WO2022012357A1 - 用于电池电极的薄膜及其制备方法 - Google Patents

用于电池电极的薄膜及其制备方法 Download PDF

Info

Publication number
WO2022012357A1
WO2022012357A1 PCT/CN2021/104360 CN2021104360W WO2022012357A1 WO 2022012357 A1 WO2022012357 A1 WO 2022012357A1 CN 2021104360 W CN2021104360 W CN 2021104360W WO 2022012357 A1 WO2022012357 A1 WO 2022012357A1
Authority
WO
WIPO (PCT)
Prior art keywords
particles
film
size
dry particles
dry
Prior art date
Application number
PCT/CN2021/104360
Other languages
English (en)
French (fr)
Inventor
沙玉静
李硕宇
夏圣安
Original Assignee
华为技术有限公司
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 华为技术有限公司 filed Critical 华为技术有限公司
Publication of WO2022012357A1 publication Critical patent/WO2022012357A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the embodiments of the present application relate to the technical field of electrochemical cells, and in particular, to a thin film used for battery electrodes and a preparation method thereof, an electrode sheet, an electrochemical cell, and a terminal.
  • lithium-ion batteries With the development of economy and technology, industries such as portable electronic devices (mobile phones, tablet computers, notebook computers), drones, and electric vehicles are in urgent need of energy storage devices with higher energy density, longer cycle life and safer.
  • suitable functional materials such as lithium supplements, flame retardants, etc.
  • the traditional wet electrode sheet preparation process with functional materials is to mix electrode active materials, functional materials and solvents into a slurry, and then coat and dry the substrate to form a film, but the lithium supplement (such as metal lithium)
  • the lithium supplement such as metal lithium
  • Such functional materials with active chemical properties are prone to explosion in a humid environment, and are not suitable for introduction through the traditional wet electrode preparation process.
  • Solvent-free dry electrode membrane technology solves the problem that functional materials may be incompatible with processing environments such as solvents in wet processes. Filamentation and loading of various functional material particles on it.
  • the embodiments of the present application provide a film prepared by a dry process, the dry particles in the film do not agglomerate, the film uniformity is good, and when the film is used as a battery electrode, the dry particles can well exert corresponding characteristics, Improve battery performance.
  • the first aspect of the embodiments of the present application provides a film for battery electrodes, the film comprising a fibrillated network matrix interwoven with a fibrillated binder and distributed on the fibrillated network matrix
  • the dry particles include functional material particles and conductive agent particles, some of the dry particles have a first size, and the rest of the dry particles have other sizes, and the other sizes are less than 1/2 of the first size ; Dry particles with the first size are arranged in an orderly manner, and dry particles with the other sizes are filled in the particle gaps of the dry particles with the first size, and the particle gaps are smaller than the first size.
  • the dry particles are not randomly distributed on the fibrillated network matrix composed of the fibrillated binder, but the dry particles with the largest relative particle size and the first size are arranged in an orderly manner, and the relative particle size is relatively large. Small dry particles with other sizes are filled in the particle gaps of the dry particles with the first size, so that each dry particle forms a stable and orderly arrangement, and each dry particle is not easy to agglomerate, so that the film has good continuity and integrity. High and stable. Therefore, when the film is used as a battery electrode, the functional characteristics of each particle can be better exerted, and the related performance of the battery can be improved; it will not deteriorate the energy density, cycle ability, safety, etc. of the battery.
  • the first size is in the range of 1 ⁇ m-50 ⁇ m; the other sizes include one or more particle sizes of different sizes, and the other sizes are in the range of 30 nm-7 ⁇ m.
  • Appropriate size can make the distribution of each dry particle tighter, the loading amount of dry particles is large, and ensure the structure of the film is more stable.
  • the functional material particles include at least one of an active ion supplement, a flame retardant and an expansion slowing agent.
  • the active ion supplement can effectively improve the energy density of the battery; the flame retardant can improve the flame retardant performance of the battery and improve the safety of the battery; and the expansion reducer can effectively relieve the expansion of the electrode material and improve the battery cycle stability.
  • the active ion supplement includes one of a lithium supplement, a sodium supplement, a potassium supplement, a magnesium supplement, a zinc supplement and an aluminum supplement.
  • the D50 particle size of the functional material particles is in the range of 30 nm-50 ⁇ m.
  • the size of functional material particles of different types and functions can be flexibly adjusted according to their specific functions and actual application scenarios.
  • the particle size distribution of the dry particles of each different material satisfies (D90 particle size-D10 particle size)/D50 particle size ⁇ 1.5.
  • the size concentration of the dry particles of each different material is high, which facilitates their uniform and orderly distribution in the fibrillated network matrix, thereby improving the quality of the film loaded with them, and can maximize the performance of each dry particle.
  • the corresponding characteristics of the particles ensure the quality consistency and functional reproducibility of different batches of films.
  • the thickness of the thin film is greater than or equal to 30 ⁇ m. This thickness is greater than the thickness of films produced by existing wet processes and is free of solvent residues. In a specific embodiment of the present application, the thickness of the film is 30 ⁇ m-300 ⁇ m.
  • the mass of the functional material accounts for 70%-99% of the mass of the film.
  • the mass ratio can ensure that the film has a stable structure and desired good mechanical properties, so that the loading of functional materials in the film is large without local aggregation, thereby maximizing the performance of the battery. .
  • the dry particles further include electrode active material particles.
  • the thin film can be used as the active material layer of the electrode sheet.
  • the D50 particle size of the electrode active material particles is in the range of 1-50 ⁇ m.
  • the electrode active material particles with larger size are closely arranged in the film, which can realize a larger loading amount in the film, thereby improving the energy density of the battery.
  • the particle size distribution of the electrode active material particles satisfies (D90 particle size ⁇ D10 particle size)/D50 particle size ⁇ 1.5.
  • the size concentration of electrode active material particles is high, which facilitates their uniform and orderly distribution in the fibrillated network matrix, which can improve the quality of the film containing electrode active material and exert better performance, and ensure the quality of different batches of films. Quality consistency, functional reproducibility.
  • the mass of the electrode active material accounts for 70-99% of the mass of the thin film. In a specific embodiment of the present application, the mass of the functional material accounts for 0.05%-30% of the mass of the film.
  • the mass ratio can ensure the maximum loading of electrode active materials, so that the dry particles in the film can be evenly distributed, so that the battery made of the film can take into account the high specific capacity and functional materials. Additional features.
  • each dry particle is not randomly distributed on the fibrillated network matrix composed of the fibrillated binder, but the dry particles with the largest relative size and the first size are arranged in an orderly manner , while the dry particles with other sizes with relatively small size are filled in the particle gaps of the dry particles with the first size, so as to form a stable and orderly arrangement, and the particles are not easy to agglomerate, so that the film has good continuity and integrity.
  • High stability and high stability When the film is applied to battery electrodes, the characteristics of each particle, especially the functional characteristics of functional materials, can be better utilized to improve battery-related performance.
  • a second aspect of the embodiments of the present application also provides a method for preparing a thin film for a battery electrode, including:
  • Dry particles include functional material particles and conductive agent particles, some of the dry particles have a first size, and the rest of the dry particles have other sizes, the other sizes being less than 1/2 of the first size ; formulating a first mixture of fibrillizable binder particles and dry particles having said first size in the presence of a protective gas;
  • the first mixture is subjected to high pressure shear to fibrillate the binder particles and to arrange the functional material particles of the first size with the introduction of physical field intervention, and then adding dry particles having the other dimensions and continuing high pressure shearing to obtain a second mixture;
  • the second mixed material is pressed to obtain a film; wherein, the film comprises a fibrillated network matrix interwoven by the fibrillated binder and the dry material distributed on the fibrillated network matrix particles; the dry particles having the first size are arranged in an array to form an ordered structure, and the dry particles having the other sizes are filled in the particle gaps of the dry particles having the first size, the particle gaps being smaller than the first size.
  • the physical field intervention includes at least one of ultrasonic vibration and magnetic field intervention.
  • the ultrasonic frequency of the ultrasonic oscillation is greater than or equal to 20KHz, and the ultrasonic power is greater than or equal to 20W.
  • the magnetic field strength of the magnetic field intervention is greater than or equal to 0.1T.
  • the D50 particle size of the binder particles is 1 ⁇ m-50 ⁇ m.
  • the larger particle size of the binder particles can facilitate the formation of a fibrillated network matrix with uniform interweaving, strong elasticity and sufficient viscosity.
  • the dry particles having the first size further include electrode active material particles.
  • the dry particles having the other sizes are added in batches in descending order of size.
  • the dry particles with the first size and the dry particles with other sizes can be arranged in a compact and orderly manner, and the uniform arrangement of the dry particles in the film can be better improved.
  • the particle size distribution of the dry particles of each different material satisfies (D90 particle size-D10 particle size)/D50 particle size ⁇ 1.5 .
  • the dry particles having the first size with the largest relative size and the dry particles having other sizes are subjected to high pressure shearing successively with the binder particles, and intervening by a physical field.
  • the dry particles with the first size are arranged in a close and orderly manner, and the dry particles with other sizes with a relatively small size are filled in the particle gaps of the dry particles with the first size, so that each dry particle is not easy to agglomerate, and continuity is obtained.
  • the preparation method does not involve the use of solvents, liquids and processing aids, and has strong universality and low cost.
  • a third aspect of the embodiments of the present application further provides an electrode sheet, the electrode sheet includes a current collector and the thin film according to the first aspect of the embodiments of the present application disposed on the current collector.
  • the electrode sheet has a stable structure, and the thin film contained has high flatness, high integrity and good continuity, and the electrode sheet containing the thin film can be used to provide an electrochemical cell with improved electrochemical performance.
  • the electrode sheet further includes an electrode active material layer, and the electrode active material layer is disposed between the current collector and the thin film.
  • the thin film acts as an electrode active material layer of the electrode sheet.
  • the dry particles further include electrode active material particles.
  • a fourth aspect of the embodiments of the present application further provides an electrochemical cell, comprising a positive electrode, a negative electrode, a separator and an electrolyte located between the positive electrode and the negative electrode, wherein the positive electrode and/or Or the negative electrode includes the electrode sheet described in the fourth aspect of the embodiments of the present application.
  • the electrochemical cell has high energy density, long cycle life and high safety.
  • a fifth aspect of the embodiments of the present application further provides a terminal, the terminal includes a casing, a main board and a battery located inside the casing, and the battery includes the electrochemical battery according to the fourth aspect of the embodiments of the present application, the An electrochemical cell is used to power the terminal.
  • the terminal may be an electronic product such as a mobile phone, a notebook, a tablet computer, a portable machine, and a smart wearable product.
  • 1a is a schematic diagram of the plane distribution of dry particles in a film provided in an embodiment of the application;
  • 1b is a schematic diagram of the three-dimensional distribution of dry particles in a film provided in an embodiment of the application;
  • FIG. 2 is a schematic structural diagram of an electrode sheet provided in an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of an electrode sheet provided in another embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of a terminal provided by an embodiment of the present invention.
  • FIG. 5 is a photo comparison of the battery negative electrodes in Example 2(a) and Comparative Example 2(b) of the present application after they are fully charged and disassembled.
  • an embodiment of the present application provides a film 100, which is prepared by a dry process and includes a fibrillated binder and dry particles 2, wherein the fibrillated binder is interwoven into fibers Filamentation network matrix 1, on which dry particles 2 are distributed; wherein, the dry particles 2 include functional material particles and conductive agent particles, some of the dry particles have a first size, and the rest of the dry particles have other sizes, and The other sizes are smaller than 1/2 of the first size; the dry particles 21 with the first size are arranged in an orderly manner, the particle gaps of the dry particles 21 with the first size are smaller than the first size, and the dry particles 22 with other sizes are filled in the in the particle gaps of the dry particles 21 of the first size.
  • the dry particles are not randomly distributed on the fibrillated network matrix composed of the fibrillated binder, but the dry particles with the largest relative particle size and the first size are arranged in an orderly manner,
  • the dry particles of other sizes with relatively small particle size are filled in the particle gaps of the dry particles of the first size, so that the dry particles form a stable and orderly arrangement, and the dry particles are not easy to agglomerate, so that the film is continuous. Good performance, high integrity and high stability.
  • the particle gap of the dry particles 21 with the first size is smaller than the first size
  • the third one has the first size.
  • the dry particles 21 of the size ie, the dry particles 21 having the first size, are arranged in a close order, constituting a "closely packed structure".
  • the "ordered arrangement” may specifically be an array arrangement, for example, an arrangement in the form of an a ⁇ b ⁇ c array, where a, b, and c are positive integers.
  • each dry particle having the first size is surrounded by 6-12 dry particles having the first size.
  • the dry particles 21 having the first size are arranged in a compact manner, which helps to improve the distribution density of dry particles in the thin film 100 , and when the thin film 100 is used in a battery, can improve the electrochemical performance of the battery such as energy density.
  • the porosity of the film 100 is less than 30%.
  • the void fraction of film 100 may be less than 20%, less than 10%, even less than 5% or less than 1%.
  • a smaller void ratio means that any adjacent dry particles 2 in the film 100 have a high degree of mutual filling and a high degree of compaction, the dry particles in the film 100 are more stably arranged in an orderly manner, and the film has a stable structure and better mechanical properties.
  • dry particles in this application covers powders, spheres, flakes, fibers, tubes and other particles of other shapes and aspect ratios.
  • the first size refers to the D50 particle size
  • non-spherical particles such as flakes, fibers, tubes, bars, etc.
  • the first size refers to the long wide size.
  • the size of the dry particles 2 may be in the range of 30 nm-50 ⁇ m.
  • the first size may be in the range of 1 ⁇ m-50 ⁇ m; the other sizes may be in the range of 30 nm-10 ⁇ m.
  • the first dimension may be in the range of 2 ⁇ m-30 ⁇ m, 5 ⁇ m-50 ⁇ m, 8 ⁇ m-20 ⁇ m, or 3 ⁇ m-15 ⁇ m.
  • the first dimension may be in the range of 3 ⁇ m-15 ⁇ m, and the other dimensions may be in the range of 30 nm-1 ⁇ m.
  • other dimensions may include one or more different dimensions. For example, two or more different sizes are included.
  • the dry particles may include, in addition to dry particles having a first size, dry particles having a second size, dry particles having a third size, and the third size is different from the second size, the second size and the third size All three dimensions are smaller than 1/2 of the first dimension, and all of them can be packed in the inter-particle gaps of the dry particles having the first dimension in a close and orderly arrangement.
  • the materials of dry particles having the same size may be the same or different.
  • two functional material particles such as lithium-replenishing agent particles
  • two types of lithium-replenishing agent particles with different materials and the following electrode active material particles have different functions.
  • the particles of all have the above-mentioned first size.
  • the fibrillated network matrix 1 can be used to capture, bond and support the above-mentioned dry particles 2 .
  • the dry particles 2 are entangled and captured by the fibrillated network matrix 1, and the fibrillated network matrix 1 also supports the dry particles 2 to a certain extent, and the dry particles 2 can be bonded together by a fibrillated binder. .
  • the material of the fibrillated network matrix 1 may be a chain polymer binder.
  • the chain polymer binder can facilitate the formation of fibrillated network matrix under the action of high shear force.
  • the material of the chain polymer binder can include cellulose and its derivatives, polyolefin, fluoropolymer, polyacrylic acid (PAA), polyacrylate (such as polymethyl methacrylate (PMMA)) , polyacrylonitrile (PAN), polyethylene oxide (PEO), polyimide (PI), styrene-butadiene rubber (SBR), and one or more of their copolymers.
  • fluorine-containing polymer polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF2), polyvinylidene fluoride-hexafluoropropylene copolymer P (VDF-HFP) and the like can be mentioned, Polyolefin (PP), polyethylene (PE), etc. are mentioned as a polyolefin.
  • cellulose and derivatives thereof include carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (CMC-Na), and the like.
  • the D50 particle size of the binder particles used to form the fibrillated network matrix 1 may be in the range of 1 ⁇ m-50 ⁇ m, further, may be in the range of 2 ⁇ m-20 ⁇ m or 3 ⁇ m-15 ⁇ m.
  • the binder particles with larger particle size can facilitate the formation of a fibrillated network matrix 1 with uniform interweaving, strong elasticity and sufficient viscosity.
  • the functional material particles can improve the energy density, cycle performance, safety and other properties of the battery.
  • the functional material particles may include one or more of active ion extenders, flame retardants, and expansion retarders.
  • the functional material of flame retardant does not participate in the electrochemical process of the battery. If the temperature of the battery is too high or burned, the flame retardant will prevent the combustion process and flame propagation by absorbing heat, covering, inhibiting chain reactions, etc. This improves the safety of the battery.
  • the functional material of the expansion retarder can provide a buffering effect during the expansion process of the electrode material and relieve the expansion of the electrode sheet, thereby improving the cycle stability and safety performance of the battery.
  • the active ion supplement can irreversibly release a large amount of active lithium ions during the first charge and discharge of the battery, so as to supplement the active ions and improve the energy density of the battery.
  • the active ions may include one of lithium ions, sodium ions, potassium ions, magnesium ions and aluminum ions.
  • the active ion supplements include one of lithium supplements, sodium supplements, potassium supplements, magnesium supplements, zinc supplements and aluminum supplements.
  • the lithium supplement can release a large amount of active lithium ions before the electrode active material of the battery in the formation stage of the lithium battery, so as to play the role of supplementing lithium.
  • Lithium supplements include but are not limited to lithium metal and its manufactured products, such as lithium powder, stabilized lithium powder, lithium ribbon, lithium foil, lithium-rich metal oxide, lithium-carbon composite, lithium-carbon alloy, lithium-silicon alloy at least one of etc.
  • Different lithium supplements have different residues after releasing active lithium.
  • a film using Li 2 NiO 2 as a positive lithium supplement will produce one or more of LiNiO, NiO, and Li 2 O after the battery is formed.
  • the thin film using Li 6 CoO 4 as the positive electrode lithium supplement will generate one or more of LixCoO 4 (0 ⁇ x ⁇ 6), CoO 2 and Li 2 O after the formation of the battery; Li 5 FeO 4 One or more of LiyFeO 4 (0 ⁇ y ⁇ 5), Fe 2 O 3 , and Li 2 O will be produced in the thin film as the positive electrode lithium supplement after the formation of the battery is completed.
  • the flame retardants include inorganic flame retardants and organic flame retardants.
  • the inorganic flame retardant can include tellurium compounds, aluminum hydroxides (such as aluminum hydroxide, bis(2-ethylhexanoate) hydroxyaluminum), magnesium hydroxide, borate, etc.
  • the organic flame retardant can be Including triazine and its derivatives, melamine, polyphosphate, urea, dicyandiamide, etc.
  • the expansion reducing agent includes but is not limited to at least one of glucose, phenolic resin, sodium carboxymethyl cellulose, gelatin, starch, graphene, polythiophene, carbon nanotube, polyacrylonitrile, trialkylaluminum, etc. kind.
  • the D50 particle size of each functional material particle of different material is in the range of 30 nm-50 ⁇ m. Further, the D50 particle size of the functional material particles can be in the range of 30 nm-1 ⁇ m, 50 nm-200 nm, 2 ⁇ m-50 ⁇ m, 5 ⁇ m-50 ⁇ m, 8 ⁇ m-20 ⁇ m or 3 ⁇ m-15 ⁇ m.
  • the size of functional material particles of different materials can be flexibly adjusted according to their specific functions and actual application scenarios.
  • the functional material can be dry particles 21 with the first size as the largest relative size, or dry particles 22 with other sizes. .
  • the D50 particle size of the flame retardant particles may be in the range of 30nm-500nm, acting as dry particles with other sizes
  • the D50 particle size of the lithium supplement may be in the range of 2 ⁇ m-30 ⁇ m, acting as dry particles with the first size particles.
  • the particle size distribution of the dry particles of each different material may satisfy (D90 particle size-D10 particle size)/D50 particle size ⁇ 1.5, especially the particle size distribution of each functional material particle of different material should satisfy (D90 particle size-D10 particle size)/D50 particle size ⁇ 1.5. That is, the particle size distribution of the particles of active ion supplements with different materials, the particles of flame retardants with different materials, and the particles of expansion moderators with different materials all satisfy (D90 particle size-D10 particles) diameter)/D50 particle size ⁇ 1.5.
  • the size concentration of the dry particles of each different functional material is high, which facilitates the uniform and orderly distribution of the dry particles of the same material in the fibrillated network matrix, thereby improving the quality of the film loaded with them.
  • the electrode can give full play to the best performance, and ensure the quality consistency and function reproducibility of different batches of films.
  • the type of the conductive agent is not particularly limited, and existing conventional materials in the field may be used.
  • the conductive agent may include one or more of carbon fibers, carbon nanotubes, graphite, graphene, conductive carbon black, furnace black, mesocarbon microspheres, and the like.
  • the conductive carbon black may specifically include acetylene black, Ketjen black, Supper P, 350G carbon black, and the like.
  • Graphite can include natural graphite (such as flake graphite, expanded graphite) and artificial graphite (such as KS-6, spherical graphite) and the like.
  • the size of the conductive agent is in the range of 30 nm-50 ⁇ m.
  • D50 particle size can be less than or equal to 100 nm;
  • two-dimensional layered conductive agents such as flake graphite, Graphene, etc.
  • the size refers to the lateral length and width, specifically, the length and width of flake graphite or graphene can be in the range of 1 ⁇ m-50 ⁇ m.
  • the particle size distribution of spherical or quasi-spherical conductive agent particles of each different material satisfies (D90 particle size - D10 particle size)/D50 particle size ⁇ 1.5, so that the spherical or quasi-spherical particles of each different material
  • the size concentration of the conductive agent particles is high, which imparts uniform conductivity to the film 100 of the present application.
  • the thickness of the thin film 100 may be thick or thin according to specific application scenarios. Specifically, the thickness of the thin film 100 may be greater than or equal to 30 ⁇ m. For example, the thickness of the film may be 40 ⁇ m-60 ⁇ m, 100 ⁇ m-250 ⁇ m or 30 ⁇ m-300 ⁇ m. In some embodiments of the present application, the thickness of the film 100 is 70 ⁇ m-300 ⁇ m. The film thickness is much greater than that of electrode films prepared by current wet processes, and since the films are made by solvent-free dry techniques, the film 100 is free or substantially free of any liquid (eg, solvent) and is made of The resulting residue, the film is cleaner.
  • any liquid eg, solvent
  • the thickness of the film 100 is not limited by the viscosity of the slurry and the coating method in the wet method, and the thickness of the film can be thicker, with high continuity and integrity, and with a firmer structure.
  • the dry particles in the film are more uniformly distributed, the film has high continuity and integrity, a firmer structure, and better mechanical and electrical properties.
  • the above-mentioned thin film 100 can be disposed on the surface of the electrode active material layer of the existing electrode sheet, and used as a functional layer of the electrode sheet.
  • the dry particles in the thin film 100 serving as the functional layer of the electrode sheet only include the above-mentioned functional material particles and conductive agent particles.
  • the mass of the functional material may account for 70%-99% of the total mass of the film 100 . The mass ratio can ensure that the film has a stable structure and desired good mechanical properties, so that the loading of functional materials in the film is large without local aggregation, thereby maximizing the performance of the battery. .
  • the dry particles in the thin film 100 further include electrode active material particles.
  • the thin film 100 of the present application can be directly disposed on the surface of the current collector to serve as the active material layer of the electrode sheet, and together with the current collector, constitute the electrode sheet of the battery.
  • the mass of the electrode active material may account for 70-99% of the total mass of the thin film 100 .
  • the mass of the functional material may account for 0.05%-30% of the total mass of the film 100 .
  • the D50 particle size of the electrode active material particles may be in the range of 1 ⁇ m-50 ⁇ m.
  • the electrode active material particles are preferably used as the large particle size component in the dry particles (ie, dry particles with a first size), in order to achieve their close and ordered arrangement in the film, improve their loading in the film, and then Improve the energy density of batteries using the film.
  • the D50 particle size of the electrode active material particles may be 1 ⁇ m-20 ⁇ m. For example, 1 ⁇ m-15 ⁇ m, 2 ⁇ m-20 ⁇ m, 3 ⁇ m-15 ⁇ m or 8 ⁇ m-20 ⁇ m.
  • the particle size distribution of electrode active material particles of each different material also satisfies (D90 particle size - D10 particle size)/D50 particle size ⁇ 1.5 to achieve uniform distribution in the film and avoid agglomeration, thereby increasing the content of The quality of the thin film of the electrode active material can exert better performance, ensuring the quality consistency and function reproducibility of the thin film of different batches.
  • each dry particle is not randomly distributed on the fibrillated network matrix composed of the fibrillated binder, but the dry particles with the largest relative size and the first size are arranged in an orderly manner.
  • the particle gap is smaller than the first size, and dry particles of other sizes are filled in the particle gap of the dry particles with the first size, which makes each dry particle form a stable and orderly arrangement, making the film with good continuity and high integrity , does not contain solvent residues, the dry particles are not easy to agglomerate in the film, have high stability, and can fully exert their respective functions.
  • the battery performance can be better improved.
  • the embodiments of the present application also provide a method for preparing the above-mentioned thin film for battery electrodes, including:
  • the dry particles include functional material particles and conductive agent particles, some of the dry particles have a first size, the rest of the dry particles have other sizes, and the other sizes are less than 1/2 of the first size; in the presence of protective gas, the fibrillizable binder particles and dry particles having a first size formulated into a first mixture;
  • the film comprises a fibrillated network matrix interwoven with fibrillated binders and dry particles distributed on the fibrillated network matrix; dry particles with other sizes Filled in particle gaps of dry particles having a first size, the particle gaps being smaller than the first size.
  • the D50 particle size of the binder particles may be in the range of 1 ⁇ m-50 ⁇ m, and further, may be in the range of 2 ⁇ m-20 ⁇ m or 3 ⁇ m-15 ⁇ m.
  • the larger particle size of the binder particles can facilitate the formation of a fibrillated network matrix with uniform interweaving, strong elasticity and sufficient viscosity.
  • the dry particles having the first size further include electrode active material particles. That is, the electrode active material particles may first be subjected to high pressure shearing with the binder particles as a large particle size component.
  • the size concentration of each provided dry particle may be controlled, so that the dry particles of each different material The particle size distribution of all satisfies (D90 particle size-D10 particle size)/D50 particle size ⁇ 1.5.
  • the technologies that can achieve the above-mentioned size concentration include, but are not limited to, cyclone classification, multi-frequency screen, electrostatic classification, jet classification, and the like.
  • step S102 in the embodiment of the present application if the dry particles with other sizes include a variety of different sizes, they can be added in batches in descending order according to their sizes to perform high pressure shearing in batches. Or at least according to the size of the D50 particle size of the spherical or quasi-spherical particles of different materials, they are added in batches in order from large to small. In this way, both the dry particles with the first size and the dry particles with other sizes can achieve the above-mentioned close and orderly arrangement, which better improves the uniform arrangement of the dry particles in the film.
  • the physical field intervention includes at least one of ultrasonic oscillation and magnetic field intervention.
  • the physics intervention helps to order the dry particles of the first dimension. Taking ultrasonic vibration as an example, it can promote the reciprocating high-frequency motion of the large particle size components to form a highly uniform and orderly arrangement, so that the small particle size components added later can be filled in the particle gaps of the large particle size components. middle.
  • the magnetic field intervention is applied to form an ordered arrangement of magnetic dry particles, for example, electrode active material particles or lithium supplement particles containing Fe, Co, Ni, etc.
  • the physical field intervention method of ultrasonic oscillation is suitable for preparing the above-mentioned thin films containing magnetic particles, and also suitable for preparing the above-mentioned thin films without magnetic particles. Further, when preparing the above-mentioned thin film containing magnetic particles, the used physical field intervention may include at least one of ultrasonic vibration and magnetic field intervention, and preferably, magnetic field intervention is introduced.
  • the ultrasonic frequency of the ultrasonic oscillation may be greater than or equal to 20KHz, and the ultrasonic power may be greater than or equal to 20W.
  • the magnetic field strength of the magnetic field intervention may be greater than or equal to 0.1T.
  • the introduction of the physical field intervention may be performed only when high-pressure shearing is performed in step S102. At this time, the physical field may be applied on the outer wall of the high pressure shearing device. In other embodiments of the present application, the introduction of physical field intervention may be started when the first mixture is prepared in step S101. At this time, a physical field may be applied to the outer walls of the mixing device used in step S101 and the high-pressure shearing device used in step S102. Of course, in some embodiments of the present application, the mixing device used in step S101 and the high-pressure shearing device used in step S102 may be the same device.
  • the preparation of the first mixture in the above-mentioned step S101 can be carried out by ordinary mechanical mixing methods (such as stirring, grinding, dual-motion mixing, etc.) without introducing high-pressure gas, or by introducing high-pressure gas flow. Cut and mix.
  • the mixing device used to form the first mixture may include a ribbon mixer, a rotary mixer, a planetary mixer, an acoustic mixer, a microwave mixer, a dual motion mixer, a fluidized bed mixer, a ball mill, At least one of a high-speed shear mixer, a jet mill, a hammer mill, and the like.
  • the preparation of the first mixture is formed by means of high-pressure shear mixing (such as high-speed shear mixer, jet mill, hammer mill, etc.)
  • high-pressure shear mixing such as high-speed shear mixer, jet mill, hammer mill, etc.
  • the protective gas used in preparing the first mixture is a sufficiently dry gas, including at least one of dry air, nitrogen, helium, hydrogen, etc., preferably provided under high pressure conditions Dry compressed gas. Shielding gas can prevent some chemically active material particles from changing properties/functions and improve safety. In some embodiments of the present application, during the high-pressure shearing process in step S102, the protective gas still exists. The presence of dry shielding gas during compounding and shearing can improve safety while avoiding water in the resulting film.
  • the fibrillation of the binder particles is achieved by a drying, solvent-free, and liquid-free high-pressure shear force technology, which can be specifically achieved by applying positive pressure or negative pressure, such as compression gas or vacuum.
  • high shear force is applied to the binder, which can physically elongate and fibrillate the binder. network matrix.
  • the pressure of the high-pressure airflow used is greater than or equal to 60 PSI during high-pressure shearing. Specifically, it can be 60PSI-500PSI, or 80PSI-300PSI.
  • the equipment that can fibrillate the binder includes a jet mill, a pin mill, a hammer mill, a collision mill, and the like.
  • the fibrillation of the binder particles is achieved by a jet mill.
  • the jet mill has at least one nozzle capable of ejecting high-pressure air flow in addition to the ordinary mechanical shearing flying knife.
  • the chain polymer binder will gradually agglomerate into blocks, and ordinary mechanical shearing flying knives can reduce the size of the aggregates/agglomerates formed during the mixing process to form small particles,
  • the high-pressure airflow ejected from the nozzle of the jet mill can accelerate the collision of the small particles, and make the binder elongate and fibrillate. form a fibrillated network matrix, and distribute the above-mentioned dry particles into the fibrillated network matrix.
  • the pressing of the second mixed material can be achieved by means of roll pressing, calendering, etc., and specifically can be achieved by means of a roll press, a roll mill, a calender, a belt press, a flat press, etc. equipment to achieve.
  • the large particle size component dry particles having the first size
  • the binder particles to high pressure shearing under the intervention of the physical field
  • the large particle size component can be made
  • the components are arranged in a close and orderly manner, and the small particle size components (dry particles with other sizes) are added to continue high-pressure shearing, so that the small particle size components are filled in the particle gaps of the large particle size components, so that each dry particle
  • the particles do not agglomerate, and a film with good continuity, high integrity and good stability is obtained, so that when the film is used as a battery electrode, the effect of each dry particle can be fully exerted, and the related performance of the battery can be improved.
  • the preparation method solves the problems of low battery energy density, short cycle life and poor safety caused by dry particle agglomeration of the existing dry electrode film. For example, if the above-mentioned film contains 3 wt % of the lithium supplement, the cycle life of the battery can be increased by more than 50% when the film is applied to the battery.
  • the preparation method does not involve the use of solvents, liquids and processing aids in the whole process, which solves the problem of incompatibility between functional materials with active chemical properties and solvents and other wet processes in the field of electrode membranes.
  • the preparation method has strong universality. It is suitable for introducing materials of various properties into the film; and compared with the wet process, the cost of this preparation method is lower, and the cost can be saved by 3-4%, and the thickness of the obtained film can be made thicker, and the film can be made thicker. When it is thicker, its continuity, stability and integrity are still better.
  • the process is simple, low in cost, efficient and environmentally friendly, and can be produced on a large scale.
  • an embodiment of the present application provides an electrode sheet 2000 .
  • the electrode sheet 2000 includes a current collector 10 , and an electrode active material layer 11 and a thin film 100 that are sequentially arranged on the current collector 10 .
  • the dry particles in the thin film 100 only include functional material particles and conductive agent particles, but do not include electrode active material particles.
  • the thin film 100 is used as a functional layer, with high flatness, high integrity and good continuity, which can endow the electrode sheet with good additional functions and improve the battery energy density, cycle performance, safety performance and other aspects of performance.
  • the functional material particles may include one or more of active ion extenders, flame retardants, and expansion moderators.
  • the mass of the functional material particles accounts for 70%-99% of the total mass of the film 100.
  • the mass ratio can ensure that the film has a stable structure and desired good mechanical properties, so that the loading of functional materials in the film is large without local aggregation, thereby maximizing the performance of the battery. .
  • the porosity of the film 100 may be less than 30%.
  • the dry particles in the film 100 are densely arranged, the mechanical strength of the film 100 is larger, and the distribution of functional material particles is more uniform and dense, which can better improve the function of the battery made of the film.
  • the current collector 10 includes, but is not limited to, a metal foil or an alloy foil
  • the metal foil includes copper, titanium, aluminum, platinum, iridium, ruthenium, nickel, tungsten, tantalum, gold or silver foils
  • the alloy foil material includes stainless steel, or an alloy containing at least one element of copper, titanium, aluminum, platinum, iridium, ruthenium, nickel, tungsten, tantalum, gold and silver.
  • the alloy foil material is mainly composed of the above-mentioned elements.
  • the metal foil may further include doping elements, including but not limited to one of platinum, ruthenium, iron, cobalt, gold, copper, zinc, aluminum, magnesium, palladium, rhodium, silver, and tungsten or more.
  • the current collector 10 may be etched or roughened to form a secondary structure to facilitate effective contact with the electrode active material layer 11 .
  • the electrode active material layer 11 can be prepared on the current collector 10 by a coating method or a rolling method, and the film 100 can be combined with the electrode active material layer 11 by pressing methods such as rolling and isostatic pressing.
  • the electrode active material in the electrode active material layer 11 is a material capable of energy storage by deintercalating ions, the ions including one of lithium ions, sodium ions, potassium ions, magnesium ions, and aluminum ions.
  • the electrode active materials include but are not limited to metals, inorganic non-metals (such as carbon materials), oxides, nitrides, carbides, borides, sulfides, chlorides, or composite materials of various energy storage materials .
  • the electrode active material layer 11 may be a positive electrode active material layer or a negative electrode active material layer. That is, the electrode active material in the electrode active material layer 11 may be a positive electrode active material or a negative electrode active material.
  • the positive active material can be specifically lithium iron phosphate, lithium manganese phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium cobalt oxide (LiCoO 2 ), lithium manganate, manganese nickelate At least one of lithium, lithium nickel manganate, nickel cobalt manganese (NCM), nickel cobalt aluminum (NCA), and the like.
  • the negative electrode active material can include lithium metal, graphite, hard carbon, silicon-based materials (including elemental silicon, silicon alloys, silicon oxides, and silicon-carbon composite materials), tin-based materials (including elemental tin, tin oxides, and tin-based alloys) , at least one of lithium titanate (Li 4 Ti 5 O 12 ) and TiO 2 and the like.
  • the electrode active material layer 11 may further include a binder, a conductive agent, and the like. The binder and conductive agent added to the electrode active material layer 11 are not particularly limited, and the existing conventional materials in the field can be used.
  • the binder can be polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) ), one or more of polyvinyl alcohol, carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyolefin, sodium alginate, etc.
  • the conductive agent may be one or more of conductive carbon black, artificial graphite KS6, carbon nanotubes, and graphene.
  • the electrode sheet 2000 may be a positive electrode sheet or a negative electrode sheet. If the electrode sheet is used as a positive electrode sheet, the electrode active material layer 11 is specifically a positive electrode active material layer.
  • the current collector 10 of the positive electrode sheet may be an aluminum foil. Similarly, if the electrode sheet is used as a negative electrode sheet, the electrode active material layer 11 is specifically a negative electrode active material layer, and the current collector 10 of the negative electrode sheet can be a copper foil.
  • an embodiment of the present application further provides an electrode sheet 3000 , the electrode sheet 3000 includes a current collector 10 and a thin film 100 disposed on the current collector 10 .
  • the dry particles in the thin film 100 also include electrodes Active material particles, the above-mentioned functional material particles and conductive agent particles, the thin film 100 directly acts as the electrode active material layer of the electrode sheet 3000, the thin film 100 has high flatness, high integrity and good continuity, which can effectively improve the energy density and cycle of the battery. performance, safety performance and other aspects of performance.
  • the porosity of the film 100 is less than 30%.
  • the dry particles in the film 100 are densely arranged, which is particularly helpful to improve the distribution density of electrode active material particles with larger particle size in the film 100 and increase the specific capacity of the battery made of the film.
  • the selection of the current collector 10 and the electrode active material particles is as described above, and will not be repeated here.
  • the thin film 100 may be disposed on the current collector 10 by a coating method or by a rolling method such as cold pressing or hot pressing.
  • the electrode sheet 3000 may be a positive electrode sheet or a negative electrode sheet. If the electrode sheet is used as a positive electrode sheet, the electrode active material particles in the film 100 are specifically positive electrode active material particles, and the film 100 containing the positive electrode active material particles can be referred to as a "positive electrode film". Similarly, if the electrode sheet is used as a negative electrode sheet, the electrode active material particles in the film 100 are specifically negative electrode active material particles, and the film containing the negative electrode active material particles can be referred to as a "negative electrode film".
  • the mass of the electrode active material particles accounts for 70-99% of the total mass of the film 100 .
  • the mass of the functional material may account for 0.05%-30% of the mass of the film 100 .
  • the mass ratio can ensure the maximum loading of the electrode active material, so that the dry particles in the film can be evenly distributed, so that the battery made of the film can take into account the high specific capacity and functional materials. Additional features.
  • the embodiments of the present application further provide an electrochemical cell, including a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the separator is located between the positive electrode and the negative electrode, and at least one of the positive electrode and the positive electrode It includes the electrode sheet described above in the embodiments of the present application.
  • the electrochemical cell may be a secondary battery with high cycle performance and high safety.
  • the secondary battery may be a lithium secondary battery, a sodium secondary battery, a potassium secondary battery, a magnesium secondary battery, an aluminum secondary battery, a zinc secondary battery, or the like, and the secondary battery has high cycle performance and high safety sex.
  • an embodiment of the present application further provides a terminal 300.
  • the terminal 300 may be a mobile phone, or an electronic product such as a tablet computer, a notebook, a portable computer, and a smart wearable product.
  • the terminal 300 includes a terminal assembled outside the terminal.
  • the back cover on the side, the battery can be fixed on the inner side of the back cover to supply power to the terminal 300 .
  • This embodiment provides a lithium-replenishing electrode film with a nickel-cobalt-manganese NCM811 positive electrode active material, a Li 2 NiO 2 lithium supplement, a carbon nanotube (CNTs) conductive agent, and a PVDF binder, and a soft package assembled from the film
  • the preparation of the battery specifically includes the following steps:
  • Preparation of raw materials Take the positive active material NCM811 with D50 of 12 ⁇ m, remove super-large particles and fine particles in NCM811 by cyclone classification technology, and adjust the volume distribution and number distribution of particle size (D90-D10)/D50 to 1.35; take D50 The lithium supplement Li 2 NiO 2 particles with a particle size of 5 ⁇ m and the binder PVDF particles with a D50 particle size of 5 ⁇ m, wherein the volume distribution and number distribution of the particle sizes of the Li 2 NiO 2 particles and the PVDF particles satisfy (D90-D10 )/D50 ⁇ 1.5;
  • NCM811 particles, Li 2 NiO 2 particles, PVDF particles and CNTs were weighed according to the ratio of 88:5:5:2. Under the protection of argon, the weighed NCM811 particles and PVDF were added to the mixture of the jet mill.
  • the ultrasonic generator and magnetic field are turned on, so that the ultrasonic frequency in the mixing tank is 40 kHz, the power is 40 W, and the magnetic field strength is 0.3 T; after mixing with ordinary mechanical flying knives for 10 minutes, open the high-pressure air valve of the jet mill.
  • step (2) Preparation of positive electrode sheet: the film obtained in step (1) is covered on the prepared aluminum foil current collector, and the film is hot rolled at 160°C to combine with the aluminum foil, and the positive electrode sheet is formed after cutting. ;
  • this Example 1 argon gas was used in the mixing process of preparing the lithium-replenishing electrode film, so that the chemically active lithium-replenishing agent Li 2 NiO 2 would not be denatured and deactivated, and by introducing a physical field during high-pressure shearing (Ultrasonic field, magnetic field) intervention, so that the dry particles are not randomly distributed on the fibrillated network matrix formed by the fibrillation of the binder, so that the lithium supplement Li 2 NiO 2 can exert a better lithium supplement effect.
  • this embodiment does not introduce any solvent when preparing the lithium-replenishing electrode film, which avoids problems such as difficulty in gelling and coating during Li 2 NiO 2 slurrying and homogenization, which is environmentally friendly and saves costs.
  • This embodiment provides a negative electrode active material with silicon-oxygen mixed graphite (S500-2A from Bertray Company, with a deduction capacity of 500mAh/g and an initial effect of 83%) and a stabilized lithium metal powder SLMP (Stabilized lithium metal powder) as supplementary materials.
  • Raw material preparation First, the anode active material particles (D50 particle size of 6 ⁇ m), SLMP particles (D50 particle size of 15 ⁇ m), PTFE particles (D50 particle size of 8 ⁇ m) and acetylene black particles (D50 particle size of 8 ⁇ m) of silicon-oxygen mixed graphite were prepared. 50nm) and other raw materials through electrostatic classification technology to control the concentration of particle size of each material to ensure that the volume distribution and number distribution of each material particle size satisfy (D90-D10)/D50 ⁇ 1.5;
  • graded silicon-oxygen mixed graphite negative electrode active material particles and SLMP particles, PTFE particles and acetylene black particles are weighed in a ratio of 85:5:8:2. Under the protection of argon, the weighed SLMP particles are first weighed.
  • the particles and PTFE particles are added to the mixing tank of the jet mill, and the ultrasonic generator is turned on, so that the ultrasonic frequency in the mixing tank is 40 kHz and the power is 40 W;
  • the high-pressure air valve is used to conduct high-pressure shearing on the material in the mixing tank with a high-pressure air flow of 60 PSI for 2.5 hours, then add the weighed negative electrode active material particles of silicon-oxygen mixed graphite, and continue to carry out high-pressure shearing for 2.5 hours (high pressure).
  • the ultrasonic generator was still turned on during shearing), then acetylene black particles were added to continue high-pressure shearing for 30 minutes to obtain a fibrillated mixture, and finally the obtained mixture was rolled through a rolling device connected to the outlet of the jet mill. into a thin film with a thickness of 100 ⁇ m;
  • step (2) Preparation of negative electrode sheet: the film obtained in step (1) is covered on the prepared copper foil current collector, and the film is hot-rolled under the condition of 160° C. to combine with the copper foil. forming a negative electrode sheet;
  • the above negative electrode sheet is matched with NCM811 positive electrode sheet, and the EC+DEC mixed solution of 1mol/L LiPF 6 (the volume ratio of EC and DEC is 1:1) is used as the electrolyte, and the PP/PE/PP three-layer diaphragm is used as the diaphragm.
  • a soft pack battery of about 130mAh is used to test the battery performance.
  • This embodiment provides a lithium-replenishing film using Li 6 CoO 4 as a lithium-replenishing agent, PTFE as a binder, and Ketjen Black as a conductive agent, and the preparation of a soft-pack battery assembled from the film, which specifically includes the following steps :
  • Raw material preparation Li 6 CoO 4 particles (D50 particle size is 15 ⁇ m), PTFE particles (D50 particle size is 10 ⁇ m) and Ketjen black particles (D50 particle size is 80 nm) are controlled by electrostatic classification technology to control the concentration of particle size of each material To ensure that the volume distribution and number distribution of each material particle size satisfy (D90-D10)/D50 ⁇ 1.5;
  • step (1) Covering the film prepared in step (1) on the surface of the positive electrode active material layer, performing hot rolling under the condition of 160° C. to combine the film with the positive electrode active material layer, and cutting into pieces to obtain a positive electrode sheet;
  • FIG. 2 may represent the structure of the positive electrode sheet in Embodiment 3 of the present invention
  • FIGS. 1 a and 1 b may represent the schematic structural diagrams of the lithium supplementing film 100 on the positive electrode sheet in Embodiment 3.
  • 10 is the positive electrode current collector
  • 11 is the NCM811 positive electrode active material layer
  • 1 is the binder PTFE
  • 21 is the lithium supplement Li 6 CoO 4
  • 22 is Ketjen Black.
  • the present embodiment provides a flame-retardant electrode film with nickel-cobalt-manganese NCM811 positive electrode active material, Mg(OH) 2 flame retardant, CNTs conductive agent, and PTFE binder, and the preparation of a soft-pack battery assembled from the film, Specifically include the following steps:
  • Preparation of raw materials Take the positive active material NCM811 with D50 of 12 ⁇ m, remove super-large particles and fine particles in NCM811 by jet classification technology, and adjust the volume distribution and number distribution of particle size (D90-D10)/D50 to 1.1; and The volume distribution and number distribution of Mg(OH) 2 particles (D50 particle size is 100nm) and PTFE particles (D50 particle size is 5 ⁇ m) also satisfy (D90-D10)/D50 ⁇ 1.5;
  • NCM811 particles, Mg(OH) 2 particles, PTFE particles and CNTs were weighed according to the ratio of 88:5:5:2. Under the protection of argon, the weighed NCM811 particles and PVDF were added to the mixing of the jet mill.
  • Argon gas was introduced into the material tank for protection, and the ultrasonic generator and magnetic field were turned on, so that the ultrasonic frequency in the mixing tank was 40 kHz, the power was 40 W, and the magnetic field strength was 0.3 T;
  • the high-pressure air valve of the grinder is used for high-pressure shearing of the material in the mixing tank with a high-pressure air flow of 60 PSI (the ultrasonic generator and the magnetic field are still open during high-pressure shearing).
  • step (2) Preparation of positive electrode sheet: the film obtained in step (1) is covered on the prepared aluminum foil current collector, and the film is hot rolled at 160°C to combine with the aluminum foil, and the positive electrode sheet is formed after cutting. ;
  • Comparative Example 1 provides a method for preparing a lithium-replenishing electrode film containing NCM811 positive electrode active material, Li 2 NiO 2 lithium-replenishing agent, CNTs conductive agent, and PVDF binder by using a traditional dry process, and a film assembled from the film. Soft pack battery.
  • the difference between Comparative Example 1 and Example 1 is: in step (1), the particle size concentration control of each raw material is not carried out; and the weighed NCM811 particles, Li 2 NiO 2 particles, PVDF particles and CNTs are directly added.
  • the mixing tank of the jet mill After 10 minutes of mixing by the ordinary mechanical flying knife, open the high-pressure air valve of the jet mill, and select the high-pressure air flow of 60PSI to perform high-pressure shearing on the material in the mixing tank for 3 hours, and then the high-pressure
  • the sheared mixed material was rolled into a film with a thickness of 150 ⁇ m through a rolling device connected to the outlet of the jet mill.
  • Comparative Example 2 provides a method for preparing a lithium-replenishing electrode film containing silicon-oxygen mixed graphite negative electrode active material, SLMP lithium-replenishing agent, PTFE binder, and acetylene black conductive agent by using a traditional dry process, and is assembled from the film. soft pack battery.
  • the difference between Comparative Example 2 and Example 2 is that: in step (1), the particle size concentration control of each raw material is not performed; and the ultrasonic generator and the magnetic field are not turned on during the shearing and mixing process.
  • Comparative Example 3 provides a method for preparing a conventional NCM811 positive electrode sheet using a traditional wet coating process, and also provides a soft pack battery assembled from the conventional positive electrode sheet, which specifically includes the following steps:
  • the nickel-cobalt-manganese NCM811 positive electrode active material, the Super P conductive agent and the PVDF binder are uniformly stirred in a mass ratio of 75:10:15 to obtain a positive electrode active slurry, which is coated by spin coating
  • a positive electrode active material layer was formed; then hot rolling was performed at 160 °C to combine the positive electrode active material layer with the aluminum foil, and the positive electrode sheet was obtained after cutting. ;
  • Lithium battery performance test The battery of each embodiment is charged and discharged according to the 0.5C/0.5C charge and discharge system.
  • the test voltage range of the negative electrode sheet is 3.0-4.25V, and the test voltage range of the positive electrode sheet is 3.0-4.4V. The results are listed in Table 1.
  • Figure 5 is a photo comparison of the negative electrode sheets in Example 2 (a) and Comparative Example 2 (b) of the application after they are fully charged and disassembled. It can be seen from Figure 5 and Table 1 that Comparative Example 2 is set on an aluminum foil current collector. Although the same amount of SLMP as in Example 2 was added to the lithium-replenishing electrode film as the lithium-replenishing agent, due to the uneven distribution of the lithium-replenishing agent in the film, some positions were enriched, resulting in the negative electrode sheet after 300 cycles of circulation.
  • Example 1 Comparative Example 1
  • Example 1 Comparative Example 1
  • lithium supplementation will be uneven, and some parts cannot be supplemented with lithium, while other parts have excess lithium content, which will lead to safety problems such as lithium precipitation and lithium dendrite growth, which greatly affects the cycle performance of the battery.
  • the random distribution of lithium supplements will also lead to problems such as uneven current density on the surface of the electrode sheet and excessive local impedance, which will cause the temperature of the cell to rise and aggravate polarization.
  • Example 4 Mg(OH) 2 flame retardant was introduced into the NCM811 positive electrode sheet, and by controlling the particle size concentration of each raw material and introducing a batch of high-pressure shear mixing with physical field intervention. material, etc., to achieve uniform distribution of each dry particle including flame retardant in the electrode film.
  • the flame retardant effects of the battery of Example 4 and the battery of Comparative Example 3 are listed in Table 2 below.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本申请实施例提供了一种用于电池电极的薄膜，该薄膜包括纤丝化粘结剂交织成的纤丝化网络基体及分布在所述纤丝化网络基体上的干颗粒，所述干颗粒包括功能材料颗粒和导电剂颗粒，部分所述干颗粒具有第一尺寸，其余所述干颗粒具有其他尺寸，所述其他尺寸小于所述第一尺寸的1/2；具有所述第一尺寸的干颗粒有序排布，具有所述其他尺寸的干颗粒填充在具有所述第一尺寸的干颗粒的颗粒间隙中，所述颗粒间隙小于所述第一尺寸。由于各干颗粒在薄膜中不是随机分布，各干颗粒不易团聚，使得薄膜的连续性、完整度高，薄膜用于电池电极时，功能材料可以很好地发挥功能特性，提升电池性能。本申请实施例还提供了该薄膜的制备方法、电极片、电化学电池和终端。

Description

用于电池电极的薄膜及其制备方法
本申请要求于2020年7月14日提交中国专利局、申请号为202010673302.0、申请名称为“用于电池电极的薄膜及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及电化学电池技术领域，特别是涉及一种用于电池电极的薄膜及其制备方法、电极片、电化学电池和终端。
背景技术
随着经济和科技的发展，便携式电子器件(手机、平板电脑、笔记本电脑)、无人机、电动汽车等行业都迫切需要具有更高能量密度、更长循环寿命和更安全的储能器件。为使锂离子电池达到上述要求，业界通常采取的措施是向锂离子电池体系引入合适的功能材料(如补锂剂、阻燃剂等)。但仅有少部分功能材料可以直接添加在电解液中，大多数功能材料都需要通过兼容性更强的电极片制备技术引入，以在电池中发挥作用。其中，引入功能材料的传统湿法电极片制备工艺是将电极活性材料、功能材料与溶剂等混合成浆料，再在基体上涂布、烘干成膜，但补锂剂(如金属锂)等化学性质活泼的功能材料，易在潮湿环境下发生***，不适合通过传统的湿法电极片制备工艺来引入。而不含溶剂的干法电极膜技术解决了湿法工艺中功能材料可能与溶剂等加工环境不兼容的问题，该技术具体是将高剪切力施加到干粘结剂颗粒上以将其纤丝化，并使多种功能材料颗粒在其上负载。但由于没有溶剂的缘故，在常规的干法电极膜中，各颗粒是随机分布，易出现团聚，进而影响它们优化电池性能的作用发挥，甚至会劣化电池的能量密度、循环能力、安全性等性能。
发明内容
鉴于此，本申请实施例提供一种采用干法工艺制备的薄膜，该薄膜中的干颗粒不团聚，薄膜均一性好，该薄膜用于电池电极时，干颗粒可以很好地发挥相应特性，提升电池性能。
具体地，本申请实施例第一方面提供了一种用于电池电极的薄膜，所述薄膜包括纤丝化粘结剂交织成的纤丝化网络基体及分布在所述纤丝化网络基体上的干颗粒，所述干颗粒包括功能材料颗粒和导电剂颗粒，部分所述干颗粒具有第一尺寸，其余所述干颗粒具有其他尺寸，所述其他尺寸小于所述第一尺寸的1/2；具有所述第一尺寸的干颗粒有序排布，具有所述其他尺寸的干颗粒填充在具有所述第一尺寸的干颗粒的颗粒间隙中，所述颗粒间隙小于所述第一尺寸。
上述薄膜中，各干颗粒在纤丝化粘结剂构成的纤丝化网络基体上不是随机分布，而是相对粒径最大的具有第一尺寸的干颗粒有序排布，而相对粒径较小的具有其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，从而各干颗粒形成稳定、有序的排列，各干颗粒不易团聚，使得该薄膜的连续性好、完整度高、稳定性高。从而在该薄膜用于电池电极时，能够更好地发挥各颗粒的功能特性，提升电池相关性能；也不会恶化电池能量密 度、循环能力、安全性等。
本申请实施方式中，所述第一尺寸在1μm-50μm的范围内；所述其他尺寸包括一种或多种不同尺寸粒径，所述其他尺寸在30nm-7μm的范围内。合适的尺寸可以使各干颗粒的分布更紧密、干颗粒的负载量大，并保证所述薄膜的结构更稳定。
本申请实施方式中，所述功能材料颗粒包括活性离子补充剂、阻燃剂和膨胀减缓剂中的至少一种。其中，活性离子补充剂能够有效提升电池能量密度；阻燃剂能够提升电池阻燃性能，提升电池安全性；而膨胀减缓剂能够有效缓解电极材料膨胀，提升电池循环稳定性。本申请实施方式中，所述活性离子补充剂包括补锂剂、补钠剂、补钾剂、补镁剂、补锌剂和补铝剂中的一种。
本申请实施方式中，所述功能材料颗粒的D50粒径在30nm-50μm的范围内。不同种类、不同功能的功能材料颗粒的尺寸可根据其具体功能的不同及实际应用场景来灵活调整。
本申请实施方式中，每种不同材质的干颗粒的粒度分布均满足(D90粒径-D10粒径)/D50粒径<1.5。这样每种不同材质的干颗粒的尺寸集中度较高，便于它们在纤丝化网络基体中的均匀有序分布，进而可提高负载有它们的薄膜的质量，且可以最大程度地发挥出各干颗粒的相应特性，保证不同批次薄膜的质量一致性、功能再现性。
本申请实施方式中，所述薄膜的厚度大于或等于30μm。该厚度大于通过现有湿法工艺制得的薄膜厚度，且不含溶剂残留物。本申请一具体实施方式中，薄膜的厚度为30μm-300μm。
本申请一些实施方式中，所述功能材料的质量占所述薄膜质量的70％-99％。该质量占比可以在保证薄膜具有稳定结构及期望的良好机械性能的情况下，使功能材料在该薄膜中的负载量较大且不会产生局部聚集现象，进而能最大程度地提升电池的性能。
本申请另外一些实施方式中，所述干颗粒还包括电极活性材料颗粒。此时，该薄膜可用作电极片的活性材料层。
本申请实施方式中，所述电极活性材料颗粒的D50粒径在1-50μm的范围。尺寸较大的电极活性材料颗粒在所述薄膜中紧密排布，可实现其在薄膜中的负载量较大，进而可提升电池能量密度。
本申请实施方式中，所述电极活性材料颗粒的粒度分布满足(D90粒径-D10粒径)/D50粒径<1.5。电极活性材料颗粒的尺寸集中度较高，便于它们在纤丝化网络基体中的均匀有序分布，进而可提高含有电极活性材料的薄膜的质量并发挥出较优性能，保证不同批次薄膜的质量一致性、功能再现性。
本申请一具体实施方式中，所述电极活性材料的质量占所述薄膜质量的70-99％。本申请一具体实施方式中，所述功能材料的质量占所述薄膜质量的0.05％-30％。该质量占比可在保证电极活性材料最大负载量的情况下，使该薄膜中的各干颗粒均能均匀分布，进而使由该薄膜制成的电池兼顾高比容量和功能材料带来的良好附加功能。
本申请实施例第一方面提供的薄膜，各干颗粒在纤丝化粘结剂构成的纤丝化网络基体上不是随机分布，而是相对尺寸最大的具有第一尺寸的干颗粒有序排布，而相对尺寸较小的具有其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，从而形成稳定、有序的排列，各颗粒不易团聚，使得薄膜的连续性好、完整度高、稳定性高，在该薄膜应用 到电池电极时，可以较好地发挥各颗粒的特性，尤其是功能材料的功能特性，提升电池相关性能。
本申请实施例第二方面还提供了一种用于电池电极的薄膜的制备方法，包括：
提供干颗粒，所述干颗粒包括功能材料颗粒和导电剂颗粒，部分所述干颗粒具有第一尺寸，其余所述干颗粒具有其他尺寸，所述其他尺寸小于所述第一尺寸的1/2；在保护气体存在下，将可纤丝化的粘结剂颗粒和具有所述第一尺寸的干颗粒配制成第一混合物；
在引入物理场干预的情况下，对所述第一混合物进行高压剪切，以使所述粘结剂颗粒纤丝化，以及使得具有所述第一尺寸的功能材料颗粒有序排布，然后加入具有所述其他尺寸的干颗粒，继续进行高压剪切，得到第二混合物；
对所述第二混合物料进行压制，得到薄膜；其中，所述薄膜包括所述纤丝化粘结剂交织成的纤丝化网络基体和分布在所述纤丝化网络基体上的所述干颗粒；具有所述第一尺寸的干颗粒阵列排布形成有序结构，具有所述其他尺寸的干颗粒填充在具有所述第一尺寸的干颗粒的颗粒间隙中，所述颗粒间隙小于所述第一尺寸。
本申请实施方式中，所述物理场干预包括超声震荡和磁场干预中的至少一种。
本申请一实施方式中，所述超声震荡的超声频率大于或等于20KHz，超声功率大于或等于20W。本申请一实施方式中，所述磁场干预的磁场强度大于或等于0.1T。
本申请实施方式中，所述粘结剂颗粒的D50粒径为1μm-50μm。较大粒径的粘结剂颗粒可便于形成交织均匀、弹性强、粘度足的纤丝化网络基体。
本申请某些实施方式中，所述第一混合物中，所述具有所述第一尺寸的干颗粒还包括电极活性材料颗粒。
本申请实施方式中，具有所述其他尺寸的干颗粒是按尺寸从大到小的顺序依次分批加入。这样可以使具有第一尺寸的干颗粒以及具有其他尺寸的干颗粒均能实现紧密、有序排布，更好地提高薄膜中各干颗粒的均匀排布性。
本申请实施方式中，为使所述薄膜中各种尺寸的不同材料的分布更均匀，每种不同材料的干颗粒的粒度分布均满足(D90粒径-D10粒径)/D50粒径<1.5。
本申请实施例第二方面提供的薄膜的制备方法，通过将相对尺寸最大的具有第一尺寸的干颗粒与具有其他尺寸的干颗粒先后与粘结剂颗粒进行高压剪切，并通过物理场干预使具有第一尺寸的干颗粒紧密有序排布，而相对尺寸较小的具有其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，从而各干颗粒不易团聚，得到连续性好、完整度高、稳定性好的薄膜。此外，该制备方法不涉及溶剂、液体及加工助剂的使用，普适性强、成本低。
本申请实施例第三方面还提供了一种电极片，所述电极片包括集流体和设置在所述集流体上的如本申请实施例第一方面所述的薄膜。该电极片的结构稳定，所含薄膜的平整度高、完整度高、连续性好，含有该薄膜的电极片可以用来提供具有改善的电化学性能的电化学电池。
本申请一些实施方式中，所述电极片还包括电极活性材料层，所述电极活性材料层设置在所述集流体和所述薄膜之间。
本申请另外一些实施方式中，所述薄膜就充当所述电极片的电极活性材料层。此时， 所述干颗粒还包括电极活性材料颗粒。
本申请实施例第四方面还提供了一种电化学电池，包括正电极、负电极，以及位于所述正电极和所述负电极之间的隔膜和电解液，其中，所述正电极和/或所述负电极包括本申请实施例第四方面所述的电极片。该电化学电池具有高能量密度、长循环寿命和高安全性。
本申请实施例第五方面还提供一种终端，所述终端包括外壳，以及位于所述外壳内部的主板和电池，所述电池包括本申请实施例第四方面所述的电化学电池，所述电化学电池用于为所述终端供电。该终端可以是手机、笔记本、平板电脑、便携机、智能穿戴产品等电子产品。
附图说明
图1a为本申请一实施方式中提供的薄膜中干颗粒的平面分布示意图；
图1b为本申请一实施方式中提供的薄膜中干颗粒的立体分布示意图；
图2为本申请一实施方式中提供的电极片的结构示意图；
图3为本申请另一实施方式中提供的电极片的结构示意图；
图4为本发明实施例提供的终端的结构示意图；
图5为本申请实施例2(a)和对比例2(b)中的电池负极在满电拆解后的照片对比。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例进行说明。
请一并参见图1a和图1b，本申请实施例提供一种薄膜100，其采用干法工艺制备，包括纤丝化粘结剂和干颗粒2，其中，纤丝化粘结剂交织成纤丝化网络基体1，干颗粒2分布在该纤丝化网络基体1上；其中，干颗粒2包括功能材料颗粒和导电剂颗粒，部分干颗粒具有第一尺寸，其余干颗粒具有其他尺寸，且其他尺寸小于第一尺寸的1/2；具有第一尺寸的干颗粒21有序排布，具有第一尺寸的干颗粒21的颗粒间隙小于第一尺寸，具有其他尺寸的干颗粒22填充在具有第一尺寸的干颗粒21的颗粒间隙中。
本申请实施例的薄膜100中，各干颗粒在纤丝化粘结剂构成的纤丝化网络基体上不是随机分布，而是相对粒径最大的具有第一尺寸的干颗粒有序排布，而相对粒径较小的具有其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，从而各干颗粒形成稳定、有序的排列，各干颗粒不易团聚，使得该薄膜的连续性好、完整度高、稳定性高。
本申请中“具有第一尺寸的干颗粒21的颗粒间隙小于第一尺寸”，是指任意相邻的两个具有第一尺寸的干颗粒21之间都不能再填充进来第三个具有第一尺寸的干颗粒21，即，具有第一尺寸的干颗粒21是紧密地有序排布，构成“紧密排布结构”。其中，所述“有序排布”可以具体为阵列排布，例如以a×b×c的阵列形式排布，其中，a、b、c为正整数。
本发明实施方式中，三维结构的薄膜100中(可参见图1b)，每个具有第一尺寸的干颗粒周围有6-12个具有第一尺寸的干颗粒。这样，具有第一尺寸的干颗粒21的排布方式较紧凑，有助于提升薄膜100中干颗粒的分布密度，在薄膜100用到电池中时，可提升电池的能量密度等电化学性能。
本发明实施方式中，薄膜100的空隙率小于30％。在一些实施例中，薄膜100的空隙 率可以小于20％、小于10％，甚至小于5％或小于1％。较小的空隙率代表薄膜100中任意相邻的干颗粒2之间的互相填充程度高、致密程度大，薄膜100中各干颗粒更稳定有序排列，薄膜的结构稳定、力学性能较好。
本申请中的术语“干颗粒”的范围涵盖了粉末、球、薄片、纤维、管及其他形状和纵横比的其他颗粒。其中，对于球形或类球形颗粒/粉末来说，其第一尺寸即是指其D50粒径，而对于薄片、纤维状、管、条等非球形状的颗粒，其第一尺寸指的是长宽尺寸。
本申请实施方式中，干颗粒2的尺寸可以在30nm-50μm的范围内。其中，第一尺寸可以在1μm-50μm的范围内；其他尺寸可以在30nm-10μm的范围内。在一些实施例中，第一尺寸可以在2μm-30μm、5μm-50μm、8μm-20μm或3μm-15μm的范围内。其他尺寸可以在30nm-7μm、30nm-1μm、30nm-500nm或50nm-200nm的范围内，只要满足“其他尺寸小于第一尺寸的1/2”即可，这样可便于具有其他尺寸的干颗粒填充在紧密排布的具有第一尺寸的干颗粒之间的空隙中。在本申请一些实施例中，第一尺寸可以在3μm-15μm的范围内，其他尺寸可以在30nm-1μm的范围内。本申请中，其他尺寸可以包括一种或多种不同尺寸。例如，包括2种以上的不同尺寸。举例来说，干颗粒除了包括具有第一尺寸的干颗粒，还可以包括具有第二尺寸的干颗粒、具有第三尺寸的干颗粒，且第三尺寸不同于第二尺寸，第二尺寸和第三尺寸均小于第一尺寸的1/2，它们均可填充在紧密、有序排布的具有第一尺寸的干颗粒的颗粒间隙中。
本申请中，具有相同尺寸的干颗粒的材质可以相同，也可以不同。具体来说，两种材质不同的功能材料颗粒(如补锂剂颗粒)可以均具有上述第一尺寸，也可以是两种材质不同的补锂剂颗粒和下文的电极活性材料颗粒两类作用不同的颗粒均具有上述第一尺寸。
本申请实施方式中，纤丝化网络基体1可用于捕获、粘接、支撑上述干颗粒2。具体地，干颗粒2被纤丝化网络基体1缠绕而捕获住，纤丝化网络基体1对干颗粒2也起一定支撑作用，干颗粒2之间可通过纤丝化粘结剂粘接起来。
本申请实施方式中，纤丝化网络基体1的材质可以是链式高分子粘结剂。链式高分子粘结剂可便于在高剪切力的作用下形成纤丝化网络基体。具体地，链式高分子粘结剂的材质可以包括纤维素及其衍生物、聚烯烃、含氟聚合物、聚丙烯酸(PAA)、聚丙烯酸酯(如聚甲基丙烯酸甲酯(PMMA))、聚丙烯腈(PAN)、聚环氧乙烯(PEO)、聚酰亚胺(PI)、丁苯橡胶(SBR)、以及它们的共聚物中的一种或多种。其中，对于含氟聚合物可以列举聚四氟乙烯(PTFE)、聚偏氟乙烯(PVDF)、聚氟乙烯(PVF2)、聚偏氟乙烯-六氟丙烯共聚物P(VDF-HFP)等，对于聚烯烃可以列举聚丙烯(PP)、聚乙烯(PE)等。对于纤维素及其衍生物可以列举羧甲基纤维素(CMC)、羧甲基纤维素钠(CMC-Na)等。本申请实施方式中，用于形成纤丝化网络基体1的粘结剂颗粒的D50粒径可以在1μm-50μm的范围内，进一步地，可以在2μm-20μm或3μm-15μm的范围内。较大粒径的粘结剂颗粒可便于形成交织均匀、弹性强、粘度足的纤丝化网络基体1。
本申请实施方式中，功能材料颗粒可以提升电池的能量密度、循环性能和安全性等性能。其中，功能材料颗粒可以包括活性离子补充剂、阻燃剂、膨胀减缓剂中的一种或多种。后续将该薄膜组装成电池后，可根据薄膜所含功能材料的不同特性在不同阶段起到相应功能。具体地，阻燃剂这一功能材料不参与电池的电化学过程，如遇电池温度过高或燃烧， 则阻燃剂会通过吸热、覆盖、抑制链反应等来阻止燃烧过程和火焰传播，进而提升电池的安全。膨胀减缓剂这一功能材料能在电极材料膨胀过程中提供缓冲作用、缓解电极片膨胀，进而提升电池的循环稳定性及安全性能。活性离子补充剂可以在电池的首次充放电过程中不可逆地释放出大量活性锂离子，以起到补充活性离子补锂的作用、提升电池的能量密度。其中，活性离子可以包括锂离子、钠离子、钾离子、镁离子和铝离子中的一种。
具体地，活性离子补充剂包括补锂剂、补钠剂、补钾剂、补镁剂、补锌剂和补铝剂中的一种。其中，补锂剂可以在锂电池的化成阶段先于电池的电极活性材料释放出大量活性锂离子，以起到补锂的作用。补锂剂包括但不限于锂金属及其制成品，例如可以包括锂粉、稳定化锂粉、锂带、锂箔、富锂金属氧化物、锂碳复合物、锂碳合金、锂硅合金等中的至少一种。对于富锂金属氧化物可以列举Li 2NiO 2、Li 6CoO 4、Li 5FeO 4、Li 2O·MO(M为Fe、Co、Ni、Mn、Cu、Zn、Re、Al、Ti、Zr、W和La中的一种或多种)等。不同补锂剂在释放出活性锂之后的残留物不同，例如以Li 2NiO 2作为正极补锂剂的薄膜会在电池的化成结束后产生LiNiO、NiO、Li 2O中的一种或多种；以Li 6CoO 4作为正极补锂剂的薄膜会在电池的化成结束后产生LixCoO 4(0＜x＜6)、CoO 2、Li 2O中的一种或多种；以Li 5FeO 4作为正极补锂剂的薄膜会在电池的化成结束后产生LiyFeO 4(0＜y＜5)、Fe 2O 3、Li 2O中的一种或多种。
本申请实施方式中，阻燃剂包括无机物阻燃剂和有机物阻燃剂。其中，无机物阻燃剂可以包括碲的化合物、铝的羟基化物(如氢氧化铝、双(2-乙基己酸)羟基铝)、氢氧化镁、硼酸盐等；有机物阻燃剂可以包括三嗪及其衍生物、三聚氰胺、多聚磷酸酯、尿素、双氰胺等。其中，所述膨胀减缓剂包括但不限于葡萄糖、酚醛树脂、羧甲基纤维素钠、明胶、淀粉、石墨烯、聚噻吩、碳纳米管、聚丙烯腈、三烷基铝等中的至少一种。
本申请实施方式，每一种不同材质的功能材料颗粒的D50粒径均在30nm-50μm的范围内。进一步地，功能材料颗粒的D50粒径可以在30nm-1μm、50nm-200nm、2μm-50μm、5μm-50μm、8μm-20μm或3μm-15μm。不同材质的功能材料颗粒的尺寸可根据其具体功能的不同及实际应用场景来灵活调整，功能材料可以是作为相对尺寸最大的具有第一尺寸的干颗粒21，或者作为具有其他尺寸的干颗粒22。例如，阻燃剂颗粒的D50粒径可以在30nm-500nm的范围内，充当具有其他尺寸的干颗粒，补锂剂的D50粒径可以在2μm-30μm的范围内，充当具有第一尺寸的干颗粒。
本申请实施方式中，每种不同材质的干颗粒的粒度分布可以均满足(D90粒径-D10粒径)/D50粒径<1.5，尤其是每种不同材质的功能材料颗粒的粒度分布应满足(D90粒径-D10粒径)/D50粒径<1.5。即，每一种材质不同的活性离子补充剂的颗粒、每一种材质不同的阻燃剂的颗粒、每一种材质不同的膨胀减缓剂的颗粒的粒度分布均满足(D90粒径-D10粒径)/D50粒径<1.5。这样每种不同功能材料的干颗粒的尺寸集中度较高，便于同种材质的干颗粒在纤丝化网络基体中的均匀有序分布，进而可提高负载有它们的薄膜的质量，后续在电池电极中充分发挥出较优性能，并保证不同批次薄膜的质量一致性、功能再现性。
本申请实施方式中，对导电剂的种类没有特别限制，采用本领域的现有常规材料即可。如导电剂可以包括碳纤维、碳纳米管、石墨、石墨烯、导电炭黑、炉黑、中间相碳微球等中的一种或多种。其中，导电炭黑可具体包括乙炔黑、科琴黑、Supper P、350G炭黑等。 石墨可以包括天然石墨(如鳞片石墨、膨胀石墨)和人造石墨(如KS-6、球形石墨)等。本申请实施方式，导电剂的尺寸在30nm-50μm的范围内。对于零维及三维导电剂(如导电炭黑颗粒、炉黑颗粒及中间相碳微球等)，它们的D50粒径可以小于或等于100nm；对于二维层状导电剂(如片状石墨、石墨烯等)，其尺寸是指横向的长宽尺寸，具体地，片状石墨或石墨烯的长宽尺寸可以在1μm-50μm的范围内。其中，对于导电剂来说，每种不同材质的球形或类球形导电剂颗粒的粒度分布满足(D90粒径-D10粒径)/D50粒径<1.5，这样每种不同材质的球形或类球形导电剂颗粒的尺寸集中度较高，赋予本申请的薄膜100均匀的导电性。
本申请实施方式中，上述薄膜100的厚度可根据具体的应用场景做厚或做薄。具体地，薄膜100的厚度可以大于或等于30μm。例如，薄膜的厚度可以是40μm-60μm，100μm-250μm或30μm-300μm。本申请一些实施方式中，薄膜100的厚度为70μm-300μm。该薄膜厚度远大于通过目前的湿法工艺制得的电极膜厚度，由于该薄膜是通过不含溶剂的干法技术制得，薄膜100不含或基本上不含任何液体(如溶剂)和由此产生的残留物，该薄膜较干净。薄膜100的厚度不受湿法技术中浆料粘稠度和涂布方式限制，该薄膜的厚度可以较厚、连续性、完整度高，结构更牢固。此外，相较于现有干法电极膜，该薄膜中各干颗粒的分布较均匀，薄膜的连续性及完整度高，结构更牢固，具有较好的机械性能、电性能。
本申请一些实施方式中，上述薄膜100可设置在现有电极片的电极活性材料层表面，作为电极片的功能层使用。此时，作为电极片功能层的薄膜100，其中的干颗粒仅包括上述功能材料颗粒和导电剂颗粒。该实施方式中，功能材料的质量可占薄膜100总质量的70％-99％。该质量占比可以在保证薄膜具有稳定结构及期望的良好机械性能的情况下，使功能材料在该薄膜中的负载量较大且不会产生局部聚集现象，进而能最大程度地提升电池的性能。
本申请另外一些实施方式中，薄膜100中的干颗粒还包括电极活性材料颗粒。此时，本申请的薄膜100可直接设置在集流体表面，充当电极片的活性材料层，与集流体共同构成电池的电极片。该实施方式中，电极活性材料的质量可占薄膜100总质量的70-99％。功能材料的质量可占薄膜100总质量的0.05％-30％。这些质量占比可在保证电极活性材料最大负载量的情况下，使该薄膜中的各干颗粒均能均匀分布，进而使由该薄膜制成的电池兼顾高比容量和功能材料带来的良好附加功能。
本申请实施方式中，电极活性材料颗粒的D50粒径可以在1μm-50μm的范围内。电极活性材料颗粒优选作为干颗粒中的大粒径成分(即，具有第一尺寸的干颗粒)，以实现其在薄膜中的紧密、有序排布，提高其在薄膜中的负载量，进而提高采用该薄膜的电池能量密度。在本申请一些实施例中，电极活性材料颗粒的D50粒径可以为1μm-20μm。例如为1μm-15μm、2μm-20μm、3μm-15μm或8μm-20μm。此外，每种不同材质的电极活性材料颗粒的粒度分布也满足(D90粒径-D10粒径)/D50粒径<1.5，以实现其在薄膜中的均匀分布、避免出现团聚，进而可提高含有电极活性材料的薄膜的质量并发挥出较优性能，保证不同批次薄膜的质量一致性、功能再现性。
本申请实施例提供的薄膜，由于各干颗粒在纤丝化粘结剂构成的纤丝化网络基体上不是随机分布，而是相对尺寸最大的具有第一尺寸的干颗粒有序排布，其颗粒间隙小于第一 尺寸，其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，这使得各干颗粒形成稳定、有序的排列，使得该薄膜的连续性好、完整度高，不含溶剂残留物，各干颗粒在该薄膜中不易团聚，稳定性高，能充分发挥出各自的功效，当将该薄膜应用到电池电极中，可以较好地提升电池性能。
相应地，本申请实施例还提供了一种上述用于电池电极的薄膜的制备方法，包括：
S101、提供干颗粒，干颗粒包括功能材料颗粒和导电剂颗粒，部分干颗粒具有第一尺寸，其余干颗粒具有其他尺寸，其他尺寸小于第一尺寸的1/2；在保护气体存在下，将可纤丝化的粘结剂颗粒和具有第一尺寸的干颗粒配制成第一混合物；
S102、在引入物理场干预的情况下，对第一混合物进行高压剪切，以使粘结剂颗粒纤丝化，以及使具有第一尺寸的干颗粒有序排布，然后加入具有其他尺寸的干颗粒，继续进行高压剪切，得到第二混合物；
S103、对第二混合物料进行压制，得到薄膜；其中，薄膜包括纤丝化粘结剂交织成的纤丝化网络基体和分布在纤丝化网络基体上的干颗粒；具有其他尺寸的干颗粒填充在具有第一尺寸的干颗粒的颗粒间隙中，该颗粒间隙小于第一尺寸。
本申请实施例的步骤S101中，粘结剂颗粒的D50粒径可以在1μm-50μm的范围内，进一步地，可以在2μm-20μm或3μm-15μm的范围内。较大粒径的粘结剂颗粒可便于形成交织均匀、弹性强、粘度足的纤丝化网络基体。
本申请一些实施方式中，步骤S101中，具有第一尺寸的干颗粒还包括电极活性材料颗粒。即，电极活性材料颗粒可作为大粒径组分先与粘结剂颗粒进行高压剪切。
本申请实施方式中，为使所述薄膜中各种尺寸的不同材料分布更均匀，可以在步骤S101中，对提供的各干颗粒的尺寸集中度进行控制，以使每种不同材质的干颗粒的粒度分布均满足(D90粒径-D10粒径)/D50粒径<1.5。这样同种材质的干颗粒在薄膜中的分布情况相似，并保证不同批次薄膜的质量一致性、功能再现性。其中，能实现上述尺寸集中度的技术包括但不限于旋风分级、复频筛、静电分级、射流分级等。
本申请实施例中的步骤S102中，若具有其他尺寸的干颗粒包括多种不同尺寸，可根据它们尺寸的大小，按从大到小的顺序依次分批加入以分批进行高压剪切。或者至少是根据球形或类球形的不同材质颗粒的D50粒径的大小，按从大到小的顺序依次分批加入。这样可以使具有第一尺寸的干颗粒以及具有其他尺寸的干颗粒均能实现上述紧密、有序排布，更好地提高薄膜中各干颗粒的均匀排布性。
本申请步骤S102中，所述物理场干预包括超声震荡和磁场干预中的至少一种。物理场干预有助于使具有第一尺寸的干颗粒有序排布。以超声震荡为例，它能推动大粒径组分往复高频运动，形成高度均匀的有序排布状态，进而便于后加入的小粒径组分能填充在大粒径组分的颗粒间隙中。需要说明的是，磁场干预是针对具有磁性的干颗粒形成有序排布结构来施加，例如，含Fe、Co、Ni等的电极活性材料颗粒或补锂剂颗粒。超声震荡这一物理场干预方式既适用于制备含有磁性颗粒的上述薄膜，也适用于制备不含磁性颗粒的上述薄膜。进一步地，当制备含有磁性颗粒的上述薄膜时，所采用的物理场干预可以包括超声震荡和磁场干预中的至少一种，且最好引入磁场干预。
本申请一些实施例中，超声震荡的超声频率可以大于或等于20KHz，超声功率可以大 于或等于20W。本申请一些实施例中，磁场干预的磁场强度可以大于或等于0.1T。
在本申请一些实施方式中，可以在步骤S102进行高压剪切时才开始引入物理场干预。此时，所述物理场可以在高压剪切装置的外壁施加。本申请另一些实施方式中，可以在步骤S101配制第一混合物时就开始引入物理场干预。此时，可以在步骤S101用到的混料装置和步骤S102用到的高压剪切装置的外壁均施加物理场。当然，在本申请某些实施例中，步骤S101用到的混料装置和步骤S102用到的高压剪切装置可以为同一装置。
在本申请一些实施方式中，上述步骤S101中第一混合物的配制，可以通过不引入高压气体的普通机械混合方式(如搅拌、研磨、双运动混合等)进行，或者通过引入高压气流的高压剪切混合的方式进行。具体地，用于形成第一混合物的混料装置可以包括带式混合器、旋转混合器、行星式混合器、声学混合器、微波混合器、双运动混合机、流化床混合器、球磨机、高速剪切混合器、喷射研磨机和锤磨机等中的至少一种。其中，当第一混合物的配制采用高压剪切混合的方式(如高速剪切混合器、喷射研磨机、锤磨机等)形成时，上述第一混合物的配置及高压剪切就可通过一种装置完成。
本申请实施例的步骤S101中，在配制第一混合物时所用的保护气体为足够干燥的气体，包括干燥的空气、氮气、氦气、氢气等中的至少一种，优选为高压条件下提供的干燥压缩气体。保护气体可避免有些化学性质较活泼的材料颗粒发生性质/功能的改变及提高安全性。本申请一些实施方式中，步骤S102的高压剪切的过程中，仍存在所述保护气体。混料和剪切过程中干燥的保护气体的存在，可以在提高安全性的同时，避免所得薄膜中含有水。
本申请实施例的步骤S102中，粘结剂颗粒的纤丝化通过干燥、无溶剂、无液体的高压剪切力技术来实现，具体可以通过施加正的压力或负的压力来实现，如压缩气体或真空。在纤丝化过程中，对粘结剂施加高剪切力，可使粘结剂物理伸长、纤丝化，伸长的粘结剂之间相互缠绕交叠，形成薄网状的纤丝化网络基体。本申请一实施方式中，为使粘结剂颗粒充分纤丝化，在高压剪切时，采用的高压气流的压力大于或等于60PSI。具体可以为60PSI-500PSI，或80PSI-300PSI。
本申请实施例中，可将粘结剂纤丝化的设备包括喷射研磨机、针式研磨机、锤式研磨机、碰撞粉碎机等。在一具体实施方式中，通过喷射研磨机来实现粘结剂颗粒的纤丝化。该喷射研磨机处理具有普通的机械剪切飞刀外，还具有至少一个可喷出高压气流的喷嘴。在第一混合物的配制过程中，链式高分子粘结剂会逐渐团聚成块，普通的机械剪切飞刀可将混料过程中形成的聚集物/团聚体的尺寸减小形成小颗粒，从喷射研磨机的喷嘴中喷出的高压气流可以加速各小颗粒的碰撞，并使粘结剂伸长、纤丝化，伸长的粘结剂之间相互缠绕交叠、直至交织形成薄网状的纤丝化网络基体，并使上述干颗粒分布到该纤丝化网络基体中。
本申请实施例的步骤S103中，对第二混合物料的压制可通过辊压、压延等方式实现，具体可以通过辊压机、辊式研磨机、压延机、带式压榨机、平板压榨机等设备来实现。
本申请实施例提供的薄膜的制备方法，通过在物理场干预下，先将大粒径组分(具有第一尺寸的干颗粒)与粘结剂颗粒进行高压剪切，可使大粒径组分紧密有序排布，而加入小粒径组分(具有其他尺寸的干颗粒)继续进行高压剪切，使小粒径组分填充在大粒径组 分的颗粒间隙中，从而使各干颗粒不团聚，得到连续性好、完整度高、稳定性好的薄膜，从而在该薄膜用于电池电极时，能够充分发挥出各干颗粒的功效，提升电池相关性能。该制备方法解决了现有干法电极膜因干颗粒团聚导致的电池能量密度低、循环寿命短和安全性差的问题。例如，上述薄膜中若含有3wt％的补锂剂，就可在该薄膜应用到电池中时将电池的循环寿命提高50％以上。
此外，该制备方法全程不涉及溶剂、液体及加工助剂的使用，解决了电极膜领域中化学性质活泼的功能材料与溶剂等湿法工艺不兼容的问题，该制备方法的普适性强，适用在薄膜中引入各种性质的材料；且与湿法工艺相比，该制备方法的成本较低，可节约3-4％的成本，且所得薄膜的厚度可以做得较厚，并在薄膜较厚时其连续性、稳定性仍较好、完整度较高。该工艺简单、成本低，高效环保，可大规模化生产。
参见图2，本申请一实施方式中提供了一种电极片2000，该电极片2000包括集流体10，以及依次设置在集流体10上的电极活性材料层11和薄膜100。该实施方式中，薄膜100中的干颗粒仅包括功能材料颗粒和导电剂颗粒，但不包括电极活性材料颗粒。薄膜100作为功能层使用，平整度高、完整度高、连续性好，可赋予电极片良好的附加功能，改善电池能量密度、循环性能、安全性能等各方面性能。
如前文所述，功能材料颗粒可以包括活性离子补充剂、阻燃剂、膨胀减缓剂中的一种或多种。功能材料颗粒的质量占薄膜100总质量的70％-99％。该质量占比可以在保证薄膜具有稳定结构及期望的良好机械性能的情况下，使功能材料在该薄膜中的负载量较大且不会产生局部聚集现象，进而能最大程度地提升电池的性能。
此外，该实施方式中，薄膜100的空隙率可以小于30％。此时，薄膜100中各干颗粒排布较致密，薄膜100的力学强度较大，功能材料颗粒的分布也更均匀、致密，可以更好提升提高由该薄膜制成的电池的功能。
本申请实施方式中，集流体10包括但不仅限于金属箔材或合金箔材，所述金属箔材包括铜、钛、铝、铂、铱、钌、镍、钨、钽、金或银箔材，所述合金箔材包括不锈钢、或含铜、钛、铝、铂、铱、钌、镍、钨、钽、金和银中至少一种元素的合金。可选地，所述合金箔材以上述这些元素为主体成分。所述金属箔材可进一步包含掺杂元素，所述掺杂元素包括但不限于铂、钌、铁、钴、金、铜、锌、铝、镁、钯、铑、银、钨中的一种或多种。集流体10可被蚀刻处理或粗化处理，以形成次级结构，便于和电极活性材料层11形成有效接触。
本申请实施方式中，电极活性材料层11可以通过涂覆法或辊压法制备在集流体10上，薄膜100可以通过辊压、等静压等压制方式与电极活性材料层11相复合。电极活性材料层11中的电极活性材料为可通过脱嵌离子进行能量存储的材料，所述离子包括锂离子、钠离子、钾离子、镁离子和铝离子中的一种。具体地，所述电极活性材料包括但不限于金属、无机非金属(如碳材料)、氧化物、氮化物、碳化物、硼化物、硫化物、氯化物、或多种储能材料的复合材料。例如可以是锂、镁、钾、镁、硫、磷、硅、钴酸锂、磷酸铁锂、层状梯度化合物、Li 3PO 3、TiO 2、Li 4Ti 5O 12、SiO、SnO 2、NiS、CuS、FeS、MnS、Ag 2S、TiS 2等。电极活性材料层11可以是正极活性材料层，也可以是负极活性材料层。即，电极活性材料层11中的电极活性材料可以是正极活性材料，也可以是负极活性材料。对于锂离子电 池来说，其正极活性材料可以具体为磷酸铁锂、磷酸锰锂、磷酸锰铁锂、磷酸钒锂、磷酸钴锂、钴酸锂(LiCoO 2)、锰酸锂、镍酸锰锂、镍锰酸锂、镍钴锰(NCM)、镍钴铝(NCA)等中的至少一种。负极活性材料可以包括金属锂、石墨、硬碳、硅基材料(包括单质硅、硅合金、硅氧化物、硅碳复合材料)、锡基材料(包括单质锡、锡氧化物、锡基合金)、钛酸锂(Li 4Ti 5O 12)和TiO 2等中的至少一种。另外，电极活性材料层11还可以包括粘结剂、导电剂等。电极活性材料层11层中加入的粘结剂和导电剂没有特殊限制，采用本领域现有常规材料即可，例如，粘结剂可以是聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇、羧甲基纤维素(CMC)、丁苯橡胶(SBR)、聚烯烃、海藻酸钠等的一种或多种。例如，导电剂可以是导电炭黑、人造石墨KS6、碳纳米管、石墨烯等一种或多种。
电极片2000可以为正极片，也可以是负极片。若该电极片作为正极片，则电极活性材料层11具体为正极活性材料层。正极片的集流体10可以为铝箔。类似地，若该电极片作为负极片，则电极活性材料层11具体为负极活性材料层，负极片的集流体10可以为铜箔。
参见图3，本申请实施例还提供了一种电极片3000，该电极片3000包括集流体10和设置在集流体10上的薄膜100，该实施方式中，薄膜100中的干颗粒同时包括电极活性材料颗粒、上述功能材料颗粒和导电剂颗粒，薄膜100直接充当电极片3000的电极活性材料层，薄膜100的平整度高、完整度高、连续性好，可有效改善电池的能量密度、循环性能、安全性能等各方面性能。
该实施方式中，薄膜100的空隙率小于30％。此时，薄膜100中各干颗粒排布较致密，特别有助于提高粒径较大的电极活性材料颗粒在薄膜100中的分布密度，提高由该薄膜制成的电池的比容量。
其中，集流体10、电极活性材料颗粒的选材如前文所述，在此不再赘述。薄膜100可以通过涂覆法或通过冷压、热压等辊压方式设置在集流体10上。电极片3000可以为正极片或负极片。若该电极片作为正极片，则薄膜100中的电极活性材料颗粒具体为正极活性材料颗粒，包含正极活性材料颗粒的薄膜100可称为“正电极薄膜”。类似地，若该电极片作为负极片，则薄膜100中的电极活性材料颗粒具体为负极活性材料颗粒，包含负极活性材料颗粒的该薄膜可称为“负电极薄膜”。
电极片3000中，电极活性材料颗粒的质量占薄膜100总质量的70-99％。进一步地，功能材料的质量可以占薄膜100质量的0.05％-30％。该质量占比可在保证电极活性材料最大负载量的情况下，使该薄膜中的各干颗粒均能均匀分布，进而使由该薄膜制成的电池兼顾高比容量和功能材料带来的良好附加功能。
本申请实施例还提供了一种电化学电池，包括正电极、负电极、隔膜和电解液，其中，隔膜位于正电极和负电极之间，所述正电极和所述正电极中的至少一个包括本申请实施例上述的电极片。
该电化学电池可以是二次电池，具有高循环性能和高安全性。具体地，该二次电池可以是锂二次电池，钠二次电池，钾二次电池，镁二次电池，铝二次电池，锌二次电池等，二次电池具有高循环性能和高安全性。
如图4所示，本申请实施例还提供一种终端300，该终端300可以是手机、也可以是平板电脑、笔记本、便携机、智能穿戴产品等电子产品，终端300包括组装在终端外侧的 外壳200，以及位于外壳200内部的电路板和电池(图中未示出)，其中，电池为本申请实施例上述提供的电池，外壳200可包括组装在终端前侧的显示屏和组装在后侧的后盖，电池可固定在后盖内侧，为终端300供电。
下面分多个实施例对本申请实施例进行进一步的说明。
实施例1
本实施例提供一种具有镍钴锰NCM811正极活性材料、Li 2NiO 2补锂剂、碳纳米管(CNTs)导电剂、PVDF粘结剂的补锂电极薄膜以及由该薄膜组装成的软包电池的制备，具体包括以下步骤：
(1)正极补锂电极薄膜的制备：
原材料准备：取D50为12μm的正极活性材料NCM811，通过旋风分级技术除去NCM811中的超大颗粒和细小颗粒，使其粒度的体积分布及数量分布(D90-D10)/D50均调整为1.35；取D50粒径为5μm的补锂剂Li 2NiO 2颗粒与D50粒径为5μm的粘结剂PVDF颗粒，其中，Li 2NiO 2颗粒与PVDF颗粒的粒度的体积分布及数量分布均满足(D90-D10)/D50<1.5；
将上述NCM811颗粒、Li 2NiO 2颗粒、PVDF颗粒和CNTs按照88：5：5：2的比例称量，在氩气保护下，将称量好的NCM811颗粒和PVDF加入喷射研磨机的混料罐中，并开启超声发生器和磁场，使得混料罐内的超声波频率为40kHz，功率为40W，磁场强度为0.3T；进行普通机械飞刀混料10min后，打开喷射研磨机的高压气阀，以通入60PSI的高压气流对混料罐内的物料进行高压剪切(高压剪切时超声发生器和磁场仍开启)，使PVDF颗粒纤丝化并将所有颗粒粘附，高压剪切30min后，再加入称量好的Li 2NiO 2颗粒和CNTs，继续进行高压剪切2.5h，使PVDF重复纤丝化并使新加入的物料被粘附，最后将得到的混合物料通过与喷射研磨机的出料口连接的辊压设备辊压成厚度为150μm的薄膜；
(2)正极片的制备：将步骤(1)制得的薄膜覆盖在准备好的铝箔集流体上，在160℃的条件下热辊压该薄膜使其与铝箔结合，裁片后形成正极片；
(3)锂离子电池的制备：将上述正极片搭配硅氧石墨负极(扣电容量500mAh/g，首效83％)，使用1mol/L LiPF 6的EC+DEC混合液(EC、DEC的体积比为1:1)作电解液，PP/PE/PP三层隔膜作隔膜，制作成130mAh左右的软包电池，用于测试电池性能。
在本实施例1中，在制备补锂电极薄膜的混料过程有氩气保护，使化学性质活泼的补锂剂Li 2NiO 2不会变性失活，且通过在高压剪切时引入物理场(超声场、磁场)干预，使得各干颗粒在粘结剂纤丝化形成的纤丝化网络基体上不是随机分布，使补锂剂Li 2NiO 2可以发挥出更好的补锂效果。此外，本实施例在制备补锂电极薄膜时没有引入任何溶剂，避免了Li 2NiO 2制浆、匀浆过程的凝胶及涂布困难等问题，对环境友好，节约成本。
实施例2
本实施例提供一种具有硅氧混合石墨负极活性材料(贝特瑞公司S500-2A，扣电容量500mAh/g，首效83％)、稳定化金属锂粉SLMP(Stabilized lithium metal powder)作补锂剂SLMP补锂剂、PTFE粘结剂、乙炔黑导电剂的补锂电极薄膜，以及由该薄膜组装成的软包电池的制备，具体包括以下步骤：
(1)负极补锂电极薄膜的制备：
原材料准备：首先对硅氧混合石墨的负极活性材料颗粒(D50粒径为6μm)、SLMP颗粒(D50粒径为15μm)、PTFE颗粒(D50粒径为8μm)和乙炔黑颗粒(D50粒径为50nm)等原料通过静电分级技术控制每种材料粒径的集中度，确保每种材料粒度的体积分布及数量分布均满足(D90-D10)/D50<1.5；
将上述分级好的硅氧混合石墨的负极活性材料颗粒与SLMP颗粒、PTFE颗粒和乙炔黑颗粒按照85：5：8：2的比例称量，在氩气保护下，先将称量好的SLMP颗粒与PTFE颗粒加入喷射研磨机的混料罐中，开启超声发生器，使得混料罐内的超声波频率为40kHz，功率为40W；在进行普通机械飞刀混料10min后，打开喷射研磨机的高压气阀，以通入60PSI的高压气流对混料罐内的物料进行高压剪切2.5h，然后加入称量好的硅氧混合石墨的负极活性材料颗粒，继续进行高压剪切2.5h(高压剪切时超声发生器仍开启)，再加入乙炔黑颗粒继续高压剪切30min，得到纤丝化混合物料，最后将得到的混合物料通过与喷射研磨机的出料口连接的辊压设备辊压成厚度为100μm的薄膜；
(2)负极片的制备：将步骤(1)制得的薄膜覆盖在准备好的铜箔集流体上，在160℃的条件下热辊压该薄膜，使其与铜箔结合，裁片后形成负极片；
(3)锂离子电池的制备：首先制备NCM811正极片，具体先将镍钴锰NCM811正极活性材料、Super P导电剂和PVDF粘结剂按照质量比75:10:15搅拌均匀，得到正极活性浆料，将该正极活性浆料通过旋涂方式涂布在铝箔集流体上，在120℃下真空烘烤12h后，形成正极活性材料层；然后在160℃的条件下进行热辊压，使该正极活性材料层与铝箔结合，裁片后得到正极片；
将上述负极片搭配NCM811正极片，并采用1mol/L LiPF 6的EC+DEC混合液(EC、DEC的体积比为1:1)作电解液，PP/PE/PP三层隔膜作隔膜，制作成130mAh左右的软包电池，用于测试电池性能。
实施例3
本实施例提供一种以Li 6CoO 4为补锂剂、PTFE为粘结剂、科琴黑为导电剂的补锂薄膜，以及由该薄膜组装成的软包电池的制备，具体包括以下步骤：
(1)补锂薄膜的制备：
原材料准备：将Li 6CoO 4颗粒(D50粒径为15μm)、PTFE颗粒(D50粒径为10μm)和科琴黑颗粒(D50粒径为80nm)通过静电分级技术控制每种材料粒径的集中度，确保每种材料粒度的体积分布及数量分布均满足(D90-D10)/D50<1.5；
将上述分级好的Li 6CoO 4颗粒、PTFE颗粒和科琴黑颗粒按照7:2:1的比例称量，在氩气保护下，将称量好的Li 6CoO 4颗粒和PTFE颗粒加入喷射研磨机的混料罐中，并开启超声发生器和磁场，使混料罐内的超声波频率为20kHz，功率为40W，磁场强度0.3T；在进行普通机械飞刀混料10min后，打开喷射研磨机的高压气阀，以通入60PSI的高压气流对混料罐内的物料进行高压剪切40min后，再加入称量好的科琴黑颗粒，继续进行高压剪切20min，得到纤丝化混合物料，最后将得到的混合物料压制成厚度为30μm的薄膜，放入密封袋中保存待用；
(2)正极片的制备：将镍钴锰NCM811正极活性材料、Super P导电剂和PVDF粘结 剂按照质量比75:10:15搅拌均匀，得到正极活性浆料，将该正极活性浆料通过旋涂方式涂布在铝箔集流体上，在120℃下真空烘烤12h后，形成正极活性材料层；
将步骤(1)制得的薄膜覆盖在正极活性材料层的表面，在160℃的条件下进行热辊压，使该薄膜与正极活性材料层结合，裁片后得到正极片；
(3)锂离子电池的制备：将上述正极片搭配普通硅氧材料负电极，使用1mol/L LiPF 6的EC+DEC混合液(EC、DEC的体积比为1:1)作电解液，PP/PE/PP三层隔膜作隔膜，制作成130mAh左右的软包电池，用于测试电池性能。
图2可代表本发明实施例3的正极片的结构，图1a和图1b可代表实施例3中正极片上补锂薄膜100的结构示意图。图中，10为正极集流体，11为NCM811正极活性材料层，1为粘结剂PTFE，21为补锂剂Li 6CoO 4，22为科琴黑。
实施例4
本实施例提供一种具有镍钴锰NCM811正极活性材料、Mg(OH) 2阻燃剂、CNTs导电剂、PTFE粘结剂的阻燃电极薄膜以及由该薄膜组装成的软包电池的制备，具体包括以下步骤：
(1)正极阻燃电极薄膜的制备：
原材料准备：取D50为12μm的正极活性材料NCM811，通过射流分级技术除去NCM811中的超大颗粒和细小颗粒，使其粒度的体积分布及数量分布(D90-D10)/D50均调整为1.1；并将Mg(OH) 2颗粒(D50粒径为100nm)与PTFE颗粒(D50粒径为5μm)粒度的体积分布及数量分布也均满足(D90-D10)/D50<1.5；
将上述NCM811颗粒、Mg(OH) 2颗粒、PTFE颗粒和CNTs按照88：5：5：2的比例称量，在氩气保护下，将称量好的NCM811颗粒和PVDF加入喷射研磨机的混料罐中，通入氩气保护，并开启超声发生器和磁场，使得混料罐内的超声波频率为40kHz，功率为40W，磁场强度为0.3T；启动机械飞刀混料，10min后打开喷射研磨机的高压气阀，以通入60PSI的高压气流对混料罐内的物料进行高压剪切(高压剪切时超声发生器和磁场仍开启)，高压剪切30min后，再加入称量好的Mg(OH) 2颗粒和CNTs，继续进行高压剪切2.5h，最后将得到的混合物料通过与喷射研磨机的出料口连接的辊压设备辊压成厚度为150μm的薄膜；
(2)正极片的制备：将步骤(1)制得的薄膜覆盖在准备好的铝箔集流体上，在160℃的条件下热辊压该薄膜使其与铝箔结合，裁片后形成正极片；
(3)锂离子电池的制备：将上述正极片搭配硅氧石墨负极(扣电容量500mAh/g，首效83％)，并使用1mol/L LiPF 6的EC+DEC混合液(EC、DEC的体积比为1:1)作电解液，PP/PE/PP三层隔膜作隔膜，制作成130mAh左右的软包电池，用于测试电池性能。
为突出本申请实施例的有益效果，特提供以下对比例：
对比例1
对比例1提供了一种采用传统干法工艺制备含NCM811正极活性材料、Li 2NiO 2补锂剂、CNTs导电剂、PVDF粘结剂的补锂电极薄膜的方法，以及由该薄膜组装成的软包电池。对比例1与实施例1的区别在于：步骤(1)中，未对各原料进行粒径集中度控制；且是直接将称量好的NCM811颗粒、Li 2NiO 2颗粒、PVDF颗粒和CNTs加入到喷射研磨机的混料罐 中，通过普通机械飞刀混料10min后，打开喷射研磨机的高压气阀，选用60PSI的高压气流对混料罐内的物料进行高压剪切3h，然后将高压剪切后的混合物料通过与喷射研磨机的出料口连接的辊压设备辊压成厚度为150μm的薄膜。
对比例2
对比例2提供了一种采用传统干法工艺制备含硅氧混合石墨负极活性材料、SLMP补锂剂、PTFE粘结剂、乙炔黑导电剂的补锂电极薄膜的方法，以及由该薄膜组装成的软包电池。对比例2与实施例2的区别在于：步骤(1)中，未对各原料进行粒径集中度控制；且在剪切混料过程中未开启超声发生器和磁场。
对比例3
对比例3提供了一种采用传统湿法涂布工艺制备常规NCM811正极片的方法，还提供了由该常规正极片组装成的软包电池，具体包括以下步骤：
(1)将镍钴锰NCM811正极活性材料、Super P导电剂和PVDF粘结剂按照质量比75:10:15搅拌均匀，得到正极活性浆料，将该正极活性浆料通过旋涂方式涂布在铝箔集流体上，在120℃下真空烘烤12h后，形成正极活性材料层；然后在160℃的条件下进行热辊压，使该正极活性材料层与铝箔结合，裁片后得到正极片；
(2)将上述正极片搭配硅氧石墨负极(扣电容量500mAh/g，首效83％)，使用1mol/L LiPF 6的EC+DEC混合液(EC、DEC的体积比为1:1)作电解液，PP/PE/PP三层隔膜作隔膜，制作成130mAh左右的软包电池，用于测试电池性能。
为对本实施例1-4技术方案带来的有益效果进行有力支持，特提供以下测试：
锂电池性能测试：将各实施例的电池，按照0.5C/0.5C充放电制度进行充放电测试，负极片的测试电压范围在3.0-4.25V，正极片的测试电压范围3.0-4.4V，测试结果列于表1。
表1 不同锂离子电池的性能测试结果
Figure PCTCN2021104360-appb-000001
从表1的测试结果可以获知，本申请实施例1-3中的锂电池首次库伦效率和循环300 次后的容量保持率都分别高于对应的对比例1-3中的锂电池，这表明采用本申请实施例提供的方法制得的薄膜，可显著提高电池的循环性能。具体地，对比实施例3和对比例3可以获知，对比例3的正极片不包含补锂薄膜，不能预补充活性锂离子，在首次充电过程中形成的SEI(固体电解质膜)消耗活性锂离子后，就表现出较低的库伦效率，同时导致循环性能变差。图5为本申请实施例2(a)和对比例2(b)中的负极片在满电拆解后的照片对比，从图5及表1可以看出，对比例2设置在铝箔集流体上的补锂电极薄膜虽然添加了与实施例2相同量的SLMP作为补锂剂，但由于补锂剂在薄膜中分布不均，出现某些位置富集现象，导致负极片在循环300周后，其上补锂电极薄膜破裂，且补锂剂局部团聚，造成负极片出现局部析锂，从而导致电池的循环性能迅速衰减；而本申请实施例2中的负极片循环300周后，其负极片表面的膜完整，且没有锂枝晶生成。此外，对比表1中实施例1和对比例1可以获知，常规传统干法工艺制备的补锂电极薄膜(对比例1)中，补锂剂在薄膜中的随机分布导致其容易在某些位置出现富集，会造成补锂效果不均匀，出现一部分部位无法补锂而另一部分部位锂含量却过剩，进而引发析锂及锂枝晶生长等安全问题，大大影响电池的循环性能。而且补锂剂的随机分布还会导致电极片表面电流密度不均匀，局部阻抗过大等问题，从而引起电芯温升、加剧极化等。
另外，相较于对比例3，实施例4中在NCM811正极片中引入了Mg(OH) 2阻燃剂，并通过控制各原料的粒度集中度、引入物理场干预的分批高压剪切混料等实现了包括阻燃剂在内的各干颗粒在电极膜中的均匀分布。实施例4的电池和对比例3的电池的阻燃效果列于下表2。
表2 实施例4的电池和对比例3的电池的阻燃效果对比
Figure PCTCN2021104360-appb-000002
从表2可以获知，在不同SOC下做针刺实验，相比对比例3，本申请实施例4的电池燃烧率明显下降。这表明采用本申请实施例提供的方法制得的含阻燃剂的薄膜，可显著提高电池的阻燃性能。

Claims (21)

  1. 一种用于电池电极的薄膜，其特征在于，所述薄膜包括纤丝化粘结剂交织成的纤丝化网络基体及分布在所述纤丝化网络基体上的干颗粒，所述干颗粒包括功能材料颗粒和导电剂颗粒，部分所述干颗粒具有第一尺寸，其余所述干颗粒具有其他尺寸，所述其他尺寸小于所述第一尺寸的1/2；具有所述第一尺寸的干颗粒有序排布，具有所述其他尺寸的干颗粒填充在具有所述第一尺寸的干颗粒的颗粒间隙中，所述颗粒间隙小于所述第一尺寸。
  2. 如权利要求1所述的薄膜，其特征在于，所述第一尺寸在1μm-50μm的范围内。
  3. 如权利要求1所述的薄膜，其特征在于，所述其他尺寸包括一种或多种不同尺寸，所述其他尺寸在30nm-10μm的范围内。
  4. 如权利要求1所述的薄膜，其特征在于，所述功能材料颗粒包括活性离子补充剂、阻燃剂和膨胀减缓剂中的至少一种。
  5. 如权利要求1所述的薄膜，其特征在于，所述功能材料颗粒的D50粒径在30nm-50μm的范围内。
  6. 如权利要求1-5任一项所述的薄膜，其特征在于，每种不同材质的干颗粒的粒度分布均满足(D90粒径-D10粒径)/D50粒径<1.5。
  7. 如权利要求1-6任一项所述的薄膜，其特征在于，所述薄膜的厚度大于或等于30μm。
  8. 如权利要求7所述的薄膜，其特征在于，所述薄膜的厚度为30μm-300μm。
  9. 如权利要求1-8任一项所述的薄膜，其特征在于，所述功能材料颗粒的质量占所述薄膜质量的70％-99％。
  10. 如权利要求1-8任一项所述的薄膜，其特征在于，所述干颗粒还包括电极活性材料颗粒。
  11. 如权利要求10所述的薄膜，其特征在于，所述电极活性材料颗粒的D50粒径在1μm-50μm的范围内。
  12. 如权利要求11所述的薄膜，其特征在于，所述电极活性材料颗粒的粒度分布满足(D90粒径-D10粒径)/D50粒径<1.5。
  13. 如权利要求10所述的薄膜，其特征在于，所述电极活性材料的质量占所述薄膜质量的70-99％。
  14. 如权利要求10-13任一项所述的薄膜，其特征在于，所述功能材料的质量占所述薄膜质量的0.05％-30％。
  15. 一种用于电池电极的薄膜的制备方法，其特征在于，所述制备方法包括：
    提供干颗粒，所述干颗粒包括功能材料颗粒和导电剂颗粒，部分所述干颗粒具有第一尺寸，其余所述干颗粒具有其他尺寸，所述其他尺寸小于所述第一尺寸的1/2；在保护气体存在下，将可纤丝化的粘结剂颗粒和具有所述第一尺寸的干颗粒配制成第一混合物；
    在引入物理场干预的情况下，对所述第一混合物进行高压剪切，以使所述粘结剂颗粒纤丝化，以及使具有所述第一尺寸的干颗粒有序排布，然后加入具有所述其他尺寸的干颗粒，继续进行高压剪切，得到第二混合物；
    对所述第二混合物料进行压制，得到薄膜；其中，所述薄膜包括所述纤丝化粘结剂交 织成的纤丝化网络基体和分布在所述纤丝化网络基体上的所述干颗粒；具有所述其他尺寸的干颗粒填充在具有所述第一尺寸的干颗粒的颗粒间隙中，所述颗粒间隙小于所述第一尺寸。
  16. 如权利要求15所述的制备方法，其特征在于，所述物理场干预包括超声震荡和磁场干预中的至少一种。
  17. 一种电极片，其特征在于，所述电极片包括集流体和设置在所述集流体上的如权利要求1-9任一项所述的薄膜。
  18. 如权利要求17所述的电极片，其特征在于，所述电极片还包括电极活性材料层，所述电极活性材料层设置在所述集流体和所述薄膜之间。
  19. 一种电极片，其特征在于，所述电极片包括集流体和设置在所述集流体上的如权利要求10-14任一项所述的薄膜，所述薄膜充当所述电极片的电极活性材料层。
  20. 一种电化学电池，其特征在于，包括正电极、负电极、以及位于所述正电极和所述负电极之间的隔膜和电解液，其中，所述正电极和/或所述负电极包括如权利要求18和19任一项所述的电极片或包括如权利要求19所述的电极片。
  21. 一种终端，其特征在于，包括外壳，以及位于所述外壳内部的主板和电池，所述电池包括如权利要求20所述的电化学电池，所述电化学电池用于为所述终端供电。
PCT/CN2021/104360 2020-07-14 2021-07-02 用于电池电极的薄膜及其制备方法 WO2022012357A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010673302.0A CN113937284B (zh) 2020-07-14 2020-07-14 用于电池电极的薄膜及其制备方法
CN202010673302.0 2020-07-14

Publications (1)

Publication Number Publication Date
WO2022012357A1 true WO2022012357A1 (zh) 2022-01-20

Family

ID=79273882

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/104360 WO2022012357A1 (zh) 2020-07-14 2021-07-02 用于电池电极的薄膜及其制备方法

Country Status (2)

Country Link
CN (1) CN113937284B (zh)
WO (1) WO2022012357A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114583111A (zh) * 2022-02-17 2022-06-03 道克特斯(天津)新能源科技有限公司 一种连续出料的干电极的制备方法
CN114927636A (zh) * 2022-05-16 2022-08-19 中国工程物理研究院电子工程研究所 一种热电池柔性电极片及其制备方法和热电池

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115275519B (zh) * 2022-08-29 2023-10-13 中材锂膜有限公司 一种无机涂层电池隔膜及其制备方法和电池

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006172995A (ja) * 2004-12-17 2006-06-29 Nissan Motor Co Ltd 電極インクおよび電池
CN102629681A (zh) * 2012-04-12 2012-08-08 海博瑞恩电子科技无锡有限公司 一种基于粉体的电极成型方法
CN105633349A (zh) * 2014-11-06 2016-06-01 东莞新能源科技有限公司 锂离子电池负极片及其制备方法以及锂离子电池
TW201937786A (zh) * 2018-02-23 2019-09-16 國立研究開發法人產業技術總合研究所 積層體及其製造方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050266298A1 (en) * 2003-07-09 2005-12-01 Maxwell Technologies, Inc. Dry particle based electro-chemical device and methods of making same
JP6517007B2 (ja) * 2014-11-27 2019-05-22 株式会社日立製作所 リチウムイオン二次電池の製造方法
US10923295B2 (en) * 2016-03-01 2021-02-16 Maxwell Technologies, Inc. Compositions and methods for energy storage device electrodes
KR102268081B1 (ko) * 2017-04-28 2021-06-23 주식회사 엘지에너지솔루션 양극, 이를 포함하는 이차 전지, 및 상기 양극의 제조 방법

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006172995A (ja) * 2004-12-17 2006-06-29 Nissan Motor Co Ltd 電極インクおよび電池
CN102629681A (zh) * 2012-04-12 2012-08-08 海博瑞恩电子科技无锡有限公司 一种基于粉体的电极成型方法
CN105633349A (zh) * 2014-11-06 2016-06-01 东莞新能源科技有限公司 锂离子电池负极片及其制备方法以及锂离子电池
TW201937786A (zh) * 2018-02-23 2019-09-16 國立研究開發法人產業技術總合研究所 積層體及其製造方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114583111A (zh) * 2022-02-17 2022-06-03 道克特斯(天津)新能源科技有限公司 一种连续出料的干电极的制备方法
CN114927636A (zh) * 2022-05-16 2022-08-19 中国工程物理研究院电子工程研究所 一种热电池柔性电极片及其制备方法和热电池

Also Published As

Publication number Publication date
CN113937284B (zh) 2023-09-22
CN113937284A (zh) 2022-01-14

Similar Documents

Publication Publication Date Title
WO2022012357A1 (zh) 用于电池电极的薄膜及其制备方法
WO2022105259A1 (zh) 正极补锂剂及其制备方法和应用
WO2021108982A1 (zh) 人造石墨、二次电池、制备方法及装置
WO2021108983A1 (zh) 二次电池、装置、人造石墨及制备方法
WO2021057428A1 (zh) 二次电池及含有该二次电池的电池模块、电池包、装置
JP6327249B2 (ja) 電気化学素子電極用バインダー、電気化学素子電極用粒子複合体、電気化学素子電極、電気化学素子及び電気化学素子電極の製造方法
JP2004146253A (ja) 負極および電池、並びにそれらの製造方法
WO2021108981A1 (zh) 二次电池、装置、人造石墨及制备方法
WO2020078358A1 (zh) 负极极片及电池
CN109962221B (zh) 复合正极材料及正极片及正极片制备方法及锂离子电池
WO2018139449A1 (ja) 全固体電池用電極の製造方法および全固体電池の製造方法
WO2020135110A1 (zh) 负极活性材料、电池及装置
JPWO2014192652A6 (ja) 電気化学素子電極用バインダー、電気化学素子電極用粒子複合体、電気化学素子電極、電気化学素子及び電気化学素子電極の製造方法
WO2023151459A1 (zh) 补锂添加剂及其制备方法和应用
CN114665065A (zh) 一种正极极片及其制备方法和应用
CN102800865A (zh) 一种全固体离子传导动力的锂电池
CN115820047B (zh) 电极极片及其制备方法、电池及用电装置
CN115810718A (zh) 负极极片及包含其的二次电池
WO2022134540A1 (zh) 正极材料、电化学装置和电子装置
WO2022077374A1 (zh) 负极活性材料、其制备方法、二次电池及包含二次电池的电池模块、电池包和装置
CN115548260B (zh) 一种正极极片及其制备方法和锂离子电池
CN115036458B (zh) 一种锂离子电池
CN114497553B (zh) 正极添加剂及其制备方法、正极片和锂离子电池
CN116435506A (zh) 负极浆料及其制备方法、负极极片和二次电池
CN108199042A (zh) 一种球形磷酸铁锂混合型极片的制备方法

Legal Events

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

Ref document number: 21841990

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21841990

Country of ref document: EP

Kind code of ref document: A1