WO2021189459A1 - 一种电化学装置及包含该电化学装置的电子装置 - Google Patents

一种电化学装置及包含该电化学装置的电子装置 Download PDF

Info

Publication number
WO2021189459A1
WO2021189459A1 PCT/CN2020/081812 CN2020081812W WO2021189459A1 WO 2021189459 A1 WO2021189459 A1 WO 2021189459A1 CN 2020081812 W CN2020081812 W CN 2020081812W WO 2021189459 A1 WO2021189459 A1 WO 2021189459A1
Authority
WO
WIPO (PCT)
Prior art keywords
isolation layer
electrochemical device
porous matrix
polymer particles
particles
Prior art date
Application number
PCT/CN2020/081812
Other languages
English (en)
French (fr)
Inventor
张楠
王斌
张益博
Original Assignee
宁德新能源科技有限公司
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 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to KR1020227037741A priority Critical patent/KR20220151707A/ko
Priority to CN202080095652.1A priority patent/CN115428249A/zh
Priority to JP2022558291A priority patent/JP2023518889A/ja
Priority to EP20927063.6A priority patent/EP4131538A1/en
Priority to PCT/CN2020/081812 priority patent/WO2021189459A1/zh
Publication of WO2021189459A1 publication Critical patent/WO2021189459A1/zh
Priority to US17/953,680 priority patent/US20230038029A1/en

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/446Composite material consisting of a mixture of organic and inorganic materials
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
    • H01M50/414Synthetic resins, e.g. thermoplastics or thermosetting resins
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/431Inorganic material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/44Fibrous material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/443Particulate material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491Porosity
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00Batteries for particular applications
    • H01M2220/20Batteries in motive systems, e.g. vehicle, ship, plane
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00Batteries for particular applications
    • H01M2220/30Batteries in portable systems, e.g. mobile phone, laptop
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Definitions

  • This application relates to the field of electrochemistry, and more specifically, this application relates to an electrochemical device and an electronic device including the electrochemical device.
  • Lithium-ion batteries have many advantages, such as high energy density, long cycle life, high nominal voltage (>3.7V), and low self-discharge rate. They are widely used in the field of consumer electronics. With the rapid development of electric vehicles and portable electronic equipment in recent years, people have higher and higher requirements for battery energy density (>700Wh/L), safety, cycle performance (>500 cycles) and other related requirements, looking forward to comprehensive performance The emergence of a comprehensively improved new type of lithium-ion battery. Among them, the non-diaphragm lithium-ion battery is a new type of lithium-ion battery that has attracted much attention.
  • a diaphragm-less lithium ion battery uses a method of preparing an isolation layer on the surface of the electrode pole piece to replace the traditional isolation membrane.
  • Diaphragm-free lithium-ion batteries integrate the isolation layer directly on the surface of the electrode pole piece, without the need to make a separate isolation film.
  • the production process changes from three components of pole piece-isolation film-pole piece to (integrated) pole piece-(integrated) pole piece two components
  • the laminated/winding of the battery simplifies the battery production process and reduces the difficulty of battery preparation; at the same time, the thinned separator thickness increases the battery energy density; in addition, the separator-free battery technology also has the ability to increase the porosity of the separator to improve the liquid retention capacity and speed up Many advantages such as reaction kinetics have received widespread attention.
  • Non-diaphragm lithium-ion batteries usually use a non-woven isolation layer.
  • the non-woven isolation layer is formed by oriented or random combination of nano or micro fibers. The random overlap between the fibers forms a large number of holes for ion transmission, and the fibers themselves serve as the support skeleton of the isolation layer.
  • this fiber layer does not have the function of thermally closing the pores, and cannot be blocked by melting to shut off the lithium ion path under thermal runaway (such as battery overcharge, hot box, vibration, collision, drop, internal short circuit, external short circuit, etc.) Electric current causes greater hidden dangers to the safety performance of lithium-ion batteries; secondly, the mechanical strength of the fiber layer of the non-woven separator layer itself is low, which causes the positive and negative particles to penetrate when it resists the piercing of the positive and negative particles.
  • the fiber-permeable layer causes a short circuit in the electrochemical device; in addition, the non-woven separator fiber has a large pore size and uneven distribution. The existence of some "macropores" can cause serious self-discharge problems in lithium-ion batteries.
  • the first aspect of this application first provides an electrochemical device, which includes an electrode pole piece and an isolation layer on at least one surface of the electrode pole piece, and the isolation layer contains porous nanofibers.
  • the matrix and the polymer particles distributed in the porous matrix have a melting temperature of 70°C to 150°C.
  • the number of the polymer particles in the isolation layer is 1 ⁇ 10 8 /m 2 to 1 ⁇ 10 18 /m 2 .
  • the average particle size of the polymer particles is 40 nm to 10 ⁇ m.
  • the diameter of the nanofiber is 10 nm to 5 ⁇ m
  • the pore diameter of the fiber porous matrix is 40 nm to 10 ⁇ m
  • part of the polymer particles protrude from the surface of the porous matrix to a height of 0.1 nm to 5 ⁇ m, and the surface area of the surface of the porous matrix occupied by the part of the polymer particles is 0.1% to 60% of the total surface area of the porous matrix.
  • the polymer of the polymer particles includes polystyrene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene- At least one of styrene, polylactic acid, polyvinyl chloride, polyvinyl butyral, or polyacrylate.
  • the nanofiber comprises a polymer
  • the polymer includes polyvinylidene fluoride, polyimide, polyamide, polyacrylonitrile, polyethylene glycol , Polyethylene oxide, polyphenylene ether, polypropylene carbonate, polymethyl methacrylate, polyethylene terephthalate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride) -Co-chlorotrifluoroethylene) and at least one of its derivatives, preferably polyvinylidene fluoride, polyimide, polyamide, polyacrylonitrile, polyethylene glycol, polyethylene oxide, polyphenylene ether, At least one of polypropylene carbonate, polymethyl methacrylate, polyethylene terephthalate and derivatives thereof.
  • the ratio ⁇ / ⁇ between the cross-sectional porosity ⁇ of the isolation layer and the surface open porosity ⁇ of the isolation layer is 95% or less.
  • the surface open porosity ⁇ is 35% to 90%.
  • the cross-sectional void ratio ⁇ is 30% to 85%.
  • an electronic device which includes the electrochemical device according to any one of the above technical solutions.
  • the electronic devices described in this application include electronic devices known in the art, such as notebook computers, mobile phones, electric motorcycles, electric cars, electric toys, and the like.
  • the isolation layer of the present application has low melting point polymer particles distributed in the nanofiber porous matrix, so that the isolation layer has the function of low-temperature thermal pore closure, and can cut off the current to improve the safety performance of the electrochemical device under thermal runaway.
  • low-melting polymer particles can be filled in the "macropores" of the fiber porous matrix to reduce the macropores in the pure heat-resistant spinning isolation layer, thereby further improving the self-discharge problem of electrochemical devices, reducing the K value, and due to The improvement of the mechanical strength of the isolation layer reduces the internal short circuit problem of the positive and negative electrode active material particles in the electrochemical device piercing the isolation layer, and is also beneficial to improve the electrochemical performance such as the cycle of the electrochemical device.
  • FIG. 1 is a schematic diagram of the structure of an electrode assembly according to an embodiment of the application
  • FIG. 2 is a schematic diagram of the structure of an electrode assembly according to an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of an electrode assembly according to an embodiment of the application.
  • FIG. 4 is a schematic diagram of the structure of an electrode assembly according to an embodiment of the application.
  • FIG. 5 is a schematic structural diagram of an isolation layer in an embodiment of this application.
  • FIG. 6 is a schematic structural diagram of an isolation layer in an embodiment of this application.
  • FIG. 7 is a schematic diagram of an embodiment of preparing an isolation layer according to this application.
  • FIG. 8 is a schematic diagram of an embodiment of preparing an isolation layer according to this application.
  • the electrochemical device described in the present application is not particularly limited, and may be any electrochemical device that can be used in the present application, such as lithium ion batteries, supercapacitors, and the like.
  • the following description takes a lithium ion battery as an example, but this does not mean that the electrochemical device of the present application is limited to a lithium ion battery.
  • an electrochemical device which includes an electrode pole piece and an isolation layer on at least one surface of the electrode pole piece, the isolation layer comprising a nanofiber porous matrix and polymer particles distributed in the porous matrix
  • the melting temperature of the polymer particles is 70°C to 150°C, preferably 80°C to 140°C, more preferably 90°C to 130°C, most preferably 100°C to 120°C.
  • the porous matrix is formed by oriented or random combination of nanofibers.
  • the random overlap between the nanofibers forms a large number of pores for ion transmission, and the nanofibers themselves
  • the polymer particles are filled in a porous matrix. Due to the low melting temperature of polymer particles, when the electrochemical device suffers from thermal runaway, such as battery overcharge, hot box, vibration, collision, drop, internal short circuit, external short circuit, etc., the temperature of the electrochemical device rises.
  • the polymer particles melt, seal the pores of the isolation layer, reduce or block the conduction of lithium ions, and reduce or stop charging and discharging of the electrochemical device, which can greatly improve the safety of the electrochemical device.
  • the porous nanofiber matrix itself has a high melting temperature.
  • the isolation layer maintains its original structure without shrinking and breaking the film, avoiding internal short circuits.
  • the polymer particles are distributed in the pores of the porous matrix and fill the large pores in the porous matrix, the self-discharge phenomenon can be effectively reduced.
  • the puncture resistance of the porous matrix is improved, and the positive and negative active material particles can effectively prevent the electrochemical device from piercing the separator layer and short-circuiting the electrochemical device.
  • the nanofiber porous matrix and the pole piece have good adhesion, which can effectively prevent the diaphragm from being washed by the electrolyte and turning over during the drop process of the electrochemical device, which greatly improves the safety performance of the electrochemical device.
  • the number of polymer particles in the isolation layer is not particularly limited, as long as the purpose of the application can be achieved.
  • the number of polymer particles in the isolation layer is 1 ⁇ 10 8 /m 2 to 1 ⁇ 10 18 /m 2 , preferably 1 ⁇ 10 9 /m 2 to 1 ⁇ 10 16 /m 2 , more preferably 1 ⁇ 10 10 /m 2 to 1 ⁇ 10 14 /m 2 , most preferably 1 ⁇ 10 11 /m 2 to 1 ⁇ 10 13 /m 2 .
  • the particle size of the polymer particles is not particularly limited, as long as the purpose of the application can be achieved.
  • the average particle size of the polymer particles is 40 nm to 10 ⁇ m, preferably 100 nm to 5 ⁇ m, more preferably 200 nm to 2 ⁇ m, and most preferably 500 nm to 1.5 ⁇ m.
  • the average particle size of the polymer particles is within the above range, which can better reduce or eliminate the macropores in the porous matrix and reduce the self-discharge phenomenon.
  • the pores in the isolation layer can be fully and quickly sealed in the case of thermal runaway of the electrochemical device, blocking the ion conduction path, forming an insulating layer, and preventing the battery It caught fire and exploded.
  • the diameter of the nano or micro fiber is not particularly limited, as long as it can achieve the purpose of the present application.
  • the nanofibers have a diameter of 10 nm to 5 ⁇ m, preferably 20 nm to 2 ⁇ m, more preferably 50 nm to 1 ⁇ m, and most preferably 80 nm to 400 nm.
  • the isolation layer can have a suitable porosity, improve the liquid retention capacity of the isolation layer, and at the same time ensure that the porous matrix has proper strength, which is synergistic with the polymer particles distributed in the porous matrix.
  • the pore size of the porous matrix is not particularly limited, as long as the purpose of the application can be achieved. In some preferred embodiments of the present application, the pore size of the porous matrix isolation layer is 40 nm to 10 ⁇ m, preferably 80 nm to 5 ⁇ m, more preferably 130 nm to 1 ⁇ m, and most preferably 150 nm to 500 nm.
  • the inventor believes that the pore size of the porous matrix isolation layer within the above range can accelerate lithium ion transmission, improve the reaction kinetics, and effectively reduce the probability of the positive and negative active material particles passing through the isolation layer. , To reduce the risk of self-discharge and internal short circuit.
  • the molten polymer particles can quickly fill the pores of the isolation layer, realize the closed pores of the isolation layer, block ion transmission, and improve the safety performance of the electrochemical device.
  • part of the polymer particles protrude from the surface of the porous substrate to a height of 0.1 nm to 5 ⁇ m, preferably 1 nm to 1 ⁇ m, more preferably 2 nm to 500 nm, and most preferably 5 nm to 100 nm.
  • the inventor believes that the polymer particles protruding from the porous matrix to a certain height can reduce the force of the positive and negative active material particles on the porous matrix itself, and further prevent the positive and negative particles from affecting the separator. Of piercing.
  • the surface area of the porous matrix surface occupied by the partial polymer particles is 0.1% to 60% of the total surface area of the porous matrix, preferably 0.5% to 45%, more preferably 2% to 30%, most preferably 5 % To 15%.
  • the inventor believes that the surface area of the porous substrate occupied by the polymer particles protruding from the surface is within the above range, which can make the separator have higher strength and resist puncture by the positive and negative active material particles.
  • the "porous substrate surface” refers to the surface of the side of the isolation layer away from the active material layer after the isolation layer is coated on the active material layer.
  • the polymer type of the polymer particles used in the present application is not particularly limited, as long as the melting point is 70 to 150°C.
  • the polymer particles comprise polystyrene (PS), polyethylene (PE), ethylene-propylene copolymer, polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), At least one of acrylonitrile-butadiene-styrene (ABS), polylactic acid (PLA), polyvinyl chloride (PVC), polyvinyl butyral (PVB), or polyacrylate (PA).
  • PS polystyrene
  • PE polyethylene
  • PP polypropylene
  • EVA ethylene-vinyl acetate copolymer
  • ABS acrylonitrile-butadiene-styrene
  • PLA polylactic acid
  • PVC polyvinyl chloride
  • PVB polyvinyl butyral
  • PA polyacrylate
  • the shape of the polymer particles used in the present application is not particularly limited, and can be spherical, olive, elongated, flat, pie, ring, rod, hollow, spiral, core-shell, gourd, cylindrical, and conical. , At least one of cuboid, cube, pyramid, prism or other arbitrary shapes.
  • the nanofibers used in the present application are not particularly limited, as long as they can achieve the purpose of the present application, and any materials known to those skilled in the art can be used.
  • the nanofibers comprise polymers including polyvinylidene fluoride (PVDF), polyimide (PI), polyamide (PA), polyacrylonitrile (PAN ), polyethylene glycol (PEG), polyethylene oxide (PEO), polyphenylene oxide (PPO), polypropylene carbonate (PPC), polymethyl methacrylate (PMMA), polyethylene terephthalate At least one of alcohol ester (PET), poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-PCTFE) and its derivatives Species, preferably polyvinylidene fluoride, polyimide, polyamide, polyacrylonitrile, polyethylene glycol, polyethylene
  • the melting point of the polymer is not lower than 170°C.
  • the polymer nanofibers with a melting point of not less than 170°C in the case of thermal runaway, the polymer particles begin to melt at a lower temperature, for example, at 70 to 150°C, which seals the ion transport channel of the isolation layer, but The nanofiber skeleton does not melt at this temperature, and maintains the original structure of the isolation layer without melting, so as to ensure that there will be no short circuit in the battery due to the shrinkage/rupture of the isolation layer, and the safety of the electrochemical device is improved.
  • the polymer of the nanofibers may also contain inorganic particles.
  • the inorganic particles are not particularly limited, and inorganic particles known to those skilled in the art may be used.
  • the inorganic particles may include HfO 2 , SrTiO 3 , SiO 2 , and Al 2. At least one of O 3 , MgO, CaO, NiO, BaO, ZnO, TiO 2 , ZrO 2 , SnO 2 , CeO 2 , boehmite, magnesium hydroxide, or aluminum hydroxide.
  • the size of the inorganic particles is not particularly limited, and may be, for example, 10 nm to 10 ⁇ m.
  • the content of the inorganic particles is not particularly limited, and may be, for example, 0.1% to 80%.
  • the mechanical strength of the isolation layer can be further enhanced, the self-discharge phenomenon of the electrochemical device can be reduced, and the safety performance of the electrochemical device can be improved.
  • the surface open porosity ⁇ of the isolation layer is 35% to 90%, preferably 45% to 87%, more preferably 60% to 85%, most preferably 75% to 82%.
  • the cross-sectional void ratio ⁇ of the isolation layer is 30% to 85%, preferably 40% to 80%, more preferably 50% to 75%, most preferably 55% to 65%.
  • the ratio ⁇ / ⁇ between the cross-sectional porosity ⁇ of the isolation layer and the surface open porosity ⁇ of the isolation layer is 95% or less, preferably 20% to 90%, more preferably 40% to 85%, most Preferably it is 65% to 80%.
  • the isolation layer can be provided with a high liquid holding capacity, maintain appropriate strength, and possess rapid reaction kinetics.
  • the thickness of the isolation layer according to the present application is not particularly limited, and those skilled in the art can select it according to specific conditions, preferably 1 ⁇ m to 20 ⁇ m, preferably 2 ⁇ m to 18 ⁇ m, more preferably 5 ⁇ m to 15 ⁇ m, and most preferably 6 ⁇ m to 12 ⁇ m.
  • the thickness of the isolation layer refers to the overall thickness of the integrated isolation layer including the nanofiber porous matrix and polymer particles.
  • the electrochemical device of the present application may be a lithium ion battery.
  • This application does not limit the type of lithium ion battery, and it can be any type of lithium ion battery, such as button type, cylindrical type, soft pack type lithium ion battery and any other type.
  • the lithium ion battery of the present application includes a positive pole piece, a negative pole piece, an electrolyte, and the isolation layer described in any one of the foregoing in the present application.
  • the isolation layer may be formed on one surface of the positive pole piece and one surface of the negative pole piece, and then follow the manner of negative pole piece + isolation layer, positive pole piece + isolation layer.
  • the lamination is carried out to form a lithium ion battery laminate.
  • the isolation layer may be formed on both surfaces of the positive pole piece, and then laminated in the manner of the negative pole piece, the isolation layer + the positive pole piece + the isolation layer, to form a lithium ion A battery laminate in which there is no separator on the surface of the negative electrode.
  • the isolation layer may be formed on both surfaces of the negative electrode piece, and then laminated in the manner of the positive electrode piece, the isolation layer + the negative electrode piece + the isolation layer, to form a lithium ion The battery laminate, in which there is no separator on the surface of the positive pole piece.
  • the laminated body formed in the above-mentioned embodiment may continue to be laminated in the above-mentioned order, or it may be directly wound to form a multilayer lithium ion battery laminated body.
  • This application does not limit the stacking mode, and those skilled in the art can make a selection according to the actual situation.
  • Fig. 1 shows a schematic diagram of the structure of an electrode assembly according to an embodiment of the present application.
  • an isolation layer is provided on one surface of the electrode pole piece.
  • the isolation layer 10 covers the surface of the electrode active material layer 30, and the electrode active material layer 30 is located on one surface of the current collector 20.
  • FIG. 2 shows a schematic diagram of the structure of an electrode assembly of an embodiment of the present application, in which the separator layer 10 is located between the positive electrode active material layer 301 and the negative electrode active material layer 302, and the positive electrode active material layer 301 is located on one of the positive electrode current collectors 201. On the surface, the negative active material layer 302 is located on one surface of the negative current collector 202.
  • FIG. 3 shows a schematic structural view of an electrode assembly according to an embodiment of the present application, which further includes a conductive layer 40, the conductive layer is located between the electrode active material layer 30 and the current collector 20, and the isolation layer 10 covers the electrode active material layer 30 on the surface.
  • FIG. 4 shows a schematic diagram of the structure of an electrode assembly of an embodiment of the present application, which further includes a positive electrode conductive layer 401 and a negative electrode conductive layer 402, wherein the positive electrode conductive layer 401 is located between the positive electrode current collector 201 and the positive electrode active material layer 301, The negative conductive layer 402 is located between the negative current collector 202 and the negative active material layer 302.
  • FIG. 5 shows a schematic diagram of the isolation layer structure according to an embodiment of the present application, in which the polymer particles 102 are located in the nanofiber matrix 101.
  • FIG. 6 shows a schematic diagram of an isolation layer structure according to an embodiment of the present application, in which the polymer particles 102 and the inorganic particles 103 are located in the nanofiber matrix 101.
  • the positive pole piece is not particularly limited, as long as the purpose of the present application can be achieved.
  • the positive pole piece usually includes a positive current collector and a positive active material.
  • the positive electrode current collector is not particularly limited, and can be any positive electrode current collector known in the art, such as aluminum foil, aluminum alloy foil, or composite current collector.
  • the positive electrode active material is not particularly limited, and can be any positive electrode active material in the prior art.
  • the active material includes NCM811, NCM622, NCM523, NCM111, NCA, lithium iron phosphate, lithium cobalt oxide, lithium manganate, and ferromanganese phosphate. At least one of lithium or lithium titanate.
  • the positive pole piece may further include a conductive layer located between the positive electrode current collector and the positive electrode active material.
  • the composition of the conductive layer is not particularly limited, and may be a conductive layer commonly used in the art.
  • the conductive layer includes a conductive agent and an adhesive.
  • the negative pole piece is not particularly limited, as long as it can achieve the purpose of the present application.
  • the negative pole piece usually includes a negative current collector and a negative active material.
  • the negative electrode current collector is not particularly limited, and any negative electrode current collector known in the art can be used, such as copper foil, copper alloy foil or composite current collector.
  • the negative active material is not particularly limited, and any negative active material known in the art can be used. For example, it may include at least one of graphite, hard carbon, soft carbon, silicon, silicon carbon, or silicon oxide.
  • the negative pole piece may further include a conductive layer located between the negative current collector and the negative active material.
  • the composition of the conductive layer is not particularly limited, and may be a conductive layer commonly used in the art.
  • the conductive layer includes a conductive agent and an adhesive.
  • the aforementioned conductive agent is not particularly limited, and any conductive agent known in the art can be used as long as the purpose of the application can be achieved.
  • the conductive agent may include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fiber, graphene, and the like.
  • the conductive agent can be conductive carbon black (Super P).
  • the aforementioned adhesive is not particularly limited, and any adhesive known in the art can be used as long as it can achieve the purpose of the present application.
  • the adhesive may include at least one of styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC-Na), and the like.
  • the adhesive can be styrene butadiene rubber (SBR).
  • the electrolyte of the lithium ion battery is not particularly limited, and any electrolyte known in the art can be used, and the electrolyte can be any of a gel state, a solid state, and a liquid state.
  • the liquid electrolyte includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is not particularly limited, and any lithium salt known in the art can be used as long as the purpose of the application can be achieved.
  • the lithium salt may include LiPF 6 , LiBF 4 , LiAsF 6 , 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 At least one of CF 3 ) 3 or LiPO 2 F 2 and the like.
  • LiPF 6 can be used as the lithium salt.
  • the non-aqueous solvent is not particularly limited, as long as it can achieve the purpose of the present application.
  • the non-aqueous solvent may include at least one of carbonate compounds, carboxylate compounds, ether compounds, nitrile compounds, or other organic solvents, and the like.
  • the carbonate compound may include diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethylene propyl carbonate (EPC), methyl ethyl carbonate Ester (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinyl ethylene carbonate (VEC), fluoroethylene carbonate (FEC), carbonic acid 1 ,2-Difluoroethylene, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1 -Fluoro-2-methylethylene, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluorocarbonate- At least one of 2-methylethylene, trifluoromethylethylene carbonate, and the like.
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • the present application has no particular limitation on the preparation method of the above-mentioned electrochemical device, and the preparation can be carried out by using well-known methods in the art.
  • nanofibers and polymer particles are deposited on one or both surfaces of a positive pole piece or a negative pole piece to form a porous matrix containing nanofibers and polymer particles filled in the porous matrix.
  • nanofibers, polymer particles and inorganic particles on one or both surfaces of the positive pole piece or negative pole piece to form a porous matrix containing nanofibers and polymer particles and inorganic particles filled in the porous matrix.
  • the method of depositing nanofibers, polymer particles and/or inorganic particles is not particularly limited, and can be carried out by a deposition method well-known in the art. , Meltblown method, flash evaporation method or coating method, the polymer particles and/or inorganic particles are prepared by electrodeposition method, printing method, coating method, rotation method or dipping method.
  • the order of depositing nanofibers, polymer particles and/or inorganic particles is not particularly limited, as long as the isolation layer of the present application can be formed, and the isolation layer includes a nanofiber porous matrix and polymer particles distributed in the porous matrix. And/or inorganic particles.
  • the nanofibers and polymer particles and/or inorganic particles may be deposited simultaneously or alternately.
  • FIG. 7 is a schematic diagram of an electrospinning process of this application; the electrospinning device 50 deposits nanofibers on the surface of the electrode to form an isolation layer 10.
  • FIG. 8 is a schematic diagram of an embodiment of preparing an isolation layer according to this application, in which the electrospinning device 50 and the electrodeposition device 60 respectively deposit nanofibers and polymer particles on the surface of the electrode; the electrospinning device 50 and the electro The deposition devices 60 are all connected to the voltage stabilizer 70.
  • the porous substrate can be implemented with any spinning equipment known in the art, and there is no particular limitation, as long as the purpose of the application can be achieved.
  • the electrospinning method can use any electrospinning equipment known in the art, for example, the electrospinning equipment can be the Yongkang Leye Elite series, etc.; the air spinning method can use any air spinning known in the art
  • the equipment for example, the air spinning equipment can be the air jet spinning machine of Nanjing Genus New Material;
  • the centrifugal spinning method can use any centrifugal spinning equipment known in the art, for example, the centrifugal spinning equipment can be Sichuan Centrifugal spinning machines of Zhiyan Technology, etc.
  • the electrodeposition method can be implemented with any equipment known in the art, and is not particularly limited, as long as the purpose of the application can be achieved.
  • the electrospraying method can use any electrospraying equipment known in the art, for example, the electrostatic spraying equipment of Sames, France can be used.
  • the application also provides an electronic device including the electrochemical device according to the application.
  • the electronic devices described in this application include electronic devices generally in the field, such as notebook computers, mobile phones, electric motorcycles, electric cars, electric toys, and the like.
  • Cross-sectional void ratio the percentage of void area in any cross-section perpendicular to the surface of the isolation layer to the total cross-sectional area.
  • Surface open porosity the percentage of the surface area of the open pores on the surface of the isolation layer to the total surface area.
  • Number of polymer particles the total number of polymer particles per unit area of the isolation layer.
  • Average particle size of polymer particles The average particle size of polymer particles is represented by D50, where D represents the diameter of polymer particles, D50 is based on volume distribution, and the cumulative particle size distribution percentage of polymer particles corresponds to 50% Its physical meaning is that the particles smaller than it account for 50%, and the particles larger than it account for 50%.
  • a positive electrode current collector containing a single-sided active material+separation layer+a negative electrode current collector sample containing a single-sided active material is infiltrated with an electrolyte, wherein the active material is adjacent to the separator.
  • the porosity ⁇ of the isolation layer is measured by the weight of the isolation layer M isolation layer and volume V isolation layer , the mass fraction of the porous matrix and the polymer particles occupying the weight of the isolation layer respectively w porous matrix and w polymer particles , and their density ⁇ porous
  • the prepared cross section of the isolation layer under a scanning electron microscope equipped with a certain number of square reference objects, select a unit area, and count the squares covered on the gaps, then the area of the squares covered on the gaps The ratio to the selected area is the cross-sectional void ratio ⁇ 1 of the isolation layer.
  • select the unit area of different sections and different positions of the isolation layer to measure the cross-sectional porosity, and the cross-sectional porosity is ⁇ 2 , ⁇ 3 , ⁇ 4 ... ⁇ n .
  • the measured isolation layer under a scanning electron microscope equipped with a certain number of square reference objects, select a unit area, and count the squares covering the pores, then the area of the squares covering the pores and the selected area The ratio is the surface porosity ⁇ 1 of the isolation layer.
  • select the unit area at different positions on the surface of the isolation layer to measure the surface porosity, and the surface porosity is ⁇ 2 , ⁇ 3 , ⁇ 4 ... ⁇ n .
  • the negative electrode active material graphite (Graphite), conductive carbon black (Super P), and styrene butadiene rubber (SBR) are mixed in a weight ratio of 96:1.5:2.5, and deionized water (H 2 O) is added as a solvent to prepare a solid content For the slurry of 0.7, and stir evenly.
  • the slurry was uniformly coated on one surface of a negative electrode current collector copper foil with a thickness of 8 ⁇ m, and dried at 110° C. to obtain a negative electrode sheet with a coating thickness of 130 ⁇ m on a single side coated with a negative electrode active material.
  • Repeat the above steps on the other surface of the negative pole piece to obtain a negative pole piece coated with negative active material on both sides. Then, cut the pole piece into a size of 41mm ⁇ 61mm for use.
  • the positive active material lithium cobalt oxide (LiCoO 2 ), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) was added as a solvent , Formulated into a slurry with a solid content of 0.75, and stirred evenly.
  • the slurry was uniformly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10 ⁇ m and dried at 90° C. to obtain a positive electrode piece with a coating thickness of 110 ⁇ m. Repeat the above steps on the other surface of the aluminum foil of the positive electrode current collector to obtain a positive electrode piece that has been coated on both sides. After coating, cut the pole piece into 38mm ⁇ 58mm specifications for later use.
  • the lithium salt lithium hexafluorophosphate (LiPF 6 ) is added to the organic solvent to dissolve and mix uniformly to obtain an electrolyte with a lithium salt concentration of 1.15M.
  • the following examples illustrate the preparation of the nanofiber porous matrix + polymer particle integrated isolation layer according to the present application. These embodiments are described by taking the positive pole piece as an example, and an integrated isolation layer is deposited on both surfaces of the positive pole piece. It should be understood that the integrated isolation layer may also be deposited on both surfaces of the negative pole piece, or an integrated isolation layer may be deposited on one surface of the positive pole piece and one surface of the negative pole piece. The solution can also achieve the purpose of this application. Those skilled in the art should understand that these embodiments are also within the protection scope of the present application.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 10 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 500nm, and the ratio of the average pore size of the porous matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:2.5, that is, the average pore size of the fiber porous matrix is 200nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 95:5, and the porosity of the isolation layer is 75%.
  • the cross-sectional porosity ⁇ of the isolation layer was 53%, the surface open porosity ⁇ was 88%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ was 60%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40° C. to remove dispersants and solvents such as DMF to obtain a positive pole piece coated with a separator on both sides.
  • the ratio of the fiber porous matrix material and the polymer particle content is adjusted to 80:20 as shown in Table 1, and the cross-sectional void ratio ⁇ of the isolation layer is 56%, the surface open porosity ⁇ is 80%, and the cross-sectional void ratio/surface open porosity
  • the ratio ⁇ / ⁇ is the same as in Example 1, except that the ratio ⁇ / ⁇ is 70%.
  • the ratio of the fiber porous matrix material and the polymer particle content is adjusted to 65:35 as shown in Table 1, and the cross-sectional void ratio ⁇ of the isolation layer is 60%, the surface open porosity ⁇ is 75%, and the cross-sectional void ratio/surface open porosity Except for the ratio ⁇ / ⁇ of 80%, the rest is the same as in Example 1.
  • the ratio of the fiber porous matrix material and the polymer particle content is adjusted to 35:65 as shown in Table 1, and the cross-sectional void ratio ⁇ of the isolation layer is 50%, the surface open porosity ⁇ is 65%, and the cross-sectional void ratio/surface open porosity
  • the ratio ⁇ / ⁇ is the same as in Example 1, except that the ratio ⁇ / ⁇ is 77%.
  • the ratio of the fiber porous matrix material and the polymer particle content is adjusted to 5:95 as shown in Table 1, and the cross-sectional void ratio ⁇ of the isolation layer is 35%, the surface open porosity ⁇ is 40%, and the cross-sectional void ratio/surface open porosity
  • the ratio ⁇ / ⁇ is the same as in Example 1, except that the ratio ⁇ / ⁇ is 88%.
  • the ratio of the pore diameter of the fiber porous matrix to the average particle size of the polymer particles is adjusted to 1:1, the cross-sectional void ratio ⁇ of the isolation layer is 55%, and the surface open porosity ⁇ It is 70%, and the ratio ⁇ / ⁇ of cross-sectional porosity/surface porosity is 78%, and the rest is the same as in Example 3.
  • the ratio of the pore size of the fiber porous matrix to the average particle size of the polymer particles is adjusted to 1:5, the cross-sectional void ratio ⁇ of the isolation layer is 60%, and the surface opening ratio ⁇ It was 80%, and the ratio ⁇ / ⁇ of cross-sectional porosity/surface porosity was 75%, and the rest was the same as in Example 3.
  • the ratio of the pore size of the fiber porous matrix to the average particle size of the polymer particles is adjusted to 1:15, the cross-sectional void ratio ⁇ of the isolation layer is 65%, and the surface open porosity ⁇ It was 85%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ was 75%, and the rest was the same as in Example 3.
  • the pore size of the fibrous porous matrix is 1000nm, the fiber diameter to 400nm, the polymer particle size to 5000nm, and the cross-sectional void ratio ⁇ of the isolation layer to 65%, the surface open porosity ⁇ to 80%, and cross-sectional voids according to Table 1. Except that the ratio ⁇ / ⁇ of the surface porosity to the surface porosity is 81%, the rest is the same as in Example 3.
  • the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is the same as in Example 3 except that the ratio ⁇ / ⁇ is 71%.
  • the thickness of the spacer layer is adjusted to 5 ⁇ m according to Table 1, and the cross-sectional void ratio ⁇ of the spacer layer is 65%, the surface open porosity ⁇ is 80%, and the cross-sectional void ratio/surface open porosity ratio ⁇ / ⁇ is 81%, The rest is the same as in Example 11.
  • the porosity of the isolation layer is adjusted to 30% according to Table 1, and the cross-sectional void ratio ⁇ of the isolation layer is 25%, the surface open porosity ⁇ is 35%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 71%. , And the rest is the same as in Example 11.
  • the porosity of the isolation layer is adjusted to 30% according to Table 1, and the cross-sectional porosity ⁇ of the isolation layer is 80%, the surface open porosity ⁇ is 85%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 94%. , And the rest is the same as in Example 11.
  • the low melting point polymer particle material is adjusted to EVA with a melting point of 70°C
  • the cross-sectional void ratio ⁇ of the separator is 65%
  • the surface open porosity ⁇ is 80%
  • the cross-sectional void ratio/surface open porosity ratio ⁇ / ⁇ Except for 81%, the rest is the same as in Example 11.
  • the separator In addition to adjusting the low melting point polymer particle material to PP with a melting point of 150°C, the separator has a cross-sectional porosity ⁇ of 65%, a surface open porosity ⁇ of 80%, and a cross-sectional porosity/surface open porosity ratio ⁇ / The rest is the same as in Example 11 except that ⁇ is 81%.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • PE polyethylene
  • the selected low-melting polyethylene (PE) particles have an average particle size of 10000nm, and the ratio of the average pore size of the fiber porous matrix to the average particle size of the low-melting polyethylene (PE) particles is 1:50, that is, the average pore size of the fiber porous matrix is 200nm.
  • the ratio of the content of the fiber porous matrix material to the polymer particles is 95:5, and the porosity of the isolation layer is 90%.
  • the number of the polymer particles in the porous matrix per unit area is 1 ⁇ 10 8 /m 2 .
  • the cross-sectional porosity ⁇ of the isolation layer was 75%, the surface open porosity ⁇ was 90%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ was 83%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40° C. to remove dispersants and solvents such as DMF to obtain a positive pole piece coated with a separator on both sides.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 20 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 10 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 40nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:1, that is, the average pore size of the fiber porous matrix is 40nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 5:95, and the porosity of the isolation layer is 30%.
  • the number of the polymer particles in the porous matrix per unit area is 4 ⁇ 10 17 /m 2 .
  • the cross-sectional void ratio ⁇ of the isolation layer is 25%
  • the surface open porosity ⁇ is 45%
  • the cross-sectional void ratio/surface open porosity ratio ⁇ / ⁇ is 56%.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 1 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 1000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:5, that is, the average pore size of the fiber porous matrix is 200nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 95:5, and the porosity of the isolation layer is 90%.
  • the weight of the polymer particles in the porous matrix per unit area is 0.004 g/m 2 .
  • the cross-sectional porosity ⁇ of the isolation layer is 70%, the surface open porosity ⁇ is 85%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 82%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40° C. to remove dispersants and solvents such as DMF to obtain a positive pole piece coated with a separator on both sides.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 20 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 10 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 40nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:1, that is, the average pore size of the fiber porous matrix is 40nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 5:95, and the porosity of the isolation layer is 30%.
  • the weight of the polymer particles in the porous matrix per unit area is 20 g/m 2 .
  • the cross-sectional porosity ⁇ of the isolation layer is 25%, the surface open porosity ⁇ is 45%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 56%.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 20 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 10000nm, and the ratio of the average pore diameter of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:1, that is, the average pore size of the fiber porous matrix is 10000nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 65:35, and the porosity of the isolation layer is 75%.
  • the cross-sectional void ratio ⁇ of the isolation layer is 60%
  • the surface open porosity ⁇ is 80%
  • the cross-sectional void ratio/surface open porosity ratio ⁇ / ⁇ is 75%.
  • the height of the polymer particles above the surface of the fiber porous matrix is 5000 nm. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40°C to remove the dispersant and solvent such as DMF, and then the positive pole piece with the separation layer coated on both sides can be obtained.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 20 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 1000 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 10000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:5, that is, the average pore size of the fiber porous matrix is 2000nm.
  • the ratio of the content of the porous matrix material to the polymer particles is 5:95, and the porosity of the isolation layer is 30%.
  • the cross-sectional porosity ⁇ of the isolation layer was 25%, the surface open porosity ⁇ was 35%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ was 71%.
  • the surface area occupied by the polymer particles on the surface of the isolation layer is 60%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40° C. to remove dispersants and solvents such as DMF to obtain a positive pole piece coated with a separator on both sides.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 10 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 1000 nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:5, that is, the average pore size of the porous matrix is 200 nm.
  • the ratio of the fiber porous matrix material to the polymer particle content is 65:35, the porosity of the isolation layer is 50%, the cross-sectional void ratio ⁇ of the isolation layer is 45%, the surface open porosity ⁇ is 60%, and the cross-sectional void ratio/surface open
  • the porosity ratio ⁇ / ⁇ is 75%.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 20 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 10000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:2.5, that is, the average pore size of the porous matrix is 4000nm, and the fiber is porous.
  • the ratio of the content of the matrix material to the polymer particles is 95:5.
  • the porosity of the isolation layer is 90%.
  • the cross-sectional porosity ⁇ of the separator is 85%, the surface open porosity ⁇ is 90%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 94%. .
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, the suspension B was used as the raw material, and the electrospray was used as the raw material.
  • Methods Spray low-melting polyethylene (PE) particles to form an integrated isolation layer of fiber porous matrix + low-melting polymer with a thickness of 10 ⁇ m. The low-melting polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • PE polyethylene
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 1000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:2.5, that is, the average pore size of the porous matrix is 400nm, and the fiber is porous.
  • the ratio of the content of the matrix material to the polymer particles is 65:35, and the porosity of the isolation layer is 75%.
  • the cross-sectional porosity ⁇ of the isolation layer is 40%, the surface open porosity ⁇ is 80%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 50%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40°C to remove the dispersant and solvent such as DMF to obtain a positive pole piece coated with a separator layer on both sides.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • Inorganic particles of aluminum oxide (Al 2 O 3 ) and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 90:10, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a solid content of 40% The slurry C.
  • a porous matrix of PVDF fibers was prepared by electrospinning. While spinning, suspension B and slurry C were used as raw materials. Spraying low melting point polyethylene (PE) particles and inorganic particles of aluminum oxide (Al 2 O 3 ) by electrospraying to form an integrated isolation layer of PVDF fiber porous matrix + low melting point polymer + inorganic particles with a thickness of 10 ⁇ m , Low-melting polymer particles and inorganic particles are embedded in the pores of the fiber porous matrix. Among them, the average fiber diameter is 100 nm.
  • PE low melting point polyethylene
  • Al 2 O 3 aluminum oxide
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 1000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:5, that is, the average pore size of the porous matrix is 200nm.
  • the average particle size of the inorganic ceramic (Al 2 O 3 ) particles is 400 nm, the weight ratio of the fiber porous matrix material to the polymer particles and the inorganic particles is 60:30:10, and the porosity of the isolation layer is 70%.
  • the cross-sectional porosity ⁇ of the isolation layer is 55%, the surface open porosity ⁇ is 70%, and the cross-sectional porosity/surface open porosity ratio ⁇ / ⁇ is 79%. Then, repeat the above steps on the other surface of the positive pole piece, and then vacuum dry at 40° C. to remove dispersants and solvents such as DMF to obtain a positive pole piece coated with a separator on both sides.
  • Conductive carbon black (Super P) and styrene butadiene rubber (SBR) are mixed according to a weight ratio of 97:3, and deionized water (H 2 O) is added as a solvent to prepare a slurry with a solid content of 0.85, and stir it evenly.
  • the slurry was uniformly coated on the positive electrode current collector aluminum foil and dried at 110° C. to obtain the positive electrode bottom coating.
  • the positive active material lithium cobalt oxide (LiCoO 2 ), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) was added as a solvent , Formulated into a slurry with a solid content of 0.75, and stirred evenly.
  • the slurry is uniformly coated on the positive electrode current collector aluminum foil coated with the primer layer, and dried at 90° C. to obtain the positive electrode pole piece. After coating, cut the pole piece into 38mm ⁇ 58mm specifications for later use.
  • PVDF polyvinylidene fluoride
  • DMF dimethylformamide
  • acetone 7:3 solvent
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • solution A was used as a raw material to prepare a porous matrix of PVDF fibers by electrospinning. While spinning, suspension B was used as a raw material and electricity
  • the spraying method sprays low melting point polyethylene (PE) particles to form an integrated isolation layer of a fiber porous matrix + low melting point polymer with a thickness of 10 ⁇ m.
  • the low melting point polymer particles are distributed in the fiber porous matrix in a filling manner. Among them, the average fiber diameter is 100 nm.
  • the selected low-melting-point polyethylene (PE) particles have an average particle size of 1000nm, and the ratio of the average pore size of the fiber matrix to the average particle size of the low-melting-point polyethylene (PE) particles is 1:5, that is, the average pore size of the porous matrix is 200nm, and the fiber is porous.
  • the ratio of the content of the matrix material to the polymer particles is 65:35, the cross-sectional void ratio ⁇ of the isolation layer is 65%, the surface open porosity ⁇ is 80%, and the cross-sectional void ratio/surface open porosity ratio ⁇ / ⁇ is 81%. .
  • the negative pole piece prepared in the above preparation example 1 and the positive pole piece with a separator prepared in each embodiment are opposed and stacked, as shown in FIG. 2. After fixing the four corners of the entire laminated structure with adhesive tape, it is placed in an aluminum plastic film, and the electrolyte in Preparation Example 3 is injected through the top side sealing, and then packaged to obtain a lithium-ion laminated battery.
  • Polyethylene (PE) with a thickness of 15 ⁇ m is selected as the separator, and it is placed between the negative pole piece and the positive pole piece prepared in the above preparation examples 1 and 2 as the separator. Lay the negative pole piece, the positive pole piece and the separator opposite and stack up. After fixing the four corners of the entire laminated structure with tape, placing it in an aluminum plastic film, sealing on the top side, injecting the electrolyte in Preparation Example 3, and packaging to obtain a lithium-ion laminated battery.
  • the positive pole piece and the negative pole piece prepared in Preparation Example 1 are opposed and stacked, as shown in FIG. 2. After fixing the four corners of the entire laminated structure with tape, placing it in an aluminum plastic film, sealing on the top side, injecting the electrolyte in Preparation Example 3, and packaging to obtain a lithium-ion laminated battery.
  • Polyethylene (PE) with a thickness of 15 ⁇ m is selected as the isolation membrane.
  • a coating of 5 ⁇ m low melting point polyethylene (PE) particles is prepared on the surface of the polyethylene isolation film by an electric spraying method, wherein the average particle size of the particles is 500 nm.
  • the total thickness of the isolation layer is 20 ⁇ m, and the overall porosity of the isolation layer is 30%.
  • the integrated separator containing the low-melting-point polymer particle coating prepared above is placed between the negative pole piece and the positive pole piece prepared in the above preparation examples 1 and 2. Lay the negative pole piece, the positive pole piece and the separator opposite and stack up. After fixing the four corners of the entire laminated structure with tape, placing it in an aluminum plastic film, sealing on the top side, injecting the electrolyte in Preparation Example 3, and packaging to obtain a lithium-ion laminated battery.
  • a layer of PVDF non-woven fiber layer with a thickness of 10 ⁇ m was prepared by electrospinning using solution A as a raw material, with an average fiber diameter of 100 nm, and a porous matrix of fibers. The average pore diameter is 200nm.
  • solution A as a raw material
  • the average fiber diameter is 100 nm
  • a porous matrix of fibers The average pore diameter is 200nm.
  • suspension B as the raw material to prepare low melting point polyethylene (PE) particles on the surface of the fiber porous matrix by electrospraying.
  • the selected low melting point polyethylene (PE) particles have an average particle size of 500 nm.
  • the ratio of the average pore diameter of the fiber porous matrix to the average particle diameter of the low melting point polyethylene (PE) particles is 1:2.5, and the overall porosity of the isolation layer is 75%.
  • the positive pole piece and the negative pole piece prepared in Preparation Example 1 are opposed and stacked, as shown in FIG. 2. After fixing the four corners of the entire laminated structure with tape, placing it in an aluminum plastic film, sealing on the top side, injecting the electrolyte of Preparation Example 3, and packaging to obtain a lithium-ion laminated battery.
  • the integrated isolation layer with low melting point polymer particles filled with nanofiber porous matrix can reduce the thickness of the isolation layer to increase the energy density and increase the porosity of the isolation layer. Improve the liquid retention capacity, accelerate the reaction kinetics to enhance the electrical performance, enhance the adhesion between the isolation layer and the pole piece to improve the resistance to mechanical abuse such as drop of the lithium ion battery, reduce the closed cell temperature of the isolation layer, and increase its high temperature Thermal shrinkage resistance under the environment, thereby improving the safety and stability of lithium-ion batteries.
  • the isolation layer of the present application has low melting point polymer particles distributed in the nanofiber porous matrix, so that the isolation layer of the present application has the function of low-temperature thermal pore closure, and can cut off the current under thermal runaway Improve the safety performance of lithium-ion batteries.
  • low-melting polymer particles can be filled in the "macropores" of the fiber porous matrix to reduce the macropores in the pure heat-resistant spinning isolation layer, thereby further improving the self-discharge problem of lithium-ion batteries, reducing the K value, and at the same time due to the isolation
  • the improvement of the mechanical strength of the layer reduces the internal short circuit problem of the positive and negative electrode active material particles in the lithium ion battery piercing the isolation layer, and is also beneficial to improve the cycle performance of the lithium ion battery.
  • the integrated structure design halves the thickness of the isolation layer, thereby greatly improving the volumetric energy density of the lithium-ion battery.
  • the integrated isolation layer has a higher porosity, thereby accelerating ion transmission, enhancing reaction kinetics, and improving the electrical performance of lithium-ion batteries.
  • the integrated structure design can effectively reduce the thickness of the isolation layer, so that the lithium ion battery has a higher volumetric energy density.
  • the low-melting polymer is filled in the fiber porous matrix. When thermal runaway occurs, the response speed of melting and closing the cells is faster.
  • low-melting polymer fills the "macropores" in the fiber porous matrix, optimizes the pore size distribution, improves the self-discharge problem of lithium-ion batteries, reduces the K value, and improves the mechanical strength of the fiber porous matrix, and enhances the resistance to puncture by positive and negative particles ability.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

一种电化学装置和包含电化学装置的电子装置。电化学装置包括电极极片以及在电极极片的至少一个表面上的隔离层(10),隔离层(10)包含纳米纤维多孔基体(101)和分布在纳米纤维多孔基体(101)中的聚合物颗粒(102),聚合物颗粒(102)的熔融温度为70℃至150℃。与现有技术相比,由于隔离层(10)在纳米纤维多孔基体(101)中分布了低熔点聚合物颗粒(102),使得隔离层(10)具有低温热闭孔功能,热失控下,可切断电流提升电化学装置的安全性能。低熔点聚合物颗粒(102)填充在纤维多孔基体的"大孔"中,减少大孔,从而进一步改善电化学装置自放电问题,降低K值,同时降低电化学装置内部正负极活性物质颗粒刺穿隔离层(10)的内短路问题,也有利于改善电化学装置循环等电性能。

Description

一种电化学装置及包含该电化学装置的电子装置 技术领域
本申请涉及电化学领域,更具体地,本申请涉及一种电化学装置和包含所述电化学装置的电子装置。
背景技术
锂离子电池具有能量密度高、循环寿命长、标称电压高(>3.7V)、自放电率低等许多优点,在消费电子领域具有广泛的应用。随着近年来电动汽车和可移动电子设备的高速发展,人们对电池的能量密度(>700Wh/L)、安全性、循环性能(>500圈)等相关需求越来越高,期待着综合性能全面提升的新型锂离子电池的出现。其中,无隔膜锂离子电池是一种备受瞩目的新型锂离子电池。
无隔膜锂离子电池,采用在电极极片表面制备隔离层的方法来替代传统隔离膜。无隔膜锂离子电池将隔离层直接集成至电极极片表面,无需单独制作隔离膜,制作过程由极片-隔离膜-极片三组件变为(集成)极片-(集成)极片两组件的叠片/卷绕,简化电池生产流程、降低电池制备难度;同时,减薄的隔离层厚度提高电池能量密度;此外,无隔膜电池技术还具有提高隔离层孔隙率从而提高保液能力,加快反应动力学等许多优点,因此受到广泛关注。
现有无隔膜锂离子电池通常采用无纺布隔离层。无纺布隔离层由纳米或微米纤维定向或随机的结合在一起而形成,各纤维之间的随机搭接形成了大量的孔用于离子传输,而纤维本身则作为隔离层的支撑骨架。但这种纤维层不具备热闭孔功能,在热失控(如电池过充、热箱、振动、碰撞、跌落、内短路、外短路等)下不能通过熔融关断锂离子通路的方式阻断电流,给锂离子电池的安全性能造成较大的隐患;其次,无纺布隔离层的纤维层本身的机械强度较低,导致其在抵抗正负极颗粒刺穿时,正负极颗粒会穿透纤维层造成电化学装置内短路;此外,无纺布隔离层纤维的孔径较大,且分布不均,部分“大孔”的存在会导致锂离子电池具有严重的自放电问题。
发明内容
基于现有技术的缺陷,本申请的第一方面,首先提供一种电化学装置,其包括电极极片以及在电极极片的至少一个表面上的隔离层,所述隔离层包含纳米纤维的多孔基体和分布在所述多孔基体中的聚合物颗粒,所述聚合物颗粒的熔融温度为70℃至150℃。
在本申请第一方面的一些优选实施方式中,其中,所述隔离层中的所述聚合物颗粒的数 量为1×10 8/m 2至1×10 18/m 2
在本申请第一方面的一些优选实施方式中,其中,所述聚合物颗粒的平均粒径为40nm至10μm。
在本申请第一方面的一些优选实施方式中,其中,所述纳米纤维直径为10nm至5μm,所述纤维多孔基体的孔径为40nm至10μm。
在本申请第一方面的一些优选实施方式中,其中,部分聚合物颗粒从所述多孔基体表面伸出0.1nm至5μm的高度,所述多孔基体表面被所述部分聚合物颗粒占据的表面积为所述多孔基体总表面积的0.1%至60%。
在本申请第一方面的一些优选实施方式中,其中所述聚合物颗粒的聚合物包括聚苯乙烯、聚乙烯、乙烯-丙烯共聚物、乙烯-醋酸乙烯共聚物、丙烯腈-丁二烯-苯乙烯、聚乳酸、聚氯乙烯、聚乙烯丁醛或聚丙烯酸酯中的至少一种。
在本申请第一方面的一些优选实施方式中,其中,所述纳米纤维包含聚合物,所述聚合物包括聚偏二氟乙烯、聚酰亚胺、聚酰胺、聚丙烯腈、聚乙二醇、聚氧化乙烯、聚苯醚、聚碳酸亚丙酯、聚甲基丙烯酸甲酯、聚对苯二甲酸乙二醇酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)及其衍生物中的至少一种,优选聚偏二氟乙烯、聚酰亚胺、聚酰胺、聚丙烯腈、聚乙二醇、聚氧化乙烯、聚苯醚、聚碳酸亚丙酯、聚甲基丙烯酸甲酯、聚对苯二甲酸乙二醇酯及其衍生物中至少一种。
在本申请第一方面的一些优选实施方式中,其中所述隔离层的截面空隙率β与所述隔离层的表面开孔率α之间的比值β/α为95%以下。
在本申请第一方面的一些优选实施方式中,其中所述表面开孔率α为35%至90%。
在本申请第一方面的一些优选实施方式中,其中所述截面空隙率β为30%至85%。
本申请的第二方面,提供一种电子装置,其包含上述任一项技术方案所述的电化学装置。
本申请所述的电子装置包括本领域公知的电子装置,例如笔记本电脑、手机、电动摩托车、电动汽车、电动玩具等。
与现有技术相比,由于本申请的隔离层在纳米纤维多孔基体中分布了低熔点聚合物颗粒,使得隔离层具有低温热闭孔功能,热失控下,可切断电流提升电化学装置安全性能;此外,低熔点聚合物颗粒可以填充在纤维多孔基体的“大孔”中,减少单纯耐热纺丝隔离层中的大孔,从而进一步改善电化学装置自放电问题,降低K值,同时由于隔离层机械强度的提高,降低电化学装置内部正负极活性物质颗粒刺穿隔离层的内短路问题,也有利于改善电化学装置循环等电化学性能。
附图说明
为了更清楚地说明本申请实施例和现有技术的技术方案,下面对实施例和现有技术中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本申请的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。
图1为本申请的一种实施方案的电极组件的结构示意图;
图2为本申请的一种实施方案的电极组件的结构示意图;
图3为本申请的一种实施方案的电极组件的结构示意图;
图4为本申请的一种实施方案的电极组件的结构示意图;
图5为本申请的一种实施方案中的隔离层的结构示意图;
图6为本申请的一种实施方案中的隔离层的结构示意图;
图7为本申请的一种制备隔离层的实施方案的示意图;
图8为本申请的一种制备隔离层的实施方案的示意图。
附图标记:
10:隔离层;
101:纳米纤维多孔基体;
102:聚合物颗粒;
103:无机颗粒;
20:集流体;
201:正极集流体;
202:负极集流体;
30:活性物质层;
301:正极活性物质层;
302:负极活性物质层;
40:导电层;
401:正极导电层;
402:负极导电层;
50:纺丝设备;
60:电沉积设备;
70:稳压器。
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,以下参照附图和实施例,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,都属于本申请保护的范围。
本申请中所述电化学装置没有特别限制,可以是能够使用本申请的任何电化学装置,例如锂离子电池、超级电容器等。为了方便描述,以下以锂离子电池为例进行描述,但这不意味着本申请的电化学装置仅限于锂离子电池。
本申请的一个方面提供一种电化学装置,其包括电极极片以及在电极极片的至少一个表面上的隔离层,所述隔离层包含纳米纤维多孔基体和分布在多孔基体中的聚合物颗粒,所述聚合物颗粒的熔融温度为70℃至150℃,优选为80℃至140℃,更优选为90℃至130℃,最优选为100℃至120℃。
在本申请的一些实施方案中,所述多孔基体由纳米纤维定向或随机的结合在一起而形成,各纳米纤维之间的随机搭接形成了大量的孔用于离子传输,而纳米纤维本身则作为隔离层的支撑骨架,所述聚合物颗粒填充在多孔基体中。由于聚合物颗粒的熔融温度较低,当电化学装置出现热失控时,例如在发生电池过充、热箱、振动、碰撞、跌落、内短路、外短路等时,电化学装置温度升高,在达到聚合物颗粒熔点后,聚合物颗粒发生熔融,封闭隔离层的孔隙,减少或阻断锂离子的传导,使电化学装置减少或停止充放电,可以大大提高电化学装置的安全性。此外,纳米纤维多孔基体本身具有高熔融温度,在过充/热箱等热滥用情况下,隔离层保持原有结构而不会熔缩导致破膜,避免发生内短路现象。此外,由于聚合物颗粒分布在多孔基体孔隙中,填充了多孔基体中的大孔,可有效减少自放电现象。此外,由于聚合物颗粒分布在多孔基体中,提高了多孔基体抗刺穿强度,可以有效防止正负极活性物质颗粒刺穿隔离层而发生电化学装置短路。另外,纳米纤维多孔基体与极片之间具有较好粘接力,在电化学装置跌落过程中,可以有效避免隔膜被电解液冲刷而翻折,极大提高电化学装置安全性能。
所述隔离层中的聚合物颗粒数没有特别限制,只要能够实现本申请的目的即可。在本申请的一些实施方案中,所述隔离层中的聚合物颗粒数为1×10 8/m 2至1×10 18/m 2,优选为1×10 9/m 2至1×10 16/m 2,更优选为1×10 10/m 2至1×10 14/m 2,最优选为1×10 11/m 2至1×10 13/m 2。通过将聚合物颗粒数限定在上述范围内,在电化学装置发生热失控时,可以快速响应,缩短熔融至闭孔的时间,阻断离子通路,提高电化学装置安全性能。此外,可以更好地提高隔离层抗刺穿 能力,防止正负极活性物质颗粒刺穿隔离层,并且有效减小多孔基体中的大孔,减少自放电现象,降低K值。
所述聚合物颗粒的粒径没有特别限制,只要能够实现本申请的目的即可。在本申请的一些实施方案中,所述聚合物颗粒的平均粒径为40nm至10μm,优选为100nm至5μm,更优选为200nm至2μm,最优选为500nm至1.5μm。所述聚合物颗粒的平均粒径为上述范围内,可以更好地减少或消除多孔基体中的大孔,减少自放电现象。此外,当所述聚合物颗粒的平均粒径在上述范围内,可以在电化学装置热失控情况下,充分且快速地封闭隔离层中的孔隙,阻断离子传导路径,形成绝缘层,防止电池起火爆炸。
所述纳米或微米纤维的直径没有特别限制,只要能够实现本申请的目的即可。在本申请的一些实施方案中,所述纳米纤维直径为10nm至5μm,优选为20nm至2μm,更优选为50nm至1μm,最优选为80nm至400nm。通过使所述纳米纤维直径在上述范围内,可以使隔离层具有合适的孔隙率,提高隔离层的保液能力,同时保证多孔基体具有合适的强度,与分布在多孔基体中的聚合物颗粒协同提高隔离层的机械强度,增强隔离层抗正负极活性材料颗粒刺穿的能力。所述隔离层中,所述多孔基体的孔径没有特别限制,只要能实现本申请的目的即可。在本申请的一些优选的实施方案中,所述多孔基体隔离层的孔径为40nm至10μm,优选为80nm至5μm,更优选为130nm至1μm,最优选为150nm至500nm。不限于任何理论,发明人认为,所述多孔基体隔离层的孔径在上述范围内,可以加快锂离子传输,提高反应动力学,同时,可以有效降低正负极活性物质颗粒穿过隔离层的概率,减少自放电现象和内短路的风险。此外,电化学装置在热失控的过程中,熔融的聚合物颗粒可以快速填堵隔离层孔隙,实现隔离层闭孔,阻断离子传输,提高电化学装置的安全性能。
在本申请一个优选的实施方案中,部分聚合物颗粒从所述多孔基体表面伸出0.1nm至5μm的高度,优选1nm至1μm,更优选为2nm至500nm,最优选为5nm至100nm。不限于任何理论,发明人认为,所述聚合物颗粒从多孔基体中伸出一定的高度,可以减小正负极活性材料颗粒对多孔基体本身的作用力,进一步防止正负极颗粒对隔离层的刺穿。所述多孔基体表面被所述部分聚合物颗粒占据的表面积为所述多孔基体的总表面积的0.1%至60%,优选0.5%至45%,更优选为2%至30%,最优选为5%至15%。不限于任何理论,发明人认为,所述多孔基体表面被从表面伸出的聚合物颗粒占据的表面积在上述范围内,可以使得隔离层具有较高的强度和抗正负极活性物质颗粒刺穿的能力。
在本申请中,所述的“多孔基体表面”是指:所述隔离层涂布在所述活性物质层上之后,所述隔离层远离所述活性物质层的那一侧表面。
本申请所用的聚合物颗粒的聚合物种类没有特别限制,只要其熔点为70至150℃即可。在本申请的一些实施方案中,所述聚合物颗粒包含聚苯乙烯(PS)、聚乙烯(PE)、乙烯-丙烯共聚物、聚丙烯(PP)、乙烯-醋酸乙烯共聚物(EVA)、丙烯腈-丁二烯-苯乙烯(ABS)、聚乳酸(PLA)、聚氯乙烯(PVC)、聚乙烯丁醛(PVB)或聚丙烯酸酯(PA)中的至少一种。
本申请所用的聚合物颗粒的形状没有特别限制,可以为球形,橄榄形、细长形、扁平型、饼型,环形,棒状、中空状、螺旋状、核壳状、葫芦状、圆柱、圆锥、长方体、立方体、棱锥、棱柱或者其它任意形状中的至少一种。
本申请所用的纳米纤维没有特别限制,只要能够实现本申请的目的即可,可以使用本领域技术人员公知的任何材料。在本申请的一些实施方案中,所述纳米纤维包含聚合物,所述聚合物包括聚偏二氟乙烯(PVDF)、聚酰亚胺(PI)、聚酰胺(PA)、聚丙烯腈(PAN)、聚乙二醇(PEG)、聚氧化乙烯(PEO)、聚苯醚(PPO)、聚碳酸亚丙酯(PPC)、聚甲基丙烯酸甲酯(PMMA)、聚对苯二甲酸乙二醇酯(PET)、聚(偏二氟乙烯-六氟丙烯)(PVDF-HFP)、聚(偏二氟乙烯-共-三氟氯乙烯)(PVDF-PCTFE)及其衍生物中的至少一种,优选聚偏二氟乙烯、聚酰亚胺、聚酰胺、聚丙烯腈、聚乙二醇、聚氧化乙烯、聚苯醚、聚碳酸亚丙酯、聚甲基丙烯酸甲酯、聚对苯二甲酸乙二醇酯及其衍生物中至少一种。优选地,在本申请的一些实施方案中,所述聚合物的熔点不低于170℃。使用熔点不低于170℃的所述聚合物纳米纤维,在热失控情况下,聚合物颗粒在较低温度下开始熔融,例如在70至150℃下开始熔融,封闭隔离层离子传输通道,但是纳米纤维骨架在此温度下不发生熔融,保持隔离层原有结构而不熔缩,从而保证不会由于隔离层收缩/破裂而发生电池内短路,提高了电化学装置的安全性。
所述纳米纤维的聚合物还可以含有无机颗粒,所述无机颗粒没有特别限制,可以使用本领域技术人员公知的无机颗粒,例如所述无机颗粒可以包括HfO 2、SrTiO 3、SiO 2、Al 2O 3、MgO、CaO、NiO、BaO、ZnO、TiO 2、ZrO 2、SnO 2、CeO 2、勃姆石、氢氧化镁或氢氧化铝等中的至少一种。所述无机颗粒的尺寸没有特别限制,例如可以为10nm至10μm。所述无机颗粒的含量没有特别限制,例如可以为0.1%至80%。通过添加无机颗粒,可以进一步增强隔离层的机械强度,降低电化学装置的自放电现象,提高电化学装置的安全性能。
在本申请的一些优选实施方案中,所述隔离层的表面开孔率α为35%至90%,优选为45%至87%,更优选为60%至85%,最优选为75%至82%。所述隔离层的截面空隙率β为30%至85%,优选为40%至80%,更优选为50%至75%,最优选为55%至65%。所述隔离层的截面空隙率β与所述隔离层的表面开孔率α之间的比值β/α为95%以下,优选为20%至90%,更优选为40%至85%,最优选为65%至80%。
通过将所述隔离层的表面开孔率和截面空隙率控制在上述范围内,可以为隔离层提供高保液能力,保持合适的强度,具备快速的反应动力学。
根据本申请的隔离层的厚度没有特别限制,本领域技术人员可以根据具体情况进行选择,优选为1μm至20μm,优选为2μm至18μm,更优选为5μm至15μm,最优选为6μm至12μm。所述隔离层厚度是指包含纳米纤维多孔基体和聚合物颗粒的一体化隔离层的整体厚度。
本申请的电化学装置可以是锂离子电池。本申请对锂离子电池的型式没有限制,可以为任何型式的锂离子电池,例如纽扣型、圆柱型、软包型锂离子电池等任何型式。
本申请的锂离子电池包括正极极片、负极极片、电解液和本申请上述任意一项所述的隔离层。
在本申请的一种实施方式中,所述隔离层可以形成在正极极片的一个表面上和负极极片的一个表面上,然后按照负极极片+隔离层、正极极片+隔离层的方式进行层叠,形成锂离子电池层叠体。
在本申请的另一种实施方式中,所述隔离层可以形成在正极极片的两个表面上,然后按照负极极片、隔离层+正极极片+隔离层的方式进行层叠,形成锂离子电池层叠体,其中负极极片表面上没有隔离层。
在本申请的另一种实施方式中,所述隔离层可以形成在负极极片的两个表面上,然后按照正极极片、隔离层+负极极片+隔离层的方式进行层叠,形成锂离子电池层叠体,其中正极极片表面上没有隔离层。
在上述实施方式中形成的层叠体,可以继续按照上述顺序层叠,也可以直接卷绕,形成多层的锂离子电池层叠体。本申请对于层叠方式没有限制,本领域技术人员可以根据实际情况进行选择。
图1示出了本申请的一种实施方案的电极组件结构示意图。其中,在电极极片的一个表面上设置了隔离层。隔离层10覆盖在电极活性物质层30表面上,电极活性物质层30位于集流体20的一个表面上。
图2示出了本申请的一种实施方案的电极组件结构示意图,其中,隔离层10位于正极活性物质层301和负极活性物质层302之间,正极活性物质层301位于正极集流体201的一个表面上,负极活性物质层302位于负极集流体202的一个表面上。
图3示出了本申请的一种实施方案的电极组件的结构示意图,其中还包括导电层40,导电层位于电极活性物质层30和集流体20之间,隔离层10覆盖在电极活性物质层30表面上。
图4示出了本申请的一种实施方案的电极组件结构示意图,其还包含正极导电层401和 负极导电层402,其中正极导电层401位于正极集流体201和正极活性物质层301之间,负极导电层402位于负极集流体202和负极活性物质层302之间。
图5示出了本申请的一种实施方案的隔离层结构示意图,其中,聚合物颗粒102位于纳米纤维基体101中。
图6示出了本申请的一种实施方案的隔离层结构示意图,其中,聚合物颗粒102、无机颗粒103位于纳米纤维基体101中。
在本申请的实施方案中,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,所述正极极片通常包含正极集流体和正极活性材料。其中,所述正极集流体没有特别限制,可以为本领域公知的任何正极集流体,例如铝箔、铝合金箔或复合集流体等。所述正极活性材料没有特别限制,可以为现有技术的任何正极活性材料,所述活性物质包括NCM811、NCM622、NCM523、NCM111、NCA、磷酸铁锂、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂中的至少一种。
任选地,所述正极极片还可以包含导电层,所述导电层位于正极集流体和正极活性材料之间。所述导电层的组成没有特别限制,可以是本领域常用的导电层。例如,所述导电层包括导电剂和粘接剂。
在本申请的实施方案中,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,所述负极极片通常包含负极集流体和负极活性材料。其中,所述负极集流体没有特别限制,可以使用本领域公知的任何负极集流体,例如铜箔、铜合金箔或复合集流体等。所述负极活性材料没有特别限制,可以使用本领域公知的任何负极活性材料。例如,可以包括石墨、硬碳、软碳、硅、硅碳或硅氧化物等中的至少一种。
任选地,所述负极极片还可以包含导电层,所述导电层位于负极集流体和负极活性材料之间。所述导电层的组成没有特别限制,可以是本领域常用的导电层。例如,所述导电层包括导电剂和粘接剂。
上述所述导电剂没有特别限制,可以使用本领域公知的任何导电剂,只要能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)、碳纤维或石墨烯等中的至少一种。例如,导电剂可选用导电炭黑(Super P)。上述所述粘接剂没有特别限制,可以使用本领域公知的任何粘接剂,只要能实现本申请目的即可。例如,粘接剂可以包括丁苯橡胶(SBR)、聚乙烯醇(PVA)、聚四氟乙烯(PTFE)或羧甲基纤维素钠(CMC-Na)等中的至少一种。例如,粘接剂可选用丁苯橡胶(SBR)。
锂离子电池的电解液没有特别限制,可以使用本领域公知的任何电解液,所述可以是凝 胶态、固态和液态中的任一种。例如,所述液态电解液包括锂盐和非水溶剂。
所述锂盐没有特别限制,可以使用本领域公知的任何锂盐,只要能实现本申请的目的即可。例如,锂盐可以包括LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3或LiPO 2F 2等中的至少一种。例如,锂盐可选用LiPF 6
所述非水溶剂没有特别限定,只要能实现本申请的目的即可。例如,非水溶剂可以包括碳酸酯化合物、羧酸酯化合物、醚化合物、腈化合物或其它有机溶剂等中的至少一种。
例如,碳酸酯化合物可以包括碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)、碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)、碳酸氟代亚乙酯(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等中的至少一种。
本申请对于上述电化学装置的制备方法没有特别限制,可以采用本领域公知的进行制备。例如,在正极极片或负极极片的一个或两个表面上沉积纳米纤维和聚合物颗粒,形成包含纳米纤维的多孔基体和填充在多孔基体中的聚合物颗粒。
或,在正极极片或负极极片的一个或两个表面上沉积纳米纤维、聚合物颗粒和无机颗粒,形成包含纳米纤维的多孔基体和填充在多孔基体中的聚合物颗粒和无机颗粒。
沉积纳米纤维、聚合物颗粒和/或无机颗粒的方法没有特别限制,可以采用本领域公知的沉积方法进行,例如,所述多孔基体通过电纺丝、气纺丝、离心纺丝、电吹法、熔喷法、闪蒸法或涂布法,所述聚合物颗粒和/或无机颗粒通过电沉积法、印刷法、涂布法、旋转法或浸渍法制备而成。沉积纳米纤维、聚合物颗粒和/或无机颗粒的顺序没有特别限制,只要能够形成本申请的隔离层即可,所述隔离层包含纳米纤维多孔基体和分布在所述多孔基体中的聚合物颗粒和/或无机颗粒。例如,所述纳米纤维和聚合物颗粒和/或无机颗粒可以同时沉积或者交替沉积。
图7为本申请的一种电纺丝工艺的示意图;电纺丝装置50将纳米纤维沉积在电极表面上形成隔离层10。
图8为本申请的一种制备隔离层的实施方案的示意图,其中,电纺丝装置50和电沉积装置60分别将纳米纤维和聚合物颗粒沉积在电极表面上;电纺丝装置50和电沉积装置60均连接在稳压器70上。
所述多孔基体可以用本领域已知的任何纺丝设备实施,没有特别限制,只要能实现本申 请目的即可。所述电纺丝法可以使用本领域已知的任何电纺丝设备,例如电纺丝设备可以为永康乐业Elite系列等;所述气纺丝法可以使用本领域已知的任何气纺丝设备,例如气纺丝设备可以为南京捷纳思新材料的气喷纺丝机等;所述离心纺丝法可以使用本领域已知的任何离心纺丝设备,例如离心纺丝设备可以为四川致研科技的离心纺丝机等。所述电沉积法可以用本领域已知的任何设备实施,没有特别限制,只要能实现本申请的目的即可。所述电喷涂法可以使用本领域已知的任何电喷涂设备,例如可以使用法国萨麦斯的静电喷涂设备。
本申请还提供一种电子装置,其包含根据本申请的电化学装置。
本申请所述的电子装置包括本领域一般的电子装置,例如笔记本电脑、手机、电动摩托车、电动汽车、电动玩具等。
本申请中所用的术语一般为本领域技术人员常用的术语,如果与常用术语不一致,以本申请中的术语为准。
具体地,在本申请中,以下术语的含义如下:
截面空隙率:在垂直于隔离层表面的任意截面上的空隙面积占截面总面积的百分比。
表面开孔率:在隔离层表面上的开口孔隙的表面积占表面总表面积的百分比。
聚合物颗粒的数量:隔离层单位面积上的聚合物颗粒的总个数。
聚合物颗粒的平均粒径:聚合物颗粒的平均粒径用D50表示,其中D代表聚合物颗粒的直径,D50即以体积分布为基准,聚合物颗粒的累计粒度分布百分数达到50%时所对应的粒径,它的物理意义是粒径小于它的颗粒占50%,大于它的颗粒也占50%。
测试方法:
隔离层闭孔温度测试方法:
将含单面活性物质的正极集流体+隔离层+含单面活性物质的负极集流体样品用电解液浸润,其中,所述活性物质与隔离层相邻。将多路测温仪触头放置在隔离层处。将上述组合放置在测试夹具板上,施加10MPa的压力并连接交流阻抗测试仪,然后将其放置在50℃烘箱中,并以2℃/min升温,记录电阻达1000Ω对应的温度,该温度为隔离层的闭孔温度。
隔离层破膜温度测试方法:
将含单面活性物质的正极集流体+隔离层+含单面活性物质的负极集流体样品放置在测试夹具板上,将多路测温仪触头放置在隔离层处,然后施加10MPa的压力,上述装置连接到电导率测试仪,然后将其放置在50℃烘箱中,并以2℃/min升温,电导率出现示数时对应的温 度即为隔离层的破膜温度。
1C-1.5U(其中U为截止电压)1h过充(Overcharge)性能测试方法:
将锂离子电池放电至3.0V,然后以1C恒流充电至1.5U,然后恒压充电1h,不起火不爆炸为通过测试,记为pass。
150℃,1h热箱(Hotbox)性能测试方法:
将满充锂离子电池放在烘箱中,将烘箱以5±2℃/min的升温速度升温至150℃,并保持1h后停止,不起火不爆炸为通过测试,记为pass。
隔离层孔隙率ε测试方法:
隔离层孔隙率ε通过所测隔离层的重量M 隔离层和体积V 隔离层,多孔基体和聚合物颗粒分别占隔离层重量的质量分数w 多孔基体和w 聚合物颗粒,以及它们的密度ρ 多孔基体和ρ 聚合物颗粒换算而得,ε=(V 隔离层-V 多孔基体-V 聚合物颗粒)/V 隔离层*100%,其中V 多孔基体=M 隔离层*w 多孔基体多孔基体,V 聚合物颗粒=M 隔离层*w 聚合物颗粒聚合物颗粒
截面空隙率β测试方法:
将已制备好的隔离层截面放在配有一定数量方格参考物的扫描电子显微镜下观察,选取单位面积,对其中覆盖在空隙上的方格进行计数,则覆盖在空隙上的方格面积与选取面积之比即为隔离层的截面空隙率β1。以此方法重复,选取隔离层不同截面不同位置的单位面积进行截面空隙率测算,得截面空隙率分别为β 2,β 3,β 4……β n。因此,隔离层截面空隙率β为β 1,β 2,β 3,β 4……β n的均值,β(%)=n/(β 1234+……+β n)。
表面开孔率α测试方法:
将所测隔离层放在配有一定数量方格参考物的扫描电子显微镜下观察,选取单位面积,对其中覆盖在孔隙上的方格进行计数,则覆盖在孔隙上的方格面积与选取面积之比即为隔离层的表面开孔率α 1。以此方法重复,选取隔离层表面不同位置的单位面积进行表面开孔率测算,得表面开孔率分别为α 2,α 3,α 4……α n。因此,隔离层表面开孔率α为α 1,α 2,α 3,α 4……α n的均值,α(%)=n/(α 1234+……+α n)。
锂离子电池自放电速率K值测试方法:
将锂离子电池以0.5C放电至3.0V,静置5min。然后将锂离子电池以0.5C恒定电流充电3.85V,然后以3.85V恒定电压充电至电流为0.05C,在25℃±3℃的环境中静置两天,测试并记录此时电压为OCV1。接着,将锂离子电池继续在室温下静置两天,测试并记录此时电压为OCV2,则K值通过如下公式可得:K(mV/h)=(OCV2-OCV1)/48h*1000
50个充放电循环后的放电容量/首次放电容量η测试方法:
将锂离子电池以0.5C恒定电流充电至4.4V,然后以4.4V恒定电压充电至电流0.05C,在25℃±3℃的环境中静置10min,然后0.5C电流放电至3.0V,记录首次放电容量为Q 1D,如此重复循环50次,记录此时放电容量为Q 50D,则50个充放电循环后的放电容量/首次放电容量保持率:η(%)=Q 50D/Q 1D*100%
实施例
制备例1:负极极片的制备
将负极活性材料石墨(Graphite)、导电炭黑(Super P)、丁苯橡胶(SBR)按照重量比96:1.5:2.5进行混合,加入去离子水(H 2O)作为溶剂,调配成为固含量为0.7的浆料,并搅拌均匀。将浆料均匀涂覆在厚度为8μm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。在该负极极片的另一个表面上重复以上步骤,得到双面涂布负极活性材料的负极极片。然后,将极片裁切成41mm×61mm的规格待用。
制备例2:正极极片的制备
将正极活性材料钴酸锂(LiCoO 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合,加入N-甲基吡咯烷酮(NMP)作为溶剂,调配成为固含量为0.75的浆料,并搅拌均匀。将浆料均匀涂覆在厚度为10μm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。在正极集流体铝箔的另一个表面上,重复以上步骤,得到双面涂布完成的正极极片。涂布完成后,将极片裁切成38mm×58mm的规格待用。
制备例3:电解液的制备
在干燥氩气气氛中,首先将有机溶剂碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)以质量比EC:EMC:DEC=30:50:20混合,然后向有机溶剂中加入锂盐六氟磷酸锂 (LiPF 6)溶解并混合均匀,得到锂盐的浓度为1.15M的电解液。
以下实施例举例说明根据本申请的纳米纤维多孔基体+聚合物颗粒一体化隔离层的制备。这些实施例以正极极片为例进行说明,并且在正极极片的两个表面上沉积一体化隔离层。应当理解,所述一体化隔离层也可以沉积在负极极片的两个表面上,或者在正极极片的一个表面上和负极极片的一个表面上分别沉积一层一体化隔离层,这些实施方案同样可以实现本申请的目的。本领域技术人员,应当理解,这些实施方案同样在本申请的保护范围内。
实施例1:
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为10μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为500nm,多孔基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:2.5,即纤维多孔基体的平均孔径为200nm,纤维多孔基体材料与聚合物颗粒含量的比例为95:5,隔离层孔隙率为75%。隔离层截面空隙率β为53%,表面开孔率α为88%,截面空隙率/表面开孔率的比值β/α为60%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例2
除了按表1所示调整纤维多孔基体材料与聚合物颗粒含量为比例为80:20,且隔离层截面空隙率β为56%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为70%以外,其余与实施例1相同。
实施例3
除了按表1所示调整纤维多孔基体材料与聚合物颗粒含量为比例为65:35,且隔离层截面空隙率β为60%,表面开孔率α为75%,截面空隙率/表面开孔率的比值β/α为80%以外, 其余与实施例1相同。
实施例4
除了按表1所示调整纤维多孔基体材料与聚合物颗粒含量为比例为35:65,且隔离层截面空隙率β为50%,表面开孔率α为65%,截面空隙率/表面开孔率的比值β/α为77%以外,其余与实施例1相同。
实施例5
除了按表1所示调整纤维多孔基体材料与聚合物颗粒含量为比例为5:95,且隔离层截面空隙率β为35%,表面开孔率α为40%,截面空隙率/表面开孔率的比值β/α为88%以外,其余与实施例1相同。
实施例6
除了将纤维多孔基体材料为PI以外,其余与实施例3相同。
实施例7
除了将纤维多孔基体材料调整为PAN以外,其余与实施例3相同。
实施例8
除了将聚合物颗粒材料调整为ABS以外,其余与实施例3相同。
实施例9
除了将聚合物颗粒材料调整为PVB以外,其余与实施例3相同。
实施例10
除了按表1调整聚合物颗粒平均粒径为200nm,从而调整纤维多孔基体的孔径与聚合物颗粒平均粒径之比为1:1,隔离层截面空隙率β为55%,表面开孔率α为70%,截面空隙率/表面开孔率的比值β/α为78%以外,其余与实施例3相同。
实施例11
除了按表1调整聚合物颗粒平均粒径为1000nm,从而调整纤维多孔基体的孔径与聚合物颗粒平均粒径之比为1:5,隔离层截面空隙率β为60%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为75%以外,其余与实施例3相同。
实施例12
除了按表1调整聚合物颗粒平均粒径为3000nm,从而调整纤维多孔基体的孔径与聚合物颗粒平均粒径之比为1:15,隔离层截面空隙率β为65%,表面开孔率α为85%,截面空隙率/表面开孔率的比值β/α为75%以外,其余与实施例3相同。
实施例13
除了按表1将纤维多孔基体的孔径调整为40nm、纤维直径调整为10nm、将聚合物颗粒平均粒径调整为10000nm,且隔离层截面空隙率β为60%,表面开孔率α为75%,截面空隙率/表面开孔率的比值β/α为80%以外,其余与实施例3相同。
实施例14
除了按表1将纤维多孔基体的孔径调整为1000nm、纤维直径调整为400nm、聚合物颗粒尺寸调整为5000nm,且隔离层截面空隙率β为65%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为81%以外,其余与实施例3相同。
实施例15
除了按表1将纤维多孔基体的孔径调整为40nm、纤维直径调整为20nm、聚合物颗粒平均粒径调整为40nm,且隔离层截面空隙率β为50%,表面开孔率α为70%,截面空隙率/表面开孔率的比值β/α为71%以外,其余与实施例3相同。
实施例16
除了按表1将隔离层厚度调整为5μm,且隔离层截面空隙率β为65%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为81%以外,其余与实施例11相同。
实施例17
除了按表1调整隔离层孔隙率为30%,且隔离层截面空隙率β为25%,表面开孔率α为 35%,截面空隙率/表面开孔率的比值β/α为71%以外,其余与实施例11相同。
实施例18
除了按表1调整隔离层孔隙率为30%,且隔离层截面空隙率β为80%,表面开孔率α为85%,截面空隙率/表面开孔率的比值β/α为94%以外,其余与实施例11相同。
实施例19
除了将低熔点聚合物颗粒材料调整为熔点为70℃的EVA,且隔离层截面空隙率β为65%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为81%以外,其余与实施例11相同。
实施例20
除了将低熔点聚合物颗粒材料调整为熔点为150℃的PP以外,且隔离层截面空隙率β为65%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为81%以外,其余与实施例11相同。
实施例21
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法向正极极片的同一表面上喷涂低熔点聚乙烯(PE)颗粒,形成厚度为10μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为10000nm,纤维多孔基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:50,即纤维多孔基体的平均孔径为200nm,纤维多孔基体材料与聚合物颗粒含量的比例为95:5,隔离层孔隙率为90%。每单位面积多孔基体中的所述聚合物颗粒的个数为1×10 8/m 2。隔离层截面空隙率β为75%,表面开孔率α为90%,截面空隙率/表面开孔率的比值β/α为83%。然后,在该正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离 层的正极极片。
实施例22
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为20μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为10nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为40nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:1,即纤维多孔基体的平均孔径为40nm,纤维多孔基体材料与聚合物颗粒含量的比例为5:95,隔离层孔隙率为30%。每单位面积多孔基体中的所述聚合物颗粒的个数为4×10 17/m 2。且隔离层截面空隙率β为25%,表面开孔率α为45%,截面空隙率/表面开孔率的比值β/α为56%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例23
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为1μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为1000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:5,即纤维多孔基体的平均孔径为200nm,纤维多孔基体材料与聚合物颗粒含量的比例为95:5,隔离层孔隙率为90%。每单位面积多孔基体中的聚合物颗粒的重量为0.004g/m 2。且隔离层截面空隙率β为70%,表面开孔率α为85%,截面空隙率/表面开孔率的比值β/α为82%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空 烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例24
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为20μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为10nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为40nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:1,即纤维多孔基体的平均孔径为40nm,纤维多孔基体材料与聚合物颗粒含量的比例为5:95,隔离层孔隙率为30%。每单位面积多孔基体中的聚合物颗粒的重量为20g/m 2。隔离层截面空隙率β为25%,表面开孔率α为45%,截面空隙率/表面开孔率的比值β/α为56%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例25
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为20μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为10000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:1,即纤维多孔基体的平均孔径为10000nm,纤维多孔基体材料与聚合物颗粒含量的比例为65:35,隔离层孔隙率为75%。且隔离层截面空隙率β为60%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为75%。其中,聚合物颗粒高于纤维多孔基体表面的高度为5000nm。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条 件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例26
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为20μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为1000nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为10000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:5,即纤维多孔基体的平均孔径为2000nm,纤维多孔基体材料与聚合物颗粒含量的比例为5:95,隔离层孔隙率为30%。隔离层截面空隙率β为25%,表面开孔率α为35%,截面空隙率/表面开孔率的比值β/α为71%。其中,隔离层表面被聚合物颗粒占据的表面积为60%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例27
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为10μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为1000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:5,即多孔基体的平均孔径为200nm。纤维多孔基体材料与聚合物颗粒含量的比例为65:35,隔离层的孔隙率为50%,隔离层截面空隙率β为45%,表面开孔率α为60%,截面空隙率/表面开孔率的比值β/α为75%。。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层 的正极极片。
实施例28
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为20μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为10000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:2.5,即多孔基体的平均孔径为4000nm,纤维多孔基体材料与聚合物颗粒含量的比例为95:5。隔离层的孔隙率为90%。隔离层截面空隙率β为85%,表面开孔率α为90%,截面空隙率/表面开孔率的比值β/α为94%。。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例29
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为10μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为1000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:2.5,即多孔基体的平均孔径为400nm,纤维多孔基体材料与聚合物颗粒含量的比例为65:35,隔离层孔隙率为75%。其中,隔离层截面空隙率β为40%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为50%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布 隔离层的正极极片。
实施例30
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。将无机颗粒三氧化二铝(Al 2O 3)和聚偏氟乙烯(PVDF),按照重量比90:10进行混合,加入N-甲基吡咯烷酮(NMP)作为溶剂,调配成为固含量为40%的浆料C。
在制备例2的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B和浆料C作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒和无机颗粒三氧化二铝(Al 2O 3),形成厚度为10μm的PVDF纤维多孔基体+低熔点聚合物+无机颗粒的一体化隔离层,低熔点聚合物颗粒和无机颗粒镶嵌在纤维多孔基体孔隙中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为1000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:5,即多孔基体的平均孔径为200nm,,选用的无机陶瓷(Al 2O 3)颗粒平均粒径为400nm,纤维多孔基体材料与聚合物颗粒、无机颗粒重量比为60:30:10,隔离层孔隙率为70%。隔离层截面空隙率β为55%,表面开孔率α为70%,截面空隙率/表面开孔率的比值β/α为79%。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
实施例31
正极极片的制备
将导电炭黑(Super P)、丁苯橡胶(SBR)按照重量比97:3进行混合,加入去离子水(H 2O)作为溶剂,调配成为固含量为0.85的浆料,并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上,110℃条件下烘干,得到正极底涂层。
将正极活性材料钴酸锂(LiCoO 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合,加入N-甲基吡咯烷酮(NMP)作为溶剂,调配成为固含量为0.75的浆料,并搅拌均匀。将浆料均匀涂覆在涂覆过底涂层的正极集流体铝箔上,90℃条件下烘干,得到正极极片。涂布完成后,将极片裁切成38mm×58mm的规格待用。
将聚偏二氟乙烯(PVDF)分散在二甲基甲酰胺(DMF)/丙酮(7:3)溶剂中,并搅拌均匀至浆料 粘度稳定,得到质量分数为25%的溶液A。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮(NMP)/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在本实施例中制备的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备PVDF纤维多孔基体,在纺丝的同时,利用悬浊液B作为原料,利用电喷涂的方法喷涂低熔点聚乙烯(PE)颗粒,形成厚度为10μm的纤维多孔基体+低熔点聚合物的一体化隔离层,低熔点聚合物颗粒以填充方式分布在纤维多孔基体中。其中,纤维平均直径为100nm。选用的低熔点聚乙烯(PE)颗粒平均粒径为1000nm,纤维基体平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:5,即多孔基体的平均孔径为200nm,纤维多孔基体材料与聚合物颗粒含量的比例为65:35,隔离层截面空隙率β为65%,表面开孔率α为80%,截面空隙率/表面开孔率的比值β/α为81%。。然后,在正极极片的另一个表面上重复以上步骤,然后在40℃条件下真空烘干去除DMF等分散剂和溶剂,即可得到双面涂布隔离层的正极极片。
锂离子电池的制备
将以上制备例1中制备的负极极片和各实施例中制备的带有隔离层的正极极片相对并叠好,如图2所示。用胶带将整个叠片结构的四个角固定好后,置入铝塑膜中,经过顶侧封,注入制备例3中的电解液,然后封装,得到锂离子叠片电池。
各实施例的数据和测试结果见表1、表2和表3。
对比例1
选用厚度15μm的聚乙烯(PE)作为隔离膜,将其放置于上述制备例1,2中制备的负极极片与正极极片之间作为隔离膜。将负极极片、正极极片和隔离膜相对并叠好。用胶带将整个叠片结构的四个角固定好后,置入铝塑膜中,经顶侧封、注入制备例3中的电解液、封装后,得到锂离子叠片电池。
对比例2
将PVDF分散在二甲基甲酰胺DMF/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。在制备例2中制备的正极极片的一个表面上,利用溶液A作为原料,通过电纺丝的方法,制备一层厚度为10μm的PVDF无纺布纤维层,纤维层直径为100nm,平均孔径为200nm,孔隙率为75%。然后在该正极极片的另一个表面上重复以上步骤,并在90℃条件下烘干高分子涂层的分散剂,获得双面带有PVDF无纺布纤维层的正极极片。
将该正极极片与制备例1中制备的负极极片相对并叠好,如图2所示。用胶带将整个叠 片结构的四个角固定好后,置入铝塑膜中,经顶侧封、注入制备例3中的电解液、封装后,得到锂离子叠片电池。
对比例3
选用厚度15μm的聚乙烯(PE)作为隔离膜。将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮NMP/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。采用电喷涂的方法在聚乙烯隔离膜表面制备5μm低熔点聚乙烯(PE)颗粒涂层,其中,颗粒的平均粒径为500nm。则隔离层总厚度为20μm,隔离层整体孔隙率为30%。
将上述制备的含低熔点聚合物颗粒涂层的一体化隔离膜放置于上述制备例1,2中制备的负极极片与正极极片之间。将负极极片、正极极片和隔离膜相对并叠好。用胶带将整个叠片结构的四个角固定好后,置入铝塑膜中,经顶侧封、注入制备例3中的电解液、封装后,得到锂离子叠片电池。
对比例4
将PVDF分散在二甲基甲酰胺DMF/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为25%的溶液A。同时将低熔点聚乙烯(PE)颗粒分散在N-甲基吡咯烷酮NMP/丙酮(7:3)溶剂中,并搅拌均匀至浆料粘度稳定,得到质量分数为40%的悬浊液B。
在制备例2中制备的正极极片的一个表面,利用溶液A作为原料通过电纺丝的方法,制备一层厚度为10μm的PVDF无纺布纤维层,纤维平均直径为100nm,纤维多孔基体的平均孔径为200nm。在纺丝之后,利用悬浊液B作为原料,利用电喷涂的方法将低熔点聚乙烯(PE)颗粒制备到纤维多孔基体表面,选用的低熔点聚乙烯(PE)颗粒平均粒径为500nm,纤维多孔基体的平均孔径与低熔点聚乙烯(PE)颗粒平均粒径之比为1:2.5,隔离层整体孔隙率为75%。然后在该正极极片的另一个表面上重复以上步骤,并在40℃条件下真空烘干去除DMF等分散剂,即可得到双面带有隔离层的正极极片。
将该正极极片和制备例1中制备的负极极片相对并叠好,如图2所示。用胶带将整个叠片结构的四个角固定好后,置入铝塑膜中,经顶侧封、注入制备例3的电解液、封装后,得到锂离子叠片电池。
对比例1-4的数据和测试结果见表1、表2和表3。
Figure PCTCN2020081812-appb-000001
Figure PCTCN2020081812-appb-000002
Figure PCTCN2020081812-appb-000003
表2
Figure PCTCN2020081812-appb-000004
Figure PCTCN2020081812-appb-000005
表3
Figure PCTCN2020081812-appb-000006
Figure PCTCN2020081812-appb-000007
从表1、2和3中可以看出,与普通隔膜相比,低熔点聚合物颗粒填充纳米纤维多孔基体的一体化隔离层可以减薄隔离层厚度从而提高能量密度、提高隔离层孔隙率从而提高保液能力,加快反应动力学从而增强电性能,增强隔离层与极片之间的粘接力从而改善锂离子电池抗跌落等机械滥用性能,降低隔离层的闭孔温度,同时提高其高温环境下的抗热收缩性能,从而提高锂离子电池安全稳定性。
与耐热纺丝隔离层相比,由于本申请的隔离层在纳米纤维多孔基体中分布了低熔点聚合物颗粒,使得本申请的隔离层具有低温热闭孔功能,热失控下,可切断电流提升锂离子电池安全性能。此外,低熔点聚合物颗粒可以填充在纤维多孔基体的“大孔”中,减少单纯耐热纺丝隔离层中的大孔,从而进一步改善锂离子电池自放电问题,降低K值,同时由于隔离层机械强度的提高,降低锂离子电池内部正负极活性物质颗粒刺穿隔离层的内短路问题,也有利于改善锂离子电池的循环性能。
与普通隔膜+低熔点聚合物颗粒隔离层两层结构相比,一体化结构设计减半了隔离层厚度,从而极大提高锂离子电池的体积能量密度。同时,由于纤维多孔基体熔点高,高温稳定性好,可以降低隔离层高温收缩甚至破裂的风险,使锂离子电池具有优良的安全性能。此外,一体化隔离层具有更高的孔隙率,从而加快离子传输,增强反应动力学,改善锂离子电池电性能。
与耐热纺丝层+低熔点聚合物颗粒两层结构相比,一体化结构设计可以有效降低隔离层厚度,使得锂离子电池具有较高的体积能量密度。同时将低熔点聚合物填充在纤维多孔基体中,发生热失控时,融化闭孔的响应速度更快。此外,低熔点聚合物填充纤维多孔基体中的“大孔”,优化孔径分布,改进锂离子电池自放电问题,降低K值,并提高纤维多孔基体的机械强度,增强抗正负极颗粒刺穿能力。
以上所述仅为本申请的较佳实施例,并非用于限定本申请的保护范围。凡在本申请的精神和原则之内所作的任何修改、等同替换、改进等,均包含在本申请的保护范围内。

Claims (12)

  1. 一种电化学装置,其包括电极极片以及在电极极片的至少一个表面上的隔离层,所述隔离层包含纳米纤维的多孔基体和分布在所述多孔基体中的聚合物颗粒,所述聚合物颗粒的熔融温度为70℃至150℃。
  2. 根据权利要求1所述的电化学装置,其中,所述隔离层中的所述聚合物颗粒的数量为1×10 8/m 2至1×10 18/m 2
  3. 根据权利要求1所述的电化学装置,其中,所述聚合物颗粒的平均粒径为40nm至10μm。
  4. 根据权利要求1所述的电化学装置,其中,所述纳米纤维直径为10nm至5μm,所述纤维多孔基体的孔径为40nm至10μm。
  5. 根据权利要求1所述的电化学装置,其中,部分聚合物颗粒从所述多孔基体表面伸出0.1nm至5μm的高度,所述多孔基体表面被所述部分聚合物颗粒占据的表面积为所述多孔基体总表面积的0.1%至60%。
  6. 根据权利要求1所述的电化学装置,其中所述聚合物颗粒的聚合物包括聚苯乙烯、聚乙烯、乙烯-丙烯共聚物、乙烯-醋酸乙烯共聚物、丙烯腈-丁二烯-苯乙烯、聚乳酸、聚氯乙烯、聚乙烯丁醛或聚丙烯酸酯中的至少一种。
  7. 根据权利要求1所述的电化学装置,其中,所述纳米纤维包含聚合物,所述聚合物包括聚偏二氟乙烯、聚酰亚胺、聚酰胺、聚丙烯腈、聚乙二醇、聚氧化乙烯、聚苯醚、聚碳酸亚丙酯、聚甲基丙烯酸甲酯、聚对苯二甲酸乙二醇酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)及其衍生物中的至少一种,优选聚偏二氟乙烯、聚酰亚胺、聚酰胺、聚丙烯腈、聚乙二醇、聚氧化乙烯、聚苯醚、聚碳酸亚丙酯、聚甲基丙烯酸甲酯、聚对苯二甲酸乙二醇酯或上述物质衍生物中至少一种。
  8. 根据权利要求1所述的电化学装置,其中,所述纳米纤维的聚合物还含有无机颗粒,所述无机颗粒包括HfO 2、SrTiO 3、SiO 2、Al 2O 3、MgO、CaO、NiO、BaO、ZnO、TiO 2、ZrO 2、SnO 2、CeO 2、勃姆石、氢氧化镁或氢氧化铝中的至少一种。
  9. 根据权利要求1所述的电化学装置,其中所述隔离层的截面空隙率β与所述隔离层表面开孔率α之间的比值β/α为95%以下。
  10. 根据权利要求9所述的电化学装置,其中所述表面开孔率α为35%至90%。
  11. 根据权利要求9所述的电化学装置,其中所述截面空隙率β为30%至85%。
  12. 一种电子装置,其包含权利要求1-11中任一项所述的电化学装置。
PCT/CN2020/081812 2020-03-27 2020-03-27 一种电化学装置及包含该电化学装置的电子装置 WO2021189459A1 (zh)

Priority Applications (6)

Application Number Priority Date Filing Date Title
KR1020227037741A KR20220151707A (ko) 2020-03-27 2020-03-27 전기화학 디바이스 및 이 전기화학 디바이스를 포함하는 전자 디바이스
CN202080095652.1A CN115428249A (zh) 2020-03-27 2020-03-27 一种电化学装置及包含该电化学装置的电子装置
JP2022558291A JP2023518889A (ja) 2020-03-27 2020-03-27 電気化学装置及び当該電気化学装置を含む電子装置
EP20927063.6A EP4131538A1 (en) 2020-03-27 2020-03-27 Electrochemical device and electronic device comprising electrochemical device
PCT/CN2020/081812 WO2021189459A1 (zh) 2020-03-27 2020-03-27 一种电化学装置及包含该电化学装置的电子装置
US17/953,680 US20230038029A1 (en) 2020-03-27 2022-09-27 Electrochemical device and electronic device containing same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/081812 WO2021189459A1 (zh) 2020-03-27 2020-03-27 一种电化学装置及包含该电化学装置的电子装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/953,680 Continuation US20230038029A1 (en) 2020-03-27 2022-09-27 Electrochemical device and electronic device containing same

Publications (1)

Publication Number Publication Date
WO2021189459A1 true WO2021189459A1 (zh) 2021-09-30

Family

ID=77891509

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/081812 WO2021189459A1 (zh) 2020-03-27 2020-03-27 一种电化学装置及包含该电化学装置的电子装置

Country Status (6)

Country Link
US (1) US20230038029A1 (zh)
EP (1) EP4131538A1 (zh)
JP (1) JP2023518889A (zh)
KR (1) KR20220151707A (zh)
CN (1) CN115428249A (zh)
WO (1) WO2021189459A1 (zh)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114639804A (zh) * 2020-12-16 2022-06-17 纳米及先进材料研发院有限公司 一种用于锂离子电池的电极结构及包含其的锂离子电池
WO2023066342A1 (zh) * 2021-10-21 2023-04-27 北京宇程科技有限公司 一种改性复合隔膜及其制备方法
CN116093538A (zh) * 2023-04-06 2023-05-09 宁德新能源科技有限公司 电极组件、电化学装置和电子装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116565458B (zh) * 2023-07-05 2023-10-13 宁德新能源科技有限公司 一种隔膜、电化学装置和电子装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5265823A (en) * 1975-11-27 1977-05-31 Shin Kobe Electric Machinery Method of producing battery separator
CN101707242A (zh) * 2009-10-14 2010-05-12 东莞新能源科技有限公司 有机/无机复合多孔隔离膜
CN103311486A (zh) * 2013-05-14 2013-09-18 中南大学 一种有机-无机复合隔膜及其制备和应用
CN103329309A (zh) * 2011-01-19 2013-09-25 纳幕尔杜邦公司 具有关断功能的锂电池隔膜
CN106129313A (zh) * 2016-07-28 2016-11-16 上海恩捷新材料科技股份有限公司 一种电化学装置隔离膜及其制备方法和用途
US20190393541A1 (en) * 2018-06-21 2019-12-26 Nanotek Instruments, Inc. Lithium metal secondary battery containing an elastic anode-protecting layer

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100742959B1 (ko) * 2004-09-02 2007-07-25 주식회사 엘지화학 유/무기 복합 다공성 필름 및 이를 이용하는 전기 화학소자
JP2008004438A (ja) * 2006-06-23 2008-01-10 Hitachi Maxell Ltd 電池用セパレータ、およびリチウム二次電池
KR101055536B1 (ko) * 2009-04-10 2011-08-08 주식회사 엘지화학 다공성 코팅층을 포함하는 세퍼레이터, 그 제조방법 및 이를 구비한 전기화학소자
JP5703306B2 (ja) * 2009-11-23 2015-04-15 エルジー・ケム・リミテッド 多孔性コーティング層を備えるセパレータの製造方法、その方法によって形成されたセパレータ、及びそれを備える電気化学素子
JP2011181195A (ja) * 2010-02-26 2011-09-15 Hitachi Maxell Energy Ltd リチウムイオン二次電池
JP6227411B2 (ja) * 2010-09-30 2017-11-08 アプライド マテリアルズ インコーポレイテッドApplied Materials,Incorporated リチウムイオン電池向けの一体型セパレータの電界紡糸
JP2013004336A (ja) * 2011-06-17 2013-01-07 Panasonic Corp セパレータおよびそれを有する電池
CN104124414B (zh) * 2013-04-28 2017-06-20 华为技术有限公司 一种锂离子电池复合电极片及其制备方法和锂离子电池
KR101616079B1 (ko) * 2013-06-18 2016-04-27 주식회사 엘지화학 전기화학소자용 세퍼레이터 및 그를 포함하는 전기화학소자
JP6268811B2 (ja) * 2013-08-23 2018-01-31 日本ゼオン株式会社 リチウムイオン二次電池用多孔膜組成物、リチウムイオン二次電池用保護層付きセパレータ、リチウムイオン二次電池用保護層付き電極、リチウムイオン二次電池、およびリチウムイオン二次電池用保護層付きセパレータの製造方法
WO2015065116A1 (ko) * 2013-10-31 2015-05-07 주식회사 엘지화학 유기-무기 복합 다공성 막, 이를 포함하는 세퍼레이터 및 전극 구조체
KR101933993B1 (ko) * 2013-10-31 2018-12-31 주식회사 엘지화학 전기화학소자용 세퍼레이터 및 그를 포함하는 전기화학소자
TWI560927B (en) * 2013-12-17 2016-12-01 Lg Chemical Ltd Separator for electrochemical device and electrochemical device
JP6847893B2 (ja) * 2018-07-02 2021-03-24 株式会社東芝 電極構造体および二次電池

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5265823A (en) * 1975-11-27 1977-05-31 Shin Kobe Electric Machinery Method of producing battery separator
CN101707242A (zh) * 2009-10-14 2010-05-12 东莞新能源科技有限公司 有机/无机复合多孔隔离膜
CN103329309A (zh) * 2011-01-19 2013-09-25 纳幕尔杜邦公司 具有关断功能的锂电池隔膜
CN103311486A (zh) * 2013-05-14 2013-09-18 中南大学 一种有机-无机复合隔膜及其制备和应用
CN106129313A (zh) * 2016-07-28 2016-11-16 上海恩捷新材料科技股份有限公司 一种电化学装置隔离膜及其制备方法和用途
US20190393541A1 (en) * 2018-06-21 2019-12-26 Nanotek Instruments, Inc. Lithium metal secondary battery containing an elastic anode-protecting layer

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114639804A (zh) * 2020-12-16 2022-06-17 纳米及先进材料研发院有限公司 一种用于锂离子电池的电极结构及包含其的锂离子电池
WO2023066342A1 (zh) * 2021-10-21 2023-04-27 北京宇程科技有限公司 一种改性复合隔膜及其制备方法
CN116093538A (zh) * 2023-04-06 2023-05-09 宁德新能源科技有限公司 电极组件、电化学装置和电子装置

Also Published As

Publication number Publication date
EP4131538A1 (en) 2023-02-08
CN115428249A (zh) 2022-12-02
JP2023518889A (ja) 2023-05-08
KR20220151707A (ko) 2022-11-15
US20230038029A1 (en) 2023-02-09

Similar Documents

Publication Publication Date Title
US11211594B2 (en) Composite current collector and composite electrode and electrochemical device comprising the same
WO2021189459A1 (zh) 一种电化学装置及包含该电化学装置的电子装置
JP7109384B2 (ja) ゲルポリマー層を含む電池用分離膜
JP5889271B2 (ja) 有機/無機複合多孔性フィルム及びこれを用いる電気化学素子
WO2021189454A1 (zh) 一种电极组件及包含其的电化学装置和电子装置
KR101592355B1 (ko) 플렉시블 집전체를 이용한 이차전지 및 플렉시블 집전체의 제조방법
US20210005858A1 (en) Separator, method for manufacturing same, and lithium battery including same
KR20150106808A (ko) 이차 전지 및 이의 제조 방법
CN101926024A (zh) 用于改进与电极的结合力的隔膜以及含有所述隔膜的电化学装置
US20180233727A1 (en) Separator for a non-aqueous secondary battery and non-aqueous secondary battery
WO2021189465A1 (zh) 电极组件、包含该电极组件的电化学装置及电子装置
WO2022000314A1 (zh) 一种电化学装置用隔板、电化学装置及电子装置
CN111354904A (zh) 一种锂离子电池隔膜、锂离子电池电极和锂离子电池
JP2014026946A (ja) 非水電解質電池用セパレータ及び非水電解質電池
WO2022000307A1 (zh) 一种电化学装置及包含该电化学装置的电子装置
WO2023179550A1 (zh) 一种复合油基隔膜及其制备方法和二次电池
US20230024456A1 (en) Electrode assembly, and electrochemical apparatus and electronic apparatus including such electrode assembly
WO2021184259A1 (zh) 一种电化学装置及包含该电化学装置的电子装置
KR102120446B1 (ko) 안전성이 향상된 전기화학소자용 세퍼레이터 및 이를 포함하는 전기화학소자
WO2021189469A1 (zh) 电化学装置
CN112117418B (zh) 复合极片及具有所述复合极片的电芯
WO2021189450A1 (zh) 一种电化学装置和包含所述电化学装置的电子装置
WO2021189472A1 (zh) 电化学装置
WO2021189476A1 (zh) 电化学装置
KR20240016059A (ko) 분리막 및 이를 포함하는 리튬 이차전지

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2022558291

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20227037741

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020927063

Country of ref document: EP

Effective date: 20221027

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

Ref document number: 20927063

Country of ref document: EP

Kind code of ref document: A1