品的粘接件和壳体之间的剥离强度，单位为N/m。
静摩擦系数测试：
根据GB/T 10006-2021《塑料薄膜和薄片摩擦系数的测定》使用MXD-02摩擦系数仪测试第一胶层和壳体的内表面的摩擦系数。测试过程如下：将试验板安置在水平操作台上，将粘接件通过第二胶层粘接在铝箔上，裁切为50mm×50mm的试样，将上述试样在85℃的电解液中浸泡4h，浸泡结束后用无尘纸擦拭表面的电解液，在室温环境下用双面胶(日东5000NS)将上述试样固定在试验板上，记为第一试样。将包装袋裁切为100mm×100mm作为第二试样固定在重力为65g的滑块上。将两个试样测试表面水平相对放置在一起，均匀施加接触压力，使两个试样的表面相对移动，记录初始滑动所需的力(静摩擦力)，静摩擦力除以滑块的重力即为静摩擦系数，也即第一胶层和壳体的内表面的摩擦系数x。上述电解液与实施例1-1中的电解液的制备方法相同。
滚筒测试：
将锂离子电池在室温环境下静置60min后测试电压，测试滚筒测试前锂离子电池的电压；将锂离子电池装入夹具中，在20±5℃的测试环境中采用滚筒设备进行测试，锂离子电池放置位置距离地面1m，以12圈/min的转速自由跌落250圈(2次跌落为1圈)，测试结束测量记锂离子电池的电压，测试前后均锂离子电池的检查外观并拍照。滚筒测试通过判断标准：不冒烟，不漏液，电压降<50mV。
跌落测试：
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。
保液系数测试：
在25℃下，将锂离子电池以0.5C充电至4.5V，再恒压充电到0.05C，静置5分钟后以0.1C放电至3V，记录其放电容量Cp。拆解锂离子电池，经高速离心机离心得到游离的电解液，称重，记录电解液质量m，锂离子电池的保液系数y＝m/Cp，单位为g/Ah。
溶胀性能测试：
将实施例和对比例中的粘接件裁切为50mm×50mm的规格，测试质量为a g。在85℃ 电解液中浸泡7天后，观察浸泡电解液后粘接件的形态，并测试质量为b g，溶胀率＝(b-a)/b×100％。通过溶胀率来判定溶胀性能，粘接件的溶胀率在5％至30％范围内，则判定粘接件具有良好的溶胀性能。
上述电解液与实施例1-1中的电解液的制备方法相同。
实施例1-1
<正极极片的制备>
将正极活性材料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，得到涂层厚度为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材料的正极极片。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35mm×867mm。
<负极极片的制备>
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，得到涂层厚度为130μm的单面涂布负极活性材料的负极极片。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材料的负极极片。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37.5mm×875mm。
<隔膜的制备>
将PVDF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(Celgard公司提供)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氧化铝陶瓷层的隔膜。
<电解液的制备>
在干燥氩气气氛中，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LiPF6，溶解并混合均匀，得到锂 盐的浓度为1.15mol/L的电解液。
<粘接件的制备>
将苯乙烯-异戊二烯-苯乙烯嵌段共聚物(SIS，重均分子量100000)、第一树脂丙烯腈-丁二烯-苯乙烯共聚物(ABS，重均分子量300000)、功能树脂乙烯-乙酸乙烯共聚物(EVA，重均分子量120000)、添加剂钛白粉、抗氧剂二苯胺混合均匀，加热至150℃热熔，然后涂布在厚度为8μm的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第一胶层，在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的第二胶层，得到含有依次层叠设置的第一胶层、基材层和第二胶层的粘接件。其中，基于第一胶层的质量，SIS的质量百分含量为45％，第一树脂ABS的质量百分含量为30％，功能树脂EVA的质量百分含量为15％，添加剂钛白粉的质量百分含量为5％，抗氧剂二苯胺的质量百分含量为5％。形成ABS的三种单体的质量比丙烯腈:丁二烯:苯乙烯为20:35:45。
<锂离子电池的制备>
将上述制备的正极极片、隔膜、负极极片按顺序叠好，隔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。将上述制得的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，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S1＝600mm2，S2＝1200mm2。
实施例1-2至实施例1-18
除了按照表1调整制备参数以外，其余与实施例1-1相同。
实施例2-1至实施例2-3
除了按照表2调整第一胶层厚度以外，其余与实施例1-1相同。
实施例2-4至实施例2-7
除了按照表2调整第一胶层的面积S1、电极组件的面积S2不变以外，其余与实施例1-1相同。随着第一胶层面积S1的变化，第一胶层的长和宽等比例缩放。
实施例2-8至实施例2-9
除了按照表2调整保液系数y以外，其余与实施例1-1相同。
对比例1
除了第一胶层中不含第一树脂以及按照表1调整制备参数以外，其余与实施例1-1相同。
各实施例及对比例的相关制备参数及性能测试如表1和表2所示。
表1
注：表1中的“/”表示无相关参数，x为第一胶层与壳体内表面的摩擦系数，F为粘接件与壳体之间的剥离强度；上述聚氨酯的重均分子量为800000，上述聚苯乙烯的重均分子量为200000。
从实施例1-1至实施例1-10、实施例1-17至实施例1-18、对比例1可以看出，当第一胶层不包括第一树脂时，例如对比例1，虽然粘接件与壳体之间的剥离强度较高，但是第一胶层与壳体内表面的摩擦系数较小。即当第一胶层不包括第一树脂时，无法兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度。第一胶层包括SIS和第一树脂，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值更小，说明锂离子电池具有更好的安全性能。
SIS和第一树脂的质量百分含量会影响锂离子电池的安全性能。从实施例1-1至实施例1-10、实施例1-17至实施例1-18可以看出，通过调控SIS和第一树脂的质量百分含量在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值更小，说明锂离子电池具有更好的安全性能。
第一树脂的种类会影响锂离子电池的安全性能。从实施例1-1、实施例1-11至实施例1-16可以看出，第一树脂的种类在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
第一树脂为丙烯腈-丁二烯-苯乙烯共聚物时，形成丙烯腈-丁二烯-苯乙烯共聚物的单体的质量百分含量会影响锂离子电池的安全性能。从实施例1-1、实施例1-11至实施例1-14可以看出，丙烯腈-丁二烯-苯乙烯共聚物的单体的质量百分含量在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，可以改善第一胶层的粘结性能，改善电极组件表面及其四角胀液的问题，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
功能树脂的质量百分含量的变化会影响第一胶层与壳体内表面的摩擦系数x、粘接件与壳体之间的剥离强度F，进而影响锂离子电池的安全性能。从实施例1-1、实施例1-7至
实施例1-10可以看出，功能树脂的质量百分含量在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
添加剂和抗氧剂的质量百分含量的变化会影响第一胶层与壳体内表面的摩擦系数x、粘接件与壳体之间的剥离强度F，进而影响锂离子电池的安全性能。从实施例1-1、实施例1-7至实施例1-9可以看出，添加剂和抗氧剂的质量百分含量在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
实施例1-7的粘接件与包装袋之间的剥离强度-温度变化情况如下：在锂离子电池的化成温度分别为65℃、75℃、80℃、85℃、90℃下，本申请实施例1-7的粘接件与包装袋之间的剥离强度分别为376N/m、379N/m、383N/m、384N/m、387N/m，可以看出该实施例1-7的粘接件与包装袋之间的剥离强度在65℃至90℃保持同一水平，拓宽了锂离子电池化成过程的工艺窗口(65℃至90℃)。这是因为第一胶层中的第一树脂的分子链更加柔顺，第一胶层的内聚力偏低，在较低温度(65℃)下能够快速发挥粘性。对比例1的粘接件与包装袋之间的剥离强度-温度变化情况如下：在锂离子电池的化成温度分别为65℃、75℃、80℃、85℃、90℃下，对比例1的粘接件与包装袋之间的剥离强度分别为37N/m、142N/m、417N/m、423N/m、434N/m，可以看出该剥离强度逐渐增大后保持恒定，导致锂离子电池化成过程的工艺窗口窄(80℃至90℃)。
将本申请实施例1-1和对比例1中的粘接件裁切为重量为5g的长方体，在85℃电解液中浸泡24h后，本申请实施例1-1的粘接件溶胀至5.720g，溶胀率为14.4％。而对比例1中的粘接件溶胀至6.805g，溶胀率为36.1％且不成形态。说明本申请的粘接件在电解液中能够发生溶胀且形态稳定。
表2
注：表2中y为保液系数，x为第一胶层与壳体内表面的摩擦系数，F为粘接件与壳体之间的剥离强度。
第一胶层的厚度会影响锂离子电池的安全性能。从实施例1-1、实施例2-1至实施例2-3可以看出，第一胶层的厚度在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
S1/S2的值会影响锂离子电池的安全性能。从实施例1-1、实施例2-4至实施例2-7可以看出，S1/S2的值在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
二次电池的保液系数会影响锂离子电池的安全性能。从实施例1-1、实施例2-8至实施例2-9可以看出，二次电池的保液系数在本申请范围内，可以兼顾第一胶层与壳体内表面的摩擦系数以及粘接件与壳体之间的剥离强度，x和F的值均较大，锂离子电池的滚筒测试和跌落测试的失效数/总数的比值较小，说明锂离子电池具有良好的安全性能。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (13)

  1. 一种二次电池，包括电极组件、电解液、壳体以及粘接件，所述粘接件设置于所述电极组件与所述壳体之间，
    所述粘接件包括层叠的第一胶层和第二胶层，所述第一胶层粘接所述壳体的内表面，所述第二胶层粘接所述电极组件的外表面；所述第一胶层包括苯乙烯-异戊二烯-苯乙烯嵌段共聚物和第一树脂，所述第一树脂包括丙烯腈-丁二烯-苯乙烯共聚物、聚氨酯或聚苯乙烯中的至少一种。
  2. 根据权利要求1所述的二次电池，其特征在于，基于所述第一胶层的质量，所述苯乙烯-异戊二烯-苯乙烯嵌段共聚物的质量百分含量为32.5％至75％，所述第一树脂的质量百分含量为15％至45％。
  3. 根据权利要求1所述的二次电池，其特征在于，基于所述第一胶层的质量，所述第一树脂的质量百分含量为20％至40％。
  4. 根据权利要求1所述的二次电池，其特征在于，基于所述第一胶层的质量，所述第一树脂的质量百分含量为25％至35％。
  5. 根据权利要求1所述的二次电池，其特征在于，所述第一胶层还包括功能树脂，基于所述第一胶层的质量，所述功能树脂的质量百分含量为5％至25％；所述功能树脂包括乙烯-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至少一种。
  6. 根据权利要求1所述的二次电池，其特征在于，所述第一胶层还包括添加剂和抗氧剂；基于所述第一胶层的质量，所述添加剂的质量百分含量为1％至5％，所述抗氧剂的质量百分含量为1％至5％。
  7. 根据权利要求1所述的二次电池，其特征在于，所述粘接件还包括基材层，所述基材层位于所述第一胶层和所述第二胶层之间；所述基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。
  8. 根据权利要求1所述的二次电池，其特征在于，所述第一胶层的面积为S1，所述电极组件沿所述电极组件、所述粘接件和所述壳体的层叠方向的正投影面积为S2，S1/S2满足10％≤S1/S2≤95％。
  9. 根据权利要求1所述的二次电池，其特征在于，所述壳体为包装袋。
  10. 根据权利要求1所述的二次电池，其特征在于，所述第一胶层的厚度为2μm至20μm。
  11. 根据权利要求1所述的二次电池，其特征在于，所述粘接件与所述壳体之间的剥离强度为10N/m至500N/m。
  12. 根据权利要求9所述的二次电池，其特征在于，所述二次电池的保液系数为1g/Ah至2.5g/Ah。
  13. 一种电子装置，其包括权利要求1至12中任一项所述的二次电池。
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