WO2022262556A1 - 涂覆浆料、涂覆隔膜、隔膜制备方法及电池 - Google Patents

涂覆浆料、涂覆隔膜、隔膜制备方法及电池 Download PDF

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WO2022262556A1
WO2022262556A1 PCT/CN2022/095781 CN2022095781W WO2022262556A1 WO 2022262556 A1 WO2022262556 A1 WO 2022262556A1 CN 2022095781 W CN2022095781 W CN 2022095781W WO 2022262556 A1 WO2022262556 A1 WO 2022262556A1
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Prior art keywords
coating
coated
layer
photoinitiator
slurry
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PCT/CN2022/095781
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English (en)
French (fr)
Inventor
杨丹丹
平翔
黄慧桢
林于琳
Original Assignee
深圳市星源材质科技股份有限公司
江苏星源新材料科技有限公司
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Application filed by 深圳市星源材质科技股份有限公司, 江苏星源新材料科技有限公司 filed Critical 深圳市星源材质科技股份有限公司
Priority to KR1020237044147A priority Critical patent/KR20240010728A/ko
Priority to CN202280040428.1A priority patent/CN117916939A/zh
Priority to EP22824036.2A priority patent/EP4346000A1/en
Publication of WO2022262556A1 publication Critical patent/WO2022262556A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
    • C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
    • C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C09D127/16—Homopolymers or copolymers of vinylidene fluoride
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/36—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/36—After-treatment
    • C08J9/365—Coating
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
    • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C08L27/16—Homopolymers or copolymers or vinylidene fluoride
    • C—CHEMISTRY; METALLURGY
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    • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
    • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D179/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen, with or without oxygen, or carbon only, not provided for in groups C09D161/00 - C09D177/00
    • C09D179/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C09D179/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/20—Diluents or solvents
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    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
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    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J127/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Adhesives based on derivatives of such polymers
    • C09J127/02—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
    • C09J127/12—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Adhesives based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C09J127/16—Homopolymers or copolymers of vinylidene fluoride
    • 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H—ELECTRICITY
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    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
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    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
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    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
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    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
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    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
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    • H01—ELECTRIC ELEMENTS
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    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • C—CHEMISTRY; METALLURGY
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    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
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    • C08J2427/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C08J2427/16—Homopolymers or copolymers of vinylidene fluoride
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    • C08J2479/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2461/00 - C08J2477/00
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    • C09J179/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen, with or without oxygen, or carbon only, not provided for in groups C09J161/00 - C09J177/00
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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the technical field of battery diaphragms, in particular to a coating slurry used for coating battery diaphragms, a diaphragm coated with the slurry, a preparation method of the diaphragm, and a battery.
  • Lithium battery separator is one of the four core components in lithium-ion batteries. It plays a role in separating the positive and negative electrodes, allowing lithium ions to pass through, and insulating electrons in lithium-ion batteries. The performance of the separator directly affects the performance of lithium-ion batteries, and is one of the key technologies restricting the development of lithium-ion batteries.
  • Lithium-ion battery separators used in HEV Hybrid Electric Vehicle, hybrid electric vehicle
  • EV Electric Vehicle, electric vehicle
  • energy storage fields need to have performance requirements such as high heat resistance, low impedance, and high adhesion.
  • the invention provides a coating slurry, a coating diaphragm, a preparation method and a battery, so as to improve the heat resistance of the battery diaphragm.
  • a coating slurry includes solvent, adhesive polymer resin and photoinitiator; wherein, the weight ratio of the photoinitiator in the slurry is 0.08 -1.0 wt%;
  • the adhesive polymer resin includes one of PVDF-based adhesive resin polymer, polyimide, polyetherimide, polymethyl methacrylate or a combination thereof.
  • the PVDF-based adhesive resin polymer includes PVDF homopolymer, vinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-tetrafluoroethylene-propylene terpolymer, polyvinylidene fluoride One or a combination of ethylene-trifluoroethylene-chlorotrifluoroethylene terpolymers.
  • the photoinitiator includes one of ITX, benzophenone or a combination thereof.
  • a coated diaphragm including a base film, a ceramic layer, and an adhesive layer; wherein, the ceramic layer is coated on one or both sides of the base film; the coated An adhesive layer is coated on the ceramic layer, and the adhesive layer is formed by coating the coating slurry in the aforementioned first aspect and optional solutions.
  • the weight proportion of the photoinitiator in the glue layer is 0.05-0.3wt%.
  • the entire surface of the ceramic layer is coated with the adhesive layer.
  • the adhesive layer is distributed on the ceramic layer at intervals.
  • the area ratio of the strip-shaped adhesive layer to the gap is 1:1-5:1; wherein the gap is the gap between two adjacent adhesive layers.
  • the material of the ceramic layer includes inorganic materials, acrylate adhesives, polyacrylic adhesives, dispersants, wetting agents, thickeners, and defoamers.
  • the inorganic material may be one or more of silica, alumina, boehmite, titania, magnesia or nanofibers.
  • the base film is a PP base film or a PE base film or a PP/PE/PP composite base film.
  • a coated diaphragm including a base film, a ceramic layer, and an adhesive layer, wherein the ceramic layer is coated on one or both sides of the base film; The adhesive layer is coated on the ceramic layer; the adhesive strength of the coated diaphragm is ⁇ 15gf/25mm, the membrane rupture temperature is greater than 180°C, and the surface resistance is below 1.4 ⁇ .cm 2 .
  • a method for preparing a coated diaphragm involved in the aforementioned second aspect and optional solution or third aspect comprising the following steps:
  • the base film is coated with a ceramic layer on one or both sides;
  • the coated coating film is irradiated with ultraviolet light to initiate a crosslinking reaction to obtain a corresponding ultraviolet crosslinking coated separator.
  • the coating in the step (3) is full coating, specifically coating the coating slurry prepared above on the entire surface of the ceramic layer, and covering the entire surface of the ceramic layer The surface forms an adhesive layer.
  • the coating in the step (3) is gap coating, specifically coating the coating slurry prepared above on the ceramic layer in gaps, and forming a coating on the ceramic layer at intervals. glue layer.
  • the wavelength of the ultraviolet light used is in the range of 210nm-420nm
  • the ultraviolet crosslinking time is 0.001s-10s
  • the intensity of the radiated light is above 50mj/cm 2 .
  • a battery including a coated separator, a positive electrode, a negative electrode and an electrolyte, and the coated separator is the coated separator mentioned in the aforementioned second aspect, optional solution or third aspect.
  • the present invention has at least the following technical effects:
  • the coating slurry and coating diaphragm provided by the present invention are set to 0.08-1.0wt% by weight ratio of the photoinitiator in the slurry; this weight ratio range can make the slurry photoinitiate after being coated on the base film
  • the agent can penetrate into the base layer (ceramic layer and base film) well, and on the one hand, ensure that the photoinitiator produces enough active free radicals in the base film, ceramic layer and its combined interface layer, resulting in sufficient photoinitiation efficiency and
  • the degree of cross-linking ensures the complete cross-linking effect of the entire diaphragm surface, which greatly improves the membrane rupture temperature of the product; on the other hand, the remaining photoinitiator content in the adhesive layer will not be too much, which will not affect The surface resistance of the separator will not affect the interfacial impedance of the battery.
  • the weight ratio of the photoinitiator in the coating layer is 0.05-0.3wt%, so that the product will not affect the diaphragm when the membrane rupture temperature is increased.
  • the surface resistance has almost no effect.
  • the adhesive layer is coated on the ceramic layer for gaps, that is, the adhesive layer is distributed on the ceramic layer with strip intervals;
  • gap coating achieves a better penetration effect by using capillary action, so that the photoinitiator can better penetrate into the base layer (ceramic layer and base film) after the slurry is coated on the base film.
  • Fig. 1 is a structural schematic diagram 1 of a coated diaphragm provided by an embodiment of the present invention
  • Fig. 2 is a structural schematic diagram II of a coated diaphragm provided by an embodiment of the present invention
  • Fig. 3 is a structural schematic diagram III of a coated diaphragm provided by an embodiment of the present invention.
  • Fig. 4 is a structural schematic diagram 4 of a coated diaphragm provided by an embodiment of the present invention.
  • FIG. 5 is a schematic flow diagram of a method for preparing a coated diaphragm provided by an embodiment of the present invention
  • Fig. 6A is a SEM topography diagram 1 of the coated diaphragm obtained by the preparation method of the coated diaphragm provided by an embodiment of the present invention
  • Fig. 6 B is the partial SEM topography figure of the adhesive layer in Fig. 6 A;
  • Fig. 6C is the second SEM topography diagram of the coated diaphragm obtained by the preparation method of the coated diaphragm provided by an embodiment of the present invention.
  • Fig. 7 is a schematic diagram of the fitting curve of the membrane surface resistance test.
  • one way is to adopt the CCS+NIPS layered coating preparation process, that is, first coat the ceramic layer on both sides or one side of the PP or PE or PP/PE/PP base film to To ensure its heat resistance, an adhesive resin coating is performed on the ceramic layer to satisfy its adhesive performance.
  • the membrane rupture temperature of the obtained product is still limited.
  • oil-based mixed coating which is to select a high heat-resistant adhesive resin (such as polyetherimide) and a photoinitiator to coat on the base film, and then perform UV crosslinking.
  • a high heat-resistant adhesive resin such as polyetherimide
  • a photoinitiator to coat on the base film, and then perform UV crosslinking.
  • the general performance of the product of the conventional oily mixed coating process is not good.
  • the technical solution of the present application is obtained after studying the above-mentioned problems of the layered coating preparation process and the oily mixed coating process and after a series of research and experiments, aiming to solve the problem of how to improve the heat resistance of the separator.
  • the applicant combined the advantages of the CCS+NIPS layered coating preparation process and the oily mixed coating process, and creatively obtained a new preparation process for the coated separator, that is, first in PP or PE or The PP/PE/PP base film is coated with a ceramic layer on both sides or one side, and then the adhesive polymer resin slurry added with a photoinitiator is coated on the ceramic layer, and after the crosslinking reaction is initiated by ultraviolet radiation , to obtain the corresponding coated membrane.
  • This process combines the advantages of CCS+NIPS layered coating preparation process and oily mixed coating process, and improves the heat resistance and rupture temperature of the separator. However, even under this process, the improvement of the heat resistance of the separator is still insignificant.
  • the amount of photoinitiator added is crucial to the performance of the product; if the amount of photoinitiator added is too much, side reactions will occur during the working process of the resulting diaphragm, which will affect the performance of the product ; If the amount of photoinitiator added is too small, the amount of photoinitiator penetrated into the ceramic layer is not enough, the crosslinking reaction is insufficient, and the heat resistance is affected.
  • the coating method of the adhesive polymer resin slurry (such as full coating and gap coating) also has a certain impact on the production cost and the overall performance of the product.
  • the applicant has optimized the content of the photoinitiator and the coating method on the basis of combining the advantages of the CCS+NIPS layered coating preparation process and the oily mixed coating process. It should be noted that the discovery and research process of the above technical problems should also be regarded as a factor of the inventiveness of the present invention.
  • Embodiments of the present invention firstly provide a coating slurry, the main components of which include a solvent, an adhesive polymer resin, and a photoinitiator; wherein, the weight ratio of the photoinitiator in the slurry is 0.08-1.0wt% ;
  • the adhesive polymer resin includes PVDF-based adhesive resin polymer, polyimide, polyetherimide, polymethyl methacrylate or a combination thereof.
  • the PVDF-based adhesive resin polymer includes PVDF homopolymer, vinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-tetrafluoroethylene-propylene terpolymer, polyvinylidene fluoride-three One or a combination of vinyl fluoride-chlorotrifluoroethylene terpolymers.
  • the addition amount of the adhesive polymer resin is 5-50wt%.
  • the additive amount of the adhesive polymer resin can be any point value in 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 28wt%, 30wt%, 40wt%, 50wt%, and any two The range between pip values.
  • the present invention is not limited thereto, and the addition of other adhesive polymer resins is also within the protection scope of the present invention, as long as the weight ratio of the photoinitiator in the slurry is 0.08 -1.0 wt% is sufficient.
  • the adhesive polymer resin of the present application also selects polyimide, polyetherimide, polymethacrylate Polymers such as esters are used as adhesive polymer resins. These polymers have super adhesive properties, but also have ultra-high heat resistance and good electrochemical performance; they help to improve the overall performance of the product.
  • the photoinitiator includes one of ITX, benzophenone or a combination thereof.
  • the amount of photoinitiator added is closely related to the performance of the diaphragm. If the amount of photoinitiator added is too small, the degree of crosslinking and curing will not be enough, and the improvement of the membrane rupture temperature may not be as expected; Too much remains in the separator and leads to an increase in cost.
  • the actual addition amount of the photoinitiator is usually above 1.0 wt%.
  • the weight ratio of the photoinitiator in the slurry is within the range of 0.08-1.0wt%.
  • the weight proportion of the initiator in the rubber coating layer is 0.05-0.3wt%. In this case, the performance of the product is the best.
  • the added amount of the photoinitiator in the slurry is 0.08wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt% , 0.9wt%, 1.0wt% any point value and the range between any two point values.
  • the solvent is NMP solvent.
  • the present invention also provides a kind of coated diaphragm, comprises base film 10, ceramic layer 20 and glue coating layer 30;
  • described ceramic layer 20 is coated on the single surface of described base film ( As shown in Figure 1 and Figure 3) or double-sided (as shown in Figure 2 and Figure 4);
  • the glue layer 30 is coated on the ceramic layer 20, and the glue layer 30 is formed by the aforementioned first Coating Slurry Coating Formation in Aspects and Alternatives.
  • the weight proportion of the photoinitiator in the glue layer 30 is 0.05-0.3wt%.
  • the photoinitiator can penetrate into the base layer (ceramic layer 20 and base film 10) rapidly and uniformly together with the solvent at the instant when the slurry is applied to the ceramic layer, thereby ensuring that the photoinitiator is in the base film layer, ceramic layer and Sufficient active free radicals are generated in the combined interface layer, resulting in sufficient photoinitiation efficiency and crosslinking degree, ensuring the complete crosslinking effect of the entire partition surface of the diaphragm, and the maximum increase in the membrane rupture temperature of the product; and, making the entire coating
  • the amount of photoinitiator remains in the range of 0.05-0.3wt% (for example, the content of photoinitiator in the coating can be any point value in 0.05%, 0.15%, 0.18%, 0.25%, 0.29%, 0.3%) and any two The range between point values), the applicant found that the photoinitiator in this proportion range can not only generate
  • the surface resistance of the diaphragm will increase significantly, which will affect the interface impedance of the battery; if it is lower than this range, the degree of crosslinking of the product will not be enough, and the membrane rupture temperature will not be improved.
  • the applicant has also noticed that when the photoinitiator accounts for 0.05-0.3wt% by weight in the glue layer 30, the influence of the slurry coating method is also very important, because the glue layer
  • the coverage rate is closely related to the physical properties of the product. The higher the coverage rate, the higher the bonding strength of the product surface layer, and the more photoinitiator dose is introduced; the higher the coverage rate, the lower the porosity, the greater the air permeability increase, and the electrolyte wettability speed. lower. It is necessary to comprehensively consider the various physical properties of the product and the control of the amount of initiator introduced.
  • the entire surface of the ceramic layer 20 is coated with the adhesive layer 30 , as shown in FIGS. 1 and 2 .
  • the gaps on the ceramic layer 20 are coated with the adhesive layer 30, and the adhesive layer 30 is distributed on the ceramic layer 20 at strip intervals, as shown in Figures 3 and 4 Show.
  • the area ratio of the strip-shaped adhesive layer to the gap is 1:1-5:1; wherein the gap is the gap between two adjacent adhesive-shaped layers.
  • the area ratio of the strip-shaped adhesive layer to the gap may be, for example, 1:1, 2:1, 3:1, 4:1, 5:1.
  • the material of the ceramic layer 20 is any one of inorganic materials, acrylic adhesives, polyacrylic adhesives, dispersants, wetting agents, thickeners, and defoamers.
  • the inorganic material includes any one of silica, alumina, boehmite, titanium oxide, magnesium oxide, nanofibers or a combination thereof.
  • the base film is a PP base film or a PE base film or a PP/PE/PP composite base film.
  • the thickness of the base material is 5-20 ⁇ m.
  • the thickness of the ceramic layer 20 is, for example, 1-6 ⁇ m;
  • the thickness of the adhesive layer 30 is, for example, 0.5-3 ⁇ m, and, when coated When the adhesive layer 30 is distributed on the ceramic layer 20 at strip intervals, the thickness of the adhesive layer 30 is preferably 0.5-2 ⁇ m, so that the photoinitiator penetrated into the base layer reaches a corresponding amount.
  • the adhesive layer is distributed on the ceramic layer with strip intervals, and the gap coating is not limited to the strip gap coating.
  • the gap coating is not limited to the strip gap coating.
  • It can also be dot-like gap coating, that is, the adhesive layer 30 is distributed on the ceramic layer 20 in dot-like shape.
  • the SEM topography image of the separator surface obtained on the basis of dot-like gap coating is shown in FIG. 6C .
  • the coating slurry and coating diaphragm provided by the present invention are set to 0.08-1.0wt% by weight ratio of the photoinitiator in the slurry; this weight ratio range can make the slurry photoinitiate after being coated on the base film
  • the agent can penetrate into the base layer (ceramic layer and base film) well, and on the one hand, ensure that the photoinitiator produces enough active free radicals in the base film, ceramic layer and its combined interface layer, resulting in sufficient photoinitiation efficiency and
  • the degree of cross-linking ensures the complete cross-linking effect of the entire diaphragm surface, which greatly improves the membrane rupture temperature of the product; on the other hand, the remaining photoinitiator content in the adhesive layer will not be too much, which will not affect The surface resistance of the separator will not affect the interfacial impedance of the battery.
  • the present invention also provides a method for preparing the aforementioned coated diaphragm, comprising the following steps:
  • S1 providing a base film, the base film is coated with a ceramic layer on one or both sides;
  • S4 Ultraviolet crosslinking: The coated base film is irradiated with ultraviolet light to initiate a crosslinking reaction to obtain a corresponding coated separator.
  • the coating in step S3 is full coating, specifically coating the coating slurry prepared above on the entire surface of the ceramic layer to form a Adhesive layer.
  • the coating in the step S3 is gap coating, specifically coating the coating slurry prepared above on the ceramic layer in gaps, and forming strip coatings at intervals on the ceramic layer.
  • Adhesive layer or dotted adhesive layer By applying the adhesive layer gap on the ceramic layer, that is, the adhesive layer is distributed on the ceramic layer at strip intervals or dot intervals; compared with full coating, gap coating achieves better by using capillary action. Penetration effect, so that the photoinitiator can better penetrate into the base layer (ceramic layer and base film) after the slurry is coated on the base film.
  • the gap coating ultraviolet light cross-linked lithium-ion battery separator provided by the present invention has ultra-high heat resistance, a thermal shrinkage rate of less than 5% at 150°C*30min, and an ultra-high membrane rupture temperature, which is greater than 180°C. Improve the safety performance of the product.
  • the wavelength of the ultraviolet light used is in the range of 210nm-420nm
  • the ultraviolet crosslinking time is 0.001s-10s
  • the intensity of the radiated light is above 50mj/cm 2 .
  • the photoinitiator or its combination photoinitiator can quickly generate active free radicals under the excitation of ultraviolet light, and the active free radicals can further initiate the activity in the base film layer, ceramic layer, adhesive polymer resin layer and its combined interface layer.
  • the groups generate reactive groups, dangling bonds, and free radicals, trigger grafting reactions, crosslinking reactions, and produce macromolecular network structures.
  • the graft and macromolecular network generated by the cross-linking reaction endow the separator with a stronger supporting framework, higher membrane rupture temperature and heat resistance.
  • the wavelength of ultraviolet light fluctuates within a certain range, so in other embodiments, the ultraviolet light can be in the range of 210-310nm, 250-390nm, 280-420nm, etc.
  • Cross-linking time and radiation intensity have great influence on the cross-linking effect. Since the inorganic particles contained in the formula have a certain shielding effect on ultraviolet light, when the ultraviolet light intensity is lower than 50mj/cm 2 , the cross-linking effect is poor.
  • FIG. 6A-FIG. 6B are the SEM topography diagrams of the surface of the diaphragm obtained on the basis of gap coating by adopting the preparation method of the coated diaphragm according to the embodiment of the present invention.
  • the coating The adhesive layer 30 is distributed on the ceramic layer 20 at strip intervals.
  • the adhesive layer is a surface coating full of holes, which can increase the liquid absorption rate of the electrolyte, reduce the air permeability, increase the permeability of the electrolyte, and the passage rate of lithium ions.
  • the present invention also provides a battery, including a coated separator, a positive electrode, a negative electrode and an electrolyte, and the coated separator is the aforementioned coated separator.
  • S1 Provide a base film, the base film is coated with a ceramic layer on one or both sides; specifically, the ceramic material is added into a solvent, and after fully dissolving, a ceramic slurry is obtained; then the ceramic slurry is coated on the base film single-sided or double-sided;
  • S4 Ultraviolet crosslinking: The coated base film is irradiated with ultraviolet light to initiate a crosslinking reaction to obtain a corresponding coated separator.
  • the base film used is a PP base film with a thickness of 10.4 ⁇ m; the ceramic material used is alumina; both sides of the base film are coated with ceramic layers.
  • the photoinitiator used is ITX.
  • Example 2 The differences between Example 2 and Example 1 are: the area ratio of the strip-shaped glue layer to the gap is 4:1; the content of the photoinitiator in the glue layer is 0.18wt%.
  • Other aspects of Embodiment 2 are the same as those of Embodiment 1, and will not be repeated here.
  • Example 3 The difference between Example 3 and Example 1 lies in that: the area ratio of the strip-shaped glue layer to the gap is 3:1; the content of the photoinitiator in the glue layer is 0.11wt%.
  • Other aspects of Embodiment 3 are the same as those of Embodiment 1, and will not be repeated here.
  • Example 4 The differences between Example 4 and Example 1 are: the area ratio of the strip-shaped glue layer to the gap is 2:1; the content of the photoinitiator in the glue layer is 0.1wt%.
  • Other aspects of Embodiment 4 are the same as those of Embodiment 1, and will not be repeated here.
  • Example 5 The difference between Example 5 and Example 1 lies in that: the area ratio of the strip-shaped glue layer to the gap is 1:1; the content of the photoinitiator in the glue layer is 0.06wt%.
  • Other aspects of Embodiment 5 are the same as those of Embodiment 1, and will not be repeated here.
  • Example 5 The difference between Example 5 and Example 1 lies in that the content of the photoinitiator in the slurry is 0.8wt%, and the content of the photoinitiator in the glue layer is 0.29wt%.
  • Other aspects of Embodiment 6 are the same as those of Embodiment 1, and will not be repeated here.
  • Embodiment 7 The difference between embodiment 7 and embodiment 1 is: the area ratio of the strip glued layer and the gap is 1:1; the content of photoinitiator in the slurry is 0.9wt%, and the The content of photoinitiator is 0.12wt%.
  • Other aspects of Embodiment 7 are the same as those of Embodiment 1, and will not be repeated here.
  • embodiment 8 The difference between embodiment 8 and embodiment 1 is that the gap coating is changed to full coating, that is, the adhesive layer covers the entire surface of the ceramic layer, that is, the area ratio of the strip adhesive layer to the gap is 1:0 ;
  • the content of the photoinitiator in the slurry is 0.10wt%, and the content of the photoinitiator in the glue layer is 0.08wt%.
  • Other aspects of Embodiment 8 are the same as those of Embodiment 1, and will not be repeated here.
  • Embodiment 8 The difference between embodiment 8 and embodiment 1 is that the gap coating is changed to full coating, that is, the adhesive layer covers the entire surface of the ceramic layer, that is, the area ratio of the strip adhesive layer to the gap is 1:0 ; The content of the photoinitiator in the coating layer is 0.39wt%.
  • Other aspects of Embodiment 9 are the same as Embodiment 1, and will not be repeated here.
  • embodiment 10 The difference between embodiment 10 and embodiment 6 is that the gap coating is changed to full coating, that is, the adhesive layer covers the entire surface of the ceramic layer, that is, the area ratio of the strip adhesive layer to the gap is 1:0 ;
  • the content of the photoinitiator in the coating layer is 0.78wt%.
  • Other aspects of Embodiment 10 are the same as Embodiment 6, and will not be repeated here.
  • embodiment 10 The difference between embodiment 10 and embodiment 7 is that the gap coating is changed to full coating, that is, the adhesive layer covers the entire surface of the ceramic layer, that is, the area ratio of the strip adhesive layer to the gap is 1:0 ;
  • the content of the photoinitiator in the coating layer is 0.85wt%.
  • Other aspects of Embodiment 11 are the same as Embodiment 7, and will not be repeated here.
  • Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the gap coating is changed to full coating, that is, the adhesive layer covers the entire surface of the ceramic layer, that is, the area ratio of the strip adhesive layer to the gap is 1:0 ; The content of the photoinitiator in the coating layer is 0.38wt%.
  • Other aspects of Comparative Example 1 are the same as those of Example 1, and will not be repeated here.
  • Comparative Example 2 The difference between Comparative Example 2 and Example 1 is: the area ratio of the strip glued layer and the gap is 1:1; the content of photoinitiator in the slurry is 0.04wt%, and the The content of photoinitiator is 0.03wt%.
  • Other aspects of Comparative Example 2 are the same as those of Example 1, and will not be repeated here.
  • Comparative Example 3 The difference between Comparative Example 3 and Example 1 is: the area ratio of the strip glued layer and the gap is 1:1; the content of photoinitiator in the slurry is 3.0wt%, and the The content of photoinitiator is 2.80wt%.
  • Other aspects of Comparative Example 3 are the same as those of Example 1, and will not be repeated here.
  • Table 1 shows the properties of the corresponding separator obtained in the above-mentioned Examples 1-11 and Comparative Examples 1-3.
  • the test method of the load is specifically: use the electronic balance weighing method to test the load; specifically:
  • the test method of thermal shrinkage rate at 150°C*30min is as follows: firstly, cut the diaphragm into 50mm*50mm size test samples along the transverse and longitudinal directions of the diaphragm; secondly, sandwich the cut samples between A4 papers, lay The A4 paper is: 5 sheets on the top and 5 sheets on the bottom; then, set the temperature of the oven to 150°C, wait until the temperature rises to the set temperature, and fully preheat to ensure that the internal temperature reaches the set temperature stably; And put the sample sandwiched between the A4 paper into the oven together with the A4 paper quickly. The sample should be placed in the middle of the upper layer of the oven, and the lower layer cannot be placed.
  • thermal shrinkage rate (length between initial marks-length between marks after heating)/length between initial marks ⁇ 100%.
  • the test method of adhesion force is: make a standard sample strip (coating film (25mm*180mm), pole piece (20mm*150mm)) of the coating film sample to be tested, and let the diaphragm coating surface Bond with the pole piece at a certain pressure and a temperature of 60°C, then clamp the pole piece and the other end of the sample with a clamp, and apply tension until the end of the tension machine stroke.
  • Tensile machine parameter setting positioning displacement: 150mm, test speed: 300mm/min.
  • the membrane rupture temperature is obtained through the TMA test.
  • the TMA test membrane rupture temperature refers to tensioning the separator with a certain force (simulating the state inside the battery), and then gradually increasing the temperature to membrane rupture.
  • the method for testing the surface resistance of the diaphragm is to use an electrochemical workstation to test the surface resistance of the diaphragm, specifically, comprising the following steps:
  • Example preparation Fold the diaphragm of the sample to be tested neatly, and cut out 4 circular samples with a diameter of 47mm;
  • gap coating has lower production cost with respect to full coating, shows higher liquid absorption (wetting property) and The surface resistance of the diaphragm is significantly reduced, and at the same time it shows better bonding performance, and the overall performance of its products is better.
  • Examples 1-8 and Comparative Example 2 it can be seen that when the content of the photoinitiator in the slurry is lower than the minimum content range of the application, the content of the photoinitiator in the coating layer is lower than the content of the application.
  • the minimum content range of the membrane the membrane rupture temperature is significantly reduced, such as the membrane rupture temperature in Comparative Example 2 is reduced to about 150 ° C.
  • comparative example 1-8 and comparative example 3 know, when the content of photoinitiator in the described slurry is higher than the maximum content range of the present application, the content of the photoinitiator in the described coating layer is higher than the content of the present application. In the highest content range, the adhesive force is significantly reduced, and the surface resistance of the separator is significantly increased.
  • the adhesive strength of the A side in Comparative Example 2 is reduced to below 30gf/25mm, and the adhesive strength of the B side is even reduced to 20.1gf/25mm;
  • the surface resistance of the separator reaches 2.4 ⁇ .cm 2 . Therefore, it shows that the content of the photoinitiator in the slurry of the present application and the range of the content of the photoinitiator in the glue layer can make the performance of the diaphragm product reach the optimum.

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Abstract

本发明提供了一种涂覆浆料、涂覆隔膜、制备方法及电池，该涂覆浆料主要成分包含有溶剂、粘接性聚合物树脂及光引发剂；光引发剂在浆料中的重量比为0.08-1.0wt％；粘接性聚合物树脂包括PVDF基粘接性树脂聚合物、聚酰亚胺、聚醚酰亚胺、聚甲基丙烯酸甲酯中的一种或组合。通过将光引发剂在浆料中的重量比设置为0.08-1.0wt％；该重量比范围可以使得浆料在涂覆到基膜后光引发剂能够很好地渗入到基底层内，保证光引发剂在基膜、陶瓷层以及其组合界面层内产生足够的活性自由基，产生足够的光引发效率和交联度，保证隔膜整个膜面完整的交联效果，使产品的破膜温度得到很大提升；并且剩余在涂胶层中的光引发剂的含量不会太多，从而不会影响隔膜的面电阻，不会影响电池的界面阻抗。

Description

涂覆浆料、涂覆隔膜、隔膜制备方法及电池 技术领域
本发明涉及电池隔膜技术领域，特别涉及一种电池隔膜涂覆使用的涂覆浆料、涂覆有上述浆料的隔膜、隔膜的制备方法及电池。
背景技术
锂电池隔膜是锂离子电池中四大核心组件之一，它在锂离子电池中起到分隔正负极、允许锂离子通过、对电子绝缘的作用。隔膜性能的优劣直接影响了锂离子电池的性能表现，是制约锂离子电池发展的关键技术之一。
应用于HEV(Hybrid Electric Vehicle，混合动力汽车)、EV(Electric Vehicle，电动汽车)、储能领域的锂离子电池隔膜需要具有高耐热、低阻抗、高粘接等性能要求。
然而现有的隔膜耐热性仍然不理想，因而如何有效地提高隔膜的耐热性能，已经成为业界亟需解决的技术问题。
发明内容
本发明提供一种涂覆浆料、涂覆隔膜、制备方法及电池，以提高电池隔膜的耐热性。
根据本发明的第一方面，提供了一种涂覆浆料，主要成分包含有溶剂、粘接性聚合物树脂以及光引发剂；其中，所述光引发剂在浆料中的重量比为0.08-1.0wt％；所述粘接性聚合物树脂包括PVDF基粘接性树脂聚合物、聚酰亚胺、聚醚酰亚胺、聚甲基丙烯酸甲酯中的一种或其组合。
一些实施例中，所述PVDF基粘接性树脂聚合物包括PVDF均聚物、偏氟乙烯-六氟丙烯共聚物、聚偏氟乙烯-四氟乙烯-丙烯三元共聚物、聚偏二氟 乙烯-三氟乙烯-氯三氟乙烯三元共聚物中的一种或其组合。
一些实施例中，所述光引发剂包括ITX、二苯甲酮中的一种或其组合。
根据本发明的第二方面，提供了一种涂覆隔膜，包括基膜、陶瓷层以及涂胶层；其中，所述陶瓷层涂覆在所述基膜的单面或双面；所述涂胶层涂覆在所述陶瓷层上，且所述涂胶层由前述第一方面及可选方案中的涂覆浆料涂覆形成。
一些实施例中，所述光引发剂在所述涂胶层中的重量占比为0.05-0.3wt％。
一些实施例中，所述陶瓷层的整面均涂覆有所述涂胶层。
一些实施例中，所述涂胶层间隔分布在所述陶瓷层上。
一些实施例中，条状涂胶层与间隙的面积比为1:1-5:1；其中所述间隙为相邻两涂胶层之间的间隙。
一些实施例中，所述陶瓷层的材料包含无机材料、丙烯酸酯类粘接剂、聚丙烯酸类粘接剂、分散剂、润湿剂、增稠剂、消泡剂。
一些实施例中，无机材料可以为二氧化硅、氧化铝、勃姆石、氧化钛、氧化镁或纳米纤维中的一种或多种。
一些实施例中，所述基膜为PP基膜或PE基膜或PP/PE/PP复合基膜。根据本发明的第三方面，提供了一种涂覆隔膜，包括基膜、陶瓷层以及涂胶层，其中，所述陶瓷层涂覆在所述基膜的单面或双面；所述涂胶层涂覆在所述陶瓷层上；所述涂覆隔膜的粘接强度≥15gf/25mm、破膜温度大于180℃、面电阻在1.4Ω.cm 2以下。
根据本发明的第四方面，提供了一种前述第二方面及可选方案或第三方面中涉及的涂覆隔膜的制备方法，包括以下步骤：
(1)提供基膜，所述基膜单面或双面涂覆有陶瓷层；
(2)制备浆料：把不多于5～50wt％的粘接性聚合物树脂、0.08-1.0wt％的光引发剂加入溶剂中，充分溶解后，得到涂覆浆料；
(3)涂覆：将上述制得的涂覆浆料涂覆于所述陶瓷层上，在所述陶瓷层 上形成涂胶层；
(4)紫外交联：将完成涂覆后的涂覆膜通过紫外光辐射引发交联反应，获得相应的紫外交联涂覆隔膜。
一些实施例中，所述步骤(3)中的涂覆为全涂覆，具体为将上述制得的涂覆浆料涂覆于所述陶瓷层的整面上，在所述陶瓷层的整面形成涂胶层。
一些实施例中，所述步骤(3)中的涂覆为间隙涂覆，具体为将上述制得的涂覆浆料间隙涂覆于所述陶瓷层上，在所述陶瓷层上间隔形成涂胶层。
一些实施例中，所用紫外光波长在210nm-420nm范围内，紫外交联时间为0.001s-10s，辐射光强度为50mj/cm 2以上。
根据本发明的第五方面，提供了一种电池，包括涂覆隔膜、正极、负极和电解质，所述涂覆隔膜为前述第二方面及可选方案或第三方面中涉及的涂覆隔膜。
与现有技术相比，本发明至少具有以下技术效果：
本发明提供的涂覆浆料和涂覆隔膜，通过将光引发剂在浆料中的重量比设置为0.08-1.0wt％；该重量比范围可以使得浆料在涂覆到基膜后光引发剂能够很好地渗入到基底层(陶瓷层和基膜)内，一方面保证光引发剂在基膜、陶瓷层以及其组合界面层内产生足够的活性自由基，产生足够的光引发效率和交联度，保证隔膜整个隔面完整的交联效果，使得产品的破膜温度得到很大提升；另一方面剩余在涂胶层中的光引发剂的含量不会太多，从而不会影响隔膜的面电阻，不会影响电池的界面阻抗。
在进一步优选方案中，本发明提供的涂覆隔膜，其光引发剂在所述涂胶层中的重量占比为0.05-0.3wt％，从而使得产品在提高破膜温度的情况下，对隔膜的面电阻几乎没有影响。
在进一步优选方案中，本发明提供的涂覆隔膜及涂覆隔膜的制备方法，涂胶层为间隙涂覆在陶瓷层上，即涂胶层以条状间隔分布在陶瓷层上；相对于全涂覆而言，间隙涂覆通过利用毛细作用实现更好的渗透效果，从而使得 浆料在涂覆到基膜后光引发剂能够更好地渗入到基底层(陶瓷层和基膜)内。
附图说明
以下结合附图和具体实施方式来进一步说明本发明；
图1为本发明一实施例提供的涂覆隔膜的结构示意图一；
图2为本发明一实施例提供的涂覆隔膜的结构示意图二；
图3为本发明一实施例提供的涂覆隔膜的结构示意图三；
图4为本发明一实施例提供的涂覆隔膜的结构示意图四；
图5为本发明一实施例提供的涂覆隔膜的制备方法的流程示意图；
图6A为本发明一实施例提供的涂覆隔膜的制备方法得到的涂覆隔膜的SEM形貌图一；
图6B为图6A中的涂胶层的局部SEM形貌图；
图6C为本发明一实施例提供的涂覆隔膜的制备方法得到的涂覆隔膜的SEM形貌图二；
图7为隔膜面电阻测试拟合曲线示意图。
具体实施方式
下面将对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
申请人在提出本申请之前，对现有的隔膜进行了一系列的研究及实验：
其中，为了保证耐热性，一种方式是采用CCS+NIPS分层涂覆制备工艺，即，首先在PP或PE或PP/PE/PP基膜上双面或单面涂覆陶瓷层，以保证其耐热性，之后在陶瓷层上进行粘结性树脂涂覆，以满足其粘接性能。但是得到的产品的破膜温度依然有限。
另一种方式是油性混合涂覆，也就是选择高耐热性粘接剂树脂(例如聚醚酰亚胺)和光引发剂涂覆在基膜上，然后进行UV交联。但是常规的油性混合涂覆工艺，其产品的综合性能并不好。
为了解决隔膜耐热性差的问题，申请人进行了一系列的理论研究和实验验证，比如申请人尝试了将常规的高耐热性粘接剂树脂替换为超高耐热性粘接剂树脂(例如聚醚酰亚胺)，但是耐热性的提高并不明显。
作为进一步研究方式，申请人尝试了改变粘接性聚合物树脂的含量，但是耐热性的提高并不明显。
因而，本申请的技术方案是在研究分层涂覆制备工艺和油性混合涂覆工艺的上述问题并经过系列研究和实验后得出的，旨在解决如何提高隔膜的耐热性的问题。
申请人经实验验证和分析，结合了CCS+NIPS分层涂覆制备工艺和油性混合涂覆工艺的优点，创造性地得到了一种新的涂覆隔膜的制备工艺，即先在PP或PE或PP/PE/PP基膜上双面或单面涂覆陶瓷层，然后将添加有光引发剂的粘接性聚合物树脂浆料涂覆在陶瓷层上，经过紫外光辐射引发交联反应后，获得相应的涂覆隔膜。该工艺结合了CCS+NIPS分层涂覆制备工艺和油性混合涂覆工艺的优点，提高了隔膜的耐热性和破膜温度。然而即使在该工艺下，隔膜的耐热性的提高仍然不太明显。申请人进一步研发和试验发现，一方面光引发剂的添加量对产品的性能影响至关重要；若光引发剂添加的量太多，得到的隔膜在工作过程中会发生副反应，影响产品性能；若光引发剂添加的量太少，渗入到陶瓷层中的光引发剂的量不够，交联反应不充分，影响耐热性。另一方面，粘接性聚合物树脂浆料的涂覆方式(如全涂覆、间隙涂覆)对生产成本以及产品综合性能也存在一定的影响。
有鉴于此申请人在结合了CCS+NIPS分层涂覆制备工艺和油性混合涂覆工艺的优点的基础上，对光引发剂的含量以及涂覆方式进行了优化。 需要注意的是，上述技术问题的发现和研究过程，也应作为本发明具有创造性的一个因素。
下面以具体地实施例对本发明的技术方案进行详细说明。下面这几个具体的实施例可以相互结合，对于相同或相似的概念或过程可能在某些实施例不再赘述。
本发明实施例首先提供一种涂覆浆料，主要成分包含有溶剂、粘接性聚合物树脂以及光引发剂；其中，所述光引发剂在浆料中的重量比为0.08-1.0wt％；所述粘接性聚合物树脂包括PVDF基粘接性树脂聚合物、聚酰亚胺、聚醚酰亚胺、聚甲基丙烯酸甲酯中的一种或其组合。
其中，所述PVDF基粘接性树脂聚合物包括PVDF均聚物、偏氟乙烯-六氟丙烯共聚物、聚偏氟乙烯-四氟乙烯-丙烯三元共聚物、聚偏二氟乙烯-三氟乙烯-氯三氟乙烯三元共聚物中的一种或其组合。
所述粘接性聚合物树脂的添加量为5～50wt％。例如，所述粘接性聚合物树脂的添加量可以为5wt％、10wt％、15wt％、20wt％、25wt％、28wt％、30wt％、40wt％、50wt％中的任意点值及任意两个点值之间的范围。当然，应该意识到，本发明并不以此为限，其他粘接性聚合物树脂的添加量也在本发明的保护范围之内，只需满足光引发剂在浆料中的重量比为0.08-1.0wt％即可。
需要说明的是，本申请的所述粘接性聚合物树脂在常规的PVDF基粘接性树脂聚合物的基础上，还选择了聚酰亚胺、聚醚酰亚胺、聚甲基丙烯酸甲酯等聚合物作为粘接性聚合物树脂，这些聚合物具有超强的粘接性，而且还具有超高的耐热性、良好的电化学性能；有助于改善产品的综合性能。
所述光引发剂包括ITX、二苯甲酮中的一种或其组合。光引发剂的添加量与隔膜性能密切相关，如光引发剂添加量过少，则交联固化程度不够，对破膜温度的改善可能达不到预期；如光引发剂添加量过多则在隔膜中残留过多，并且导致成本增加。现有的工艺中，光引发剂的实际添加量通常在1.0wt％以上。本发明通过研究光引发剂的机理并结合产品端的性能，得出光 引发剂在浆料中的重量比为0.08-1.0wt％的范围内，采用此浆料涂覆后得到的涂胶层中光引发剂在涂胶层中的重量占比为0.05-0.3wt％，此种情况下，产品的性能最佳。
例如，所述光引发剂在浆料中的添加量为0.08wt％、0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1.0wt％中的任意点值及任意两个点值之间的范围。
一些实施例中，所述溶剂为NMP溶剂。
请参考图1-图4，本发明还提供一种涂覆隔膜，包括基膜10、陶瓷层20以及涂胶层30；其中，所述陶瓷层20涂覆在所述基膜的单面(如图1、图3所示)或双面(如图2、图4所示)；所述涂胶层30涂覆在所述陶瓷层20上，且所述涂胶层30由前述第一方面及可选方案中的涂覆浆料涂覆形成。
其中，所述光引发剂在所述涂胶层30中的重量占比为0.05-0.3wt％。光引发剂可以在将浆料涂覆至陶瓷层的瞬间随着溶剂一起快速均匀地渗透至基底层(陶瓷层20和基膜10)中，从而保证光引发剂在基膜层、陶瓷层以及其组合界面层内产生足够的活性自由基，产生足够的光引发效率和交联度，保证隔膜整个隔面完整的交联效果，产品的破膜温度得到最大提升；并且，使整个涂层中的光引发剂量保持在0.05-0.3wt％范围内(例如涂层中光引发剂的含量可以是0.05％、0.15％、0.18％、0.25％、0.29％、0.3％中的任意点值及任意两个点值之间的范围)，申请人研究发现，此占比范围内的光引发剂不但可以产生足够的活性自由基，提高了光引发效率和交联度，产品的破膜温度得到最大提升；并且对隔膜的面电阻没有影响，超过此用量范围，隔膜的面电阻明显升高，影响电池的界面阻抗；如果低于此范围，产品的交联度不够，破膜温度得不到改善。
此外，申请人还注意到，当光引发剂在所述涂胶层30中的重量占比为0.05-0.3wt％，浆料的涂覆方式带来的影响也非常重要，因为涂胶层的 覆盖率和产品的物性紧密关系，覆盖率越高产品表层粘接强度越高，引入的光引发剂量也越多；覆盖率越高孔隙率越低，透气增量越大，电解液浸润性速度越低。需要综合考虑产品的各个物性以及对引发剂引入量的控制。
基于此，一种具体实施例中，所述陶瓷层20的整面均涂覆有所述涂胶层30，如图1及图2所示。
一种具体实施例中，所述陶瓷层20上间隙涂覆有所述涂胶层30，所述涂胶层30以条状间隔分布在所述陶瓷层20上，如图3及图4所示。
其中，作为具体实施方式，条状涂胶层与间隙的面积比为1:1-5:1；其中所述间隙为相邻两条状涂胶层之间的间隙。具体地，条状涂胶层与间隙的面积比例如可以为1:1、2:1、3:1、4:1、5:1。通过将涂胶层30以条状间隔分布在所述陶瓷层20上，可以充分地利用毛细作用，增加溶剂的浸润性，使得溶剂更好地渗透到基底层中。同时，减小了涂覆原料用量，降低了生产成本；粘接力满足设计要求，例如粘接强度≥15gf/25mm。
其中，所述陶瓷层20的材料为无机材料、丙烯酸酯类粘接剂、聚丙烯酸类粘接剂、分散剂、润湿剂、增稠剂、消泡剂中的任一种。具体地，无机材料包括二氧化硅、氧化铝、勃姆石、氧化钛、氧化镁、纳米纤维中的任一种或其组合。
其中，所述基膜为PP基膜或PE基膜或PP/PE/PP复合基膜。所述基材的厚度为5-20μm作为一种可选的实施方式，所述陶瓷层20的厚度例如为1-6μm；所述涂胶层30的厚度例如为0.5-3μm，并且，当涂胶层30以条状间隔分布在所述陶瓷层20上时，所述涂胶层30的厚度优选为0.5-2μm，从而进一步使得基底层中渗入的光引发剂达到对应的量。
当然，在间隙涂覆中，涂胶层以条状间隔分布在所述陶瓷层上仅是本发明的一种实施例，间隙涂覆并不仅限于条状间隙涂覆，在其它实施例中，还可以是点状间隙涂覆，也即涂胶层30呈点状分布在陶瓷层20上，在点状间隙涂覆的基础上得到的隔膜表面的SEM形貌图如图6C所示。
本发明提供的涂覆浆料和涂覆隔膜，通过将光引发剂在浆料中的重量比设置为0.08-1.0wt％；该重量比范围可以使得浆料在涂覆到基膜后光引发剂能够很好地渗入到基底层(陶瓷层和基膜)内，一方面保证光引发剂在基膜、陶瓷层以及其组合界面层内产生足够的活性自由基，产生足够的光引发效率和交联度，保证隔膜整个隔面完整的交联效果，使得产品的破膜温度得到很大提升；另一方面剩余在涂胶层中的光引发剂的含量不会太多，从而不会影响隔膜的面电阻，不会影响电池的界面阻抗。
请参考图5，如图5所示，本发明还提供了一种前述所涉及的涂覆隔膜的制备方法，包括以下步骤：
S1：提供基膜，所述基膜单面或双面涂覆有陶瓷层；
S2：制备浆料：把不多于5～50wt％的粘接性聚合物树脂、0.08-1.0wt％的光引发剂加入溶剂中，充分溶解后，得到涂覆浆料；
S3：涂覆：将上述制得的涂覆浆料涂覆于所述陶瓷层上，在所述陶瓷层上形成涂胶层；
S4：紫外交联：将完成涂覆后的基膜通过紫外光辐射引发交联反应，获得相应的涂覆隔膜。
一些实施例中，所述步骤S3中的涂覆为全涂覆，具体为将上述制得的涂覆浆料涂覆于所述陶瓷层的整面上，在所述陶瓷层的整面形成涂胶层。
一些实施例中，所述步骤S3中的涂覆为间隙涂覆，具体为将上述制得的涂覆浆料间隙涂覆于所述陶瓷层上，在所述陶瓷层上间隔形成条状涂胶层或点状涂胶层。通过将涂胶层间隙涂覆在陶瓷层上，即涂胶层以条状间隔或点状间隔分布在陶瓷层上；相对于全涂覆而言，间隙涂覆通过利用毛细作用实现更好的渗透效果，从而使得浆料在涂覆到基膜后光引发剂能够更好地渗入到基底层(陶瓷层和基膜)内。
本发明所提供间隙式涂覆紫外光交联锂离子电池用隔膜具有超高耐热性，150℃*30min热收缩率小于5％，以及超高破膜温度，破膜温度大 于180℃,进一步提升了产品的安全性能。
一些实施例中，所用紫外光波长在210nm-420nm范围内，紫外交联时间为0.001s-10s，辐射光强度为50mj/cm 2以上。光引发剂或其组合光引发剂在紫外光激发下能够迅速产生活性自由基，由活性自由基进一步引发基膜层、陶瓷层、粘接性聚合物树脂层以及其结合的界面层中的活性基团产生反应基、悬挂键、自由基，引发接枝反应、交联反应，产生大分子网络结构。交联反应产生的接枝和大分子网络赋予隔膜更强的支撑框架，具有更高的破膜温度、耐热性。
其中，紫外光的波长是在一定范围内波动的，因此在其他实施例中，紫外光可以是210～310nm、250～390nm、280～420nm等范围值，在波长范围值一定的情况下，紫外交联时间与辐射光强度对交联效果的影响较大，由于配方中含有无机粒子对紫外光有一定的遮蔽作用，当紫外光强度低于50mj/cm 2时，交联效果较差。
请参考图6A-图6B，其为采用本发明实施例的涂覆隔膜的制备方法，在间隙涂覆的基础上得到的隔膜表面的SEM形貌图，由图6A可以清楚地看出，涂胶层30以条状间隔分布在陶瓷层20上。由图6B可以看出，涂胶层则是表面充满孔洞的表面涂层，即可以增大电解液吸液率，也可以降低透气度，增加电解液的渗透性，以及锂离子的通过率。
此外，本发明还提供了一种电池，包括涂覆隔膜、正极、负极和电解质，所述涂覆隔膜为前述涉及的涂覆隔膜。
下面将通过实验分析本发明一些实施例的产品性能。
实施例1
S1：提供基膜，所述基膜单面或双面涂覆有陶瓷层；具体地，将陶瓷材料加入溶剂中，充分溶解后，得到陶瓷浆料；然后将陶瓷浆料涂覆至基膜的单面或双面；
S2：制备浆料：把不多于5～30wt％的粘接性聚合物树脂、0.4wt％的光引发剂加入溶剂中，充分溶解后，得到涂覆浆料；
S3：涂覆：将上述制得的涂覆浆料间隙涂覆于所述陶瓷层上，在所述陶瓷层上形成间隔分布的条状涂胶层；所述涂胶层中的光引发剂的含量为0.25wt％；条状涂胶层与间隙的面积比为5:1；
S4：紫外交联：将完成涂覆后的基膜通过紫外光辐射引发交联反应，获得相应的涂覆隔膜。
在本实施例中，所使用的基膜为PP基膜，其厚度为10.4μm；所使用的陶瓷材料为氧化铝；在基膜的双面涂覆有陶瓷层。所述光引发剂使用的为ITX。
实施例2
实施例2与实施例1的不同之处在于：条状涂胶层与间隙的面积比为4:1；所述涂胶层中的光引发剂的含量为0.18wt％。实施例2的其他方面与实施例1相同，在此不再赘述。
实施例3
实施例3与实施例1的不同之处在于：条状涂胶层与间隙的面积比为3:1；所述涂胶层中的光引发剂的含量为0.11wt％。实施例3的其他方面与实施例1相同，在此不再赘述。
实施例4
实施例4与实施例1的不同之处在于：条状涂胶层与间隙的面积比为2:1；所述涂胶层中的光引发剂的含量为0.1wt％。实施例4的其他方面与实施例1相同，在此不再赘述。
实施例5
实施例5与实施例1的不同之处在于：条状涂胶层与间隙的面积比为1:1；所述涂胶层中的光引发剂的含量为0.06wt％。实施例5的其他方面与实施例1相同，在此不再赘述。
实施例6
实施例5与实施例1的不同之处在于：所述浆料中光引发剂的含量为0.8wt％，所述涂胶层中的光引发剂的含量为0.29wt％。实施例6的其他方面与实施例1相同，在此不再赘述。
实施例7
实施例7与实施例1的不同之处在于：条状涂胶层与间隙的面积比为1:1；所述浆料中光引发剂的含量为0.9wt％，所述涂胶层中的光引发剂的含量为0.12wt％。实施例7的其他方面与实施例1相同，在此不再赘述。
实施例8
实施例8与实施例1的不同之处在于：将间隙涂覆改成全涂覆，即涂胶层覆盖陶瓷层的整面，也即条状涂胶层与间隙的面积比为1:0；所述浆料中光引发剂的含量为0.10wt％，所述涂胶层中的光引发剂的含量为0.08wt％。实施例8的其他方面与实施例1相同，在此不再赘述。
实施例9
实施例8与实施例1的不同之处在于：将间隙涂覆改成全涂覆，即涂胶层覆盖陶瓷层的整面，也即条状涂胶层与间隙的面积比为1:0；所述涂胶层中的光引发剂的含量为0.39wt％。实施例9的其他方面与实施例1相同，在此不再赘述。
实施例10
实施例10与实施例6的不同之处在于：将间隙涂覆改成全涂覆，即涂胶层覆盖陶瓷层的整面，也即条状涂胶层与间隙的面积比为1:0；所述涂胶层中的光引发剂的含量为0.78wt％。实施例10的其他方面与实施例6相同，在此不再赘述。
实施例11
实施例10与实施例7的不同之处在于：将间隙涂覆改成全涂覆，即涂胶层覆盖陶瓷层的整面，也即条状涂胶层与间隙的面积比为1:0；所述涂胶层中的光引发剂的含量为0.85wt％。实施例11的其他方面与实施例7相同，在此不再赘述。
对比例1
对比例1与实施例1的不同之处在于：将间隙涂覆改成全涂覆，即涂胶层覆盖陶瓷层的整面，也即条状涂胶层与间隙的面积比为1:0；所述涂胶层中的光引发剂的含量为0.38wt％。对比例1的其他方面与实施例1相同，在此不再赘述。
对比例2
对比例2与实施例1的不同之处在于：条状涂胶层与间隙的面积比为1:1；所述浆料中光引发剂的含量为0.04wt％，所述涂胶层中的光引发剂的含量为0.03wt％。对比例2的其他方面与实施例1相同，在此不再赘述。
对比例3
对比例3与实施例1的不同之处在于：条状涂胶层与间隙的面积比为1:1；所述浆料中光引发剂的含量为3.0wt％，所述涂胶层中的光引发剂的含量为2.80wt％。对比例3的其他方面与实施例1相同，在此不再赘述。
请参考表1，表1给出了上述实施例1-11和对比例1-3得到的对应的隔膜的性能。
其中，负载量的测试方法具体为：用电子天平称量法进行负载量测试；具体的：
首先，测试涂覆过陶瓷层的隔膜的面密度：取涂覆陶瓷膜，裁成长297mm*宽210mm大小样片；将样片膜卷成团后放入称量台称重并记录重量m1；按照如下公式计算面密度M1(单位g/m2):Ps＝M/(长*宽*10 -6)；按照上述同样方法测出涂胶后隔膜的面密度M2；
负载量计算：M2-M1。
150℃*30min热收缩率的测试方法具体为：首先，沿着隔膜的横向和纵向将隔膜裁成50mm*50mm大小测试样；其次，将裁好的样品夹在A4纸之间，上下层铺A4纸张为：上5张，下5张；接着，将烘箱温度设定为150℃,待温度上升至设定温度，并充分预热，保证其内部温度稳定达到设定温度；再将准备好并夹在A4纸中间的样品连同A4纸一起迅速放进烘箱，样品要放到烘箱的上层正中间的位置，下层不可放置，立即关上烘箱门；关上烘箱门后，按照测试要求设定测试时间30min，时间到后，从烘箱中取出样品膜，待其冷却到室温后，轻轻将膜展平，量取横向/纵向隔膜边缘之间的距离，记录数据并计算热收缩率：热收缩率计算公式：热收缩率％＝(初始标记间长度-加热后标记间长度)/初始标记间长度×100％。
吸液表征的是隔膜对电解液的吸附量性能；吸液的测试方法为：裁取150mm*150mm(s＝0.0225m 2)大小待测样品隔膜，称重并记录重量m1；将待测样品隔膜浸泡进电解液中1小时；取出浸泡过电解液的隔膜用纸巾擦拭掉多余电解液；称重擦干后的隔膜样品并记录重量m2，计算吸液率(单位g/m 2):吸液率＝(m2-m1)/s。
粘接力的测试方法为：将待测涂覆膜样品制成一标准试样条(涂覆膜 (25mm*180mm)、极片(20mm*150mm))，用热压整形机让隔膜涂覆面与极片在一定压力、60℃温度下粘接，然后用夹具夹住极片及试样另一端，施加拉力，直到拉力机行程结束。拉力机参数设定：定位移：150mm，试验速度：300mm/min。
破膜温度通过TMA测试得到，TMA测试破膜温度是指用一定的力对隔膜进行张紧(模拟在电池内部的状态)，然后逐渐升温至破膜。
隔膜面电阻测试方法为用电化学工作站进行隔膜面电阻测试，具体地，包括以下步骤：
①制样：将待测样品隔膜折叠整齐，裁剪4张直径为47mm的圆形片样；
②将圆形片样置于电解液中，密封浸泡1h；
③连接测试模块与电化学工作站，打开电化学工作站中阻抗谱测试软件进行阻抗测试R1---第一层阻抗；
④再依次放入第2、3、4层，测量其阻抗谱，分别得到其阻值R2、R3、R4；
⑤以层数为横坐标，对应不同层数的阻值为纵坐标作图，求出曲线的斜率A和线性拟合度，当线性拟合度大于0.999时，测试结果有效，否则重新测试。示例性的拟合曲线如图7所示。
其中，隔膜面电阻值R计算公式为：R＝A.S；
式中：R为试样面电阻(Ω.cm 2)；A为曲线斜率；S为隔膜的测试面积(cm 2)；隔膜测试面积为有效的电极面积＝9.616cm 2；
离子电导率σ的计算公式为：σ＝d/R；
式中：σ为离子电导率(S/cm)；d为隔膜厚度(cm)。
Figure PCTCN2022095781-appb-000001
表1
由表1可以看出，本申请极大地提升了隔膜的整体耐热性，实施例1-实施例8的150℃*30min热收缩率小于4％；且破膜温度均在200℃以上。因而产品的整体性能优异。
此外，比较实施例1-7与实施例8-11可知，当所述浆料中的光引发剂含量在本申请的含量范围内时，全涂覆的所得到的隔膜的吸液(浸润性)大部分在6.2g/m 2-6.5g/m 2之间，且面电阻大部分在1.2Ω.cm 2-2.3g/m 2之间，而间隙涂覆所得到的隔膜的吸液(浸润性)大部分在6.3g/m 2-7.0g/m 2之间，隔膜面电阻大部分在1.0Ω.cm 2-1.4g/m 2之间。尤其比对实施例6与实施例10以及实施例7与实施例11可知，间隙涂覆相对于全涂覆而言，用更低的生产成本，表现出较高的吸液(浸润性)且隔膜面电阻明显降低，同时表现出较优的粘接性能，其产品的综合性能更优。
另外，比较实施例1-8与对比例2可知，当所述浆料中光引发剂的含量低于本申请的最低含量范围，所述涂胶层中的光引发剂的含量低于本申请的最低含量范围，隔膜的破膜温度明显降低，如对比例2中的破膜温度降低到了150℃左右。而比较实施例1-8与对比例3可知，当所述浆料中光引发剂的含量高于本申请的最高含量范围，所述涂胶层中的光引发剂的含量高于本申请的最高含量范围，粘接力显著降低，隔膜面电阻明显增加， 如对比例2中的A面的粘接强度降低到了30gf/25mm以下，B面的粘接强度更是降低到了20.1gf/25mm；隔膜面电阻达到了2.4Ω.cm 2。从而，说明了本申请的浆料中光引发剂的含量与范围涂胶层中的光引发剂的含量范围可以使得隔膜产品的性能达到最优。
在本说明书的描述中，参考术语“一种实施方式”、“一种实施例”、“具体实施过程”、“一种举例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，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，或者对其中部分或者全部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发明各实施例技术方案的范围。

Claims (14)

  1. 一种涂覆浆料，其特征在于，主要成分包含有溶剂、粘接性聚合物树脂以及光引发剂；其中，所述光引发剂在浆料中的重量比为0.08-1.0wt％；所述粘接性聚合物树脂包括PVDF基粘接性树脂聚合物、聚酰亚胺、聚醚酰亚胺、聚甲基丙烯酸甲酯中的一种或其组合。
  2. 根据权利要求1所述的涂覆浆料，其特征在于，所述PVDF基粘接性树脂聚合物包括PVDF均聚物、偏氟乙烯-六氟丙烯共聚物、聚偏氟乙烯-四氟乙烯-丙烯三元共聚物、聚偏二氟乙烯-三氟乙烯-氯三氟乙烯三元共聚物中的一种或其组合。
  3. 根据权利要求1所述的涂覆浆料，其特征在于，所述光引发剂包括ITX、二苯甲酮中的一种或其组合。
  4. 一种涂覆隔膜，其特征在于，包括基膜、陶瓷层以及涂胶层；其中，所述陶瓷层涂覆在所述基膜的单面或双面；所述涂胶层涂覆在所述陶瓷层上，且所述涂胶层由权利要求1-3任一项所述的涂覆浆料涂覆形成。
  5. 根据权利要求4所述的涂覆隔膜，其特征在于，所述光引发剂在所述涂胶层中的重量占比为0.05-0.3wt％。
  6. 根据权利要求5所述的涂覆隔膜，其特征在于，所述涂胶层间隔分布在所述陶瓷层上。
  7. 根据权利要求7所述的涂覆隔膜，其特征在于，涂胶层与间隙的面积比为1:1-5:1；其中所述间隙为相邻两涂胶层之间的间隙。
  8. 根据权利要求4所述的涂覆隔膜，其特征在于，所述陶瓷层包含无机材料，所述无机材料为二氧化硅、氧化铝、勃姆石、氧化钛、氧化镁或纳米纤维一种或其组合。
  9. 一种涂覆隔膜，其特征在于，包括基膜、陶瓷层以及涂胶层，其中，所述陶瓷层涂覆在所述基膜的单面或双面；所述涂胶层涂覆在所述陶瓷层上；所述涂覆隔膜的粘接强度≥15gf/25mm、破膜温度大于180℃、面电 阻在1.4Ω.cm 2以下。
  10. 一种权利要求4-8任一项或权利要求9所述的涂覆隔膜的制备方法，其特征在于，包括以下步骤：
    (1)提供基膜，所述基膜单面或双面涂覆有陶瓷层；
    (2)制备浆料：把不多于5～30wt％的粘接性聚合物树脂、0.08-1.0wt％的光引发剂加入溶剂中，充分溶解后，得到涂覆浆料；
    (3)涂覆：将上述制得的涂覆浆料涂覆于所述陶瓷层上，在所述陶瓷层上形成涂胶层；
    (4)紫外交联：将完成涂覆后的基膜通过紫外光辐射引发交联反应，获得相应的涂覆隔膜。
  11. 根据权利要求10所述的涂覆隔膜的制备方法，其特征在于，所述步骤(3)中的涂覆为全涂覆，具体为将上述制得的涂覆浆料涂覆于所述陶瓷层的整面上，在所述陶瓷层的整面形成涂胶层。
  12. 根据权利要求10所述的涂覆隔膜的制备方法，其特征在于，所述步骤(3)中的涂覆为间隙涂覆，具体为将上述制得的涂覆浆料间隙涂覆于所述陶瓷层上，在所述陶瓷层上间隔形成涂胶层。
  13. 根据权利要求10所述的涂覆隔膜的制备方法，其特征在于，所用紫外光波长在210nm-420nm范围内，紫外交联时间为0.001s-10s，辐射光强度为50mj/cm 2以上。
  14. 一种电池，其特征在于，包括涂覆隔膜、正极、负极和电解质，所述涂覆隔膜为权利要求4-8任一项或权利要求9所述的涂覆隔膜。
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