WO2023184234A1 - Dispositif électrochimique et dispositif électronique - Google Patents

Dispositif électrochimique et dispositif électronique Download PDF

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Publication number
WO2023184234A1
WO2023184234A1 PCT/CN2022/084053 CN2022084053W WO2023184234A1 WO 2023184234 A1 WO2023184234 A1 WO 2023184234A1 CN 2022084053 W CN2022084053 W CN 2022084053W WO 2023184234 A1 WO2023184234 A1 WO 2023184234A1
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WIPO (PCT)
Prior art keywords
protective layer
positive electrode
electrochemical device
inorganic particles
lithium
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PCT/CN2022/084053
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English (en)
Chinese (zh)
Inventor
韩冬冬
刘晓欠
张青文
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宁德新能源科技有限公司
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to CN202280021200.8A priority Critical patent/CN117043977A/zh
Priority to PCT/CN2022/084053 priority patent/WO2023184234A1/fr
Publication of WO2023184234A1 publication Critical patent/WO2023184234A1/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
    • 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

Definitions

  • This application relates to the field of energy storage, and specifically to an electrochemical device and an electronic device.
  • the present application provides an electrochemical device, which includes: a positive electrode, the positive electrode includes a positive electrode current collector, a protective layer and a positive electrode active material layer.
  • the protective layer is disposed between the cathode current collector and the cathode active material layer.
  • the protective layer contains inorganic particles, which are tested using a laser particle size analyzer.
  • the inorganic particles satisfy Dv5 ⁇ 0.5 ⁇ m, where Dv5 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 5%.
  • the protective layer will have internal stress as the pole piece bends, especially at the corners of the rolled structure, because the corners It has bending stress. When it is squeezed from the side, the stress will be more concentrated.
  • the small-sized inorganic particles in the protective layer can promote the slip between inorganic particles, reduce the internal stress, inhibit the shedding of the protective layer, thereby reducing the concentration of the positive electrode. The risk of short circuit between the fluid and the negative active material layer, thereby improving the safety performance of the electrochemical device.
  • the thickness of the protective layer is H1 ⁇ m, which satisfies Dv50/H1 ⁇ 0.4, where Dv50 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 50% when tested using a laser particle size analyzer. diameter in ⁇ m.
  • Dv90/H1 ⁇ 1 is satisfied, where Dv90 represents the particle diameter corresponding to when the cumulative volume distribution number of the inorganic particles reaches 90%, in ⁇ m. At this time, the number of particles with excessively large diameters in the inorganic particles is small.
  • the stress inside the protective layer can be further reduced, inhibiting the shedding of the protective layer, thereby reducing the positive electrode current collector and the negative electrode. The risk of short circuits between active material layers further improves the safety performance of electrochemical devices.
  • 0.5 ⁇ H1 ⁇ 10 is satisfied.
  • the inorganic particles include first particles and second particles.
  • the first particles include an A element including at least one of Al, Mg, Si, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, or Sn.
  • the second particles include Li element and M element, and the M element includes at least one of Mn or Fe.
  • the first particles comprise aluminum oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, boehmite, hydroxide At least one of aluminum, magnesium hydroxide, calcium hydroxide, calcium silicate, diaspore, barium sulfate, calcium sulfate or calcium silicate.
  • the second particles comprise at least one of lithium iron phosphate, lithium iron manganese phosphate, or lithium manganate.
  • the protective layer includes an adhesive.
  • the binder is an aqueous binder.
  • the water-based binder can improve the bonding force between the protective layer and the cathode current collector and cathode active material layer, and improve the internal resistance growth rate of the electrochemical device during high-temperature storage.
  • the binder includes a polymer formed from at least one of acrylic acid, an acrylate, acrylonitrile, acrylamide, or an acrylate.
  • the binder includes at least one of carboxymethyl cellulose salts or nitrile rubber.
  • the binder has a weight average molecular weight of 180,000 to 2.2 million.
  • the protective layer further includes a conductive agent.
  • the conductive agent includes at least one of sheet-like, mesh-like, linear or granular conductive agents.
  • the mass percentage of the conductive agent is 0.3% to 20% based on the mass of the protective layer.
  • the protective layer further includes a leveling agent. In some embodiments, based on the mass of the protective layer, the mass percentage of the leveling agent is greater than 0% and less than or equal to 6%.
  • 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 resistance of the positive electrode is R ⁇ , satisfying 1 ⁇ R ⁇ 10.
  • the present application provides an electronic device including the 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 provides 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 contains inorganic particles, which are tested using a laser particle size analyzer.
  • the inorganic particles satisfy Dv5 ⁇ 0.5 ⁇ m, where Dv5 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 5%.
  • the risk of a short circuit between the positive current collector and the negative active material layer can be reduced when the electrochemical device is impacted or squeezed by external forces, thereby improving Safety performance of electrochemical devices.
  • the inorganic particles in the protective layer can more uniformly and comprehensively cover the cathode current collector, especially at the corners of the winding structure, which can have sufficient small particle size inorganic
  • the particles are filled to better cover the positive electrode current collector at the corners; and when the electrochemical device is squeezed from the side, the protective layer has internal stress as the electrode piece bends, especially at the corners of the rolled structure , due to the bending stress at the corner itself, the stress will be more concentrated when squeezed by the side.
  • the small-sized inorganic particles in the protective layer can promote the slip between inorganic particles, reduce the internal stress, and inhibit the shedding of the protective layer. This reduces the risk of short circuit between the positive electrode current collector and the negative electrode active material layer, and further improves the safety performance of the electrochemical device.
  • Dv5 is 0.05 ⁇ m, 0.08 ⁇ m, 0.1 ⁇ m, 0.15 ⁇ m, 0.2 ⁇ m, 0.25 ⁇ m, 0.3 ⁇ m, 0.35 ⁇ m, 0.4 ⁇ m, 0.45 ⁇ m, 0.5 ⁇ m, or a range between any two of the aforementioned values.
  • the thickness of the protective layer is H1 ⁇ m, which satisfies Dv50/H1 ⁇ 0.4, where Dv50 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 50% when tested using a laser particle size analyzer, The unit is ⁇ m.
  • Dv50 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 50% when tested using a laser particle size analyzer, The unit is ⁇ m.
  • the electrochemical device is impacted or squeezed by an external force, sufficient inorganic particles can slide each other in the thickness direction of the protective layer, thereby further reducing the stress inside the protective layer, inhibiting the shedding of the protective layer, and thus reducing the positive electrode
  • the risk of short circuit between the current collector and the negative active material layer further improves the safety performance of the electrochemical device.
  • the value of Dv50/H1 is 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, or a range between
  • the protective layer satisfies Dv90/H1 ⁇ 1, where Dv90 represents the particle size corresponding to when the cumulative volume distribution number of the inorganic particles reaches 90% when tested using a laser particle size analyzer. At this time, the number of particles with excessively large diameters in the inorganic particles is small.
  • the stress inside the protective layer can be further reduced, inhibiting the shedding of the protective layer, thereby reducing the positive electrode current collector and the negative electrode. The risk of short circuits between active material layers further improves the safety performance of electrochemical devices.
  • the value of Dv90/H1 is 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or The range between any two values mentioned above.
  • Dv50 is 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 1, 1.05, 1.15, 1.2, 1.4, 1.5 or the range between any two values mentioned above.
  • Dv90 is 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, or a range between any two of the aforementioned values .
  • H1 is 0.5 ⁇ m to 10 ⁇ m. In some embodiments, H1 is 0.5 ⁇ m, 0.8 ⁇ m, 1.2 ⁇ m, 1.6 ⁇ m, 2 ⁇ m, 2.4 ⁇ m, 2.8 ⁇ m, 3.2 ⁇ m, 3.6 ⁇ m, 4 ⁇ m, 4.4 ⁇ m, 4.8 ⁇ m, 5.2 ⁇ m, 5.6 ⁇ m, 6 ⁇ m, 6.4 ⁇ m, 6.8 ⁇ m, 7.2 ⁇ m, 7.6 ⁇ m, 8 ⁇ m, 8.4 ⁇ m, 9 ⁇ m, 9.4 ⁇ m, 9.8 ⁇ m, 10 ⁇ m or the range between any two of the aforementioned values.
  • the inorganic particles include first particles and/or second particles. In some embodiments, the inorganic particles include first particles and second particles.
  • the first particles include A element, and the A element may include at least one of Al, Mg, Si, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, or Sn.
  • the first particles comprise aluminum oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, boehmite, aluminum hydroxide, At least one of magnesium hydroxide, calcium hydroxide, calcium silicate, diaspore, barium sulfate, calcium sulfate or calcium silicate.
  • Al is derived from at least one of boehmite, aluminum oxide, aluminum hydroxide, and diaspore.
  • Si is derived from at least one of kaolin or calcium silicate.
  • Ba is derived from barium sulfate.
  • Ca is derived from at least one of calcium oxide, calcium sulfate, or calcium silicate.
  • Mg is derived from at least one of magnesium oxide or magnesium hydroxide.
  • the mass percentage of the first particles is 0% to 93.5%. In some embodiments, the mass percentage of the first particles is 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60 %, 65%, 70%, 75%, 80%, 85%, 90%, 93.5% or the range between any two of the aforementioned values.
  • the second particles include Li element and M element, and the M element includes at least one of Mn or Fe.
  • the second particles include at least one of lithium iron phosphate (abbreviated as LFP), lithium iron manganese phosphate (abbreviated as LFMP), or lithium manganate (abbreviated as LMO).
  • LFP lithium iron phosphate
  • LFMP lithium iron manganese phosphate
  • LMO lithium manganate
  • Mn is derived from at least one of lithium iron manganese phosphate (LFMP) or lithium manganate (LMO).
  • Fe is derived from at least one of lithium iron phosphate (LFP) or lithium iron manganese phosphate (LFMP).
  • the mass percentage of the second particles is 0% to 98.5% based on the mass of the protective layer. In some embodiments, the mass percentage of the second particles is 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60 %, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98.5% or the range between any two of the aforementioned values.
  • the protective layer includes a first adhesive.
  • the first binder is an aqueous binder.
  • the water-based binder can improve the bonding force between the protective layer and the cathode current collector and cathode active material layer, and improve the internal resistance growth rate of the electrochemical device during high-temperature storage.
  • the first binder includes a polymer formed from at least one of acrylic acid, an acrylate, acrylonitrile, acrylamide, or an acrylate.
  • the first binder includes at least one of carboxymethylcellulose salt or nitrile rubber.
  • the first binder includes an acrylate and a polymer formed from at least one of acrylic acid, acrylonitrile, and acrylate.
  • the first binder has a weight average molecular weight of 180,000 to 2.2 million. 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 180,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 70 Ten thousand, 750,000, 800,000, 900,000, 950,000, 1 million, 1.1 million, 1.2 million, 1.2 million, 1.3 million, 1.4 million, 1.5 million, 1.6 million, 1.7 million, 1.8 million, 1.9 million, 2 million, 2.2 million or the range between any two values mentioned above.
  • the mass percentage of the first binder is 0.5% to 21% based on the mass of the protective layer. In some embodiments, the mass percentage of the first binder is 0.5%, 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%, 21% or any two of the above values range between.
  • the protective layer includes a first conductive agent.
  • the first conductive agent may include at least one of sheet-like, mesh-like, linear or granular conductive agents.
  • the first conductive agent includes at least one of graphene (GN for short), graphite fiber, carbon nanotube (CNT for short), Ketjen black or conductive carbon (SP for short).
  • the mass percentage of the first conductive agent is 0.3% to 20%. In some embodiments, the mass percentage of the first conductive agent is 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.2%, 3.4%, 3.6% , 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 10%, 12%, 14%, 16 %, 18%, 20% or the range between any two of the aforementioned values.
  • the protective layer further includes a leveling agent.
  • the leveling agent may include silicone compounds, silicone derivatives, oxygen-containing olefin polymers, acrylate polymers, acrylate polymers, alcohol compounds, ethers At least one of compounds or fluorocarbons.
  • the leveling agent includes at least one of polydimethylsiloxane, ethoxypropylene-propoxypropylene polymer, or fluorocarbon modified polyacrylate.
  • the mass percentage of the leveling agent is greater than 0% and less than or equal to 6%. In some embodiments, the mass percentage of the leveling agent is 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.15%, 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%, 5.5%, 6% or the range between any two of the aforementioned values.
  • the leveling agent is beneficial 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, thereby inhibiting the growth of the internal resistance of the electrochemical device during high-temperature storage.
  • the positive active material layer includes an active material, a second binder, and a second conductive agent.
  • the active material includes lithium cobalt oxide (abbreviated as LCO).
  • the mass percentage of the active material is 94% to 99% based on the mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the active material is 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99% or the range between any two values mentioned above.
  • the second adhesive includes at least one of polyvinylidene fluoride (abbreviated as PVDF), nitrile rubber, or polyacrylate.
  • the mass percentage of the second binder is 0.5% to 2.5% based on the mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the second binder is 0.5%, 1%, 1.5%, 2%, 2.5% or a range between any two of the aforementioned values.
  • the second conductive agent includes at least one of graphene, graphite fibers, carbon nanotubes, Ketjen black, or conductive carbon.
  • the mass percentage of the second conductive agent is 0.5% to 3.5% based on the total mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the second conductive agent is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or between any two of the aforementioned values. scope.
  • the present application can reduce the risk of short circuit between the positive electrode current collector and the negative electrode active material layer when the electrochemical device is impacted or squeezed by external force. , thereby improving the safety performance of electrochemical devices.
  • the present application recognizes that by controlling the material of the protective layer to include inorganic particles, and controlling it to be tested using a laser particle size analyzer, the inorganic particles satisfy Dv5 ⁇ 0.5 ⁇ m (wherein, Dv5 represents the size of the inorganic particles)
  • Dv5 represents the size of the inorganic particles
  • the corresponding particle size when the cumulative volume distribution number reaches 5% which can make the inorganic particles more uniformly and comprehensively cover the cathode current collector, especially at the corners of the winding structure, there can be sufficient small-sized inorganic particles for filling , thereby better covering the positive electrode current collector at the corners; and when the electrochemical device is squeezed from the side, the protective layer will have internal stress as the pole piece bends, especially at the corners of the rolled structure, due to the corner There is bending stress at the surface itself.
  • the small-sized inorganic particles in the protective layer can promote the slip between the inorganic particles, reduce the internal stress, inhibit the shedding of the protective layer, and thereby reduce the cost of the positive electrode.
  • the risk of short circuit between the current collector and the negative active material layer further improves the safety performance of the electrochemical device.
  • the electrochemical device of the present application also includes a separator, an electrolyte and a negative electrode.
  • electrochemical devices of the present application include, but are not limited to: all kinds of 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, 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) and negative electrode binder, as well as optional conductive material, into the solvent system according to a certain mass ratio and stir thoroughly. After uniformity, 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 as well as optional conductive material
  • first slurry a slurry for the protective layer
  • 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;
  • second slurry Disperse the active material, the second conductive agent, and the second binder in a solvent system at a certain mass ratio and stir thoroughly to mix evenly to obtain a slurry of the positive electrode active material (hereinafter referred to as "second slurry" );
  • step (6) Dry the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • first conductive agent first binder
  • active material second conductive agent and second binder
  • 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 such as copper-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 or ethyl 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 bare battery core 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-ion capacitors, etc.
  • Step (1) Add inorganic particles, first binder, first conductive agent, and optional leveling agent to water and mix evenly to obtain a protective layer slurry (hereinafter referred to as "first slurry”). );
  • 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 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) , the second binder (polyvinylidene fluoride (abbreviated as PVDF) with a mass percentage of 1.6%) is dispersed in the N-methylpyrrolidone solvent system and stirred thoroughly to obtain a slurry of the positive electrode active material (hereinafter referred to 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 38 and Comparative Examples 1 to 2.
  • the positive electrode of the lithium-ion battery is produced 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 being thoroughly stirred and mixed in a deionized water solvent system, it is coated on a 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 ⁇ 10 ppm, mix ethylene carbonate (abbreviated as EC), diethyl carbonate (abbreviated as DEC), and propylene carbonate (abbreviated as PC) according to 2:6: Mix evenly with a weight ratio of 2, then dissolve the fully dried lithium salt LiPF6 in the above solvent, the content of LiPF6 is 12.5%, add 1.5% 1,3-propane sultone, 3% fluoroethylene carbonate, 2 % adiponitrile. The content of each substance is based on the total weight of the electrolyte.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • Isolation film Polyethylene (abbreviated as PE) porous polymer film is used as the isolation film.
  • a laser particle size analyzer (Malvern 3000) for testing: After the instrument is turned on, add deionized water to the sample chamber and conduct a blank background test first. When the blank background has no obvious characteristic peaks, conduct a particle size test of the inorganic particles. Add the aqueous dispersion of inorganic particles uniformly dispersed by ultrasonic into the sample chamber and start testing. The particle size distribution of the inorganic particles can be obtained. The relevant software automatically outputs the particle size distribution of the material and calculates Dv5/Dv50/Dv90 (sample's The corresponding particle size when the cumulative volume distribution number reaches 5%/50%/90% respectively).
  • the test lasts for 3 minutes or The test is stopped after the surface temperature of the lithium-ion battery drops to 50°C.
  • a group of 20 lithium-ion batteries is used to observe the status of the lithium-ion battery during the test.
  • the passing criterion is that the lithium-ion battery does not burn or explode.
  • Record the side extrusion pass rate the number of passes/20.
  • Table 2 below shows various properties of Examples 1 to 38 and Comparative Examples 1 to 2.
  • lithium-ion batteries can have a high side extrusion pass rate (more than 70%).
  • the protective layer can make The inorganic particles more uniformly and comprehensively cover the cathode current collector, especially at the corners of the rolled structure, which can be filled with sufficient small-sized inorganic particles to better cover the cathode current collector at the corners; and in lithium ion
  • the protective layer will have internal stress as the pole piece bends, especially at the corners of the winding structure. Due to the bending stress at the corner itself, the stress will be even greater when it is squeezed from the side.
  • Concentrated, small-sized inorganic particles in the protective layer can promote slippage between inorganic particles, reduce internal stress, thereby inhibiting the shedding of the protective layer, thereby reducing the risk of short circuit between the positive electrode current collector and the negative electrode active material layer, and improving Side crush pass rate of lithium-ion batteries.
  • the inorganic particles used in the protective layer in Examples 1 to 38 of the present application may include first particles and/or second particles.
  • the first particles include at least one of boehmite, aluminum oxide, barium sulfate, calcium sulfate or calcium silicate.
  • the second particles include at least one of lithium iron phosphate, lithium iron manganese phosphate, and lithium manganate.
  • the inorganic particles used in the protective layer of the present application are not limited to the types listed in the specific embodiments, and may include their analogs.
  • the first binder used for the protective layer in Examples 1 to 38 of the present application may include acrylonitrile-lithium acrylate-acrylamide polymer, polyacrylic acid, sodium carboxymethylcellulose, sodium polyacrylate, polyacrylate, polypropylene At least one of nitrile or nitrile rubber.
  • the first 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 acrylate. things.
  • the leveling agent used in the protective layer in Examples 1 to 38 of the present application may include ethoxypropylene-propoxypropylene copolymer, polydimethylsilane, acrylate polymer, sodium acrylate polymer or fluorocarbon modified polyethylene. At least one kind of acrylate.
  • 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 a high side extrusion pass rate, that is, it has excellent safety; and it can maintain the growth rate of high-temperature storage internal resistance within a certain range, and has good high-temperature stability. sex.
  • 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)
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Abstract

Est divulgué dans la présente demande un dispositif électrochimique. Ce dispositif électrochimique comprend : une électrode positive qui comprend 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. La couche de protection comprend des particules inorganiques. En utilisant un analyseur de taille de particule laser pour test, les particules inorganiques satisfont Dv5 ≤ 0,5 µm, Dv5 représentant la taille de particule correspondante lorsque le nombre de distribution de volume cumulé des particules inorganiques atteint 5 %, de telle sorte que le dispositif électrochimique peut avoir une bonne sécurité.
PCT/CN2022/084053 2022-03-30 2022-03-30 Dispositif électrochimique et dispositif électronique WO2023184234A1 (fr)

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CN202280021200.8A CN117043977A (zh) 2022-03-30 2022-03-30 一种电化学装置及电子装置
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015149237A (ja) * 2014-02-07 2015-08-20 株式会社豊田自動織機 蓄電装置用電極
CN113078282A (zh) * 2021-03-23 2021-07-06 珠海冠宇电池股份有限公司 一种正极片和锂离子电池
CN113632273A (zh) * 2020-11-27 2021-11-09 东莞新能源科技有限公司 一种电化学装置和电子装置
CN114156487A (zh) * 2021-11-29 2022-03-08 珠海冠宇电池股份有限公司 一种极片和锂离子电池
CN114156429A (zh) * 2021-11-29 2022-03-08 珠海冠宇电池股份有限公司 一种极片和锂离子电池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015149237A (ja) * 2014-02-07 2015-08-20 株式会社豊田自動織機 蓄電装置用電極
CN113632273A (zh) * 2020-11-27 2021-11-09 东莞新能源科技有限公司 一种电化学装置和电子装置
CN113078282A (zh) * 2021-03-23 2021-07-06 珠海冠宇电池股份有限公司 一种正极片和锂离子电池
CN114156487A (zh) * 2021-11-29 2022-03-08 珠海冠宇电池股份有限公司 一种极片和锂离子电池
CN114156429A (zh) * 2021-11-29 2022-03-08 珠海冠宇电池股份有限公司 一种极片和锂离子电池

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