WO2023184227A1 - Dispositif électrochimique et dispositif électronique utilisant un revêtement de sécurité - Google Patents

Dispositif électrochimique et dispositif électronique utilisant un revêtement de sécurité Download PDF

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Publication number
WO2023184227A1
WO2023184227A1 PCT/CN2022/084041 CN2022084041W WO2023184227A1 WO 2023184227 A1 WO2023184227 A1 WO 2023184227A1 CN 2022084041 W CN2022084041 W CN 2022084041W WO 2023184227 A1 WO2023184227 A1 WO 2023184227A1
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Prior art keywords
protective layer
active material
positive electrode
electrochemical device
lithium
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PCT/CN2022/084041
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English (en)
Chinese (zh)
Inventor
刘晓欠
张青文
韩冬冬
陈梅锋
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宁德新能源科技有限公司
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Priority to CN202280010595.1A priority Critical patent/CN117015866A/zh
Priority to PCT/CN2022/084041 priority patent/WO2023184227A1/fr
Publication of WO2023184227A1 publication Critical patent/WO2023184227A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

  • This application relates to the field of energy storage, and specifically to an electrochemical device and an electronic device using a safety coating.
  • the present application relates to an electrochemical device, which includes: a positive electrode including a positive current collector, a protective layer and a positive active material layer.
  • the protective layer is disposed between the positive current collector and the positive active material layer, wherein X g of the protective layer is dispersed in 50X g of water at 25°C to 35°C, and a dispersion disk with a diameter of 50mm to 80mm is used.
  • the stirrer is stirred at a stirring speed of 1200r/min. After filtering and drying using a 100-mesh filter, the weight of the protective layer on the filter is W g, where W/X ⁇ 10%.
  • the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer can be suppressed during impact or puncture by external forces, thereby improving electrochemical performance.
  • the safety performance of the device on the other hand, the overall tendency of the protective layer that satisfies W/X ⁇ 10% is hydrophilic rather than lipophilic, which can avoid the large-area loss of adhesive force of the protective layer due to swelling in the oily electrolyte. This maintains the bonding effect and inhibits the growth of internal resistance in high-temperature storage.
  • the infrared spectrum of the protective layer has characteristic peaks in the range of 1400 cm -1 to 1700 cm -1 and/or 2100 cm -1 to 2300 cm -1 .
  • the protective layer contains polar functional groups such as carbonyl and/or cyano groups, which can enhance its adhesion to the positive electrode current collector, thereby improving the high-temperature storage internal resistance growth rate of the electrochemical device.
  • the resistance of the positive electrode is R ⁇ , 1.5 ⁇ R ⁇ 5.
  • controlling R to be greater than or equal to 1.5 ⁇ can significantly improve the central nail penetration rate of the electrochemical device; on the other hand, controlling R to be less than or equal to 5 ⁇ can further improve the high-temperature storage process of the electrochemical device.
  • the internal resistance increases.
  • the thickness of the protective layer is T ⁇ m, T ⁇ 0.5.
  • the thickness of the protective layer T ⁇ 0.5 ⁇ m can effectively suppress the short circuit between the positive electrode current collector and the negative electrode active material layer during impact or puncture by external forces, and improve the safety of the electrochemical device.
  • the protective layer includes a first active material, a first binder, and a first conductive agent.
  • the protective layer further includes a leveling agent.
  • the mass percentage of the first conductive agent is 0.5% to 15%
  • the mass percentage of the first active material is 60% to 98.5%
  • the first The mass percentage of binder is 1% to 20%.
  • the leveling agent includes silicone compounds, silicone derivatives, oxygen-containing olefin polymers, acrylate polymers, acrylate polymers, alcohol compounds, ethers At least one of compounds or fluorocarbons.
  • the mass percentage of the leveling agent is 0.01% to 5% based on the mass of the protective layer.
  • the first binder meets at least one of the following characteristics: (a) includes a polymer formed from at least one of acrylic acid, acrylamide, acrylate, acrylonitrile or acrylate; ( b) Contains at least one of carboxymethyl cellulose salt or nitrile rubber.
  • the first adhesive is an aqueous adhesive.
  • the first binder has a weight average molecular weight of 200,000 to 2,000,000.
  • the first active material includes at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium manganate, or lithium nickel cobalt manganate.
  • the first conductive agent includes at least one of graphene, graphite fiber, carbon nanotube, Ketjen black or conductive carbon.
  • the positive active material layer includes a second active material, a second binder, and a second conductive agent.
  • the mass percentage of the second active material is 91.5% to 99%, and the mass percentage of the second binder is 0.5% to 5%, so The mass percentage of the second conductive agent is 0.5% to 3.5%.
  • the second active material includes at least one of lithium cobalt oxide, lithium manganate, or lithium nickel cobalt manganate.
  • the second binder includes at least one of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene-hexafluoropropylene, sodium polyacrylate, nitrile rubber, or polyacrylate.
  • the second conductive agent includes at least one of graphene, graphite fiber, carbon nanotube, Ketjen black or conductive carbon.
  • the present application relates to an electronic device comprising an electrochemical device according to any of the preceding embodiments.
  • a list of items connected by the term "at least one of,” “at least one of,” “at least one of,” or other similar terms may mean that the listed items any combination of.
  • the phrase “at least one of A and B” means only A; only B; or A and B.
  • the phrase “at least one of A, B, and C” means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C.
  • Project A can contain a single component or multiple components.
  • Project B can contain a single component or multiple components.
  • Project C may contain a single component or multiple components.
  • the present application relates to an electrochemical device, which includes a positive electrode including a positive current collector, a protective layer and a positive active material layer.
  • the protective layer is disposed between the cathode current collector and the cathode active material layer.
  • the protective layer satisfies: W/X ⁇ 10%, where The mass of the protective layer remaining on the filter (unit: g) after stirring with a mixer of 50mm to 80mm at a stirring speed of 1200r/min, filtering and drying through a 100-mesh screen.
  • the protective layer can inhibit the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer during impact or puncture by external forces, improving the safety performance of the electrochemical device; at the same time, by meeting the protection requirement of W/X ⁇ 10%
  • the layer can control the high-temperature storage internal resistance growth rate of the lithium-ion battery below 40%, where, in some embodiments, high-temperature storage refers to storage of the electrochemical device at 85° C. for 6 hours. This is because the overall protective layer tends to be hydrophilic rather than lipophilic, which can avoid large-area loss of adhesive force due to swelling of the protective layer in the oily electrolyte, thereby maintaining the adhesive effect and inhibiting the growth of internal resistance in high-temperature storage. .
  • the value of X is 20-80 g.
  • the infrared spectrum of the protective layer has characteristic peaks in the range of 1400 cm -1 to 1700 cm -1 - and/or 2100 cm -1 to 2300 cm -1 .
  • the protective layer contains polar functional groups such as carbonyl and/or cyano groups, which can enhance its adhesion to the positive electrode current collector, thereby improving the high-temperature storage internal resistance growth rate of the electrochemical device.
  • the protective layer includes a first active material, a first binder, and a first conductive agent.
  • the mass percentage of the first active material is 60% to 98.5%. In some embodiments, based on the mass of the protective layer, the mass percentage of the first active material is 65% to 96%. In some embodiments, based on the mass of the protective layer, the mass percentage of the first active material is 70% to 95%. In some embodiments, based on the mass of the protective layer, the mass percentage of the first active material is 75% to 95%.
  • the mass percentage of the first active material is 60%, 65%, 70%, 75%, 77%, 78%, 80%, 82%, 84%, 85%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 98.5% or the range between any two of the aforementioned values.
  • the first active material includes at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium manganate, or lithium nickel cobalt manganate.
  • the mass percentage of the first binder is 1% to 20% based on the mass of the protective layer. In some embodiments, the mass percentage of the first binder is 1%, 2%, 3%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% , 8.5%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or the range between any two of the aforementioned values.
  • the first binder is an aqueous binder.
  • the first binder satisfies at least one of the following characteristics: (a) includes a polymer formed from at least one of acrylic acid, acrylamide, acrylate, acrylonitrile or acrylate; (b) Contains at least one of carboxymethyl cellulose salt or nitrile rubber.
  • the first adhesive is a polymer composed of acrylate. In this case, the first adhesive has good hydrophilic and oleophobic properties, so that the protective layer has excellent adhesion and stability. This can then improve the nail penetration safety performance and high-temperature storage internal resistance growth rate of the electrochemical device.
  • the first binder has a weight average molecular weight of 200,000 to 2,000,000. In some embodiments, the first binder has a weight average molecular weight of 200,000 to 1.8 million. In some embodiments, the first binder has a weight average molecular weight of 200,000 to 1.6 million.
  • the weight average molecular weight of the first binder is 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 75
  • the weight average molecular weight of the first binder is within the above range, which can achieve both film-forming property and adhesive force, and improve the uniformity and stability of the protective layer.
  • the mass percentage of the first conductive agent is 0.5% to 15%. In some embodiments, based on the mass of the protective layer, the mass percentage of the first conductive agent is 0.5% to 10%. In some embodiments, the mass percentage of the first conductive agent is 0.5% to 8% based on the mass of the protective layer. In some embodiments, the mass percentage of the first conductive agent is 1% to 7% based on the mass of the protective layer.
  • the mass percentage of the first conductive agent is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.2%, 2.3%, 2.4%, 2.5%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4% , 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or the range between any two of the aforementioned values.
  • the first conductive agent includes at least one of graphene, graphite fiber, carbon nanotube, Ketjen black or conductive carbon.
  • the protective layer further includes a leveling agent.
  • the leveling agent includes silicone compounds, silicone derivatives, oxygen-containing olefin polymers, acrylate polymers, acrylate polymers, alcohol compounds, ether compounds or fluorine compounds. At least one of the carbon compounds.
  • the mass percentage of the leveling agent is 0.01% to 5% based on the mass of the protective layer. In some embodiments, the mass percentage of the leveling agent is 0.03% to 4% based on the mass of the protective layer. In some embodiments, the mass percentage of the leveling agent is 0.05% to 4% based on the mass of the protective layer.
  • the mass percentage of the leveling agent is 0.08% to 4% based on the mass of the protective layer. In some embodiments, based on the quality of the protective layer, the mass percentage of the leveling agent is 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or The range between any two values mentioned above.
  • the addition of the above-mentioned leveling agent is conducive to forming a uniform and smooth protective layer, increasing the contact area between the protective layer and the current collector and the positive active material layer, improving the conductivity, and improving the internal resistance growth during high-temperature storage.
  • the resistance of the positive electrode is R ⁇ .
  • R is from 1 to 10.
  • R is from 1.5 to 9.
  • R is from 1.5 to 5.
  • R is 1, 1.5, 2, 2.1, 2.3, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, or The range between any two values mentioned above. . When R is within this range, the electrochemical device can maintain a high nail penetration rate while having a low high-temperature storage internal resistance growth rate.
  • the thickness of the protective layer is T ⁇ m, T ⁇ 0.5. In some embodiments, T is 0.5 to 10. In some embodiments, T ranges from 1 to 9. In some embodiments, T is 1.5 to 8.5. In some embodiments, T is from 2 to 8. In some embodiments, T is 2.5 to 7.5. In some embodiments, T is 1.5 to 5. In some embodiments, T is 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, or any of the foregoing The range between two values.
  • the thickness of the protective layer is within the above range, which can effectively suppress the short circuit between the positive electrode current collector and the negative electrode active material layer during impact or puncture by external force, and improve the safety of the electrochemical device.
  • the positive active material layer includes a second active material, a second binder, and a second conductive agent.
  • the mass percentage of the second active material is 91.5% to 99%
  • the mass percentage of the second binder is 0.5% to 5%
  • the mass percentage of the second conductive agent is 0.5% to 3.5%.
  • the second active material includes at least one of lithium cobalt oxide, lithium manganate, or lithium nickel cobalt manganate.
  • the second binder includes at least one of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene-hexafluoropropylene, sodium polyacrylate, nitrile rubber, or polyacrylate.
  • the second conductive agent includes at least one of graphene, graphite fiber, carbon nanotube, Ketjen black or conductive carbon.
  • this application can suppress the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer during impact or puncture by external forces, and improve the performance of the electrochemical device.
  • Safety performance at the same time, this application recognizes that by controlling the material of the protective layer so that W/X ⁇ 10% (where After the protective layer is dispersed in water under the aforementioned conditions, use a stirrer with a dispersion disk diameter of 50mm to 80mm to stir at a stirring speed of 1200r/min. Use a 100-mesh filter to filter and dry the remaining protective layer on the filter.
  • the protective layer when the protective layer tends to be hydrophilic rather than lipophilic, it can avoid large-area loss of adhesive force due to swelling of the protective layer in the oily electrolyte, thereby maintaining the bonding effect and inhibiting high-temperature storage Growth of internal resistance. For example, it can control the growth rate of high-temperature storage internal resistance below 40%.
  • the electrochemical device of the present application also includes a separator, an electrolyte and a negative electrode.
  • electrochemical devices of the present application include primary or secondary batteries.
  • the electrochemical device is a lithium secondary battery.
  • lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, sodium ion batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
  • the preparation method of the electrochemical device of the present application is described in detail below by taking a lithium-ion battery as an example.
  • Preparation of the negative electrode Disperse the negative electrode active material (at least one of carbon material, silicon material or lithium titanate), negative electrode binder, and optional conductive material in the solvent system according to a certain mass ratio, and stir thoroughly to mix evenly. Then, it is coated on the negative electrode current collector, dried and cold pressed to obtain the negative electrode.
  • the negative electrode active material at least one of carbon material, silicon material or lithium titanate
  • the negative electrode binder at least one of carbon material, silicon material or lithium titanate
  • optional conductive material in the solvent system according to a certain mass ratio
  • Preparation of the positive electrode (1) Add the first active material, the first conductive agent, the first binder, and the optional leveling agent to the solvent and mix evenly to obtain a protective layer slurry (hereinafter referred to as "first slurry”); (2) apply the first slurry in step (1) to the target area of the positive electrode current collector; (3) apply the positive electrode containing the first slurry obtained in step (2) The current collector is dried to remove the solvent, and a positive electrode current collector coated with a protective layer is obtained; (4) The second active material, the second conductive agent, and the second binder are dispersed in the solvent system according to a certain mass ratio and stirred thoroughly Mix evenly to obtain a slurry of positive active material (hereinafter referred to as "second slurry”); (5) Coat the second slurry on the positive electrode current collector coated with a protective layer obtained in step (3). Target area; (6) Dry the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • the types of the first active material, the first conductive agent, the first binder, the leveling agent, the second active material, the second conductive agent and the second binder are as described above.
  • examples of the solvent include, but are not limited to, N-methylpyrrolidone, acetone, or water. In some embodiments, the amount of solvent can be adjusted appropriately.
  • the current collector has a thickness in the range of 3 microns to 20 microns, although the disclosure is not limited thereto.
  • the current collector is not particularly limited as long as the current collector is conductive without causing adverse chemical changes in the manufactured battery.
  • Examples of the current collector include copper, stainless steel, aluminum, nickel, titanium, or alloys (eg, homo-nickel alloys), but the disclosure is not limited thereto.
  • fine irregularities eg, surface roughness
  • the current collector can be used in various forms, and examples thereof include films, sheets, foils, meshes, porous structures, foams, or similar materials, but the disclosure is not limited thereto.
  • Isolation film In some embodiments, a polyethylene (abbreviated as PE) porous polymer film is used as the isolation film.
  • the material of the isolation membrane may include fiberglass, polyester, polyethylene, polypropylene, polytetrafluoroethylene or combinations thereof.
  • the pores in the isolation film have a diameter in the range of 0.01 micron to 1 micron, and the thickness of the isolation film ranges from 5 microns to 500 microns.
  • the electrolyte includes an organic solvent, a lithium salt, and additives.
  • the organic solvent includes ethylene carbonate (abbreviated as EC), propylene carbonate (abbreviated as PC), diethyl carbonate (abbreviated as DEC), ethyl methyl carbonate (abbreviated as EMC), dimethyl carbonate At least one of ester (abbreviated as DMC), propylene carbonate, ethyl acetate, ethyl propionate or propyl propionate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • DMC dimethyl carbonate
  • ester abbreviated as DMC
  • propylene carbonate ethyl acetate, ethyl propionate or propyl propionate.
  • the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt.
  • lithium salts include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bis(fluorosulfonyl)borate LiB(C 2 O 4 ) 2 (LiBOB) or lithium difluoroxalatoborate At least one of LiBF 2 (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiN CF 3 SO 2 ) 2
  • LiTFSI lithium bis(fluorosulfonyl)imide Li(N
  • the content of the lithium salt is 8%-30% based on the quality of the electrolyte. In some embodiments, the lithium salt content is 8%, 9%, 10%, 11%, 12%, 15%, 18%, 20%, 23%, 25%, 28%, 30% or any of the foregoing. The range between two values.
  • the additives include fluoroethylene carbonate (FEC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), 1,3-propane sultone (PS), vinyl sulfate ( DTD), at least one of succinonitrile (SN), adiponitrile (ADN), 1,3,6-hexanetrinitrile (HTCN), and succinic anhydride (SA).
  • FEC fluoroethylene carbonate
  • VC vinylene carbonate
  • VEC vinyl ethylene carbonate
  • PS 1,3-propane sultone
  • DTD vinyl sulfate
  • SN succinonitrile
  • ADN adiponitrile
  • HTCN 1,3,6-hexanetrinitrile
  • SA succinic anhydride
  • the bare cell obtained by winding is placed in an outer package, electrolyte is injected and packaged, and a lithium-ion battery is obtained through processes such as formation, degassing, and trimming.
  • the present application provides an electronic device comprising the electrochemical device according to the foregoing content.
  • the electronic devices include, but are not limited to: notebook computers, pen-input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, head-mounted Stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles , bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries or lithium/sodium ion capacitors, etc.
  • Step (1) Add the first active material, the first conductive agent, the first binder, and the optional leveling agent to water and mix evenly to obtain a protective layer slurry (hereinafter referred to as "first slurry”). material”);
  • Step (2) Coating the first slurry in step (1) on the target area of the positive electrode current collector;
  • Step (3) drying the positive electrode current collector containing the first slurry obtained in step (2) to remove the solvent to obtain a positive electrode current collector coated with a protective layer;
  • Step (4) Combine the second active material (lithium cobalt oxide, 97.3% by mass), the second conductive agent (0.6% by mass of conductive carbon (trade name: Super P)) and 0.5% by mass of carbon nanotubes (abbreviated as CNT) and the second binder (polyvinylidene fluoride (abbreviated as PVDF) with a mass percentage of 1.6%) are dispersed in the N-methylpyrrolidone solvent system and stirred thoroughly to obtain a slurry of the positive electrode active material (hereinafter referred to as as "second slurry");
  • Step (5) applying the second slurry to the target area of the positive electrode current collector coated with the protective layer obtained in step (3);
  • Step (6) Drying the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • Table 1 below specifically shows the differences in protective layers in the positive electrodes in Examples 1 to 33 and Comparative Examples 1 to 2.
  • the positive electrode of the electrochemical device was fabricated as described above.
  • Negative electrode Combine the active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (abbreviated as SBR), and thickener sodium carboxymethylcellulose (abbreviated as CMC) in a mass ratio of 95:2:2:1 After thoroughly stirring and mixing in water, it is coated on Cu foil, dried, and cold pressed to obtain a negative electrode.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethylcellulose
  • Electrolyte In an argon atmosphere glove box with a water content of ⁇ 10ppm, mix ethylene carbonate (abbreviated as EC), diethyl carbonate (abbreviated as DEC), and propylene carbonate (abbreviated as PC) according to 2:6: Mix evenly at a mass ratio of 2, then dissolve the fully dried lithium salt LiPF 6 in the above solvent, and then add 1,3-propane sultone, fluoroethylene carbonate and adiponitrile.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • the content of LiPF 6 is 12.5%
  • the content of 1,3-propane sultone is 1.5%
  • the content of fluoroethylene carbonate is 3%
  • the content of adiponitrile is 2%
  • the rest are EC and DEC and PC, where the content of each substance is based on the total weight of the electrolyte.
  • Isolation film Polyethylene (abbreviated as PE) porous polymer film is used as the isolation film.
  • Table 2 below shows various properties of Examples 1 to 33 and Comparative Examples 1 to 2.
  • Example 15 From the comparison between Example 15 and Example 16, it can be found that when the W/X of the protective layer becomes smaller (that is, when the water solubility of the binder is better), it can improve the central nail penetration rate of the electrochemical device. At the same time, the effect of improving the growth rate of high-temperature storage internal resistance is more obvious.
  • Example 1 to 33 it can be found that the center nail penetration rate (throughput/total test amount) of Examples 1 to 32 that satisfies R ⁇ 1.5 is significantly better than that of Example 33. It can be seen that by controlling the full-charge positive electrode resistance R ⁇ 1.5 by adding a protective layer, the center nail penetration rate of lithium-ion batteries can be significantly improved. At the same time, the high-temperature storage internal resistance growth rate of Examples 1 to 31 satisfying R ⁇ 5 is also significantly better than that of Example 32. It can be seen that by controlling 1.5 ⁇ R ⁇ 5, a lithium-ion battery with both a higher nail penetration rate and a lower high-temperature storage internal resistance growth rate can be obtained.
  • the thickness of the protective layer T ⁇ 0.5 ⁇ m can effectively improve the center nail penetration rate of the lithium-ion battery, and at the same time, the improvement effect of high-temperature storage internal resistance growth rate is also more obvious.
  • the conductive agent used in the protective layer in Examples 1 to 33 of the present application includes at least one of carbon nanotubes (abbreviated as CNT), conductive carbon (abbreviated as SP), Ketjen black, graphene (abbreviated as GN), and graphite fiber. kind.
  • CNT carbon nanotubes
  • SP conductive carbon
  • GN graphene
  • GN graphite fiber
  • the binder used for the protective layer in Examples 1 to 33 of the present application may include acrylonitrile, acrylate, acrylamide polymer, polyacrylic acid, sodium carboxymethyl cellulose, sodium polyacrylate, polyacrylate, polyacrylonitrile or At least one type of nitrile rubber.
  • the adhesive used in the protective layer of the present application is not limited to the types listed in the specific embodiments. It may include a polymer formed from at least one of acrylic acid, acrylamide, acrylate, acrylonitrile or acrylic ester, or Contains its analogues.
  • Examples 17 to 20 show that when the binder includes at least one selected from the group consisting of sodium polyacrylate, polyacrylate, polyacrylonitrile, and nitrile rubber, it is possible to improve the center penetration of the electrochemical device. At the same time, it improves the growth rate of high-temperature storage internal resistance.
  • the leveling agent used for the protective layer in Examples 1 to 33 of the present application may include at least one of oxygen-containing olefin polymers, ethanol, silicone compounds, acrylate polymers, acrylate polymers, diethyl ether or ethanol.
  • the leveling agent used in the protective layer of the present application is not limited to the types listed in the specific embodiments, and may include analogs thereof.
  • the electrochemical device of the present application can have improved high-temperature storage internal resistance growth rate and a higher center penetration rate.
  • references throughout this specification to “some embodiments,” “partial embodiments,” “one embodiment,” “another example,” “example,” “specific example,” or “partial example” mean the following: At least one embodiment or example in this application includes a specific feature, structure, material or characteristic described in the embodiment or example. Accordingly, phrases such as “in some embodiments,” “in an embodiment,” “in one embodiment,” “in another example,” “in one example,” etc. may appear in various places throughout this specification. "in”, “in a particular example” or “for example” do not necessarily refer to the same embodiment or example in this application. Furthermore, the specific features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

La présente demande concerne un dispositif électrochimique. Ce dispositif électrochimique comprend : une électrode positive, l'électrode positive comportant un collecteur de courant d'électrode positive, une couche de protection et une couche de matériau actif d'électrode positive. La couche de protection est disposée entre le collecteur de courant d'électrode positive et la couche de matériau actif d'électrode positive, X g de la couche de protection étant dispersés dans 50X g d'eau à température de 25 °C à 35 °C, le tout étant agité à une vitesse d'agitation de 1200 r/min à l'aide d'un agitateur présentant un diamètre de disque de dispersion de 50 à 80 mm, et étant filtré à l'aide d'un filtre écran pourvu d'un tamis de 100 mesh, puis séché, après quoi le poids de la couche de protection sur le filtre écran est alors W g, W/X étant inférieur ou égal à 10 %.
PCT/CN2022/084041 2022-03-30 2022-03-30 Dispositif électrochimique et dispositif électronique utilisant un revêtement de sécurité WO2023184227A1 (fr)

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CN202280010595.1A CN117015866A (zh) 2022-03-30 2022-03-30 一种使用安全涂层的电化学装置及电子装置
PCT/CN2022/084041 WO2023184227A1 (fr) 2022-03-30 2022-03-30 Dispositif électrochimique et dispositif électronique utilisant un revêtement de sécurité

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015015156A (ja) * 2013-07-05 2015-01-22 株式会社Ｇｓユアサ 電池の製造方法
CN112216822A (zh) * 2019-07-10 2021-01-12 宁德时代新能源科技股份有限公司 一种锂离子二次电池及其制备方法
CN113474913A (zh) * 2020-12-31 2021-10-01 东莞新能源科技有限公司 电化学装置、电子装置及电化学装置的制备方法
CN113498558A (zh) * 2020-12-31 2021-10-12 东莞新能源科技有限公司 一种电化学装置和电子装置
CN113939927A (zh) * 2020-12-31 2022-01-14 东莞新能源科技有限公司 一种电化学装置、电子装置及电化学装置制备方法
CN114175306A (zh) * 2021-03-30 2022-03-11 宁德新能源科技有限公司 电化学装置和电子装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015015156A (ja) * 2013-07-05 2015-01-22 株式会社Ｇｓユアサ 電池の製造方法
CN112216822A (zh) * 2019-07-10 2021-01-12 宁德时代新能源科技股份有限公司 一种锂离子二次电池及其制备方法
CN113474913A (zh) * 2020-12-31 2021-10-01 东莞新能源科技有限公司 电化学装置、电子装置及电化学装置的制备方法
CN113498558A (zh) * 2020-12-31 2021-10-12 东莞新能源科技有限公司 一种电化学装置和电子装置
CN113939927A (zh) * 2020-12-31 2022-01-14 东莞新能源科技有限公司 一种电化学装置、电子装置及电化学装置制备方法
CN114175306A (zh) * 2021-03-30 2022-03-11 宁德新能源科技有限公司 电化学装置和电子装置

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