WO2023184365A1 - 电化学装置和电子装置 - Google Patents

电化学装置和电子装置 Download PDF

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Publication number
WO2023184365A1
WO2023184365A1 PCT/CN2022/084462 CN2022084462W WO2023184365A1 WO 2023184365 A1 WO2023184365 A1 WO 2023184365A1 CN 2022084462 W CN2022084462 W CN 2022084462W WO 2023184365 A1 WO2023184365 A1 WO 2023184365A1
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Prior art keywords
electrochemical device
functional layer
layer
current collector
insulating layer
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PCT/CN2022/084462
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English (en)
French (fr)
Inventor
王星永
韩冬冬
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宁德新能源科技有限公司
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to PCT/CN2022/084462 priority Critical patent/WO2023184365A1/zh
Priority to CN202280006591.6A priority patent/CN116250106A/zh
Publication of WO2023184365A1 publication Critical patent/WO2023184365A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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 energy storage, and specifically to an electrochemical device and an electronic device.
  • Secondary batteries are used more and more widely and are closely related to people's daily life. With the rapid development of smart electronic products, the requirements for the various properties of secondary batteries (such as energy density, cycle life and safety) are getting higher and higher.
  • the compaction density of positive and negative electrode sheets is constantly increasing. The high compaction density causes the electrolyte to be absorbed by the positive and negative active materials less and less, and the unabsorbed electrolyte
  • the liquid is free on the internal surface of the packaging bag (such as aluminum-plastic film), which easily causes the secondary battery packaging bag to be uneven and swollen in appearance, sacrificing the energy density of the secondary battery.
  • the safety performance of secondary batteries needs to be improved urgently. Therefore, there is an urgent need to provide a technical means that can significantly improve the appearance flatness, liquid retention capacity and safety performance of secondary batteries.
  • this application provides an electrochemical device and an electronic device including the electrochemical device.
  • the electrochemical device of the present application has good appearance, high liquid retention capacity and high safety.
  • the present application provides an electrochemical device, which includes an electrode assembly.
  • the electrode assembly includes an electrode pole piece.
  • the electrode pole piece includes a blank current collector and a composite layer disposed on the blank current collector.
  • the composite layer It includes an insulating layer and a functional layer, where the functional layer is located between the blank current collector and the insulating layer.
  • the thickness of the functional layer is H1 ⁇ m, and the thickness of the insulating layer is H2 ⁇ m, 1 ⁇ H1/H2 ⁇ 20.
  • the inventor of the present application has discovered through research that by providing an insulating layer and a functional layer capable of absorbing electrolyte in the current collector area where no active material is provided on the pole piece, that is, the blank current collector, on the one hand, the functional layer can improve the electrochemical device liquid retention. At the same time, it prevents the uneven surface of the electrochemical device caused by excess electrolyte dissociating unevenly inside the packaging bag (such as aluminum-plastic film), thus improving the appearance smoothness of the electrochemical device and reducing its energy density loss.
  • the insulating layer can avoid failure caused by internal short circuit when the electrochemical device is punctured by external force, thereby effectively improving the safety performance of the electrochemical device in puncture tests.
  • the ratio of the thickness of the functional layer to the insulating layer is within the above range, the electrochemical device can have the lowest energy density loss while meeting high liquid retention capacity and safety performance.
  • the functional layer is used to absorb electrolyte.
  • the functional layer is mainly used to absorb electrolyte.
  • the electrolyte retention rate of the functional layer is low, which is not conducive to improving the appearance of the electrochemical device.
  • the thickness of the functional layer is too high, the energy density of the electrochemical device will be reduced.
  • the insulating layer can avoid failure caused by internal short circuit when the electrochemical device is punctured by external force, and improves the safety performance of the electrochemical device. However, when the thickness of the insulating layer is too high, it will also reduce the energy density of the electrochemical device.
  • the bonding strength between the functional layer and the blank current collector is greater than the bonding strength between the insulating layer and the functional layer.
  • the bonding strength of the insulating layer is too high, and it is easy to stick to the roll during the preparation process, which is not conducive to processing.
  • the electrode assembly is a rolled electrode assembly, in which the composite layer is disposed on a blank current collector at the rolled end of the electrode pole piece.
  • the coverage rate of the composite layer on the blank current collector at the rolled end of the electrode pole piece is 80% to 100%.
  • the area of the projection of the insulating layer in the thickness direction of the electrode piece is greater than or equal to the area of the projection of the functional layer in the thickness direction of the electrode piece.
  • a non-destructive ultrasonic intelligent diagnostic system is used to test, and ultrasonic waves are emitted to the electrochemical device along the thickness direction of the electrochemical device to obtain a signal feedback distribution diagram of the ultrasonic wave from the electrochemical device.
  • the area of the chemical device, the area proportion of the area with super signal intensity greater than or equal to 1333mV is 30% to 95%.
  • Ultrasonic waves are mechanical waves that rely on media to propagate. When there is no electrolyte infiltration between electrode materials, ultrasonic waves can only propagate by relying on direct contact between electrode material particles. Irregular particles cause a large amount of reflection and refraction of ultrasonic waves.
  • the signal intensity is severely attenuated, and when the electrolyte can completely infiltrate the electrode material, the liquid environment provides a good propagation path for ultrasonic waves, and a considerable part of the ultrasonic waves will not be interfered by particles, thus ensuring the signal strength. Therefore, in the test of the non-destructive ultrasonic intelligent diagnosis system, the signal feedback intensity of the ultrasonic wave at each position of the electrochemical device can well characterize the distribution and infiltration of the electrolyte inside the electrochemical device. The higher the proportion of areas with high signal intensity, the greater the electrolysis. The liquid is more evenly distributed inside the electrochemical device.
  • the swelling degree of the functional layer ranges from 200% to 800%.
  • the swelling degree of the functional layer is less than 200%, the electrolyte retention rate of the functional layer is low, which is not conducive to improving the appearance of the electrochemical device.
  • the swelling degree of the functional layer is greater than 800%, the stability of the functional layer itself is poor, and defilming is likely to occur during the cycle, affecting the performance of the electrochemical device.
  • the functional layer has a swelling degree of 300% to 600%.
  • the functional layer includes substances whose spectra have absorption peaks in at least one of the following ranges: 2700cm -1 to 3100cm -1 , 1600cm -1 to 1800cm -1 , 1100cm - 1 to 1200cm -1 .
  • the functional layer includes a polymer formed from at least one of acrylic monomers, acrylic ester monomers, and styrenic monomers.
  • the insulating layer includes a binder and inorganic particles.
  • the content of the binder is 3% to 20% based on the quality of the insulation layer.
  • the binder content within the above range not only ensures that the functional layer improves the liquid retention function in the electrochemical device, but also ensures the adhesive force of the functional layer.
  • the binder includes acrylate, acrylate copolymer, acrylonitrile, acrylate copolymer, acrylic acid, acrylate, carboxymethyl cellulose salt, nitrile rubber, polyvinylidene fluoride or polyvinylidene fluoride. At least one kind of tetrafluoroethylene.
  • the inorganic particles include at least one of boehmite, diaspore, alumina, barium sulfate, calcium sulfate or calcium silicate.
  • the Dv90 of the inorganic particles is D1 ⁇ m, where D1 ⁇ H2 ⁇ 10.
  • the thickness of the functional layer can be controlled.
  • the thickness can be made smaller, thereby reducing the energy density loss of the electrochemical device.
  • the bonding force between the composite layer and the blank current collector is ⁇ 100 N/m.
  • the electrolyte retention rate of the composite layer is 40% to 120%.
  • the flatness of the electrochemical device is 0 to 0.50 mm.
  • the present application provides an electronic device including the electrochemical device of the first aspect.
  • This application provides an insulating layer and a functional layer capable of absorbing electrolyte in the current collector area where the active material is not provided on the pole piece.
  • the functional layer can improve the liquid retention capacity of the electrochemical device and at the same time prevent the excess electrolyte from being exhausted. Evenly dissociated inside the packaging bag (such as aluminum-plastic film), causing the surface of the electrochemical device to be uneven, thereby improving the smoothness of the appearance of the electrochemical device and reducing its energy density loss.
  • the insulating layer can avoid failure caused by internal short circuit when the electrochemical device is punctured by external force, thereby effectively improving the safety performance of the electrochemical device in puncture tests.
  • Figure 1 is a schematic diagram of an electrode plate in an electrochemical device according to some embodiments of the present application, where 1—current collector; 2—active material layer; 3—functional layer; 4—insulating layer.
  • the present application provides an electrochemical device, which includes an electrode assembly.
  • the electrode assembly includes an electrode pole piece.
  • the electrode pole piece includes a blank current collector and a composite layer disposed on the blank current collector.
  • the composite layer includes an insulating layer and a functional layer. Among them, the functional layer is located between the blank current collector and the insulating layer.
  • the thickness of the functional layer is H1 ⁇ m
  • the thickness of the insulating layer is H2 ⁇ m, 1 ⁇ H1/H2 ⁇ 20.
  • the inventor of this application has discovered through research that by arranging an insulating layer and a functional layer capable of absorbing electrolyte in the current collector area of the pole piece where no active material is provided, on the one hand, the functional layer can improve the liquid retention capacity of the electrochemical device and at the same time prevent Because the excess electrolyte is unevenly dissociated inside the packaging bag (such as aluminum-plastic film), the surface of the electrochemical device is uneven, thereby improving the appearance smoothness of the electrochemical device and reducing its energy density loss.
  • the insulating layer can avoid failure caused by internal short circuit when the electrochemical device is punctured by external force, thereby effectively improving the safety performance of the electrochemical device in puncture tests.
  • H1/H2 is 1.5, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 11, 12, 13, A range of 14, 15, 16, 17, 18, 19, or any two of these values.
  • the electrochemical device can have the lowest energy density loss while meeting high liquid retention capacity and safety performance.
  • H1 is 1.5, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 11, 12, 13, 14, 15, A range of 16, 17, 18, 19, or any two of these values.
  • the functional layer is used to absorb electrolyte.
  • the functional layer is mainly used to absorb electrolyte. When the thickness of the functional layer is too low, the electrolyte retention rate of the functional layer is low, which is not conducive to improving the appearance of the electrochemical device. When the thickness of the functional layer is too high, the energy density of the electrochemical device will be reduced.
  • H2 is a range consisting of 1.5, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or any two of these values.
  • the insulating layer can avoid failure caused by internal short circuit when the electrochemical device is punctured by external force, and improves the safety performance of the electrochemical device. However, when the thickness of the insulating layer is too high, the energy density of the electrochemical device is reduced.
  • the bonding strength between the functional layer and the blank current collector is greater than the bonding strength between the insulating layer and the functional layer.
  • the bonding strength of the insulating layer is too high, and it is easy to stick to the roll during the preparation process, which is not conducive to processing.
  • the electrode assembly is a rolled electrode assembly, in which the composite layer is disposed on a blank current collector at the rolled end of the electrode pole piece.
  • the coverage rate of the composite layer on the blank current collector at the rolled end of the electrode pole piece is 80% to 100%. In some embodiments, coverage is 85%, 90%, or 95%. When the coverage is within the above range, the safety of the electrochemical device can be improved and its liquid retention capacity can be increased.
  • the coverage rate of the blank current collector at the winding end of the composite layer represents the degree of coverage of the blank current collector surface by the composite layer, and is determined by the following method: in an environment of (25 ⁇ 3)°C, the composite layer will be coated with The pole piece is removed from the electrochemical device. Place it in an oven at 85°C for drying. Measure the area W3 of the composite layer and the total area W2 of the blank current collector at the winding end of the electrode piece. Then, the coverage rate of the composite layer on the blank current collector at the winding end of the electrode piece It is W3/W2 ⁇ 100%.
  • the area of the projection of the insulating layer in the thickness direction of the electrode piece is greater than or equal to the area of the projection of the functional layer in the thickness direction of the electrode piece.
  • a non-destructive ultrasonic intelligent diagnostic system is used to test, and ultrasonic waves are emitted to the electrochemical device along the thickness direction of the electrochemical device to obtain a signal feedback distribution diagram of the ultrasonic wave from the electrochemical device.
  • the area of the chemical device, the area proportion of the area with super signal intensity greater than or equal to 1333mV is 30% to 95%.
  • Ultrasonic waves are mechanical waves that rely on media to propagate. When there is no electrolyte infiltration between electrode materials, ultrasonic waves can only propagate by relying on direct contact between electrode material particles. Irregular particles cause a large amount of reflection and refraction of ultrasonic waves.
  • the signal intensity is severely attenuated, and when the electrolyte can completely infiltrate the electrode material, the liquid environment provides a good propagation path for ultrasonic waves, and a considerable part of the ultrasonic waves will not be interfered by particles, thus ensuring the signal strength. Therefore, in the test of the non-destructive ultrasonic intelligent diagnosis system, the signal feedback intensity of the ultrasonic wave at each position of the electrochemical device can well characterize the distribution and infiltration of the electrolyte inside the electrochemical device. The higher the proportion of areas with high signal intensity, the greater the electrolysis. The liquid is more evenly distributed inside the electrochemical device.
  • the area proportion of the area where the signal intensity is greater than or equal to 1333mV is 35%, 38%, 40%, 45%, 47%, 50%, 53%, 55%, 57%, 60% , 63%, 65%, 67%, 70%, 73%, 75%, 77%, 80%, 83%, 85%, 87%, 90%, 92%, 94%, or any two of these values range.
  • the area proportion of the area where the signal intensity is greater than or equal to 1333 mV is 50% to 95%.
  • the swelling degree of the functional layer ranges from 200% to 800%.
  • the swelling degree of the functional layer is 220%, 250%, 270%, 320%, 350%, 370%, 390%, 400%, 420%, 450%, 470%, 500%, 520% , 540%, 570%, 600%, 620%, 650%, 670%, 700%, 720%, 750%, 770% or a range consisting of any two of these values.
  • the swelling degree of the functional layer is less than 200%, the electrolyte retention rate of the functional layer is low, which is not conducive to improving the appearance of the electrochemical device.
  • the functional layer has a swelling degree of 300% to 600%.
  • the functional layer includes substances whose spectra have absorption peaks in at least one of the following ranges: 2700cm -1 to 3100cm -1 , 1600cm -1 to 1800cm -1 , 1100cm - 1 to 1200cm -1 .
  • the absorption peaks in the range of 2700cm -1 to 3100cm -1 , 1600cm -1 to 1800cm -1 and 1100cm -1 to 1200cm -1 represent the vibration of the ester group.
  • the functional layer contains ester groups, which can provide swelling properties. High swelling properties can absorb more electrolyte and improve the liquid retention rate.
  • the functional layer includes a polymer formed from at least one of acrylic monomers, acrylic ester monomers, and styrenic monomers.
  • the acrylic monomer includes at least one of the compounds represented by Formula I,
  • R 1 is selected from hydrogen or C 1 -C 10 alkyl, or halogen-substituted C 1 -C 10 alkyl. According to some embodiments of the present application, R 1 is selected from C 1 -C 6 alkyl, halogen-substituted C 1 -C 6 alkyl. In some embodiments of the present application, R1 is selected from methyl, ethyl, fluorine-containing ethyl, propyl, fluorine-containing propyl, butyl, fluorine-containing butyl, pentyl or fluorine-containing pentyl.
  • the acrylic monomer includes at least one of acrylic acid, methacrylic acid, and ethacrylic acid.
  • the acrylate monomer includes at least one of the compounds represented by Formula II,
  • R 2 is selected from hydrogen, C 1 -C 10 alkyl or halogen-substituted C 1 -C 10 alkyl
  • R 3 is selected from C 1 -C 10 alkyl, halogen-substituted C 1 -C 10 alkyl.
  • R 2 is selected from hydrogen, C 1 -C 6 alkyl or halogen substituted C 1 -C 6 alkyl
  • R 3 is selected from C 1 -C 6 alkyl, halogen substituted C 1 -C 6 alkyl.
  • R 2 is selected from hydrogen, methyl, ethyl or propyl
  • R 3 is selected from methyl, ethyl, fluoroethyl, propyl, fluoropropyl, butyl, Fluorine-containing butyl, pentyl or fluorine-containing pentyl.
  • acrylate monomers include methyl acrylate, methyl methacrylate, ethyl methyl acrylate, ethyl acrylate, ethyl methacrylate, ethyl ethyl acrylate, propyl acrylate, methyl At least one of propyl acrylate, propyl ethylacrylate, butyl acrylate, butyl methacrylate, butyl ethylacrylate, amyl methacrylate or amyl acrylate.
  • the styrenic monomer includes at least one of the compounds represented by Formula III,
  • n is an integer from 1 to 5, such as 2, 3 or 4; each R 4 is the same or different and is independently selected from hydrogen, C 1 -C 10 alkyl or halogen-substituted C 1 -C 10 alkyl; R 5 and R 6 are the same or different and are independently selected from hydrogen, C 1 -C 10 alkyl, or halogen-substituted C 1 -C 10 alkyl.
  • R 4 is selected from hydrogen, C 1 -C 6 alkyl or halogen-substituted C 1 -C 6 alkyl;
  • R 5 and R 6 are the same or different, and are independently selected from C 1 -C 16 Alkyl or halogen substituted C 1 -C 6 alkyl.
  • R 4 , R 5 and R 6 are independently selected from hydrogen, methyl, ethyl or propyl.
  • the styrenic monomer includes at least one of styrene, methylstyrene, 2-methylstyrene, and 2,4-dimethylstyrene.
  • the raw material forming the functional layer includes at least one of pure acrylic emulsion, styrene acrylic emulsion or acrylic ester emulsion.
  • the functional layer includes at least one of pure acrylic emulsion, styrene acrylic emulsion or acrylic emulsion.
  • the functional layer includes pure acrylic emulsion, styrene acrylic emulsion and acrylic emulsion.
  • the raw materials forming the functional layer include pure acrylic emulsion, styrene acrylic emulsion and acrylate emulsion.
  • the mass content of pure acrylic emulsion is 40% to 95%
  • the mass content of styrene acrylic emulsion is 5% to 50%
  • the acrylic ester emulsion The mass content of the emulsion is 1% to 15%.
  • the functional layer includes pure acrylic emulsion and acrylic ester emulsion.
  • the raw materials forming the functional layer include pure acrylic emulsion and acrylate emulsion.
  • the mass content of the pure acrylic emulsion is 70% to 95%, and the mass content of the acrylic ester emulsion is 5% to 30%.
  • the functional layer includes pure acrylic emulsion and styrene acrylic emulsion.
  • the raw materials forming the functional layer include pure acrylic emulsion and styrene acrylic emulsion.
  • the mass content of the pure acrylic emulsion is 70% to 95%, and the mass content of the styrene-acrylic emulsion is 5% to 30%.
  • the functional layer includes styrene acrylic emulsion and acrylic emulsion.
  • the raw materials forming the functional layer include styrene acrylic emulsion and acrylate emulsion.
  • the mass content of the styrene-acrylic emulsion is 70% to 95%, and the mass content of the acrylic emulsion is 5% to 30%.
  • the insulating layer includes a binder and inorganic particles.
  • the content of the binder is 3% to 20% based on the quality of the insulation layer.
  • the binder content is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, A range of 18%, 19%, or any two of these values.
  • the binder content within the above range not only ensures that the functional layer improves the liquid retention function in the electrochemical device, but also ensures the adhesive force of the functional layer.
  • the binder includes acrylate, acrylate copolymer, acrylonitrile, acrylate copolymer, acrylic acid, acrylate, carboxymethyl cellulose salt, nitrile rubber, polyvinylidene fluoride or polyvinylidene fluoride. At least one kind of tetrafluoroethylene.
  • the inorganic particles include at least one of boehmite, diaspore, alumina, barium sulfate, calcium sulfate or calcium silicate.
  • the Dv90 of the inorganic particles is D1 ⁇ m, where D1 ⁇ H2 ⁇ 10.
  • the thickness of the functional layer can be controlled.
  • the thickness can be made smaller, thereby reducing the energy density loss of the electrochemical device.
  • Dv90 means that in the volume-based particle size distribution of the inorganic particles, 90% of the particles have a particle size smaller than this value.
  • the bonding force between the composite layer and the blank current collector is ⁇ 100 N/m. In some embodiments, the bonding force between the composite layer and the blank current collector is 100N/m to 300N/m, such as 120N/m, 150N/m, 170N/m, 200N/m, 220N/m, 250N/m Or 270N/m.
  • the electrolyte retention rate of the composite layer is 40% to 120%.
  • the electrolyte retention rate of the functional layer is 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, A range consisting of 105%, 110%, 115%, or any two of these values.
  • the flatness of the electrochemical device is 0 to 0.50 mm.
  • the electrode plate further includes an active material layer, and the active material layer is a positive active material layer and/or a negative active material layer.
  • the positive active material layer includes a positive active material, a binder, and a conductive agent.
  • the positive active material may include lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminate, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium iron manganese phosphate, silicic acid At least one of lithium iron, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, spinel type lithium manganate, spinel type lithium nickel manganate and lithium titanate.
  • the binder may include various binder polymers, such as polyvinylidene fluoride, polytetrafluoroethylene, polyolefins, sodium carboxymethylcellulose, lithium carboxymethylcellulose, modified At least one of polyvinylidene fluoride, modified SBR rubber or polyurethane.
  • any conductive material can be used as the conductive agent as long as it does not cause chemical changes.
  • conductive agents include: carbon-based materials, such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.; metal-based materials, such as metal powder or metal fibers including copper, nickel, aluminum, silver, etc. ; Conductive polymers, such as polyphenylene derivatives, etc.; or mixtures thereof.
  • the negative active material layer includes a negative active material, a binder, and a conductive agent.
  • the negative active material may include a material that reversibly intercalates/deintercalates lithium ions or sodium ions, lithium metal, lithium metal alloy, or transition metal oxide.
  • the negative active material includes at least one of carbon material or silicon material, the carbon material includes at least one of graphite and hard carbon, and the silicon material includes silicon, silicon oxy compound, silicon carbon compound or silicon alloy. of at least one.
  • the binder includes styrene-butadiene rubber, polyacrylic acid, polyacrylate, polyimide, polyamideimide, polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, water-based acrylic resin , at least one of polyvinyl formal or styrene-acrylic acid copolymer resin.
  • any conductive material can be used as the conductive material as long as it does not cause chemical changes.
  • the conductive material includes at least one of conductive carbon black, acetylene black, carbon nanotubes, Ketjen black, conductive graphite, or graphene.
  • the electrode pole piece includes a current collector, and the blank current collector is an area on the current collector that is not provided with an active material layer.
  • the current collector is a positive current collector and/or a negative current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil can be used.
  • the composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer substrate.
  • the negative electrode current collector may be copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with conductive metal, or a combination thereof.
  • the electrochemical device of the present application also includes an isolation membrane.
  • the material and shape of the isolation membrane used in the electrochemical device of the present application are not particularly limited, and it can be any technology disclosed in the prior art.
  • the isolation membrane includes polymers or inorganic substances formed of materials that are stable to the electrolyte of the present application.
  • the isolation film may include a base material layer and a surface treatment layer.
  • the base material layer is a non-woven fabric, film or composite film with a porous structure.
  • the base material layer is made of at least one material selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate and polyimide.
  • polypropylene porous membrane, polyethylene porous membrane, polypropylene non-woven fabric, polyethylene non-woven fabric or polypropylene-polyethylene-polypropylene porous composite membrane can be used.
  • a surface treatment layer is provided on at least one surface of the base layer.
  • the surface treatment layer may be a polymer layer or an inorganic layer, or may be a layer formed by mixing a polymer and an inorganic layer.
  • the inorganic layer includes inorganic particles and a binder.
  • the inorganic particles are selected from aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, At least one of yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate.
  • the binder is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyethylene alkoxy , at least one of polymethylmethacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer is selected from polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyethylene alkoxy, polyvinylidene fluoride, At least one of poly(vinylidene fluoride-hexafluoropropylene).
  • the electrochemical device of the present application also includes an electrolyte. Electrolytes useful in this application may be electrolytes known in the art.
  • the electrolyte includes an organic solvent, a lithium salt, and optional additives.
  • the organic solvent of the electrolyte solution according to the present application may be any organic solvent known in the prior art that can be used as a solvent for the electrolyte solution.
  • the electrolyte used in the electrolyte solution according to the present application is not limited, and it can be any electrolyte known in the prior art.
  • the additives of the electrolyte according to the present application may be any additives known in the art that can be used as electrolyte additives.
  • organic solvents include, but are not limited to: ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC) ), propylene carbonate or ethyl propionate.
  • the organic solvent includes ether solvents, such as at least one of 1,3-dioxane (DOL) and ethylene glycol dimethyl ether (DME).
  • the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt.
  • lithium salts include, but are not limited to: lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bisoxalatoborate LiB(C 2 O 4 ) 2 (LiBOB) or Lithium difluorooxalate borate LiBF 2 (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiN CF 3 SO 2 ) 2
  • LiTFSI lithium bistrifluoromethanesulfonimide LiN
  • electrochemical devices of the present application include, but are not limited to: all types of primary batteries, secondary batteries, or capacitors.
  • the electrochemical device is a secondary battery.
  • secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, sodium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
  • the present application further provides an electronic device, which includes the electrochemical device of the first aspect of the present application.
  • electronic devices of the present application 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, and stereo headsets. , VCR, LCD TV, portable cleaner, portable CD player, mini CD, transceiver, electronic notepad, calculator, memory card, portable recorder, radio, backup power supply, motor, automobile, motorcycle, power-assisted bicycle, bicycle , lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • Functional layer slurry preparation Mix the binder (see the table below for specific composition) and solvent evenly to make a slurry, recorded as slurry A.
  • the slurry needs to be controlled: viscosity 200-3000mPa ⁇ S, solid content 35%-50%.
  • the solvent is selected according to the type of binder.
  • a water-based solvent such as deionized water, etc.
  • an oil-based solvent such as N-methylpyrrolidone, etc.
  • Preparation of insulation layer slurry Mix the binder, inorganic particles (see the table below for specific composition) and solvent evenly to make a slurry, recorded as slurry B.
  • the slurry parameter control viscosity 200-800mPa ⁇ S, solid content 20%-30%.
  • the solvent is selected according to the type of binder.
  • a water-based solvent such as deionized water, etc.
  • an oil-based solvent such as N-methylpyrrolidone, etc.
  • Preparation of electrode pole pieces Set the slurry A in the target area, and dry the solvent to obtain the functional layer. Then slurry B is placed in the same target area to completely cover the functional layer, and the composite layer is obtained after drying. A slurry containing active material is placed in the area where the composite layer is not provided, and after drying and rolling, the electrode pole piece is obtained.
  • the slurry containing active material is a positive active material slurry or a negative active material slurry.
  • the positive active material slurry is: a slurry made by mixing lithium cobalt oxide, conductive carbon, and polyvinylidene fluoride in a mass ratio of 96:2:2, and adding the solvent N-methyl-2-pyrrolidone (NMP).
  • the negative active material slurry is a slurry made by mixing graphite, polymethacrylic acid and styrene-butadiene rubber in a mass ratio of 98:1:1 and adding deionized water.
  • Preparation of secondary batteries Stack the positive electrode, separator (PE porous polymer film), and negative electrode in order so that the separator is between the positive electrode and the negative electrode for isolation, and then wind or stack them in sequence to obtain the electrode assembly. ; Place the electrode assembly in the outer packaging aluminum plastic film, inject the electrolyte (the solvent is EC and DMC with a volume ratio of 1:1, 1M LiPF 6 solution) into the dried battery, vacuum seal, let stand, Formation, shaping and other processes complete the preparation of secondary batteries.
  • the electrolyte the solvent is EC and DMC with a volume ratio of 1:1, 1M LiPF 6 solution
  • Use non-destructive ultrasonic intelligent diagnostic equipment (model: UBSC-LD) to emit ultrasonic waves (50MHZ, 400mV) to the secondary battery along the thickness direction of the secondary battery, and obtain the signal feedback distribution map of the ultrasonic wave throughout the battery.
  • Use integration software such as JMP software, to calculate that the total area of the battery test in the signal feedback distribution diagram is S, and the area of the area with signal strength ⁇ 1333mV is S1. Then the proportion of the area with signal strength ⁇ 1333mV is: S1/S ⁇ 100% .
  • the high-speed rail tensile machine commonly used in the lithium battery industry and the 90° angle method are used to test the bonding force between the composite layer and the current collector, namely:
  • the composite layer needs to be removed by physical or chemical methods, but the corresponding current collector cannot be damaged.
  • the corresponding current collector is weighed and recorded as G1; G2; G3... to obtain the average value G;
  • Laser scanning method is used to test the flatness of secondary batteries. Specifically, optical equipment is used to scan the entire contour of the secondary battery and make a 3D model, and then the difference between the overall thickness value and the thickness value of the cross-section is calculated, which is recorded as P. This difference is the flatness of the secondary battery. Spend. If P ⁇ 0.50mm, then the flatness of the secondary battery is OK and meets the requirements; if P>0.50mm, the flatness is NG and does not meet the requirements.
  • the binder in the slurry forming the functional layer, the binder is 100% (mass percentage) pure acrylic emulsion, the swelling degree of the functional layer is 550%; the insulation layer is 15% (mass percentage) binder polyacrylic acid copolymer + 85% (mass percentage) inorganic particle boehmite.
  • the H1/H2 ratio will affect the electrolyte retention rate, which will in turn affect the proportion of the wave number area ⁇ 1333.
  • the electrolyte retention rate increases, and the proportion of the wave number area ⁇ 1333 also increases.
  • the area with ⁇ 1333 wave number accounts for a large proportion, indicating that the electrolyte is evenly distributed inside the secondary battery and the secondary battery has good flatness.
  • the insulating layer directly affects the safety performance of secondary batteries.
  • the thickness of the insulation layer decreases, the nail penetration rate decreases, and the safety performance of the secondary battery becomes worse.
  • the percentage content of each component in the composition of the composite layer is the mass fraction content.
  • the percentage content of each component in the composition of the composite layer is the mass fraction content; the thickness of the functional layer is 10 ⁇ m, and the thickness of the insulating layer is 5 ⁇ m.
  • the percentage content of each component in the composition of the composite layer is the mass fraction content; the thickness of the functional layer is 10 ⁇ m, and the thickness of the insulating layer is 5 ⁇ m.

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Abstract

提供一种电化学装置，其包括电极组件，所述电极组件包括电极极片，所述电极极片包括空白集流体以及设置在所述空白集流体的复合层，所述复合层包括绝缘层和功能层，其中，所述功能层位于所述空白集流体和所述绝缘层之间，所述功能层的厚度为H1μm，所述绝缘层的厚度为H2μm，1≤H1/H2≤20。本申请的电化学装置具有良好的外观以及高保液量和高安全性。本申请还提供一种包括电化学装置的电子装置。

Description

电化学装置和电子装置 技术领域
本申请涉及储能领域，具体涉及一种电化学装置和电子装置。
背景技术
二次电池(电化学装置)的应用越来越广泛，已经与人们的日常生活息息相关。随着智能电子产品的迅速发展，对二次电池的各项性能(例如能量密度、循环寿命以及安全性)要求越来越高。目前，为了提升二次电池的能量密度，正负极极片的压实密度不断提高，高的压实密度导致电解液被正负极活性物质吸收的越来越少，而未被吸收的电解液则游离在包装袋(如铝塑膜)内部表面，从而容易导致二次电池包装袋凹凸不平、外观涨液，牺牲二次电池的能量密度。此外，二次电池安全性能亟需提高。因此，急需提供一种能够显著提高二次电池外观平整度、保液量以及安全性能的技术手段。
发明内容
针对现有技术的不足，本申请提供了一种电化学装置及包括该电化学装置的电子装置。本申请的电化学装置具有良好的外观以及高保液量和高安全性。
在第一方面，本申请提供了一种电化学装置，其包括电极组件，电极组件包括电极极片，该电极极片包括空白集流体以及设置在所述空白集流体上的复合层，复合层包括绝缘层和功能层，其中，功能层位于空白集流体和绝缘层之间，功能层的厚度为H1μm，绝缘层的厚度为H2μm，1≤H1/H2≤20。本申请的发明人研究发现，通过在极片未设置活性材料的集流体区域，即空白集流体设置绝缘层和能够吸收电解液的功能层，一方面，功能层可以在提高电化学装置保液量的同时，防止由于富余的电解液不均匀地游离在包装袋(如铝塑膜)内部而造成电化学装置表面凹凸不平，进而提高电化学装置的外观平整度，降低其能量密度损失。另一方面，绝缘层可以避免电化学装置受外力刺穿时所产生的内短路从而造成的失效，进而有效提升电化学装置在穿刺测试中的安全性能。功能层和绝缘层厚度的比值在上述范围内时，电化学装置能够在满足高保液量和安全性能的前提下，具有最低的能量密度损失。
根据本申请的一些实施方式，2≤H1/H2≤10。
根据本申请的一些实施方式，1≤H1≤20。在一些实施方式中，功能层用于吸收电解液。功能层主要用于吸收电解液，功能层的厚度过低时，功能层的电解液保有率较低，不利于电化学装置外观的改善。功能层的厚度过高时，会降低电化学装置的能量密度。
根据本申请的一些实施方式，1≤H2≤10。绝缘层可以避免电化学装置受外力刺穿时所产生的内短路从而造成的失效，提高电化学装置的安全性能。但绝缘层的厚度过高时，同样会降低电化学装置的能量密度。
根据本申请的一些实施方式，功能层与空白集流体之间的粘结强度大于绝缘层与功能层之间的粘结强度。绝缘层的粘结强度过大，在制备过程中容易产生黏辊，不利于加工。
根据本申请的一些实施方式，电极组件为卷绕式电极组件，其中复合层设置在电极极片的卷绕末端的空白集流体上。
根据本申请的一些实施方式，复合层在电极极片的卷绕末端的空白集流体的覆盖率为80％至100％。
根据本申请的一些实施方式，绝缘层在电极极片的厚度方向上的投影的面积大于等于功能层在电极极片的厚度方向上的投影的面积。
根据本申请的一些实施方式，采用无损超声波智能诊断系统测试，沿电化学装置的厚度方向，向电化学装置发射超声波，得到电化学装置对超声波的信号反馈分布图，基于信号反馈分布图中电化学装置的面积，超信号强度大于或等于1333mV的区域的面积占比为30％至95％。超声波是一种需要依靠介质传播的机械波，当电极材料之间没有电解液的浸润时，超声波只能依靠电极材料颗粒间的直接接触实现传播，不规则的颗粒使得超声波发生大量的反射与折射，信号强度严重衰减，而当电解液可以完全浸润电极材料时，液体环境为超声波提供了良好的传播途径，相当一部分超声波不会受到颗粒的干扰从而保证了信号的强度。因此，无损超声波智能诊断系统测试中，电化学装置各个位置对超声波的信号反馈强度，能够很好地表征电化学装置内部电解液的分布及浸润情况，信号强度高的区域占比越高，电解液在电化学装置内部分布越均匀。
根据本申请的一些实施方式，功能层的溶胀度为200％至800％。功能层的溶胀度低于200％时，功能层的电解液保有率较低，不利于电化学装置外观的改善。功能层的溶胀度大于800％时，功能层本身的稳定性差，在循环过程中容易产生脱膜影响电化学装置的性能。在一些实施方式中，功能层的溶胀度为300％至600％。
根据本申请的一些实施方式，采用傅里叶红外测试，功能层包含谱图在如下至少一个 范围内具有吸收峰的物质：2700cm -1至3100cm -1、1600cm -1至1800cm -1、1100cm -1至1200cm -1。
根据本申请的一些实施方式，功能层包括由丙烯酸类单体、丙烯酸酯类单体、苯乙烯类单体中的至少一种形成的聚合物。
根据本申请的一些实施方式，绝缘层包括粘结剂和无机颗粒。
根据本申请的一些实施方式，基于绝缘层的质量，粘结剂的含量为3％至20％。粘结剂含量在上述范围内，既保证功能层在电化学装置中提升保液功能，又可以保证功能层的粘结力。
根据本申请的一些实施方式，粘结剂包括丙烯酸酯、丙烯酸酯共聚物、丙烯腈、丙烯酸盐共聚物、丙烯酸、丙烯酸盐、羧甲基纤维素盐、丁腈橡胶、聚偏氟乙烯或聚四氟乙烯中的至少一种。
根据本申请的一些实施方式，无机颗粒包括勃姆石、水铝石、氧化铝、硫酸钡、硫酸钙或硅酸钙中的至少一种。
根据本申请的一些实施方式，无机颗粒的Dv90为D1μm，其中，D1≤H2≤10。通过控制Dv90颗粒的大小能够控制功能层的厚度，在保证功能层保液量的前提下，促使其厚度较小，进而降低电化学装置的能量密度损失。
根据本申请的一些实施方式，复合层与空白集流体间的粘结力≥100N/m。
根据本申请的一些实施方式，复合层的电解液保有率为40％至120％。
根据本申请的一些实施方式，电化学装置的平整度为0至0.50mm。
在第二方面，本申请提供一种电子装置，其包括第一方面的电化学装置。
本申请通过在极片未设置活性材料的集流体区域设置绝缘层和能够吸收电解液的功能层，一方面，功能层可以在提高电化学装置保液量的同时，防止由于富余的电解液不均匀地游离在包装袋(如铝塑膜)内部而造成电化学装置表面凹凸不平，进而提高电化学装置的外观平整度，降低其能量密度损失。另一方面，绝缘层可以避免电化学装置受外力刺穿时所产生的内短路从而造成的失效，进而有效提升电化学装置在穿刺测试中的安全性能表现。
附图说明
图1为根据本申请的一些实施方式的电化学装置中电极极片的示意图，其中，1—集流体；2—活性材料层；3—功能层；4—绝缘层。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
一、电化学装置
本申请提供了一种电化学装置，其包括电极组件，电极组件包括电极极片，该电极极片包括空白集流体以及设置在空白集流体上的复合层，复合层包括绝缘层和功能层，其中，功能层位于空白集流体和绝缘层之间，功能层的厚度为H1μm，绝缘层的厚度为H2μm，1≤H1/H2≤20。本申请的发明人研究发现，通过在极片未设置活性材料的集流体区域设置绝缘层和能够吸收电解液的功能层，一方面，功能层可以在提高电化学装置保液量的同时，防止由于富余的电解液不均匀地游离在包装袋(如铝塑膜)内部而造成电化学装置表面凹凸不平，进而提高电化学装置的外观平整度，降低其能量密度损失。另一方面，绝缘层可以避免电化学装置受外力刺穿时所产生的内短路从而造成的失效，进而有效提升电化学装置在穿刺测试中的安全性能表现。
根据本申请的一些实施方式，H1/H2为1.5、2.5、3.0、3.5、4.0、4.5、5.0、5.5、6.0、6.5、7.0、7.5、8.0、8.5、9.0、9.5、11、12、13、14、15、16、17、18、19或这些值中任意两者组成的范围。功能层和绝缘层厚度的比值在上述范围内时，电化学装置能够在满足高保液量和安全性能的前提下，具有最低的能量密度损失。在一些实施方式中，2≤H1/H2≤10。
根据本申请的一些实施方式，1≤H1≤20。在一些实施方式中，H1为1.5、2.5、3.0、3.5、4.0、4.5、5.0、5.5、6.0、6.5、7.0、7.5、8.0、8.5、9.0、9.5、11、12、13、14、15、16、17、18、19或这些值中任意两者组成的范围。在一些实施方式中，功能层用于吸收电解液。功能层主要用于吸收电解液，功能层的厚度过低时，功能层的电解液保有率较低，不利于电化学装置外观的改善。功能层的厚度过高时，会降低电化学装置的能量密度。
根据本申请的一些实施方式，1≤H2≤10。在一些实施方式中，H2为1.5、2.5、3.0、3.5、4.0、4.5、5.0、5.5、6.0、6.5、7.0、7.5、8.0、8.5、9.0、9.5或这些值中任意两者组成的范围。绝缘层可以避免电化学装置受外力刺穿时所产生的内短路从而造成的失效，提高电化学装置的安全性能。但绝缘层的厚度过高时，使电化学装置的能量密度降低。
根据本申请的一些实施方式，功能层与空白集流体之间的粘结强度大于绝缘层与功能 层之间的粘结强度。绝缘层的粘结强度过大，在制备过程中容易产生黏辊，不利于加工。
根据本申请的一些实施方式，电极组件为卷绕式电极组件，其中复合层设置在电极极片的卷绕末端的空白集流体上。
根据本申请的一些实施方式，复合层在电极极片的卷绕末端的空白集流体的覆盖率为80％至100％。在一些实施方式中，覆盖率为85％、90％或95％。覆盖度在上述范围时，能够提高电化学装置的安全性和提升其更多的保液量。
本申请中，复合层在卷绕末端的空白集流体的覆盖率表示复合层对空白集流体表面的覆盖程度，通过以下方式确定：在(25±3)℃的环境下，将涂有复合层的极片从电化学装置中拆出。放在85℃烘箱进行烘干，分别测量复合层的面积W3，以及极片卷绕末端的空白集流体的总面积W2，则复合层在电极极片的卷绕末端的空白集流体的覆盖率为W3/W2×100％。
根据本申请的一些实施方式，绝缘层在电极极片的厚度方向上的投影的面积大于等于功能层在电极极片的厚度方向上的投影的面积。
根据本申请的一些实施方式，采用无损超声波智能诊断系统测试，沿电化学装置的厚度方向，向电化学装置发射超声波，得到电化学装置对超声波的信号反馈分布图，基于信号反馈分布图中电化学装置的面积，超信号强度大于或等于1333mV的区域的面积占比为30％至95％。超声波是一种需要依靠介质传播的机械波，当电极材料之间没有电解液的浸润时，超声波只能依靠电极材料颗粒间的直接接触实现传播，不规则的颗粒使得超声波发生大量的反射与折射，信号强度严重衰减，而当电解液可以完全浸润电极材料时，液体环境为超声波提供了良好的传播途径，相当一部分超声波不会受到颗粒的干扰从而保证了信号的强度。因此，无损超声波智能诊断系统测试中，电化学装置各个位置对超声波的信号反馈强度，能够很好地表征电化学装置内部电解液的分布及浸润情况，信号强度高的区域占比越高，电解液在电化学装置内部分布越均匀。
根据本申请的一些实施方式，信号强度大于或等于1333mV的区域的面积占比为35％、38％、40％、45％、47％、50％、53％、55％、57％、60％、63％、65％、67％、70％、73％、75％、77％、80％、83％、85％、87％、90％、92％、94％或这些值中任意两者组成的范围。在一些实施方式中，信号强度大于或等于1333mV的区域的面积占比为50％至95％。
根据本申请的一些实施方式，功能层的溶胀度为200％至800％。在一些实施方式中，功能层的溶胀度为220％、250％、270％、320％、350％、370％、390％、400％、420％、450％、470％、500％、520％、540％、570％、600％、620％、650％、670％、700％、720％、 750％、770％或这些值中任意两者组成的范围。功能层的溶胀度低于200％时，功能层的电解液保有率较低，不利于电化学装置外观的改善。功能层的溶胀度大于800％时，功能层本身的稳定性差，在循环过程中容易产生脱膜影响电化学装置的性能。在一些实施方式中，功能层的溶胀度为300％至600％。
根据本申请的一些实施方式，采用傅里叶红外测试，功能层包含谱图在如下至少一个范围内具有吸收峰的物质：2700cm -1至3100cm -1、1600cm -1至1800cm -1、1100cm -1至1200cm -1。
本申请中，傅里叶红外测试谱图中，在2700cm -1至3100cm -1、1600cm -1至1800cm -1和1100cm -1至1200cm -1范围内的吸收峰代表酯基的振动。功能层中含有酯基，能够提供其溶胀性，高溶胀性能够吸收更多电解液，提升保液率。
根据本申请的一些实施方式，功能层包括由丙烯酸类单体、丙烯酸酯类单体、苯乙烯类单体中的至少一种形成的聚合物。
在一些实施方式中，丙烯酸类单体包括式I所示的化合物中的至少一种，
Figure PCTCN2022084462-appb-000001
其中，R 1选自氢或C 1-C 10烷基、卤素取代的C 1-C 10烷基。根据本申请的一些实施例，R 1选自C 1-C 6烷基、卤素取代的C 1-C 6烷基。在本申请的一些实施例中，R 1选自甲基、乙基、含氟乙基、丙基、含氟丙基、丁基、含氟丁基、戊基或含氟戊基。
在一些实施方式中，丙烯酸类单体包括丙烯酸、甲基丙烯酸、乙基丙烯酸中的至少一种。
在一些实施方式中，丙烯酸酯类单体包括式II所示的化合物中的至少一种，
Figure PCTCN2022084462-appb-000002
其中，R 2选自氢、C 1-C 10烷基或卤素取代的C 1-C 10烷基；R 3选自C 1-C 10烷基、卤素取代的C 1-C 10烷基。根据本申请的一些实施例，R 2选自氢、C 1-C 6烷基或卤素取代的C 1-C 6烷基；R 3选自C 1-C 6烷基、卤素取代的C 1-C 6烷基。在本申请的一些实施例中，R 2选自氢、甲基、乙基或丙基；R 3选自甲基、乙基、含氟乙基、丙基、含氟丙基、丁基、含氟丁基、戊基或含氟戊基。
在一些实施方式中，丙烯酸酯类单体包括丙烯酸甲酯、甲基丙烯酸甲酯、乙基丙烯酸 甲酯、丙烯酸乙酯、甲基丙烯酸乙酯、乙基丙烯酸乙酯、丙烯酸丙酯、甲基丙烯酸丙酯、乙基丙烯酸丙酯、丙烯酸丁酯、甲基丙烯酸丁酯、乙基丙烯酸丁酯、甲基丙烯酸戊酯或丙烯酸戊酯中的至少一种。
根据本申请的一些实施方式，苯乙烯类单体包括式III所示的化合物中的至少一种，
Figure PCTCN2022084462-appb-000003
其中，n为1-5的整数，例如2、3或4；每个R 4相同或不同，独立地选自氢、C 1-C 10烷基或卤素取代的C 1-C 10烷基；R 5和R 6相同或不同，独立地选自氢、C 1-C 10烷基或卤素取代的C 1-C 10烷基。根据本申请的一些实施例，R 4选自氢、C 1-C 6烷基或卤素取代的C 1-C 6烷基；R 5和R 6相同或不同，独立地选C 1-C 16烷基或卤素取代的C 1-C 6烷基。在本申请的一些实施例中，R 4、R 5和R 6独立地选自氢、甲基、乙基或丙基。
在一些实施方式中，苯乙烯类单体包括苯乙烯、甲基苯乙烯、2-甲基苯乙烯、2,4-二甲基苯乙烯中的至少一种。
根据本申请的一些实施方式，形成功能层的原料包括纯丙乳液，苯丙乳液或丙烯酸酯乳液中的至少一种。在一些实施方式中，功能层包括纯丙乳液，苯丙乳液或丙烯酸酯乳液中的至少一种。
根据本申请的一些实施方式，功能层包括纯丙乳液，苯丙乳液和丙烯酸酯乳液。在一些实施方式中，形成功能层的原料包括纯丙乳液，苯丙乳液和丙烯酸酯乳液。在一些实施方式中，基于纯丙乳液，苯丙乳液和丙烯酸酯乳液的总质量，纯丙乳液的质量含量为40％至95％、苯丙乳液的质量含量为5％至50％，丙烯酸酯乳液的质量含量为1％至15％。
根据本申请的一些实施方式，功能层包括纯丙乳液和丙烯酸酯乳液。在一些实施方式中，形成功能层的原料包括纯丙乳液和丙烯酸酯乳液。在一些实施方式中，基于纯丙乳液和丙烯酸酯乳液的总质量，纯丙乳液的质量含量为70％至95％、丙烯酸酯乳液的质量含量为5％至30％。
根据本申请的一些实施方式，功能层包括纯丙乳液和苯丙乳液。在一些实施方式中，形成功能层的原料包括纯丙乳液和苯丙乳液。在一些实施方式中，基于纯丙乳液和苯丙乳液的总质量，纯丙乳液的质量含量为70％至95％、苯丙乳液的质量含量为5％至30％。
根据本申请的一些实施方式，功能层包括苯丙乳液和丙烯酸酯乳液。在一些实施方式中，形成功能层的原料包括苯丙乳液和丙烯酸酯乳液。在一些实施方式中，基于苯丙乳液 和丙烯酸酯乳液的总质量，苯丙乳液的质量含量为70％至95％、丙烯酸酯乳液的质量含量为5％至30％。
根据本申请的一些实施方式，绝缘层包括粘结剂和无机颗粒。
根据本申请的一些实施方式，基于绝缘层的质量，粘结剂的含量为3％至20％。在一些实施方式中，粘结剂含量为5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％或这些值中任意两者组成的范围。粘结剂含量在上述范围内，既保证功能层在电化学装置中提升保液功能，又可以保证功能层的粘结力。
根据本申请的一些实施方式，粘结剂包括丙烯酸酯、丙烯酸酯共聚物、丙烯腈、丙烯酸盐共聚物、丙烯酸、丙烯酸盐、羧甲基纤维素盐、丁腈橡胶、聚偏氟乙烯或聚四氟乙烯中的至少一种。
根据本申请的一些实施方式，无机颗粒包括勃姆石、水铝石、氧化铝、硫酸钡、硫酸钙或硅酸钙中的至少一种。
根据本申请的一些实施方式，无机颗粒的Dv90为D1μm，其中，D1≤H2≤10。通过控制Dv90颗粒的大小能够控制功能层的厚度，在保证功能层保液量的前提下，促使其厚度较小，进而降低电化学装置的能量密度损失。
本申请中，Dv90表示该无机颗粒在体积基准的粒度分布中，90％的颗粒粒径小于该值。
根据本申请的一些实施方式，复合层与空白集流体间的粘结力≥100N/m。在一些实施方式中，复合层与空白集流体间的粘结力为100N/m至300N/m，例如120N/m、150N/m、170N/m、200N/m、220N/m、250N/m或270N/m。
根据本申请的一些实施方式，复合层的电解液保有率为40％至120％。在一些实施方式中，功能层的电解液保有率为45％、50％、55％、60％、65％、70％、75％、80％、85％、90％、95％、100％、105％、110％、115％或这些值中任意两者组成的范围。在电化学装置出货外观满足要求的情况下，提高电解液保有率，有利于提升电化学装置后期的循环稳定性。
根据本申请的一些实施方式，电化学装置的平整度为0至0.50mm。
根据本申请的一些实施方式，电极极片还包括活性物质层，该活性材料层为正极活性材料层和/或负极活性材料层。
根据本申请的一些实施方式，正极活性材料层包括正极活性材料、粘结剂和导电剂。在一些实施方式中，正极活性材料可以包括钴酸锂、镍锰钴酸锂、镍锰铝酸锂、磷酸铁锂、 磷酸钒锂、磷酸钴锂、磷酸锰锂、磷酸锰铁锂、硅酸铁锂、硅酸钒锂、硅酸钴锂、硅酸锰锂、尖晶石型锰酸锂、尖晶石型镍锰酸锂和钛酸锂中的至少一种。在一些实施方式中，粘结剂可以包括各种粘合剂聚合物，例如聚偏氟乙烯、聚四氟乙烯、聚烯烃类、羧甲基纤维素钠、羧甲基纤维素锂、改性聚偏氟乙烯、改性SBR橡胶或聚氨酯中的至少一种。在一些实施例中，可以使用任何导电的材料作为导电剂，只要它不引起化学变化即可。导电剂的示例包括：碳基材料，例如天然石墨、人造石墨、炭黑、乙炔黑、科琴黑、碳纤维等；金属基材料，例如包括铜、镍、铝、银等的金属粉或金属纤维；导电聚合物，例如聚亚苯基衍生物等；或它们的混合物。
根据本申请的一些实施方式，负极活性材料层包括负极活性材料、粘结剂和导电剂。在一些实施方中，负极活性材料可以包括可逆地嵌入/脱嵌锂离子或钠离子的材料、锂金属、锂金属合金或过渡金属氧化物。在一些实施方式中，负极活性材料包括碳材料或硅材料中的至少一种，碳材料包括石墨、硬碳中的至少一种，硅材料包括硅、硅氧化合物、硅碳化合物或硅合金中的至少一种。在一些实施方式中，粘结剂包括丁苯橡胶、聚丙烯酸、聚丙烯酸盐、聚酰亚胺、聚酰胺酰亚胺、聚偏氟乙烯、聚二氟乙烯、聚四氟乙烯、水性丙烯酸树脂、聚乙烯醇缩甲醛或苯乙烯-丙烯酸共聚树脂中的至少一种。在一些实施方式中，可以使用任何导电的材料作为该导电材料，只要它不引起化学变化即可。在一些实施方式中，导电材料包括导电炭黑、乙炔黑、碳纳米管、科琴黑、导电石墨或石墨烯中的至少一种。
根据本申请的一些实施方式，电极极片包括集流体，空白集流体为集流体上未设置有活性材料层的区域。在一些实施方式中，集流体为正极集流体和/或负极集流体。在一些实施方式中，正极集流体可以采用金属箔片或复合集流体。例如，可以使用铝箔。复合集流体可以通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子基材上而形成。在一些实施方式中，负极集流体可以为铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、包覆有导电金属的聚合物基板或它们的组合。
本申请的电化学装置还包括隔离膜，本申请的电化学装置中使用的隔离膜的材料和形状没有特别限制，其可为任何现有技术中公开的技术。在一些实施例中，隔离膜包括由对本申请的电解液稳定的材料形成的聚合物或无机物等。例如隔离膜可包括基材层和表面处理层。基材层为具有多孔结构的无纺布、膜或复合膜，基材层的材料选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。具体的，可选用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。
基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层包括无机颗粒和粘结剂，无机颗粒选自氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡中的至少一种。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、聚乙烯呲咯烷酮、聚乙烯烷氧、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的至少一种。
聚合物层中包含聚合物，聚合物的材料选自聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯烷氧、聚偏氟乙烯、聚(偏氟乙烯-六氟丙烯)中的至少一种。
本申请的电化学装置还包括电解液。可用于本申请的电解液可以为现有技术中已知的电解液。
在一些实施方式中，电解液包括有机溶剂、锂盐和可选的添加剂。根据本申请的电解液的有机溶剂可为现有技术中已知的任何可作为电解液的溶剂的有机溶剂。根据本申请的电解液中使用的电解质没有限制，其可为现有技术中已知的任何电解质。根据本申请的电解液的添加剂可为现有技术中已知的任何可作为电解液添加剂的添加剂。在一些实施例中，有机溶剂包括，但不限于：碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、碳酸二甲酯(DMC)、碳酸亚丙酯或丙酸乙酯。在一些实施例中，有机溶剂包括醚类溶剂，例如包括1，3-二氧五环(DOL)和乙二醇二甲醚(DME)中的至少一种。在一些实施例中，锂盐包括有机锂盐或无机锂盐中的至少一种。在一些实施例中，锂盐包括，但不限于：六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、二氟磷酸锂(LiPO 2F 2)、双三氟甲烷磺酰亚胺锂LiN(CF 3SO 2) 2(LiTFSI)、双(氟磺酰)亚胺锂Li(N(SO 2F) 2)(LiFSI)、双草酸硼酸锂LiB(C 2O 4) 2(LiBOB)或二氟草酸硼酸锂LiBF 2(C 2O 4)(LiDFOB)。
在一些实施例中，本申请的电化学装置包括，但不限于：所有种类的一次电池、二次电池或电容。在一些实施例中，电化学装置是二次电池。在一些实施例中，二次电池包括，但不限于：锂金属二次电池、锂离子二次电池、钠离子二次电池锂聚合物二次电池或锂离子聚合物二次电池。
二、电子装置
本申请进一步提供了一种电子装置，其包括本申请第一方面的电化学装置。
本申请的电子设备或装置没有特别限定。在一些实施例中，本申请的电子设备包括但不限于，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。
在下述实施例及对比例中，所使用到的试剂、材料以及仪器如没有特殊的说明，均可商购获得。
实施例及对比例
功能层浆料制备：将粘结剂(具体组成见下表)，溶剂混合均匀，制成浆料，记为浆料A。该浆料需控制：粘度200-3000mPa·S，固含量35％-50％。其中，溶剂根据粘结剂的种类选择。当粘结剂为水性时，可选用水性溶剂(如去离子水等)；当粘结剂为油性时，可选用油性溶剂(如N-甲基吡咯烷酮等)。
绝缘层浆料制备：将粘结剂、无机颗粒(具体组成见下表)和溶剂混合均匀，制成浆料，记为浆料B。该浆料参数控制:粘度200-800mPa·S，固含量20％-30％。其中，溶剂根据粘结剂的种类选择。当粘结剂为水性时，可选用水性溶剂(如去离子水等)；当粘结剂为油性时，可选用油性溶剂(如N-甲基吡咯烷酮等)。
电极极片的制备：将浆料A设置在目标区域，经过烘干溶剂得到功能层。然后将浆料B设置在相同目标区域，完全覆盖功能层，经过烘干得到复合层。在未设置复合层的区域设置含有活性材料的浆料，经过烘干、辊压，得到电极极片
其中，含有活性材料的浆料为正极活性材料浆料或负极活性材料浆料。具体地，正极活性材料浆料为：将钴酸锂、导电碳、聚偏氟乙烯按照质量比96:2:2混合，加入溶剂N-甲基-2-吡咯烷酮(NMP)制成的浆料。负极活性材料浆料为：将石墨、聚甲基丙烯酸和丁苯橡胶按照质量比98:1:1混合，加入去离子水制成的浆料。
二次电池的制备：将正极、隔离膜(PE多孔聚合物薄膜)、负极按顺序叠好，使隔离膜处于正极和负极之间起到隔离的作用，然后卷绕或者依次叠片得到电极组件；将电极组件置于外包装铝塑膜中，将电解液(溶剂为体积比为1:1的EC和DMC，1M LiPF 6溶液)注入到干燥后的电池中，经过真空封装、静置、化成、整形等工序，即完成二次电池 的制备。
测试方法
1、超声检测
使用无损超声波智能诊断设备(型号：UBSC-LD)，沿二次电池的厚度方向，向二次电池发射超声波(50MHZ、400mV)，得到电池各处对超声波的信号反馈分布图。使用积分软件，例如JMP软件计算出信号反馈分布图中电池测试的总面积为S，信号强度≥1333mV的区域面积为S1，则信号强度≥1333mV的区域的占比为：S1/S×100％。
2、粘结力
采用锂电行业内常用的高铁拉力机、90°角法测试复合层与集流体的粘结力，即：
将二次电池中涂有复合层的部分极片制成条状，沿长度方向从极片的一端将极片的一部分通过双面胶粘附在钢板上；然后将钢板固定在高铁拉力机相应位置，拉起未被粘在钢板上的极片，通过连接物或直接将极片放入夹头内夹紧，待夹口拉力在大于0kgf且小于0.02kgf时，即可开始用高铁拉力机测试，最终测得平稳区域的拉力平均值记为复合层与集流体的粘结力。
3、电解液保有率
a)在(25±3)℃的环境下，将涂有复合层的极片从二次电池中拆出。如涂复合层的集流体的另一侧有其它层，需用物理或化学方法去除，但不能损伤复合层。然后用裁片机将复合层(包括集流体)完整裁切；
b)用电子天平分别称取上述裁取复合层(包括集流体)至少3次，分别记为m1；m2；m3……，求得平均值m；
c)将上述称量后的复合层(包括集流体)放进85℃烘箱，烘30min至60min，保证复合层内部电解液全部烘干，然后再次分别称取复合层重量，分别记为M1；M2；M3……，求得平均值M；
d)将复合层需用物理或化学方法去除，但不能损伤对应的集流体，称取对应集流体重记为G1；G2；G3……，求得平均值G；
e)复合层的电解液保有率记为：R＝(m-M)/(M-G)。
4、溶胀度
a)在(25±3)℃的环境下，将涂有功能层的极片从二次电池中拆出。如涂功能层的集流体的另一侧有其它层，需用物理或化学方法去除，但不能损伤功能层。然后用裁片机 将功能层完整裁切；放到碳酸二甲酯DMC中进行去除溶解在功能层中的电解液，将其取出进行风干，再将其放入水中进行溶解，将溶解后的该溶液倒入胶膜制备模具中，如有气泡提起去除；将模具放入60℃烘箱，条件：60℃，12h，烘烤结束后，观察胶膜的外观及硬度；如没有完全干燥，继续烘烤，直到烘干为止；
b)将制备好的胶膜用剪刀裁成2g左右的小条；
c)将胶膜小条分别称重；记录初始重量a；放入小瓶中，；加入电解液(溶剂为体积比为1:1的EC和DMC，基于电解液的质量，LiPF 6的质量浓度为12.5％的溶液)，超过胶膜2～3cm，密封好小瓶，放入真空干燥炉，温度85℃，6h；
d)测试胶膜溶胀度：将胶膜取出，用无尘纸擦拭干净，记录此时胶膜重量b，溶胀度＝(b-a)/a×100％。做3个平行样，将得到的溶胀度进行算数平均即得到该功能层的溶胀度。
5、功能层以及绝缘层的厚度
a)在(25±3)℃的环境下，将涂有复合层的极片从二次电池中拆出。如涂复合层的集流体的另一侧有其它材料层，需用物理或化学方法去除，但不能损伤复合层；
b)将上述的复合层(包括集流体)放进85℃烘箱，烘30min至60min，保证功能层内部电解液全部烘干；
c)将上述复合层(包括集流体)用剪刀剪成6mm×6mm的大小并使用石蜡将其固定在样品台上，使用IB-09010CP/离子抛光仪在Ar气氛围下切割极片，然后使用JY/T O1O-1966扫描测试仪对样品选择5个点测试功能层、绝缘层厚度，功能层厚度分别为H11、H12、H13、H14、H15，求其平均值得H1，绝缘层厚度为H21、H22、H23、H24、H25，求其平均值得H2。
6、平整度
采用激光扫描法测试二次电池的平整度。具体地，利用光学设备，将二次电池的整个轮廓扫描后制作成3D模型，然后计算整体的厚度值与断面的厚度值的差值，记为P，该差值即为二次电池的平整度。若P≤0.50mm，则此时二次电池的平整度OK，符合要求；若P＞0.50mm，则此时平整度NG，不符合要求。
7、穿钉通过率
将待测的二次电池以0.05C的倍率恒流充电至设计满充电压，随后以设计满充电压充电至电流为0.025C(截止电流)，使二次电池达到满充状态，记录测试前二次电池外观。在25±3℃环境中对电池进行穿钉测试，钢钉直径4mm，穿刺速度30mm/s，穿钉位置位 于二次电池几何中心，测试进行3.5min或电极组件表面温度降到50℃以后停止测试，以10个二次电池为一组，观察测试过程中二次电池状态，以二次电池不燃烧、不爆炸为判定标准。
8、复合层在卷绕末端的空白集流体的覆盖率
在(25±3)℃的环境下，将涂有复合层的极片从电化学装置中拆出。放在85℃烘箱进行烘干，分别测量复合层的面积W3，以及极片卷绕末端的空白集流体的总面积W2，则复合层在电极极片的卷绕末端的空白集流体的覆盖率为W3/W2×100％。
测试结果
表1
Figure PCTCN2022084462-appb-000004
注：表1中各实施例与对比例中，形成功能层的浆料中，粘结剂为100％(质量百分含量)的纯丙乳液，功能层的溶胀度为550％；绝缘层为15％(质量百分含量)的粘结剂聚丙烯酸共聚物+85％(质量百分含量)的无机颗粒勃姆石。
从表1的数据可以看出，H1/H2比值会影响电解液保有率，进而会影响≥1333波数区域占比。随着H1/H2比值增大，电解液保有率随之增大，≥1333波数区域占比也随之增大。≥1333波数区域占比大，说明电解液在二次电池内部分布均匀，二次电池具有良好的 平整度。
另外从表1的数据可以看出，绝缘层直接影响二次电池的安全性能。绝缘层厚度降低，穿钉通过率降低，二次电池的安全性能变差。
表2
Figure PCTCN2022084462-appb-000005
Figure PCTCN2022084462-appb-000006
注：复合层的组成中各组分的百分含量均为质量分数含量。
从表2的数据可以看出，功能层的组成以及溶胀度会影响电解液保有率和≥1333mV波数区域占比。随着功能层溶胀度的增大，电解液保有率随之增大，≥1333mV波数区域占比也随之增大。≥1333mV波数区域占比大，说明电解液在二次电池内部分布均匀，二次电池具有良好的平整度。
表3
Figure PCTCN2022084462-appb-000007
Figure PCTCN2022084462-appb-000008
注：复合层的组成中各组分的百分含量均为质量分数含量；功能层的厚度均为10μm，绝缘层的厚度均为5μm。
从表3的数据可以看出，绝缘层的粘结剂种类和无机颗粒种类影响二次电池的穿钉通过率，当粘结剂中的丙烯酸酯共聚物和勃姆石配比为15％：85％时，二次电池的安全性效果更好。
表4
Figure PCTCN2022084462-appb-000009
注：复合层的组成中各组分的百分含量均为质量分数含量；功能层的厚度均为10μm，绝缘层的厚度均为5μm。
从表4的数据可以看出，复合层在空白集流体上的覆盖度会影响电解液保有率和≥1333mV波数区域占比。随着覆盖度的增大，电解液保有率随之增大，≥1333mV波数区域占比也随之增大。≥1333mV波数区域占比大，说明电解液在二次电池内部分布均匀，二次电池具有良好的平整度。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (15)

  1. 一种电化学装置，包括电极组件，所述电极组件包括电极极片，所述电极极片包括空白集流体以及设置在所述空白集流体上的复合层，所述复合层包括绝缘层和功能层，
    其中，所述功能层位于所述空白集流体和所述绝缘层之间，所述功能层的厚度为H1μm，所述绝缘层的厚度为H2μm，1≤H1/H2≤20。
  2. 根据权利要求1所述的电化学装置，其中，2≤H1/H2≤10。
  3. 根据权利要求1所述的电化学装置，其中，1≤H1≤20和/或1≤H2≤10。
  4. 根据权利要求1所述的电化学装置，其中，所述功能层与所述空白集流体之间的粘结强度大于所述绝缘层与所述功能层之间的粘结强度。
  5. 根据权利要求1所述的电化学装置，所述功能层用于吸收电解液。
  6. 根据权利要求1所述的电化学装置，其中，所述电极组件为卷绕式电极组件，所述复合层设置在所述电极极片的卷绕末端的空白集流体上。
  7. 根据权利要求6所述的电化学装置，所述复合层在所述电极极片的卷绕末端的空白集流体上的覆盖率为80％-100％。
  8. 根据权利要求1所述的电化学装置，所述绝缘层在所述电极极片的厚度方向上的投影的面积大于等于所述功能层在所述电极极片的厚度方向上的投影的面积。
  9. 根据权利要求1所述的电化学装置，其中，采用无损超声波智能诊断系统测试，沿所述电化学装置的厚度方向，向所述电化学装置发射超声波，得到所述电化学装置对超声波的信号反馈分布图，基于所述信号反馈分布图中电化学装置的面积，超信号强度大于或等于1333mV的区域的面积占比为30％至95％。
  10. 根据权利要求1所述的电化学装置，其中，所述功能层满足如下条件(a)至(c)中的至少一者：
    (a)所述功能层的溶胀度为200％至800％；
    (b)采用傅里叶红外测试，所述功能层包含谱图在如下至少一个范围内具有吸收峰的物质：2700cm -1至3100cm -1、1600cm -1至1800cm -1、1100cm -1至1200cm -1；
    (c)所述功能层包括由丙烯酸类单体、丙烯酸酯类单体、苯乙烯类单体中的至少一种形成的聚合物。
  11. 根据权利要求10所述的电化学装置，其中，所述功能层的溶胀度为300％至600％。
  12. 根据权利要求1所述的电化学装置，其中，所述绝缘层包括粘结剂和无机颗粒。
  13. 根据权利要求12所述的电化学装置，其中，所述绝缘层满足如下条件(d)至(g) 中的至少一者：
    (d)基于所述绝缘层的质量，所述粘结剂的含量为3％至20％；
    (e)所述粘结剂包括丙烯酸酯、丙烯酸酯共聚物、丙烯腈、丙烯酸盐共聚物、丙烯酸、丙烯酸盐、羧甲基纤维素盐、丁腈橡胶、聚偏氟乙烯或聚四氟乙烯中的至少一种；
    (f)所述无机颗粒包括勃姆石、水铝石、氧化铝、硫酸钡、硫酸钙或硅酸钙中的至少一种；
    (g)所述无机颗粒的Dv90为D1μm，其中，D1≤H2≤10。
  14. 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如下条件(h)至(j)中的至少一者：
    (h)所述复合层与所述空白集流体间的粘结力≥100N/m；
    (i)所述复合层的电解液保有率为40％至120％；
    (j)所述电化学装置的平整度为0至0.50mm。
  15. 一种电子装置，包括权利要求1至14中任一项所述的电化学装置。
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