WO2022198401A1 - Electrochemical device and electronic device - Google Patents

Electrochemical device and electronic device Download PDF

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Publication number
WO2022198401A1
WO2022198401A1 PCT/CN2021/082144 CN2021082144W WO2022198401A1 WO 2022198401 A1 WO2022198401 A1 WO 2022198401A1 CN 2021082144 W CN2021082144 W CN 2021082144W WO 2022198401 A1 WO2022198401 A1 WO 2022198401A1
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WO
WIPO (PCT)
Prior art keywords
coating
coating layer
electrochemical device
conductive agent
current collector
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PCT/CN2021/082144
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French (fr)
Chinese (zh)
Inventor
郭俊
Original Assignee
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 CN202180003997.4A priority Critical patent/CN114008819A/en
Priority to PCT/CN2021/082144 priority patent/WO2022198401A1/en
Publication of WO2022198401A1 publication Critical patent/WO2022198401A1/en

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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
    • 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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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 present application relates to the field of electrochemical energy storage, in particular to electrochemical devices and electronic devices.
  • the pole piece is usually cut into a multi-pole structure, and an insulating layer is coated near the cutting position to insulate and prevent burrs generated by cutting from piercing the isolation membrane.
  • the electrochemical device includes an electrode, the electrode includes a current collector, a first coating layer and a second coating layer, the second coating layer includes an active material, and the second coating layer is disposed on the collector On at least one surface of the fluid, the first coating is arranged along the side of the current collector near the tab portion, and is adjacent to or partially overlapped with the second coating, the first coating comprising ceramic particles, a binder and conductive agent.
  • the conductive agent includes at least one of conductive carbon black, carbon nanotubes, carbon fibers, or graphene. In some embodiments, the mass content of the conductive agent is 0.1% to 1.4% based on the total mass of the first coating layer.
  • the first coating further includes a dispersant, and the dispersant includes at least one of an amide compound, a lipid compound, or an ether compound.
  • the dispersant includes polypyrrolidone, polyacrylate, polyether-modified siloxane, polyether-modified polyacrylate, polyether-modified alkoxysilane, fatty acid methyl ester, isobutanolamine, ethylene - at least one of vinyl acetate copolymer, polymethyl methacrylate, or poly(1,4-butanediol succinate).
  • the first coating layer further includes a dispersant, and the mass content of the dispersant is 0.05% to 0.7% based on the total mass of the first coating layer.
  • the mass content ratio of the dispersant to the conductive agent in the first coating is 0.07 to 1.
  • the ratio of the thickness of the first coating to the thickness of the second coating is 0.7 or less, and the thickness of the first coating ranges from 20 ⁇ m to 100 ⁇ m.
  • the width of the first coating ranges from 3 mm to 10 mm.
  • the conductive agent has a specific surface area of 50 m 2 /g to 1500 m 2 /g.
  • the ceramic particles include at least one of oxides, nitrides, or carbides. In some embodiments, the ceramic particles include at least one of Al 2 O 3 , ZrO 2 , TiN, Si 3 N 4 , SiC, TiC, Cr 3 C 2 , VC, or B 4 C. In some embodiments, the mass content of the ceramic particles in the first coating is 77% to 98%. In some embodiments, the binder includes at least one of polyvinylidene fluoride, polyimide, or peroxyacetyl nitrate. In some embodiments, the mass content of the binder in the first coating is 1% to 22%.
  • Embodiments of the present application also provide an electronic device, including the above electrochemical device.
  • a first coating is provided on the surface of the current collector near the tab portion, and the first coating includes ceramic particles, a binder and a conductive agent.
  • the first coating can prevent the tab from being cut.
  • the first coating layer and the second coating layer can be improved due to the interdiffusion of components at the junction The destruction of the conductive network of the two-coating layer avoids the increase of electrode resistance and the decrease of the electrical performance of the battery, thereby improving the capacity exertion and kinetic performance of the electrochemical device under the premise of ensuring the electrochemical device has good safety performance.
  • 1 to 2 illustrate cross-sectional views of the positive electrode of some embodiments of the present application taken along a plane defined by a thickness direction and a width direction of the positive electrode current collector.
  • an insulating coating eg, ceramic coating
  • the insulating coating has a problem of diffusion to the active material layer after drying (the diffusion distance is usually 0.1 mm to 2 mm), which leads to the destruction of the conductive network of the active material layer, which in turn leads to the capacity fading and the deterioration of the kinetic performance of the electrochemical device. .
  • the damage to the conductive network of the second coating layer can be alleviated or mitigated, thereby ensuring the electrical conductivity.
  • the capacity and kinetic performance of the electrochemical device can be improved.
  • an electrochemical device that includes an electrode.
  • the electrode includes a current collector, a first coating layer and a second coating layer, the second coating layer includes an active material, the second coating layer is disposed on at least one surface of the current collector, and the first coating layer is along the current collector. Set near the side of the tab.
  • the first coating is adjacent to or partially coincident with the second coating.
  • the electrode may be a positive electrode or a negative electrode.
  • the embodiment of the present application uses the electrode as an example for illustration, and the negative electrode may also have a corresponding structure.
  • the positive electrode includes a positive electrode current collector 111 , a first coating layer 112 and a second coating layer 113 , and the second coating layer 113 is disposed on at least one surface of the positive electrode current collector 111 .
  • the first coating layer 112 is disposed along the side of the positive electrode current collector 111 close to the tab portion 1111 and is adjacent to the second coating layer 113 .
  • the tab portion 1111 may be connected to an external tab.
  • the tab portion 1111 itself can function as a tab, thereby eliminating the need for an external tab.
  • the second coating 113 includes an active material.
  • the second coating layer 113 of the positive electrode is also referred to as a positive electrode active material layer, and includes a positive electrode active material. It should be understood that although the first coating layer 112 and the second coating layer 113 are shown on both sides of the positive electrode current collector 111 in FIG. 112 and/or the second coating 113 may be located on only one side of the positive electrode current collector 111 .
  • the first coating 112 includes ceramic particles, a binder, and a conductive agent.
  • the first coating layer 112 may protect the separator from the adverse effects of burrs on the positive electrode current collector 111 produced by the cutting when the positive electrode tabs forming the positive electrode are cut.
  • the ceramic particles themselves are insulating, so that the first coating 112 has a certain resistance, even if the first coating 112 is in direct contact with the negative electrode, it does not cause a great risk.
  • the damage to the conductive network of the second coating layer 113 can be alleviated or mitigated, so as to ensure the electrochemical performance.
  • the capacity exertion and kinetic performance of the electrochemical device can be improved.
  • the ceramic particles in the first coating layer 112 enable the first coating layer 112 to function to prevent short circuits between the positive and negative electrodes and prevent burrs generated when the tabs are cut from piercing the separator.
  • the binder in the first coating 112 allows the first coating 112 to form a stable layer and bond well with the current collector 111 .
  • the presence of the conductive agent in the first coating 112 allows the first coating 112 to diffuse into the second coating 113 without causing too much impact on the conductive network of the second coating 113, Thereby, the capacity development and kinetic performance of the electrochemical device can be improved.
  • FIG. 1 shows a situation where the first coating 112 is adjacent to the second coating 113 .
  • the overlapping distance between the first coating layer 112 and the second coating layer 113 is zero.
  • the first coating layer 112 and the second coating layer 113 may partially overlap, and the width of the overlapping region of the first coating layer 112 and the second coating layer 113 is equal to the width of the first coating layer 112 and the second coating layer 113 .
  • the width of the interaction area of the second coating layer 113 is a situation where the first coating 112 is adjacent to the second coating 113 .
  • the overlapping distance between the first coating layer 112 and the second coating layer 113 is zero.
  • the first coating layer 112 and the second coating layer 113 may partially overlap, and the width of the overlapping region of the first coating layer 112 and the second coating layer 113 is equal to the width of the first coating layer 112 and the second coating layer 113 .
  • the width of the interaction area of the second coating layer 113 is not limited to the width of the first coating layer
  • the conductive agent in the first coating 112 includes at least one of conductive carbon black, carbon nanotubes, carbon fibers, or graphene.
  • the mass content of the conductive agent is 0.1% to 1.4% based on the total mass of the first coating layer 112 . In this way, under the condition of ensuring the safety performance of the electrochemical device, the kinetic performance of the electrochemical device is improved.
  • the conductive agent has a specific surface area of 50 m 2 /g to 1500 m 2 /g.
  • the conductive agent with a specific surface area in this range increases the number of network paths constructed per unit area in the first coating layer 112, thereby achieving better conductive connectivity, which is beneficial to improve the rate performance and kinetic performance of the electrochemical device . If the specific surface area of the conductive agent is too small, it is not conducive to the construction of the conductive network in the first coating layer 112, which is not conducive to the improvement of the electrical performance of the electrochemical device; if the specific surface area of the conductive agent is too large, it is not conducive to the conductive agent. uniform dispersion.
  • the binder in the first coating 112 includes at least one of polyvinylidene fluoride, polyimide, or peroxyacetyl nitrate.
  • the mass content of the binder in the first coating layer 112 is 1% to 22%. If the mass content of the binder in the first coating layer 112 is too low, it is unfavorable for the bonding between the ceramic particles and the conductive agent, so that the bonding force between the first coating layer 112 and the positive electrode current collector 111 is weakened. If the mass content of the binder in the first coating layer 112 is too large, the resistance of the first coating layer 112 will be increased due to the insulating properties of the binder, affecting the electrical performance of the electrochemical device.
  • the ceramic particles include at least one of oxides, nitrides, or carbides. In some embodiments, the ceramic particles include at least one of Al 2 O 3 , ZrO 2 , TiN, Si 3 N 4 , SiC, TiC, Cr 3 C 2 , VC, or B 4 C. On the one hand, these ceramic particles play the role of insulation, so that the resistance of the first coating layer 112 reaches, for example, more than 1000 ⁇ , and on the other hand, play the role of preventing the burrs generated when cutting the tabs from piercing the isolation membrane. In some embodiments, the mass content of the ceramic particles in the first coating 112 is 77% to 98%.
  • the effect of the ceramic particles to prevent burrs from piercing the isolation membrane is relatively limited; if the mass content of the ceramic particles in the first coating 112 is too large, If the conductive agent and/or binder in the first coating layer 112 is too small, and the conductive agent in the first coating layer 112 is too small, the effect of the conductive agent in improving the electrical performance of the electrochemical device is relatively limited, and the first coating layer 112 If the amount of the binder is too small, the stability of the first coating layer 112 is weak, and it is difficult to bond to form a stable layer.
  • the first coating layer 112 may further include a dispersant, and the dispersant includes at least one of an amide compound, a lipid compound, or an ether compound.
  • the dispersant includes polypyrrolidone, polyacrylate, polyether-modified siloxane, polyether-modified polyacrylate, polyether-modified alkoxysilane, fatty acid methyl ester, isobutanolamine, ethylene - at least one of vinyl acetate copolymer, polymethyl methacrylate, or poly(1,4-butanediol succinate).
  • These dispersants can coat the conductive agent on the surface of the ceramic particles, and improve the conductivity of a single ceramic particle under the premise of ensuring the overall insulation of the first coating 112 (safety guarantee), even if the second coating 113 and the first coating
  • the coating layer 112 diffuses into each other during the coating and drying process, and it will not have a significant impact on the appearance of the pole piece, and because a single ceramic particle already has a certain conductivity, it will no longer affect the second coating layer 113 after diffusing into the second coating layer 113.
  • the conductive network structure of the coating 113 thereby improving the capacity development and kinetic performance of the electrochemical device.
  • the mass content of the dispersant is 0.05% to 0.7% based on the total mass of the first coating layer 112 . If the mass content of the dispersing agent is too small, the effect of the dispersing agent to coat the conductive agent on the surface of the ceramic particles is relatively limited; if the mass content of the dispersing agent is too large, the dispersing agent coats the conductive agent on the ceramic particles The effect on the surface is no longer significantly increased, and too much dispersant is not conducive to the improvement of the energy density of the electrochemical device.
  • the mass content ratio of the dispersant to the conductive agent in the first coating layer 112 is 0.07 to 1. If the ratio of the mass content of the dispersant to the conductive agent is too small, the dispersant cannot coat as much conductive agent as possible on the surface of the ceramic particles; if the ratio of the mass content of the dispersant to the conductive agent is too large, the dispersant The effect of coating the conductive agent on the surface of the ceramic particles is no longer significantly increased, and at the same time, too much dispersant is not conducive to the improvement of the energy density of the electrochemical device.
  • the ratio of the thickness of the first coating 112 to the thickness of the second coating 113 is less than or equal to 0.7. If the ratio of the thickness of the first coating layer 112 to the thickness of the second coating layer 113 is too large, it indicates that the thickness of the first coating layer 112 is too large. On the one hand, it is not conducive to the improvement of the energy density of the electrochemical device; in addition, if the thickness of the first coating 112 is too large, it is easy to cause a gap to be formed between the second coating 113 and the isolation film, resulting in an increase in the polarization of the second coating 113. . In some embodiments, the thickness T of the first coating 112 ranges from 20 ⁇ m to 100 ⁇ m.
  • the thickness of the first coating layer 112 is too small, the protective effect of the first coating layer 112 cannot be sufficiently exerted. If the thickness of the first coating layer 112 is too large, on the one hand, the protective effect of the first coating layer 112 is not significantly increased, and on the other hand, it is not conducive to the improvement of the energy density of the electrochemical device.
  • the thickness of the first coating layer 112 or the second coating layer 113 can be measured by a micrometer.
  • the width W of the first coating 112 ranges from 3 mm to 10 mm. If the width W of the first coating layer 112 is too small, it is easy to cause coating leakage, and it is difficult to achieve stable implementation. On the other hand, if the width W of the first coating layer 112 is too large, the energy density of the overall electrochemical device may be reduced, and the electrochemical performance of the overall electrochemical device may be reduced.
  • the resistance of the first coating 112 in a fully charged state is greater than or equal to 1000 ⁇ . In this way, a better protection effect can be achieved and the safety performance of the electrochemical device can be improved. If the resistance in the fully charged state is too low, when there is a short circuit between the first coating and the negative electrode, the short-circuit current is too large, which leads to an excessively high temperature rise, which is prone to the risk of thermal runaway.
  • the resistance of the first coating 112 can be tested by the following methods: disassemble the fully charged battery and keep the complete pole piece (positive or negative pole); rinse the pole piece with dimethyl carbonate for 30min, and dry it at 100°C for 4h After that, cut out the first coating and test it with a four-probe resistance instrument.
  • the second coating layer 113 is a positive electrode active material layer and includes a positive electrode active material.
  • the positive active material includes lithium cobalt oxide, lithium iron phosphate, lithium iron manganese phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadyl phosphate, sodium vanadyl phosphate, lithium vanadate, manganese At least one of lithium oxide, lithium nickelate, lithium nickel cobalt manganese oxide, lithium rich manganese based material or lithium nickel cobalt aluminate.
  • the positive electrode active material layer may further include a conductive agent.
  • the conductive agent in the positive active material layer may include at least one of conductive carbon black, Ketjen black, lamellar graphite, graphene, carbon nanotubes, or carbon fibers.
  • the positive electrode active material layer may further include a binder, and the binder in the positive electrode active material layer may include carboxymethyl cellulose (CMC), polyacrylic acid, polyvinylpyrrolidone, polyaniline, polyamide At least one of imine, polyamideimide, polysiloxane, styrene-butadiene rubber, epoxy resin, polyester resin, polyurethane resin or polyfluorene.
  • CMC carboxymethyl cellulose
  • the mass ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode active material layer may be (80 to 99):(0.1 to 10):(0.1 to 10).
  • the thickness of the cathode active material layer may be 10 ⁇ m to 500 ⁇ m. It should be understood that the above description is only an example, and the positive electrode active material layer of the positive electrode may adopt any other suitable material, thickness and mass ratio.
  • the current collector of the positive electrode can use Al foil, of course, other current collectors commonly used in the art can also be used.
  • the thickness of the current collector of the positive electrode may be 1 ⁇ m to 200 ⁇ m.
  • the positive electrode active material layer may be coated only on a partial area of the current collector of the positive electrode.
  • the second coating layer 113 is a negative electrode active material layer.
  • the anode active material layer includes an anode active material, and the anode active material may include at least one of graphite, hard carbon, silicon, silicon oxide, or organic silicon.
  • a conductive agent and a binder may also be included in the anode active material layer.
  • the conductive agent in the negative active material layer may include at least one of conductive carbon black, Ketjen black, lamellar graphite, graphene, carbon nanotubes, or carbon fibers.
  • the binder in the negative active material layer may include carboxymethyl cellulose (CMC), polyacrylic acid, polyvinylpyrrolidone, polyaniline, polyimide, polyamideimide, polysilicon At least one of oxane, styrene-butadiene rubber, epoxy resin, polyester resin, polyurethane resin or polyfluorene.
  • the mass ratio of the anode active material, the conductive agent, and the binder in the anode active material layer may be (80 to 98):(0.1 to 10):(0.1 to 10). It should be understood that the above are only examples and any other suitable materials and mass ratios may be employed.
  • the current collector of the negative electrode can be at least one of copper foil, nickel foil or carbon-based current collector.
  • the release membrane includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid.
  • the polyethylene includes at least one selected from high density polyethylene, low density polyethylene or ultra-high molecular weight polyethylene. Especially polyethylene and polypropylene, they have a good effect on preventing short circuits and can improve the stability of the battery through the shutdown effect.
  • the thickness of the isolation film is in the range of about 5 ⁇ m to 50 ⁇ m.
  • the surface of the separator may further include a porous layer, the porous layer is disposed on at least one surface of the substrate of the separator, the porous layer includes inorganic particles and a binder, and the inorganic particles are selected from alumina (Al 2 O 3 ), silicon oxide (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), hafnium dioxide (HfO 2 ), tin oxide (SnO 2 ), ceria (CeO 2 ), nickel oxide (NiO) ), zinc oxide (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, hydroxide At least one of calcium or barium sulfate.
  • alumina Al 2 O 3
  • silicon oxide SiO 2
  • magnesium oxide MgO
  • titanium oxide TiO 2
  • hafnium dioxide
  • the pores of the isolation membrane have diameters in the range of about 0.01 ⁇ m to 1 ⁇ m.
  • the binder of the porous layer is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyamide At least one of vinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the porous layer on the surface of the separator can improve the heat resistance, oxidation resistance and electrolyte wettability of the separator, and enhance the adhesion between the separator and the pole piece.
  • the electrode assembly of the electrochemical device is a wound electrode assembly, a stacked electrode assembly, or a folded electrode assembly.
  • the positive electrode and/or the negative electrode of the electrochemical device may be a multi-layer structure formed by winding or stacking, or may be a single-layer structure in which a single-layer positive electrode, a separator, and a single-layer negative electrode are stacked.
  • the electrochemical device includes a lithium-ion battery, although the present application is not so limited.
  • the electrochemical device may also include an electrolyte.
  • the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolytic solution, and the electrolytic solution includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF6, LiBF4 , LiAsF6, LiClO4 , LiB ( C6H5 ) 4 , LiCH3SO3 , LiCF3SO3 , LiN ( SO2CF3 ) 2 , LiC ( SO2CF3 ) 3 , LiSiF 6 , LiBOB or one or more of lithium difluoroborate.
  • LiPF 6 is chosen as the lithium salt because it has high ionic conductivity and can improve cycle characteristics.
  • the non-aqueous solvent may be carbonate compounds, carboxylate compounds, ether compounds, other organic solvents, or a combination thereof.
  • the carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl esters (MEC) and combinations thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl esters (MEC) and combinations thereof.
  • Examples of the cyclic carbonate compound are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), or a combination thereof.
  • fluorocarbonate compound examples include fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate Fluoroethylene, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-carbonate -Difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, or a combination thereof.
  • FEC fluoroethylene carbonate
  • 1,2-difluoroethylene carbonate 1,1-difluoroethylene carbonate
  • 1,1,2-trifluoroethylene carbonate Fluoroethylene, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-carbonate -Difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene
  • carboxylate compounds are methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, decolactone, Valerolactone, mevalonolactone, caprolactone, methyl formate, or a combination thereof.
  • ether compounds are dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxy Ethane, 2-methyltetrahydrofuran, tetrahydrofuran, or a combination thereof.
  • organic solvents examples include dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, methyl amide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters or combinations thereof.
  • the positive electrode, the separator, and the negative electrode are wound or stacked in sequence to form electrode parts, and then packed into, for example, an aluminum-plastic film for encapsulation, injected with electrolyte, and formed into, Encapsulation, that is, to make a lithium-ion battery. Then, the performance test of the prepared lithium-ion battery was carried out.
  • electrochemical devices eg, lithium ion batteries
  • electrochemical devices eg, lithium ion batteries
  • Other methods commonly used in the art may be employed without departing from the disclosure of the present application.
  • Embodiments of the present application also provide electronic devices including the above electrochemical devices.
  • the electronic device in the embodiment of the present application is not particularly limited, and it may be used in any electronic device known in the prior art.
  • electronic devices may 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, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
  • the preparation of the positive electrode using aluminum foil as the positive electrode current collector of the positive electrode, dissolving the positive electrode active material lithium iron phosphate, conductive carbon black, and polyvinylidene fluoride in a ratio of 96:2.4:1.6 by weight in N-methylpyrrolidone ( NMP) solution, form the slurry of the second coating layer, and coat the slurry on the positive electrode current collector with a coating thickness of 120 ⁇ m to obtain a second coating layer, which is coated adjacent to the second coating layer on the positive electrode current collector A layer of first coating slurry to obtain a first coating, specifically, 88.9 wt% ceramic particles Al 2 O 3 , 0.1 wt % carbon nanotubes and 11 wt % polyvinylidene fluoride were dissolved in N-methylpyrrolidone ( NMP) solution to form a first coating slurry. Then the positive electrode is obtained after drying, cold pressing and cutting. Wherein, the coating thickness of the first coating layer is 60 ⁇ m, the width
  • negative electrode artificial graphite, sodium carboxymethyl cellulose (CMC) and binder styrene-butadiene rubber were dissolved in deionized water in a weight ratio of 97.7:1.3:1 to form a negative electrode slurry.
  • a 10 ⁇ m-thick copper foil was used as the current collector of the negative electrode, and the negative electrode slurry was coated on the current collector of the negative electrode, dried, and cut to obtain the negative electrode.
  • the isolation film substrate is polyethylene (PE) with a thickness of 8 ⁇ m, and 2 ⁇ m alumina ceramic layers are coated on both sides of the isolation film substrate, and finally, 2.5 ⁇ m alumina ceramic layers are coated on both sides of the coated ceramic layer. mg/cm 2 binder polyvinylidene fluoride (PVDF), dried.
  • PE polyethylene
  • PVDF polyvinylidene fluoride
  • EC ethylene carbonate
  • PC propylene carbonate
  • Preparation of lithium ion battery stack the positive electrode, the separator and the negative electrode in sequence, so that the separator is placed between the positive electrode and the negative electrode for isolation, and then the electrode assembly is obtained by winding.
  • the electrode assembly is placed in the outer packaging aluminum-plastic film, and after dehydration at 80°C, the above electrolyte is injected and packaged, and the lithium ion battery is obtained through the process of forming, degassing, and trimming.
  • Example 1 Examples and comparative examples are based on the steps of Example 1 or Example 5, and parameters are changed, and the specific parameters to be changed are shown in the following table.
  • Stand for 30min in 25 ⁇ 3°C environment charge with 0.5C (1C is the rated capacity of lithium-ion battery) current constant current until the voltage reaches 3.6V (rated voltage), transfer to constant voltage charging, stop charging when the current reaches 0.05C ; Stand for 30min; discharge the lithium-ion battery to 2.5V with 0.2C current, and let it stand for 30min; take the discharge capacity as the actual capacity of the lithium-ion battery.
  • the battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in dimethyl carbonate (DMC) solvent for 30 minutes, and then the electrolyte was washed off, and the soaking and cleaning were repeated 3 times.
  • the positive electrode was then air-dried naturally. After air-drying the pole piece, use Deheng DHTW-15 sampling cutting table to cut the pole piece along the distance of 0.5mm from the second coating layer to obtain the pole piece containing the current collector and the first coating layer, and then cut the pole piece with a length of 40mm. There are 20 samples in total.
  • the battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in DMC solvent for 30 minutes, and then the electrolyte was washed away, and the soaking and cleaning were repeated 3 times.
  • the positive electrode was then air-dried naturally. After air-drying the pole piece, use a micrometer to measure the thickness of the empty aluminum foil at the pole tab T3, the thickness of the pole piece of the first coating at the pole tab (the center of the first coating is required to be tested) T4, and the pole piece of the second coating.
  • the battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in DMC solvent for 30 minutes, and then the electrolyte was washed away, and the soaking and cleaning were repeated 3 times.
  • the obtained first-coated pole piece sample was collected using a Nippon BT3562 resistance meter, the diameter of the contact copper column was 14 mm, the test pressure was 25 MPa (0.4 t), and the sampling time was 15 s. Place the sample between two copper posts and press the switch to test the resistance.
  • Test principle AC four-terminal test method, load AC current Is to the test object, the sensor collects the voltage drop V IS caused by the test object, and derives the corresponding resistance R according to Ohm 's law.
  • Table 1 shows the respective parameters and evaluation results of Examples 1 to 7 and Comparative Example 1. Among them, in Examples 3 and 4, the contents of the ceramic particles and the conductive agent in the first coating layer were different from those in Example 1.
  • the composition of the first coating was 88 wt % of ceramic particles Al 2 O 3 and 12 wt % of polyvinylidene fluoride (PVDF).
  • Example 4 the dispersant PVP was added in the first coating layer, and the content of each component of the first coating layer was different from that of Example 1.
  • Table 2 shows the respective parameters and evaluation results of Examples 8 to 35. Among them, in Examples 8 to 11, the kinds of ceramic particles in the first coating layer were different from those in Example 5.
  • Example 12 the mass contents of the ceramic particles and the binder polyvinylidene fluoride of the first coating layer were different from those of Example 5.
  • Example 15 to 17 the kind of the dispersant of the first coating layer was different from that of Example 5.
  • Example 18 the mass content of the dispersant PVP of the first coating layer was different from that of Example 5.
  • Example 21 the thickness of the first coating was different from Example 5.
  • Example 25 the width of the first coating was different from Example 5.
  • Example 28 the specific surface area (BET) of the conductive agent in the first coating was different from Example 5.
  • Example 33 the width of the interaction zone of the first coating and the second coating was different from that of Example 5. It should be understood that the interaction zone is caused by overlapping application of the first coating and the second coating or diffusion of the first coating to the second coating.
  • the dispersant in the first coating improves the dispersion of the conductive agent, which is beneficial to the construction of the conductive network in the interactive region of the first coating and the second coating, but too much dispersant will hinder the diffusion of Li + , which affects the capacity performance and rate discharge of the second coating, and the mass content of the dispersant in the first coating is preferably less than or equal to 0.7%.
  • the thicker the thickness of the first coating the more insulating ceramic particles in the interaction area formed by the first coating and the second coating, which is not conducive to the construction of the conductive network of the second coating , thereby deteriorating the capacity exertion and rate capability of the second coating.
  • the ratio of the thickness of the first coating to the thickness of the second coating is preferably less than or equal to 0.7, so as to avoid damage to the first coating caused by the contact of the cold pressing roller with the first coating during cold pressing.

Abstract

The present application provides an electrochemical device and an electronic device. The electrochemical device comprises a positive electrode, a negative electrode, and a separator arranged between the positive electrode and the negative electrode. At least one of the positive electrode and the negative electrode comprises a current collector, a first coating and a second coating, the second coating comprising an active material, the second coating being arranged on a surface of at least one side of the current collector, and the first coating being provided on a surface of the side of the current collector close to a tab portion. The first coating comprises ceramic particles, a binder and a conductive agent. According to the present application, the first coating can prevent the problem of a short circuit caused by burrs generated during tab cutting piercing an isolating membrane from occurring. Moreover, the conductive agent is added into the first coating, such that contact bonding points between the ceramic particles and the current collector can be increased, and the bonding force of the first coating is increased, thereby improving, on the premise of ensuring that the electrochemical device has a good safety performance, the capacity exertion and the dynamic performance of the electrochemical device.

Description

电化学装置和电子装置Electrochemical and electronic devices 技术领域technical field
本申请涉及电化学储能领域，尤其涉及电化学装置和电子装置。The present application relates to the field of electrochemical energy storage, in particular to electrochemical devices and electronic devices.
背景技术Background technique
随着电化学装置(例如，锂离子电池)的发展和进步，对其安全性能、容量和动力学性能提出了越来越高的要求。为了提升电化学装置的动力学性能，目前通常将极片切割成多极耳结构，同时在切割位置附近涂覆一层绝缘层，起到绝缘和防止切割产生的毛刺刺穿隔离膜的作用。With the development and advancement of electrochemical devices (eg, lithium-ion batteries), higher and higher requirements have been placed on their safety performance, capacity, and kinetic performance. In order to improve the dynamic performance of electrochemical devices, the pole piece is usually cut into a multi-pole structure, and an insulating layer is coated near the cutting position to insulate and prevent burrs generated by cutting from piercing the isolation membrane.
然而，该绝缘层与活性材料层在涂布过程中存在相互扩散，形成交互区域，不仅影响极片的外观，而且因绝缘层浆料完全绝缘，扩散到活性材料层后导致靠近绝缘层的活性材料层的导电网络结构受到破坏，恶化电化学装置的容量发挥和动力学性能。因此，期待进一步的改进。However, there is mutual diffusion between the insulating layer and the active material layer during the coating process, forming an interactive area, which not only affects the appearance of the pole piece, but also causes the active material close to the insulating layer because the insulating layer slurry is completely insulated and diffused into the active material layer. The conductive network structure of the material layer is damaged, deteriorating the capacity development and kinetic performance of the electrochemical device. Therefore, further improvements are expected.
发明内容SUMMARY OF THE INVENTION
本申请的一些实施例提供了一种电化学装置，电化学装置包括电极，电极包括集流体、第一涂层和第二涂层，第二涂层包括活性材料，第二涂层设置于集流体的至少一个表面上，第一涂层沿集流体靠近极耳部的侧边设置，并邻接于第二涂层或与第二涂层部分重合，第一涂层包括陶瓷颗粒、粘结剂和导电剂。Some embodiments of the present application provide an electrochemical device, the electrochemical device includes an electrode, the electrode includes a current collector, a first coating layer and a second coating layer, the second coating layer includes an active material, and the second coating layer is disposed on the collector On at least one surface of the fluid, the first coating is arranged along the side of the current collector near the tab portion, and is adjacent to or partially overlapped with the second coating, the first coating comprising ceramic particles, a binder and conductive agent.
在一些实施例中，导电剂包括导电炭黑、碳纳米管、碳纤维或石墨烯中的至少一种。在一些实施例中，基于第一涂层的总质量，导电剂的质量含量为0.1％至1.4％。在一些实施例中，第一涂层还包括分散剂，分散剂包括酰胺化合物、脂类化合物或醚类化合物中的至少一种。在一些实施例中，分散剂包括聚吡咯烷酮、聚丙烯酸脂、聚醚改性硅氧烷、聚醚改性聚丙烯酸酯、聚醚改性醇氧硅烷、脂肪酸甲酯、异丁醇胺、乙烯-醋酸乙烯共聚物、聚甲基丙烯酸甲酯或聚(1,4-丁二醇丁二酸)酯中的至少一种。In some embodiments, the conductive agent includes at least one of conductive carbon black, carbon nanotubes, carbon fibers, or graphene. In some embodiments, the mass content of the conductive agent is 0.1% to 1.4% based on the total mass of the first coating layer. In some embodiments, the first coating further includes a dispersant, and the dispersant includes at least one of an amide compound, a lipid compound, or an ether compound. In some embodiments, the dispersant includes polypyrrolidone, polyacrylate, polyether-modified siloxane, polyether-modified polyacrylate, polyether-modified alkoxysilane, fatty acid methyl ester, isobutanolamine, ethylene - at least one of vinyl acetate copolymer, polymethyl methacrylate, or poly(1,4-butanediol succinate).
在一些实施例中，第一涂层还包括分散剂，基于第一涂层的总质量，分散剂的质量含量为0.05％至0.7％。在一些实施例中，第一涂层中的分散剂与导电剂的质量含量的比率为0.07至1。在一些实施例中，第一涂层的厚度与第二涂层的厚度的比率小于等于0.7，并且第一涂层的厚度范围为20μm至100μm。在一些实施例中，第一涂层的宽度范围为3mm至10mm。在一些实施例中，导电剂的比表面积为50m 2/g至1500m 2/g。 In some embodiments, the first coating layer further includes a dispersant, and the mass content of the dispersant is 0.05% to 0.7% based on the total mass of the first coating layer. In some embodiments, the mass content ratio of the dispersant to the conductive agent in the first coating is 0.07 to 1. In some embodiments, the ratio of the thickness of the first coating to the thickness of the second coating is 0.7 or less, and the thickness of the first coating ranges from 20 μm to 100 μm. In some embodiments, the width of the first coating ranges from 3 mm to 10 mm. In some embodiments, the conductive agent has a specific surface area of 50 m 2 /g to 1500 m 2 /g.
在一些实施例中，陶瓷颗粒包括氧化物、氮化物或碳化物中的至少一种。在一些实施例中，陶瓷颗粒包括Al 2O 3、ZrO 2、TiN、Si 3N 4、SiC、TiC、Cr 3C 2、VC或B 4C中的至少一种。在一些实施例中，第一涂层中的陶瓷颗粒的质量含量为77％至98％。在一些实施例中，粘结剂包括聚偏氟乙烯、聚酰亚胺或过氧乙酰硝酸酯中的至少一种。在一些实施例中，第一涂层中的所述粘结剂的质量含量为1％至22％。 In some embodiments, the ceramic particles include at least one of oxides, nitrides, or carbides. In some embodiments, the ceramic particles include at least one of Al 2 O 3 , ZrO 2 , TiN, Si 3 N 4 , SiC, TiC, Cr 3 C 2 , VC, or B 4 C. In some embodiments, the mass content of the ceramic particles in the first coating is 77% to 98%. In some embodiments, the binder includes at least one of polyvinylidene fluoride, polyimide, or peroxyacetyl nitrate. In some embodiments, the mass content of the binder in the first coating is 1% to 22%.
本申请的实施例还提供了一种电子装置，包括上述电化学装置。Embodiments of the present application also provide an electronic device, including the above electrochemical device.
本申请的实施例通过在集流体的靠近极耳部的一侧表面设置第一涂层，第一涂层包括陶瓷颗粒、粘结剂和导电剂，一方面第一涂层可以防止切割极耳时产生的毛刺刺穿隔离膜引起短路的问题，另一方面，通过在第一涂层中添加导电剂，可以改善由于第一涂层与第二涂层相接处组分互相扩散引起的第二涂层导电网络的破坏，避免了电极电阻增大和电池电性能的降低，从而在保证电化学装置具备良好安全性能的前提下，改善电化学装置的容量发挥和动力学性能。In the embodiments of the present application, a first coating is provided on the surface of the current collector near the tab portion, and the first coating includes ceramic particles, a binder and a conductive agent. On the one hand, the first coating can prevent the tab from being cut. On the other hand, by adding a conductive agent to the first coating layer, the first coating layer and the second coating layer can be improved due to the interdiffusion of components at the junction The destruction of the conductive network of the two-coating layer avoids the increase of electrode resistance and the decrease of the electrical performance of the battery, thereby improving the capacity exertion and kinetic performance of the electrochemical device under the premise of ensuring the electrochemical device has good safety performance.
附图说明Description of drawings
图1至图2示出了本申请的一些实施例的正极沿着正极集流体的厚度方向和宽度方向限定的平面获得的截面图。1 to 2 illustrate cross-sectional views of the positive electrode of some embodiments of the present application taken along a plane defined by a thickness direction and a width direction of the positive electrode current collector.
具体实施方式Detailed ways
下面的实施例可以使本领域技术人员更全面地理解本申请，但不以任何方式限制本申请。The following examples may enable those skilled in the art to more fully understand the present application, but do not limit the present application in any way.
为了防止切割多极耳结构时产生的毛刺刺穿隔离膜，在集流体的靠近极耳部的位置设置绝缘涂层(例如，陶瓷涂层)。然而，该绝缘涂层干燥 后存在向活性材料层扩散的问题(扩散距离通常为0.1mm至2mm)，导致活性材料层的导电网络受到破坏，进而导致电化学装置的容量衰减和动力学性能恶化。为此，通过在第一涂层中添加导电剂，即使第一涂层向包括活性材料的第二涂层扩散，也能缓解或减轻对第二涂层的导电网络的破坏，从而在保证电化学装置具备良好安全性能的前提下，改善电化学装置的容量发挥和动力学性能。In order to prevent the burrs generated when the multi-tab structure is cut from piercing the isolation film, an insulating coating (eg, ceramic coating) is provided on the current collector near the tab portion. However, the insulating coating has a problem of diffusion to the active material layer after drying (the diffusion distance is usually 0.1 mm to 2 mm), which leads to the destruction of the conductive network of the active material layer, which in turn leads to the capacity fading and the deterioration of the kinetic performance of the electrochemical device. . For this reason, by adding a conductive agent to the first coating layer, even if the first coating layer diffuses to the second coating layer including the active material, the damage to the conductive network of the second coating layer can be alleviated or mitigated, thereby ensuring the electrical conductivity. On the premise that the chemical device has good safety performance, the capacity and kinetic performance of the electrochemical device can be improved.
本申请的一些实施例提供了一种电化学装置，电化学装置包括电极。在一些实施例中，电极包括集流体、第一涂层和第二涂层，第二涂层包括活性材料，第二涂层设置于集流体的至少一个表面上，第一涂层沿集流体靠近极耳部的侧边设置。第一涂层邻接于第二涂层或与第二涂层部分重合。其中电极可以为正极或者负极，为了简单的目的，本申请实施例中以电极为正极作为示例进行说明，负极也可以具有相应的结构。Some embodiments of the present application provide an electrochemical device that includes an electrode. In some embodiments, the electrode includes a current collector, a first coating layer and a second coating layer, the second coating layer includes an active material, the second coating layer is disposed on at least one surface of the current collector, and the first coating layer is along the current collector. Set near the side of the tab. The first coating is adjacent to or partially coincident with the second coating. The electrode may be a positive electrode or a negative electrode. For the sake of simplicity, the embodiment of the present application uses the electrode as an example for illustration, and the negative electrode may also have a corresponding structure.
如图1所示，正极包括正极集流体111、第一涂层112和第二涂层113，第二涂层113设置在正极集流体111的至少一个表面上。在一些实施例中，第一涂层112沿正极集流体111靠近极耳部1111的侧边设置且邻接于第二涂层113。在一些实施例中，极耳部1111可以与外接极耳连接。在一些实施例中，极耳部1111本身可以作为极耳，从而省去了外接极耳。在一些实施例中，第二涂层113包括活性材料。正极的第二涂层113也称为正极活性材料层，并且包括正极活性材料。应该理解，虽然图1中将第一涂层112和第二涂层113示出为正极集流体111的两侧上，但是这仅是示例性的，而不用于限制本申请，第一涂层112和/或第二涂层113可以仅位于正极集流体111的一侧上。As shown in FIG. 1 , the positive electrode includes a positive electrode current collector 111 , a first coating layer 112 and a second coating layer 113 , and the second coating layer 113 is disposed on at least one surface of the positive electrode current collector 111 . In some embodiments, the first coating layer 112 is disposed along the side of the positive electrode current collector 111 close to the tab portion 1111 and is adjacent to the second coating layer 113 . In some embodiments, the tab portion 1111 may be connected to an external tab. In some embodiments, the tab portion 1111 itself can function as a tab, thereby eliminating the need for an external tab. In some embodiments, the second coating 113 includes an active material. The second coating layer 113 of the positive electrode is also referred to as a positive electrode active material layer, and includes a positive electrode active material. It should be understood that although the first coating layer 112 and the second coating layer 113 are shown on both sides of the positive electrode current collector 111 in FIG. 112 and/or the second coating 113 may be located on only one side of the positive electrode current collector 111 .
在一些实施例中，第一涂层112包括陶瓷颗粒、粘结剂和导电剂。在一些实施例中，在切割形成正极的正极极耳时，第一涂层112可以保护隔离膜免受切割产生的正极集流体111的毛刺的不利影响。此外，陶瓷颗粒本身是绝缘的，使得该第一涂层112具有一定的电阻，即使该第一涂层112与负极直接接触，也不会引起大的风险。通过在正极集流体111上设置第一涂层112，提高了相应的电化学装置的安全性能。另外，通过在第一涂层112中添加导电剂，即使第一涂层112向第二涂层113扩散，也能缓解或减轻对第 二涂层113的导电网络的破坏，从而在保证电化学装置具备良好安全性能的前提下，改善电化学装置的容量发挥和动力学性能。In some embodiments, the first coating 112 includes ceramic particles, a binder, and a conductive agent. In some embodiments, the first coating layer 112 may protect the separator from the adverse effects of burrs on the positive electrode current collector 111 produced by the cutting when the positive electrode tabs forming the positive electrode are cut. In addition, the ceramic particles themselves are insulating, so that the first coating 112 has a certain resistance, even if the first coating 112 is in direct contact with the negative electrode, it does not cause a great risk. By disposing the first coating layer 112 on the positive electrode current collector 111, the safety performance of the corresponding electrochemical device is improved. In addition, by adding a conductive agent to the first coating layer 112, even if the first coating layer 112 diffuses to the second coating layer 113, the damage to the conductive network of the second coating layer 113 can be alleviated or mitigated, so as to ensure the electrochemical performance. On the premise that the device has good safety performance, the capacity exertion and kinetic performance of the electrochemical device can be improved.
在一些实施例中，第一涂层112中的陶瓷颗粒使得第一涂层112可以起到防止正负极短路以及防止切割极耳时产生的毛刺刺穿隔离膜的作用。在一些实施例中，第一涂层112中的粘结剂使得第一涂层112可以形成稳定的层并且与集流体111较好地粘结在一起。在一些实施例中，第一涂层112中的导电剂的存在使得第一涂层112即使扩散至第二涂层113，也不会对第二涂层113的导电网络造成太大的影响，从而可以改善电化学装置的容量发挥和动力学性能。In some embodiments, the ceramic particles in the first coating layer 112 enable the first coating layer 112 to function to prevent short circuits between the positive and negative electrodes and prevent burrs generated when the tabs are cut from piercing the separator. In some embodiments, the binder in the first coating 112 allows the first coating 112 to form a stable layer and bond well with the current collector 111 . In some embodiments, the presence of the conductive agent in the first coating 112 allows the first coating 112 to diffuse into the second coating 113 without causing too much impact on the conductive network of the second coating 113, Thereby, the capacity development and kinetic performance of the electrochemical device can be improved.
在一些实施例中，如图1所示，图1示出了第一涂层112与第二涂层113邻接的情况。此时，第一涂层112与第二涂层113重合的距离为0。在一些实施例中，如图2所示，第一涂层112与第二涂层113可以部分重合，第一涂层112与第二涂层113重合区域的宽度为第一涂层112与第二涂层113的交互区宽度。In some embodiments, as shown in FIG. 1 , FIG. 1 shows a situation where the first coating 112 is adjacent to the second coating 113 . At this time, the overlapping distance between the first coating layer 112 and the second coating layer 113 is zero. In some embodiments, as shown in FIG. 2 , the first coating layer 112 and the second coating layer 113 may partially overlap, and the width of the overlapping region of the first coating layer 112 and the second coating layer 113 is equal to the width of the first coating layer 112 and the second coating layer 113 . The width of the interaction area of the second coating layer 113 .
在一些实施例中，第一涂层112中的导电剂包括导电炭黑、碳纳米管、碳纤维或石墨烯中的至少一种。在一些实施例中，基于第一涂层112的总质量，导电剂的质量含量为0.1％至1.4％。如此在确保电化学装置的安全性能的情况下，提升电化学装置的动力学性能。若导电剂的质量含量太高，则满充后的第一涂层112的电阻过低，影响电化学装置的安全性能；若导电剂的质量含量太低，则第一涂层112的电阻太高，第一涂层112的电化学性能变差，并且在第一涂层112扩散到第二涂层113时缓解第二涂层113的导电网络的破坏的作用相对受限。在一些实施例中，导电剂的比表面积为50m 2/g至1500m 2/g。具有处于该范围的比表面积的导电剂提高了第一涂层112中单位面积构建的网络通路的数量，从而达到更好的导电连通作用，有利于提升了电化学装置的倍率性能和动力学性能。如果导电剂的比表面积太小，则不利于第一涂层112中的导电网络的构建，进而不利于电化学装置的电性能的提升；如果导电剂的比表面积太大，则不利于导电剂的均匀分散。 In some embodiments, the conductive agent in the first coating 112 includes at least one of conductive carbon black, carbon nanotubes, carbon fibers, or graphene. In some embodiments, the mass content of the conductive agent is 0.1% to 1.4% based on the total mass of the first coating layer 112 . In this way, under the condition of ensuring the safety performance of the electrochemical device, the kinetic performance of the electrochemical device is improved. If the mass content of the conductive agent is too high, the resistance of the fully charged first coating 112 will be too low, affecting the safety performance of the electrochemical device; if the mass content of the conductive agent is too low, the resistance of the first coating 112 will be too low high, the electrochemical performance of the first coating layer 112 is deteriorated, and the effect of mitigating the destruction of the conductive network of the second coating layer 113 when the first coating layer 112 diffuses into the second coating layer 113 is relatively limited. In some embodiments, the conductive agent has a specific surface area of 50 m 2 /g to 1500 m 2 /g. The conductive agent with a specific surface area in this range increases the number of network paths constructed per unit area in the first coating layer 112, thereby achieving better conductive connectivity, which is beneficial to improve the rate performance and kinetic performance of the electrochemical device . If the specific surface area of the conductive agent is too small, it is not conducive to the construction of the conductive network in the first coating layer 112, which is not conducive to the improvement of the electrical performance of the electrochemical device; if the specific surface area of the conductive agent is too large, it is not conducive to the conductive agent. uniform dispersion.
在一些实施例中，第一涂层112中的粘结剂包括聚偏氟乙烯、聚酰亚胺或过氧乙酰硝酸酯中的至少一种。在一些实施例中，第一涂层112中的粘结剂的质量含量为1％至22％。如果第一涂层112中的粘结剂的质量含量太 低，则不利于陶瓷颗粒和导电剂的粘结，使得第一涂层112与正极集流体111之间的粘结力变弱。如果第一涂层112中的粘结剂的质量含量太大，则由于粘结剂的绝缘性而增大第一涂层112的电阻，影响电化学装置的电性能。In some embodiments, the binder in the first coating 112 includes at least one of polyvinylidene fluoride, polyimide, or peroxyacetyl nitrate. In some embodiments, the mass content of the binder in the first coating layer 112 is 1% to 22%. If the mass content of the binder in the first coating layer 112 is too low, it is unfavorable for the bonding between the ceramic particles and the conductive agent, so that the bonding force between the first coating layer 112 and the positive electrode current collector 111 is weakened. If the mass content of the binder in the first coating layer 112 is too large, the resistance of the first coating layer 112 will be increased due to the insulating properties of the binder, affecting the electrical performance of the electrochemical device.
在一些实施例中，陶瓷颗粒包括氧化物、氮化物或碳化物中的至少一种。在一些实施例中，陶瓷颗粒包括Al 2O 3、ZrO 2、TiN、Si 3N 4、SiC、TiC、Cr 3C 2、VC或B 4C中的至少一种。这些陶瓷颗粒一方面起到绝缘的作用，使得第一涂层112的电阻例如达到1000Ω以上，另一方面起到防止切割极耳时产生的毛刺刺穿隔离膜的作用。在一些实施例中，第一涂层112中的陶瓷颗粒的质量含量为77％至98％。如果第一涂层112中的陶瓷颗粒的质量含量太小，则陶瓷颗粒起到防止毛刺刺穿隔离膜的作用相对受限；如果第一涂层112中的陶瓷颗粒的质量含量太大，则第一涂层112中的导电剂和/或粘结剂太少，第一涂层112中的导电剂太少则导电剂改善电化学装置的电性能的作用相对受限，第一涂层112中的粘结剂太少则第一涂层112的稳定性较弱，难以粘结形成稳定的层。 In some embodiments, the ceramic particles include at least one of oxides, nitrides, or carbides. In some embodiments, the ceramic particles include at least one of Al 2 O 3 , ZrO 2 , TiN, Si 3 N 4 , SiC, TiC, Cr 3 C 2 , VC, or B 4 C. On the one hand, these ceramic particles play the role of insulation, so that the resistance of the first coating layer 112 reaches, for example, more than 1000Ω, and on the other hand, play the role of preventing the burrs generated when cutting the tabs from piercing the isolation membrane. In some embodiments, the mass content of the ceramic particles in the first coating 112 is 77% to 98%. If the mass content of the ceramic particles in the first coating 112 is too small, the effect of the ceramic particles to prevent burrs from piercing the isolation membrane is relatively limited; if the mass content of the ceramic particles in the first coating 112 is too large, If the conductive agent and/or binder in the first coating layer 112 is too small, and the conductive agent in the first coating layer 112 is too small, the effect of the conductive agent in improving the electrical performance of the electrochemical device is relatively limited, and the first coating layer 112 If the amount of the binder is too small, the stability of the first coating layer 112 is weak, and it is difficult to bond to form a stable layer.
在一些实施例中，第一涂层112还可以包括分散剂，分散剂包括酰胺化合物、脂类化合物或醚类化合物中的至少一种。在一些实施例中，分散剂包括聚吡咯烷酮、聚丙烯酸脂、聚醚改性硅氧烷、聚醚改性聚丙烯酸酯、聚醚改性醇氧硅烷、脂肪酸甲酯、异丁醇胺、乙烯-醋酸乙烯共聚物、聚甲基丙烯酸甲酯或聚(1,4-丁二醇丁二酸)酯中的至少一种。这些分散剂可以将导电剂包覆到陶瓷颗粒的表面，在保证第一涂层112整体绝缘的前提下(安全性保证)，改善单个陶瓷颗粒的导电性，即使第二涂层113和第一涂层112在涂布干燥过程中发生相互扩散，也不会对极片的外观有明显影响，而且因单个陶瓷颗粒已具备一定导电性，扩散到第二涂层113之后也不再影响第二涂层113的导电网络结构，从而改善电化学装置的容量发挥和动力学性能。In some embodiments, the first coating layer 112 may further include a dispersant, and the dispersant includes at least one of an amide compound, a lipid compound, or an ether compound. In some embodiments, the dispersant includes polypyrrolidone, polyacrylate, polyether-modified siloxane, polyether-modified polyacrylate, polyether-modified alkoxysilane, fatty acid methyl ester, isobutanolamine, ethylene - at least one of vinyl acetate copolymer, polymethyl methacrylate, or poly(1,4-butanediol succinate). These dispersants can coat the conductive agent on the surface of the ceramic particles, and improve the conductivity of a single ceramic particle under the premise of ensuring the overall insulation of the first coating 112 (safety guarantee), even if the second coating 113 and the first coating The coating layer 112 diffuses into each other during the coating and drying process, and it will not have a significant impact on the appearance of the pole piece, and because a single ceramic particle already has a certain conductivity, it will no longer affect the second coating layer 113 after diffusing into the second coating layer 113. The conductive network structure of the coating 113, thereby improving the capacity development and kinetic performance of the electrochemical device.
在一些实施例中，基于第一涂层112的总质量，分散剂的质量含量为0.05％至0.7％。如果分散剂的质量含量太小，则分散剂实现将导电剂包覆到陶瓷颗粒的表面上的作用相对受限；如果分散剂的质量含量太大，则分散剂将导电剂包覆到陶瓷颗粒的表面上的作用不再显著增加，同时分散剂过多也不利于电化学装置的能量密度的提升。In some embodiments, the mass content of the dispersant is 0.05% to 0.7% based on the total mass of the first coating layer 112 . If the mass content of the dispersing agent is too small, the effect of the dispersing agent to coat the conductive agent on the surface of the ceramic particles is relatively limited; if the mass content of the dispersing agent is too large, the dispersing agent coats the conductive agent on the ceramic particles The effect on the surface is no longer significantly increased, and too much dispersant is not conducive to the improvement of the energy density of the electrochemical device.
在一些实施例中，第一涂层112中的分散剂与导电剂的质量含量的比率为0.07至1。如果分散剂与导电剂的质量含量的比率太小，则分散剂不能将尽量多的导电剂包覆到陶瓷颗粒的表面上；如果分散剂与导电剂的质量含量的比率太大，则分散剂将导电剂包覆到陶瓷颗粒的表面上的作用不再显著增加，同时分散剂过多也不利于电化学装置的能量密度的提升。In some embodiments, the mass content ratio of the dispersant to the conductive agent in the first coating layer 112 is 0.07 to 1. If the ratio of the mass content of the dispersant to the conductive agent is too small, the dispersant cannot coat as much conductive agent as possible on the surface of the ceramic particles; if the ratio of the mass content of the dispersant to the conductive agent is too large, the dispersant The effect of coating the conductive agent on the surface of the ceramic particles is no longer significantly increased, and at the same time, too much dispersant is not conducive to the improvement of the energy density of the electrochemical device.
在一些实施例中，第一涂层112的厚度与第二涂层113的厚度的比率小于等于0.7。如果第一涂层112的厚度与第二涂层113的厚度的比率太大，则表明第一涂层112的厚度过大，一方面第一涂层112的保护作用不再显著增加，另一方面不利于电化学装置的能量密度的提升；另外，第一涂层112的厚度过大容易引起在第二涂层113与隔离膜之间形成间隙，导致第二涂层113的极化增大。在一些实施例中，第一涂层112的厚度T的范围为20μm至100μm。如果第一涂层112的厚度太小，则第一涂层112的保护作用不能充分地发挥。如果第一涂层112的厚度太大，一方面第一涂层112的保护作用不再显著增加，另一方面不利于电化学装置的能量密度的提升。第一涂层112或第二涂层113的厚度可以通过万分尺来测量。In some embodiments, the ratio of the thickness of the first coating 112 to the thickness of the second coating 113 is less than or equal to 0.7. If the ratio of the thickness of the first coating layer 112 to the thickness of the second coating layer 113 is too large, it indicates that the thickness of the first coating layer 112 is too large. On the one hand, it is not conducive to the improvement of the energy density of the electrochemical device; in addition, if the thickness of the first coating 112 is too large, it is easy to cause a gap to be formed between the second coating 113 and the isolation film, resulting in an increase in the polarization of the second coating 113. . In some embodiments, the thickness T of the first coating 112 ranges from 20 μm to 100 μm. If the thickness of the first coating layer 112 is too small, the protective effect of the first coating layer 112 cannot be sufficiently exerted. If the thickness of the first coating layer 112 is too large, on the one hand, the protective effect of the first coating layer 112 is not significantly increased, and on the other hand, it is not conducive to the improvement of the energy density of the electrochemical device. The thickness of the first coating layer 112 or the second coating layer 113 can be measured by a micrometer.
在一些实施例中，第一涂层112的宽度W的范围为3mm至10mm。第一涂层112的宽度W太小容易出现漏涂情况，难以稳定实现。另一方面，第一涂层112的宽度W太大会降低整体电化学装置的能量密度，并降低整体电化学装置的电化学性能。In some embodiments, the width W of the first coating 112 ranges from 3 mm to 10 mm. If the width W of the first coating layer 112 is too small, it is easy to cause coating leakage, and it is difficult to achieve stable implementation. On the other hand, if the width W of the first coating layer 112 is too large, the energy density of the overall electrochemical device may be reduced, and the electrochemical performance of the overall electrochemical device may be reduced.
在一些实施例中，第一涂层112在满充状态下的电阻大于等于1000Ω。如此可以起到更好的保护效果，改善电化学装置的安全性能。若满充状态下的电阻过低，当出现第一涂层-负极短路时，短路电流过大导致温升过高，易出现热失控风险。可以通过以下方法测试第一涂层112的电阻：将满充的电池进行拆解，保留完整极片(正极或负极)；将极片用碳酸二甲酯漂洗30min，在100℃下烘干4h；之后将第一涂层裁剪出来，用四探针电阻仪器测试，测试时将第一涂层置于探针平面中间，取第15秒的电阻值，即为第一涂层的电阻。应该理解，电阻的该测试方法仅是示例性的，而不用于限制，还可以采用其他合适的方法。In some embodiments, the resistance of the first coating 112 in a fully charged state is greater than or equal to 1000Ω. In this way, a better protection effect can be achieved and the safety performance of the electrochemical device can be improved. If the resistance in the fully charged state is too low, when there is a short circuit between the first coating and the negative electrode, the short-circuit current is too large, which leads to an excessively high temperature rise, which is prone to the risk of thermal runaway. The resistance of the first coating 112 can be tested by the following methods: disassemble the fully charged battery and keep the complete pole piece (positive or negative pole); rinse the pole piece with dimethyl carbonate for 30min, and dry it at 100°C for 4h After that, cut out the first coating and test it with a four-probe resistance instrument. During the test, place the first coating in the middle of the probe plane, and take the resistance value of the 15th second, which is the resistance of the first coating. It should be understood that this test method of resistance is only exemplary and not for limitation, and other suitable methods may also be used.
在一些实施例中，在正极包括上述结构时，第二涂层113为正极活性材料层，并且包括正极活性材料。在一些实施例中，正极活性材料包括钴酸锂、 磷酸铁锂、磷酸锰铁锂、磷酸铁钠、磷酸钒锂、磷酸钒钠、磷酸钒氧锂、磷酸钒氧钠、钒酸锂、锰酸锂、镍酸锂、镍钴锰酸锂、富锂锰基材料或镍钴铝酸锂中的至少一种。在一些实施例中，正极活性材料层还可以包括导电剂。在一些实施例中，正极活性材料层中的导电剂可以包括导电炭黑、科琴黑、片层石墨、石墨烯、碳纳米管或碳纤维中的至少一种。在一些实施例中，正极活性材料层还可以包括粘结剂，正极活性材料层中的粘结剂可以包括羧甲基纤维素(CMC)、聚丙烯酸、聚乙烯基吡咯烷酮、聚苯胺、聚酰亚胺、聚酰胺酰亚胺、聚硅氧烷、丁苯橡胶、环氧树脂、聚酯树脂、聚氨酯树脂或聚芴中的至少一种。在一些实施例中，正极活性材料层中的正极活性材料、导电剂和粘结剂的质量比可以为(80至99)：(0.1至10)：(0.1至10)。在一些实施例中，正极活性材料层的厚度可以为10μm至500μm。应该理解，以上所述仅是示例，正极的正极活性材料层可以采用任何其他合适的材料、厚度和质量比。In some embodiments, when the positive electrode includes the above structure, the second coating layer 113 is a positive electrode active material layer and includes a positive electrode active material. In some embodiments, the positive active material includes lithium cobalt oxide, lithium iron phosphate, lithium iron manganese phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadyl phosphate, sodium vanadyl phosphate, lithium vanadate, manganese At least one of lithium oxide, lithium nickelate, lithium nickel cobalt manganese oxide, lithium rich manganese based material or lithium nickel cobalt aluminate. In some embodiments, the positive electrode active material layer may further include a conductive agent. In some embodiments, the conductive agent in the positive active material layer may include at least one of conductive carbon black, Ketjen black, lamellar graphite, graphene, carbon nanotubes, or carbon fibers. In some embodiments, the positive electrode active material layer may further include a binder, and the binder in the positive electrode active material layer may include carboxymethyl cellulose (CMC), polyacrylic acid, polyvinylpyrrolidone, polyaniline, polyamide At least one of imine, polyamideimide, polysiloxane, styrene-butadiene rubber, epoxy resin, polyester resin, polyurethane resin or polyfluorene. In some embodiments, the mass ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode active material layer may be (80 to 99):(0.1 to 10):(0.1 to 10). In some embodiments, the thickness of the cathode active material layer may be 10 μm to 500 μm. It should be understood that the above description is only an example, and the positive electrode active material layer of the positive electrode may adopt any other suitable material, thickness and mass ratio.
在一些实施例中，正极的集流体可以采用Al箔，当然，也可以采用本领域常用的其他集流体。在一些实施例中，正极的集流体的厚度可以为1μm至200μm。在一些实施例中，正极活性材料层可以仅涂覆在正极的集流体的部分区域上。In some embodiments, the current collector of the positive electrode can use Al foil, of course, other current collectors commonly used in the art can also be used. In some embodiments, the thickness of the current collector of the positive electrode may be 1 μm to 200 μm. In some embodiments, the positive electrode active material layer may be coated only on a partial area of the current collector of the positive electrode.
在一些实施例中，当负极包括上述结构时，第二涂层113为负极活性材料层。在一些实施例中，负极活性材料层包括负极活性材料，负极活性材料可以包括石墨、硬碳、硅、氧化亚硅或有机硅中的至少一种。在一些实施例中，负极活性材料层中还可以包括导电剂和粘结剂。在一些实施例中，负极活性材料层中的导电剂可以包括导电炭黑、科琴黑、片层石墨、石墨烯、碳纳米管或碳纤维中的至少一种。在一些实施例中，负极活性材料层中的粘结剂可以包括羧甲基纤维素(CMC)、聚丙烯酸、聚乙烯基吡咯烷酮、聚苯胺、聚酰亚胺、聚酰胺酰亚胺、聚硅氧烷、丁苯橡胶、环氧树脂、聚酯树脂、聚氨酯树脂或聚芴中的至少一种。在一些实施例中，负极活性材料层中的负极活性材料、导电剂和粘结剂的质量比可以为(80至98)：(0.1至10)：(0.1至10)。应该理解，以上所述仅是示例，可以采用任何其他合适的材料和质量比。在一些实施例中，负极的集流体可以采用铜箔、镍箔或碳基集流体中的至少一种。In some embodiments, when the negative electrode includes the above structure, the second coating layer 113 is a negative electrode active material layer. In some embodiments, the anode active material layer includes an anode active material, and the anode active material may include at least one of graphite, hard carbon, silicon, silicon oxide, or organic silicon. In some embodiments, a conductive agent and a binder may also be included in the anode active material layer. In some embodiments, the conductive agent in the negative active material layer may include at least one of conductive carbon black, Ketjen black, lamellar graphite, graphene, carbon nanotubes, or carbon fibers. In some embodiments, the binder in the negative active material layer may include carboxymethyl cellulose (CMC), polyacrylic acid, polyvinylpyrrolidone, polyaniline, polyimide, polyamideimide, polysilicon At least one of oxane, styrene-butadiene rubber, epoxy resin, polyester resin, polyurethane resin or polyfluorene. In some embodiments, the mass ratio of the anode active material, the conductive agent, and the binder in the anode active material layer may be (80 to 98):(0.1 to 10):(0.1 to 10). It should be understood that the above are only examples and any other suitable materials and mass ratios may be employed. In some embodiments, the current collector of the negative electrode can be at least one of copper foil, nickel foil or carbon-based current collector.
在一些实施例中，隔离膜包括聚乙烯、聚丙烯、聚偏氟乙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺或芳纶中的至少一种。例如，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯或超高分子量聚乙烯中的至少一种。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善电池的稳定性。在一些实施例中，隔离膜的厚度在约5μm至50μm的范围内。In some embodiments, the release membrane includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid. For example, the polyethylene includes at least one selected from high density polyethylene, low density polyethylene or ultra-high molecular weight polyethylene. Especially polyethylene and polypropylene, they have a good effect on preventing short circuits and can improve the stability of the battery through the shutdown effect. In some embodiments, the thickness of the isolation film is in the range of about 5 μm to 50 μm.
在一些实施例中，隔离膜表面还可以包括多孔层，多孔层设置在隔离膜的基材的至少一个表面上，多孔层包括无机颗粒和粘结剂，无机颗粒选自氧化铝(Al 2O 3)、氧化硅(SiO 2)、氧化镁(MgO)、氧化钛(TiO 2)、二氧化铪(HfO 2)、氧化锡(SnO 2)、二氧化铈(CeO 2)、氧化镍(NiO)、氧化锌(ZnO)、氧化钙(CaO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、碳化硅(SiC)、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡中的至少一种。在一些实施例中，隔离膜的孔具有在约0.01μm至1μm的范围的直径。多孔层的粘结剂选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。隔离膜表面的多孔层可以提升隔离膜的耐热性能、抗氧化性能和电解质浸润性能，增强隔离膜与极片之间的粘结性。 In some embodiments, the surface of the separator may further include a porous layer, the porous layer is disposed on at least one surface of the substrate of the separator, the porous layer includes inorganic particles and a binder, and the inorganic particles are selected from alumina (Al 2 O 3 ), silicon oxide (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), hafnium dioxide (HfO 2 ), tin oxide (SnO 2 ), ceria (CeO 2 ), nickel oxide (NiO) ), zinc oxide (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, hydroxide At least one of calcium or barium sulfate. In some embodiments, the pores of the isolation membrane have diameters in the range of about 0.01 μm to 1 μm. The binder of the porous layer is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyamide At least one of vinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene. The porous layer on the surface of the separator can improve the heat resistance, oxidation resistance and electrolyte wettability of the separator, and enhance the adhesion between the separator and the pole piece.
在本申请的一些实施例中，电化学装置的电极组件为卷绕式电极组件、堆叠式电极组件或折叠式电极组件。在一些实施例中，电化学装置的正极和/或负极可以是卷绕或堆叠式形成的多层结构，也可以是单层正极、隔离膜、单层负极叠加的单层结构。In some embodiments of the present application, the electrode assembly of the electrochemical device is a wound electrode assembly, a stacked electrode assembly, or a folded electrode assembly. In some embodiments, the positive electrode and/or the negative electrode of the electrochemical device may be a multi-layer structure formed by winding or stacking, or may be a single-layer structure in which a single-layer positive electrode, a separator, and a single-layer negative electrode are stacked.
在一些实施例中，电化学装置包括锂离子电池，但是本申请不限于此。在一些实施例中，电化学装置还可以包括电解质。电解质可以是凝胶电解质、固态电解质和电解液中的一种或多种，电解液包括锂盐和非水溶剂。锂盐选自LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6、LiBOB或者二氟硼酸锂中的一种或多种。例如，锂盐选用LiPF 6，因为它具有高的离子导电率并可以改善循环特性。 In some embodiments, the electrochemical device includes a lithium-ion battery, although the present application is not so limited. In some embodiments, the electrochemical device may also include an electrolyte. The electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolytic solution, and the electrolytic solution includes a lithium salt and a non-aqueous solvent. The lithium salt is selected from LiPF6, LiBF4 , LiAsF6, LiClO4 , LiB ( C6H5 ) 4 , LiCH3SO3 , LiCF3SO3 , LiN ( SO2CF3 ) 2 , LiC ( SO2CF3 ) 3 , LiSiF 6 , LiBOB or one or more of lithium difluoroborate. For example, LiPF 6 is chosen as the lithium salt because it has high ionic conductivity and can improve cycle characteristics.
非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶 剂或它们的组合。The non-aqueous solvent may be carbonate compounds, carboxylate compounds, ether compounds, other organic solvents, or a combination thereof.
碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物、氟代碳酸酯化合物或其组合。The carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
链状碳酸酯化合物的实例为碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)及其组合。所述环状碳酸酯化合物的实例为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)或者其组合。所述氟代碳酸酯化合物的实例为碳酸氟代亚乙酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯、碳酸三氟甲基亚乙酯或者其组合。Examples of chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl esters (MEC) and combinations thereof. Examples of the cyclic carbonate compound are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), or a combination thereof. Examples of the fluorocarbonate compound are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate Fluoroethylene, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-carbonate -Difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, or a combination thereof.
羧酸酯化合物的实例为乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯、甲酸甲酯或者其组合。Examples of carboxylate compounds are methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, decolactone, Valerolactone, mevalonolactone, caprolactone, methyl formate, or a combination thereof.
醚化合物的实例为二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基乙烷、2-甲基四氢呋喃、四氢呋喃或者其组合。Examples of ether compounds are dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxy Ethane, 2-methyltetrahydrofuran, tetrahydrofuran, or a combination thereof.
其它有机溶剂的实例为二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、和磷酸酯或者其组合。Examples of other organic solvents are dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, methyl amide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters or combinations thereof.
在本申请的一些实施例中，以锂离子电池为例，将正极、隔离膜、负极按顺序卷绕或堆叠成电极件，之后装入例如铝塑膜中进行封装，注入电解液，化成、封装，即制成锂离子电池。然后，对制备的锂离子电池进行性能测试。In some embodiments of the present application, taking a lithium-ion battery as an example, the positive electrode, the separator, and the negative electrode are wound or stacked in sequence to form electrode parts, and then packed into, for example, an aluminum-plastic film for encapsulation, injected with electrolyte, and formed into, Encapsulation, that is, to make a lithium-ion battery. Then, the performance test of the prepared lithium-ion battery was carried out.
本领域的技术人员将理解，以上描述的电化学装置(例如，锂离子电池)的制备方法仅是实施例。在不背离本申请公开的内容的基础上，可以采用本领域常用的其他方法。Those skilled in the art will understand that the methods of making electrochemical devices (eg, lithium ion batteries) described above are only examples. Other methods commonly used in the art may be employed without departing from the disclosure of the present application.
本申请的实施例还提供了包括上述电化学装置的电子装置。本申请实施例的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。Embodiments of the present application also provide electronic devices including the above electrochemical devices. The electronic device in the embodiment of the present application is not particularly limited, and it may be used in any electronic device known in the prior art. In some embodiments, electronic devices may 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, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
下面列举了一些具体实施例和对比例以更好地对本申请进行说明，其中，采用锂离子电池作为示例。Some specific embodiments and comparative examples are listed below to better illustrate the present application, wherein a lithium-ion battery is used as an example.
实施例1Example 1
正极的制备：采用铝箔作为正极的正极集流体，将正极活性材料磷酸铁锂、导电剂导电炭黑、聚偏二氟乙烯按重量比96：2.4：1.6的比例溶于N-甲基吡咯烷酮(NMP)溶液中，形成第二涂层的浆料，将该浆料涂覆于正极集流体上，涂覆厚度为120μm，得到第二涂层，在正极集流体上邻接第二涂层涂布一层第一涂层浆料，得到第一涂层，具体地，将88.9wt％陶瓷颗粒Al 2O 3、0.1wt％碳纳米管和11wt％聚偏氟乙烯溶于N-甲基吡咯烷酮(NMP)溶液中，形成第一涂层浆料。然后经过干燥、冷压、裁切后得到正极。其中，第一涂层的涂覆厚度为60μm，宽度为5μm，第一涂层和第二涂层之间的交互宽度为1mm。 The preparation of the positive electrode: using aluminum foil as the positive electrode current collector of the positive electrode, dissolving the positive electrode active material lithium iron phosphate, conductive carbon black, and polyvinylidene fluoride in a ratio of 96:2.4:1.6 by weight in N-methylpyrrolidone ( NMP) solution, form the slurry of the second coating layer, and coat the slurry on the positive electrode current collector with a coating thickness of 120 μm to obtain a second coating layer, which is coated adjacent to the second coating layer on the positive electrode current collector A layer of first coating slurry to obtain a first coating, specifically, 88.9 wt% ceramic particles Al 2 O 3 , 0.1 wt % carbon nanotubes and 11 wt % polyvinylidene fluoride were dissolved in N-methylpyrrolidone ( NMP) solution to form a first coating slurry. Then the positive electrode is obtained after drying, cold pressing and cutting. Wherein, the coating thickness of the first coating layer is 60 μm, the width is 5 μm, and the interaction width between the first coating layer and the second coating layer is 1 mm.
负极的制备：将人造石墨，羧甲基纤维素钠(CMC)和粘结剂丁苯橡胶按重量比97.7：1.3：1的比例溶于去离子水中，形成负极浆料。采用10μm厚度铜箔作为负极的集流体，将负极浆料涂覆于负极的集流体上，干燥，裁切后得到负极。Preparation of negative electrode: artificial graphite, sodium carboxymethyl cellulose (CMC) and binder styrene-butadiene rubber were dissolved in deionized water in a weight ratio of 97.7:1.3:1 to form a negative electrode slurry. A 10 μm-thick copper foil was used as the current collector of the negative electrode, and the negative electrode slurry was coated on the current collector of the negative electrode, dried, and cut to obtain the negative electrode.
隔离膜的制备：隔离膜基材为8μm厚的聚乙烯(PE)，在隔离膜基材的两侧各涂覆2μm氧化铝陶瓷层，最后在涂布了陶瓷层的两侧各涂覆2.5mg/cm 2的粘结剂聚偏氟乙烯(PVDF)，烘干。 Preparation of isolation film: The isolation film substrate is polyethylene (PE) with a thickness of 8 μm, and 2 μm alumina ceramic layers are coated on both sides of the isolation film substrate, and finally, 2.5 μm alumina ceramic layers are coated on both sides of the coated ceramic layer. mg/cm 2 binder polyvinylidene fluoride (PVDF), dried.
电解液的制备：在含水量小于10ppm的环境下，将LiPF 6加入非水有机溶剂(碳酸乙烯酯(EC)：碳酸丙烯酯(PC)＝50：50，重量比)，LiPF 6的浓度为1.15mol/L，混合均匀，得到电解液。 Preparation of electrolyte: in an environment with a water content of less than 10 ppm, LiPF 6 is added to a non-aqueous organic solvent (ethylene carbonate (EC): propylene carbonate (PC) = 50:50, weight ratio), and the concentration of LiPF 6 is 1.15mol/L, mixed evenly to obtain electrolyte.
锂离子电池的制备：将正极、隔离膜、负极按顺序依次叠好，使隔离膜处于正极和负极中间起到隔离的作用，并卷绕得到电极组件。将电极组件置于外包装铝塑膜中，在80℃下脱去水分后，注入上述电解液并封装，经过化成，脱气，切边等工艺流程得到锂离子电池。Preparation of lithium ion battery: stack the positive electrode, the separator and the negative electrode in sequence, so that the separator is placed between the positive electrode and the negative electrode for isolation, and then the electrode assembly is obtained by winding. The electrode assembly is placed in the outer packaging aluminum-plastic film, and after dehydration at 80°C, the above electrolyte is injected and packaged, and the lithium ion battery is obtained through the process of forming, degassing, and trimming.
实施例和对比例是在实施例1或实施例5的步骤的基础上进行参数变更，具体变更的参数如下面的表格所示。Examples and comparative examples are based on the steps of Example 1 or Example 5, and parameters are changed, and the specific parameters to be changed are shown in the following table.
下面描述本申请的各个参数的测试方法。The test methods for each parameter of the present application are described below.
锂离子电池的容量测试：Lithium-ion battery capacity test:
在25±3℃环境中静置30min，以0.5C(1C为锂离子电池的额定容量)电流恒流充电至电压至3.6V(额定电压)，转恒压充电，电流至0.05C时停止充电；静置30min；以0.2C电流将锂离子电池放电至2.5V，静置30min；取放电容量作为锂离子电池的实际容量。Stand for 30min in 25±3℃ environment, charge with 0.5C (1C is the rated capacity of lithium-ion battery) current constant current until the voltage reaches 3.6V (rated voltage), transfer to constant voltage charging, stop charging when the current reaches 0.05C ; Stand for 30min; discharge the lithium-ion battery to 2.5V with 0.2C current, and let it stand for 30min; take the discharge capacity as the actual capacity of the lithium-ion battery.
倍率放电容量保持率测试：Rate discharge capacity retention test:
将锂离子电池置于25℃±2℃的恒温箱中静置2小时，以1C倍率进行充电至4.48V，然后在4.48V下恒压充电至0.05C。以1C倍率放电至3.0V进行循环性能测试，得到参考放电容量；以2C倍率放电至3.0V进行循环性能测试，得到实际放电容量，2C放电倍率下容量保持率＝实际放电容量/参考放电容量*100％。The lithium-ion battery was placed in a constant temperature box at 25°C ± 2°C for 2 hours, charged to 4.48V at a rate of 1C, and then charged to 0.05C at a constant voltage of 4.48V. Discharge at 1C rate to 3.0V for cycle performance test to obtain reference discharge capacity; discharge at 2C rate to 3.0V for cycle performance test to obtain actual discharge capacity, capacity retention rate at 2C discharge rate = actual discharge capacity/reference discharge capacity* 100%.
导电剂BET的测试方法：Test method of conductive agent BET:
将电池拆解得到正极(含集流体、第一涂层和第二涂层)，使用碳酸二甲酯(DMC)溶剂将极片浸泡30min后清洗掉电解液，反复浸泡与清洗3次。然后将正极自然风干。风干后的极片，使用德亨DHTW-15取样切台，沿距离第二涂层0.5mm处将极片切开，得到含集流体和第一涂层的极片，然后裁切成长40mm的样品，共20份。将20份样品放入洁净的500mL烧杯中，加入NMP 200g浸泡1h，然后用镊子夹取样品清洗后，将铝箔捞出，得到含第一涂层的浆料。将烧杯浆料使用超声清洗机(频率10Hz)分散1h，然后将浆料 倒入离心管，使用离心机离心(转速4000rpm，时间30min)，取上层液体超声分散后用0.5μm的滤纸过滤，并用NMP反复冲洗5次，将滤纸表面所得固态样品放入烤箱100℃烘烤30min，得到的粉末使用Micromeritics TriStar Ⅱ 3020设备测试其BET。The battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in dimethyl carbonate (DMC) solvent for 30 minutes, and then the electrolyte was washed off, and the soaking and cleaning were repeated 3 times. The positive electrode was then air-dried naturally. After air-drying the pole piece, use Deheng DHTW-15 sampling cutting table to cut the pole piece along the distance of 0.5mm from the second coating layer to obtain the pole piece containing the current collector and the first coating layer, and then cut the pole piece with a length of 40mm. There are 20 samples in total. Put 20 samples into a clean 500mL beaker, add 200g of NMP to soak for 1 hour, then pick up the samples with tweezers and wash them, then remove the aluminum foil to obtain a slurry containing the first coating. Disperse the slurry in the beaker with an ultrasonic cleaner (frequency 10Hz) for 1 hour, then pour the slurry into a centrifuge tube and centrifuge with a centrifuge (speed 4000rpm, time 30min), take the upper layer of liquid after ultrasonic dispersion and filter with 0.5μm filter paper, and use NMP was rinsed repeatedly for 5 times, and the solid sample obtained on the surface of the filter paper was placed in an oven at 100 °C for 30 min, and the obtained powder was tested for its BET using Micromeritics TriStar II 3020 equipment.
厚度的测试方法：Thickness test method:
将电池拆解得到正极(含集流体、第一涂层和第二涂层)，使用DMC溶剂将极片浸泡30min后清洗掉电解液，反复浸泡与清洗3次。然后将正极自然风干。风干后的极片，使用万分尺分别测试极耳处空铝箔的厚度T3、极耳处第一涂层的极片厚度(要求测试第一涂层的中心)T4、第二涂层的极片厚度(要求测试第二涂层距离边缘50mm处)T5，然后通过公式计算：(1)第一涂层厚度T1＝(T4-T3)/2；(2)第二涂层厚度T2＝(T5-T3)/2。要求测试15组数据，取平均值。The battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in DMC solvent for 30 minutes, and then the electrolyte was washed away, and the soaking and cleaning were repeated 3 times. The positive electrode was then air-dried naturally. After air-drying the pole piece, use a micrometer to measure the thickness of the empty aluminum foil at the pole tab T3, the thickness of the pole piece of the first coating at the pole tab (the center of the first coating is required to be tested) T4, and the pole piece of the second coating. Thickness (required to test the second coating at a distance of 50mm from the edge) T5, and then calculated by the formula: (1) the thickness of the first coating T1=(T4-T3)/2; (2) the thickness of the second coating T2=(T5 -T3)/2. It is required to test 15 sets of data and take the average value.
第一涂层的电阻测试：Resistance test of the first coating:
将电池拆解得到正极(含集流体、第一涂层和第二涂层)，使用DMC溶剂将极片浸泡30min后清洗掉电解液，反复浸泡与清洗3次。然后将正极自然风干。风干后的极片，使用德亨DHTW-15取样切台，沿距离第二涂层0.5mm处将极片切开，得到含集流体和第一涂层的极片，然后裁切成长*宽＝40mm*2mm的样品，共100份。将100份样品放入洁净的50mL烧杯中，加入NMP 10g浸泡1h，然后用镊子夹取样品清洗后，将铝箔捞出，得到含第一涂层的浆料。将烧杯浆料使用超声清洗机(频率10Hz)分散1h后，使用深圳科晶MSK-AFA-SC200平板涂覆机，50um的刮刀将浆料刮涂到10um厚的铝箔上，然后将刮涂极片放入烘箱120℃烘烤30min干燥。得到的第一涂层的极片样品使用日置BT3562电阻仪进行数据采集，接触铜柱直径14mm，测试压力25MPa(0.4t)，采点时间15s。将样品放置于两个铜柱之间，按下开关测试电阻。测试原理：交流四端子测试法，向测试物加载交流电流I s，传感器采集测试物引起的电压降V IS，根据欧姆定律推导相应电阻R。 The battery was disassembled to obtain the positive electrode (including the current collector, the first coating layer and the second coating layer), and the electrode piece was soaked in DMC solvent for 30 minutes, and then the electrolyte was washed away, and the soaking and cleaning were repeated 3 times. The positive electrode was then air-dried naturally. After air-drying the pole piece, use Deheng DHTW-15 sampling cutting table to cut the pole piece along 0.5mm from the second coating layer to obtain the pole piece containing the current collector and the first coating layer, and then cut to length*width = 40mm*2mm samples, 100 copies in total. Put 100 samples into a clean 50mL beaker, add 10g of NMP to soak for 1 hour, then pick up the samples with tweezers and wash them, then remove the aluminum foil to obtain a slurry containing the first coating. After dispersing the slurry in the beaker with an ultrasonic cleaner (frequency 10Hz) for 1 hour, use Shenzhen Kejing MSK-AFA-SC200 flat-panel coating machine and a 50um scraper to scrape the slurry onto a 10um thick aluminum foil, and then apply the scraper to the aluminum foil. The sheets were placed in an oven at 120°C for 30 min to dry. The obtained first-coated pole piece sample was collected using a Nippon BT3562 resistance meter, the diameter of the contact copper column was 14 mm, the test pressure was 25 MPa (0.4 t), and the sampling time was 15 s. Place the sample between two copper posts and press the switch to test the resistance. Test principle: AC four-terminal test method, load AC current Is to the test object, the sensor collects the voltage drop V IS caused by the test object, and derives the corresponding resistance R according to Ohm 's law.
表1示出了实施例1至7和对比例1的各个参数和评估结果。其中，在实施例3和4中，第一涂层中的陶瓷颗粒和导电剂的含量与实施例1不同。Table 1 shows the respective parameters and evaluation results of Examples 1 to 7 and Comparative Example 1. Among them, in Examples 3 and 4, the contents of the ceramic particles and the conductive agent in the first coating layer were different from those in Example 1.
在对比例1中，第一涂层的成分为88wt％的陶瓷颗粒Al 2O 3和12wt％聚偏氟乙烯(PVDF)。 In Comparative Example 1, the composition of the first coating was 88 wt % of ceramic particles Al 2 O 3 and 12 wt % of polyvinylidene fluoride (PVDF).
在实施例4至7中，在第一涂层中添加了分散剂PVP，并且第一涂层的各成分含量与实施例1不同。In Examples 4 to 7, the dispersant PVP was added in the first coating layer, and the content of each component of the first coating layer was different from that of Example 1.
表1Table 1
Figure PCTCN2021082144-appb-000001
Figure PCTCN2021082144-appb-000001
Figure PCTCN2021082144-appb-000002
Figure PCTCN2021082144-appb-000002
其中，“/”表示不存在，下同。Among them, "/" means does not exist, the same below.
通过比较实施例1至3和对比例1可知，通过在第一涂层中添加导电剂，电化学装置的容量和容量保持率均具有显著提升，这是由于第一涂层中的导电剂可以缓解或减轻对第二涂层的导电网络的破坏。By comparing Examples 1 to 3 and Comparative Example 1, it can be seen that by adding a conductive agent in the first coating, the capacity and capacity retention rate of the electrochemical device are significantly improved, because the conductive agent in the first coating can Alleviate or mitigate damage to the conductive network of the second coating.
另外，通过比较实施例1至3可知，随着第一涂层中的导电剂的质量含量的增大，电化学装置的容量和容量保持率有增大的趋势。这是由于添加导电剂的第一涂层在扩散到第二涂层之后对第二涂层的导电网络的影响更小，有利于第二涂层的容量发挥和倍率性能。In addition, by comparing Examples 1 to 3, it can be seen that with the increase of the mass content of the conductive agent in the first coating layer, the capacity and capacity retention rate of the electrochemical device tend to increase. This is because the first coating with the conductive agent added has less influence on the conductive network of the second coating after diffusing into the second coating, which is beneficial to the capacity exertion and rate performance of the second coating.
通过比较实施例1和4可知，在第一涂层中添加聚吡咯烷酮(PVP)之后，电化学装置的容量和容量保持率提升。这是由于作为分散剂的PVP可以将导电剂包覆到陶瓷颗粒的表面，在保证第一涂层整体绝缘的前提下，改善单个陶瓷颗粒的导电性，即使第二涂层和第一涂层在涂布干燥过程中发生相互扩散，也不会对极片的外观有明显影响，而且因单个陶瓷颗粒已具备一定导电性，扩散到第二涂层之后也不再影响第二涂层的导电网络结构，从而改善电化学装置的容量发挥和动力学性能。通过比较2和5以及比较实施例3和6可以得到同样的结论。By comparing Examples 1 and 4, it can be seen that after adding polypyrrolidone (PVP) to the first coating, the capacity and capacity retention rate of the electrochemical device are improved. This is because PVP as a dispersant can coat the surface of the ceramic particles with the conductive agent, and improve the conductivity of a single ceramic particle under the premise of ensuring the overall insulation of the first coating, even if the second coating and the first coating Interdiffusion occurs during the coating and drying process, and it will not have a significant impact on the appearance of the pole piece, and because a single ceramic particle already has a certain conductivity, it will not affect the conductivity of the second coating after diffusion into the second coating. network structure, thereby improving the capacity and kinetic performance of electrochemical devices. The same conclusion can be drawn by comparing 2 and 5 and comparing Examples 3 and 6.
通过比较实施例4至7可知，在导电剂含量较大时，第一涂层的电阻减小，会增加正极和负极接触短路的几率。By comparing Examples 4 to 7, it can be seen that when the conductive agent content is larger, the resistance of the first coating decreases, which increases the probability of short circuit between the positive electrode and the negative electrode.
表2示出了实施例8至35的各个参数和评估结果。其中，在实施例8至11中，第一涂层中的陶瓷颗粒的种类与实施例5不同。Table 2 shows the respective parameters and evaluation results of Examples 8 to 35. Among them, in Examples 8 to 11, the kinds of ceramic particles in the first coating layer were different from those in Example 5.
在实施例12至14中，第一涂层的陶瓷颗粒和粘结剂聚偏氟乙烯的质量含量与实施例5不同。In Examples 12 to 14, the mass contents of the ceramic particles and the binder polyvinylidene fluoride of the first coating layer were different from those of Example 5.
在实施例15至17中，第一涂层的分散剂的种类与实施例5不同。In Examples 15 to 17, the kind of the dispersant of the first coating layer was different from that of Example 5.
在实施例18至20中，第一涂层的分散剂PVP的质量含量与实施例5不同。In Examples 18 to 20, the mass content of the dispersant PVP of the first coating layer was different from that of Example 5.
在实施例21至24中，第一涂层的厚度与实施例5不同。In Examples 21 to 24, the thickness of the first coating was different from Example 5.
在实施例25和27中，第一涂层的宽度与实施例5不同。In Examples 25 and 27, the width of the first coating was different from Example 5.
在实施例28至32中，第一涂层中的导电剂的比表面积(BET)与实施例5不同。In Examples 28 to 32, the specific surface area (BET) of the conductive agent in the first coating was different from Example 5.
在实施例33至35中，第一涂层和第二涂层的交互区宽度与实施例5不同。应该理解，该交互区是由第一涂层和第二涂层的重叠涂布或第一涂层向第二涂层的扩散引起的。In Examples 33 to 35, the width of the interaction zone of the first coating and the second coating was different from that of Example 5. It should be understood that the interaction zone is caused by overlapping application of the first coating and the second coating or diffusion of the first coating to the second coating.
表2Table 2
Figure PCTCN2021082144-appb-000003
Figure PCTCN2021082144-appb-000003
Figure PCTCN2021082144-appb-000004
Figure PCTCN2021082144-appb-000004
Figure PCTCN2021082144-appb-000005
Figure PCTCN2021082144-appb-000005
Figure PCTCN2021082144-appb-000006
Figure PCTCN2021082144-appb-000006
通过比较实施例8至11可知，采用不同种类的陶瓷颗粒，均可以获得较好的电化学装置的容量和容量保持率，陶瓷颗粒种类对第一涂层与第二涂层交互区或重叠区构建导电网络的能力无明显影响，对第二涂层的容量发挥和放电倍率无明显影响。By comparing Examples 8 to 11, it can be seen that with different types of ceramic particles, better capacity and capacity retention rate of electrochemical devices can be obtained. The ability to build a conductive network has no significant effect, and has no significant effect on the capacity development and discharge rate of the second coating.
通过比较实施例12至14可知，陶瓷颗粒的质量含量越高，PVDF的质量含量降低，第一涂层的导电性提升，与第二涂层形成的交互区构建导电网络能力越强，第二涂层的容量发挥和放电倍率更好。By comparing Examples 12 to 14, it can be seen that the higher the mass content of ceramic particles, the lower the mass content of PVDF, the higher the conductivity of the first coating, the stronger the ability to build a conductive network in the interactive area formed with the second coating, and the greater the ability of the second coating to build a conductive network. The capacity play and discharge rate of the coating are better.
通过比较实施例15至17可知，采用不同种类的分散剂，均可以获得较好的电化学装置的容量和容量保持率，第一涂层中的分散剂种类对与第二涂层形成的交互区构建导电网络能力无影响，不影响第二涂层的容量发挥和倍率放电。By comparing Examples 15 to 17, it can be seen that with different types of dispersants, better capacity and capacity retention rate of electrochemical devices can be obtained, and the interaction between the types of dispersants in the first coating and the formation of the second coating The ability to build a conductive network in the region has no effect, and does not affect the capacity development and rate discharge of the second coating.
通过比较实施例18至20可知，第一涂层中的分散剂改善导电剂的分散，有利于第一涂层和第二涂层的交互区导电网络构建，但过多分散剂会阻碍Li +扩散，影响第二涂层的容量发挥和倍率放电，第一涂层中的分散剂的质量含量优选小于等于0.7％。 By comparing Examples 18 to 20, it can be seen that the dispersant in the first coating improves the dispersion of the conductive agent, which is beneficial to the construction of the conductive network in the interactive region of the first coating and the second coating, but too much dispersant will hinder the diffusion of Li + , which affects the capacity performance and rate discharge of the second coating, and the mass content of the dispersant in the first coating is preferably less than or equal to 0.7%.
通过比较实施例21至24可知，第一涂层的厚度越厚，则第一涂层与第二涂层形成的交互区中的绝缘陶瓷颗粒越多，不利于第二涂层的导电网络构建，从而恶化第二涂层的容量发挥和倍率性能。另外，第一涂层的厚度与第二涂层的厚度的比值优选小于等于0.7，以避免在冷压时冷压辊接触第一涂层导致第一涂层的损坏。By comparing Examples 21 to 24, it can be seen that the thicker the thickness of the first coating, the more insulating ceramic particles in the interaction area formed by the first coating and the second coating, which is not conducive to the construction of the conductive network of the second coating , thereby deteriorating the capacity exertion and rate capability of the second coating. In addition, the ratio of the thickness of the first coating to the thickness of the second coating is preferably less than or equal to 0.7, so as to avoid damage to the first coating caused by the contact of the cold pressing roller with the first coating during cold pressing.
通过比较实施例25至27可知，在第一涂层和第二涂层的交互区宽度相同条件下，第一涂层的宽度对第二涂层的容量发挥和倍率性能无明显影响，但宽度太大会降低电化学装置的能量密度。By comparing Examples 25 to 27, it can be seen that under the condition that the width of the interaction area of the first coating and the second coating is the same, the width of the first coating has no obvious effect on the capacity performance and rate performance of the second coating, but the width Too large will reduce the energy density of the electrochemical device.
通过比较实施例28至32可知，第一涂层的导电剂的比表面积在50m 2/g至1500m 2/g时，导电剂的比表面积越大，越有利于第一涂层和第二涂层的交互区的导电网络的构建，容量发挥和倍率放电更优。但时在第一涂层的导电剂的比表面积小于50m 2/g或者大于1500m 2/g，第一涂层和第二涂层的交互区的导电网络的构建较差，容量发挥和倍率放电反而恶化。另外，导电剂的比表面积过大影响导电剂的均匀分散。 By comparing Examples 28 to 32, it can be seen that when the specific surface area of the conductive agent of the first coating is 50 m 2 /g to 1500 m 2 /g, the larger the specific surface area of the conductive agent, the more favorable the first coating and the second coating are. The construction of the conductive network in the interaction area of the layers, the capacity development and the rate discharge are better. However, when the specific surface area of the conductive agent in the first coating layer is less than 50 m 2 /g or greater than 1500 m 2 /g, the construction of the conductive network in the interactive area of the first coating layer and the second coating layer is poor, and the capacity exertion and rate discharge are poor. Instead it worsens. In addition, if the specific surface area of the conductive agent is too large, the uniform dispersion of the conductive agent is affected.
通过比较实施例33至35可知，第一涂层与第二涂层的交互区宽度越小，则第一涂层对第二涂层的导电网络影响越小，第二涂层的容量发挥和倍率性能越好。By comparing Examples 33 to 35, it can be seen that the smaller the width of the interaction area between the first coating and the second coating, the less the first coating has on the conductive network of the second coating, and the capacity of the second coating is better. The better the rate performance.
以上描述仅为本申请的较佳实施例以及对所运用技术原理的说明。本领域技术人员应当理解，本申请中所涉及的公开范围，并不限于上述技术特征的特定组合而成的技术方案，同时也应涵盖由上述技术特征或其等同特征进行任意组合而形成的其它技术方案。例如上述特征与本申请中公开的具有类似功能的技术特征进行互相替换而形成的技术方案。The above description is only a preferred embodiment of the present application and an illustration of the applied technical principles. Those skilled in the art should understand that the scope of disclosure involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also covers other technical solutions formed by any combination of the above-mentioned technical features or their equivalents. Technical solutions. For example, a technical solution is formed by replacing the above-mentioned features with the technical features disclosed in this application with similar functions.

Claims (9)

  1. 一种电化学装置，其包括电极，所述电极包括集流体、第一涂层和第二涂层，所述第二涂层包括活性材料，所述第二涂层设置于所述集流体的至少一个表面上，所述第一涂层沿所述集流体靠近极耳部的侧边设置，并邻接于所述第二涂层或与所述第二涂层部分重合，其中，所述第一涂层包括陶瓷颗粒、粘结剂和导电剂。An electrochemical device comprising an electrode comprising a current collector, a first coating layer and a second coating layer, the second coating layer comprising an active material, the second coating layer disposed on the current collector On at least one surface, the first coating is disposed along the side of the current collector close to the tab portion, and is adjacent to or partially overlapped with the second coating, wherein the first coating is A coating includes ceramic particles, a binder, and a conductive agent.
  2. 根据权利要求1所述的电化学装置，其中，所述导电剂包括导电炭黑、碳纳米管、碳纤维或石墨烯中的至少一种。The electrochemical device of claim 1, wherein the conductive agent comprises at least one of conductive carbon black, carbon nanotubes, carbon fibers, or graphene.
  3. 根据权利要求1所述的电化学装置，其中，基于所述第一涂层的总质量，所述导电剂的质量含量为0.1％至1.4％。The electrochemical device of claim 1, wherein the mass content of the conductive agent is 0.1% to 1.4% based on the total mass of the first coating layer.
  4. 根据权利要求1所述的电化学装置，其中，所述第一涂层还包括分散剂，所述分散剂包括酰胺化合物、脂类化合物或醚类化合物中的至少一种。The electrochemical device of claim 1, wherein the first coating layer further comprises a dispersant, the dispersant comprising at least one of an amide compound, a lipid compound, or an ether compound.
  5. 根据权利要求4所述的电化学装置，其中，所述分散剂包括聚吡咯烷酮、聚丙烯酸脂、聚醚改性硅氧烷、聚醚改性聚丙烯酸酯、聚醚改性醇氧硅烷、脂肪酸甲酯、异丁醇胺、乙烯-醋酸乙烯共聚物、聚甲基丙烯酸甲酯或聚(1,4-丁二醇丁二酸)酯中的至少一种。The electrochemical device according to claim 4, wherein the dispersing agent comprises polypyrrolidone, polyacrylate, polyether-modified siloxane, polyether-modified polyacrylate, polyether-modified alkoxysilane, fatty acid At least one of methyl ester, isobutanolamine, ethylene-vinyl acetate copolymer, polymethyl methacrylate or poly(1,4-butanediol succinate).
  6. 根据权利要求1所述的电化学装置，其中，所述第一涂层还包括分散剂，基于所述第一涂层的总质量，所述分散剂的质量含量为0.05％至0.7％。The electrochemical device of claim 1, wherein the first coating layer further comprises a dispersant, and the mass content of the dispersant is 0.05% to 0.7% based on the total mass of the first coating layer.
  7. 根据权利要求1所述的电化学装置，其中，所述电化学装置满足以下条件中的至少一个：The electrochemical device of claim 1, wherein the electrochemical device satisfies at least one of the following conditions:
    所述第一涂层还包括分散剂，所述第一涂层中的所述分散剂与所述导电剂的质量含量的比率为0.07至1；The first coating layer further includes a dispersant, and the ratio of the mass content of the dispersant to the conductive agent in the first coating layer is 0.07 to 1;
    所述第一涂层的厚度与所述第二涂层的厚度的比率小于等于0.7，并且所述第一涂层的厚度范围为20μm至100μm；The ratio of the thickness of the first coating layer to the thickness of the second coating layer is less than or equal to 0.7, and the thickness of the first coating layer ranges from 20 μm to 100 μm;
    所述第一涂层的宽度范围为3mm至10mm；The width of the first coating layer ranges from 3mm to 10mm;
    所述导电剂的比表面积为50m 2/g至1500m 2/g。 The conductive agent has a specific surface area of 50 m 2 /g to 1500 m 2 /g.
  8. 根据权利要求1所述的电化学装置，其中，所述电化学装置满足以下条件中的至少一个：The electrochemical device of claim 1, wherein the electrochemical device satisfies at least one of the following conditions:
    所述陶瓷颗粒包括氧化物、氮化物或碳化物中的至少一种；The ceramic particles include at least one of oxides, nitrides or carbides;
    所述陶瓷颗粒包括Al 2O 3、ZrO 2、TiN、Si 3N 4、SiC、TiC、Cr 3C 2、VC或B 4C中的至少一种； The ceramic particles include at least one of Al 2 O 3 , ZrO 2 , TiN, Si 3 N 4 , SiC, TiC, Cr 3 C 2 , VC or B 4 C;
    所述第一涂层中的所述陶瓷颗粒的质量含量为77％至98％；The mass content of the ceramic particles in the first coating is 77% to 98%;
    所述粘结剂包括聚偏氟乙烯、聚酰亚胺或过氧乙酰硝酸酯中的至少一种；The binder includes at least one of polyvinylidene fluoride, polyimide or peroxyacetyl nitrate;
    所述第一涂层中的所述粘结剂的质量含量为1％至22％。The mass content of the binder in the first coating layer is 1% to 22%.
  9. 一种电子装置，包括根据权利要求1至8中任一项所述的电化学装置。An electronic device comprising the electrochemical device according to any one of claims 1 to 8.
PCT/CN2021/082144 2021-03-22 2021-03-22 Electrochemical device and electronic device WO2022198401A1 (en)

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CN114530673A (en) * 2022-02-21 2022-05-24 广州小鹏汽车科技有限公司 Battery cell manufacturing method
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080138699A1 (en) * 2006-12-07 2008-06-12 Jinhee Kim Jelly roll electrode assembly and secondary battery using the assembly
CN110178247A (en) * 2016-11-04 2019-08-27 株式会社杰士汤浅国际 The manufacturing method of charge storage element electrode, charge storage element and charge storage element electrode
CN110518249A (en) * 2019-09-09 2019-11-29 江苏塔菲尔新能源科技股份有限公司 A kind of battery core pole piece and obtained battery core is assembled by it
CN112490403A (en) * 2020-04-08 2021-03-12 万向一二三股份公司 Pole piece with uniform thickness of lug ceramic coating and preparation method thereof
CN113036075A (en) * 2021-02-26 2021-06-25 珠海冠宇电池股份有限公司 Pole piece and battery cell

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100438146C (en) * 2005-10-12 2008-11-26 比亚迪股份有限公司 Lithium ion cell, anode therefor and preparing method thereof
KR102494519B1 (en) * 2015-07-14 2023-01-31 니폰 제온 가부시키가이샤 Binder composition for secondary battery electrodes, conductive material paste composition for secondary battery electrodes, slurry composition for secondary battery electrodes, electrode for secondary batteries, and secondary battery
WO2019010405A1 (en) * 2017-07-07 2019-01-10 Ppg Industries Ohio, Inc. Electrode slurry composition for lithium ion electrical storage devices
CN110828826A (en) * 2018-08-08 2020-02-21 宁德时代新能源科技股份有限公司 Electrode plate and secondary battery
CN110957476A (en) * 2019-10-30 2020-04-03 深圳市卓能新能源股份有限公司 High-rate lithium ion power battery and manufacturing method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080138699A1 (en) * 2006-12-07 2008-06-12 Jinhee Kim Jelly roll electrode assembly and secondary battery using the assembly
CN110178247A (en) * 2016-11-04 2019-08-27 株式会社杰士汤浅国际 The manufacturing method of charge storage element electrode, charge storage element and charge storage element electrode
CN110518249A (en) * 2019-09-09 2019-11-29 江苏塔菲尔新能源科技股份有限公司 A kind of battery core pole piece and obtained battery core is assembled by it
CN112490403A (en) * 2020-04-08 2021-03-12 万向一二三股份公司 Pole piece with uniform thickness of lug ceramic coating and preparation method thereof
CN113036075A (en) * 2021-02-26 2021-06-25 珠海冠宇电池股份有限公司 Pole piece and battery cell

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