WO2023216473A1 - 一种电化学装置和电子装置 - Google Patents

一种电化学装置和电子装置 Download PDF

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WO2023216473A1
WO2023216473A1 PCT/CN2022/117005 CN2022117005W WO2023216473A1 WO 2023216473 A1 WO2023216473 A1 WO 2023216473A1 CN 2022117005 W CN2022117005 W CN 2022117005W WO 2023216473 A1 WO2023216473 A1 WO 2023216473A1
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positive electrode
electrochemical device
lithium
electrolyte
performance
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PCT/CN2022/117005
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English (en)
French (fr)
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徐春瑞
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宁德新能源科技有限公司
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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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/533—Electrode connections inside a battery casing characterised by the shape of the leads or tabs
    • 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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of electrochemical technology, and in particular to an electrochemical device and an electronic device.
  • Lithium-ion batteries have the advantages of high energy storage density, high open circuit voltage, low self-discharge rate, long cycle life, and good safety. They are widely used in various fields such as portable electric energy storage, electronic equipment, and electric vehicles, and have gradually become the above-mentioned fields. mainstream batteries.
  • the rapid development of lithium-ion batteries has also put forward higher requirements for the comprehensive performance of lithium-ion batteries. For example, on the basis of ensuring that lithium-ion batteries have higher energy density and lower cost, how to improve the cycle performance, high-temperature performance and safety performance of lithium-ion batteries. Therefore, how to improve the comprehensive performance of lithium-ion batteries has become an urgent problem to be solved.
  • the purpose of this application is to provide an electrochemical device and an electronic device to improve the overall performance of the electrochemical device.
  • a first aspect of the application provides an electrochemical device.
  • the electrochemical device includes a positive electrode piece and an electrolyte, wherein the positive electrode piece includes a positive electrode tab, and the working length b of the positive electrode tab is 0.5 m to 3m; the electrolyte includes cyclic carbonate, based on the quality of the electrolyte, the mass percentage of the cyclic carbonate is a%, the cyclic carbonate includes ethylene carbonate and/or carbonic acid Propylene; the electrochemical device satisfies 13 ⁇ a/b ⁇ 110, preferably 20 ⁇ a/b ⁇ 110.
  • the positive electrode piece along the length direction of the positive electrode piece, includes an opposite first edge and a second edge; there is one positive electrode tab, and the distance from the positive electrode tab to the first edge is L1 , the distance from the positive electrode tab to the second edge is L2, and the working length b is equal to the maximum value of L1 and L2; or, there are two positive electrode tabs, one of which is close to the first edge
  • the positive electrode tab is the first positive electrode tab
  • the positive electrode tab close to the second edge is the second positive electrode tab
  • the distance from the first positive electrode tab to the first edge is L3
  • the second positive electrode tab is
  • the distance from the positive electrode tab to the second edge is L4, the distance between the first positive electrode tab and the second positive electrode tab is L5, and the working length b is equal to L3, L4, 0.5 ⁇ L5 the maximum value.
  • the safety performance of the electrochemical device can be improved without affecting the kinetic performance of the electrochemical device, thereby improving the overall performance of the electrochemical device.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer disposed on at least one surface of the positive electrode current collector, and the coating quality of the positive electrode material layer is C g/1540.25mm. 2 , the electrochemical device satisfies 50 ⁇ a/C ⁇ 300.
  • the cycle performance, high temperature performance and safety performance of the electrochemical device can be improved without affecting the kinetic performance and energy density of the electrochemical device, thus improving the overall performance of the electrochemical device. performance.
  • 0.2 ⁇ C ⁇ 0.5 By regulating the value of C within the above range, the safety performance of the electrochemical device can be improved without affecting the energy density of the electrochemical device, thereby improving the overall performance of the electrochemical device.
  • the electrolyte includes a polynitrile compound, and based on the mass of the electrolyte, the mass percentage d% of the polynitrile compound is 0.5% to 5%, and the polynitrile compound Including glutaronitrile, adiponitrile, succinonitrile, butenenitrile, 3-methylbutenenitrile, 1,2-bis(cyanoethoxy)ethane, 1,3,5-hexanetrinitrile, At least one of 1,3,6-hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane or 1,3,4,6-hexanetetranitrile.
  • the polynitrile compound Including glutaronitrile, adiponitrile, succinonitrile, butenenitrile, 3-methylbutenenitrile, 1,2-bis(cyanoethoxy)ethane, 1,3,5-hexanetrinitrile, At least one of 1,3,6-hexanetrinitrile, 1,2,
  • the electrolyte includes: at least one of glutaronitrile, adiponitrile, succinonitrile or 1,2-bis(cyanoethoxy)ethane; and, 1,3,5-hexane At least one of trinitrile, 1,3,6-hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane or 1,3,4,6-hexanetetranitrile.
  • glutaronitrile adiponitrile, succinonitrile or 1,2-bis(cyanoethoxy)ethane
  • 1,3,5-hexane At least one of trinitrile, 1,3,6-hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane or 1,3,4,6-hexanetetranitrile.
  • the positive electrode sheet includes a positive active material, and the Dv10 of the positive active material and the mass percentage d% of the polynitrile compound numerically satisfy: 0.2 ⁇ d/Dv10 ⁇ 4; 1 ⁇ m ⁇ Dv10 ⁇ 5 ⁇ m.
  • the electrolyte includes a sulfur-oxygen double bond-containing compound, and based on the mass of the electrolyte, the mass percentage of the sulfur-oxygen double bond-containing compound is 0.01% to 8%, so
  • the sulfur-oxygen double bond-containing compounds include 1,3-propane sultone, ethylene sulfate, methylene methane disulfonate, propenyl-1,3-sultone, tetrafluoroethane-beta-sulfonate At least one of lactone, 2,4-butanesultone, 1,4-butanesultone, 1,8-naphthalenesultone or ethylene sulfite.
  • the mass percentage of the sulfur-oxygen double bond-containing compound within the above range, it is beneficial to improve the safety performance and cycle performance of the electrochemical device without affecting the kinetic performance of the electrochemical device.
  • the cycle performance, high temperature performance, safety performance, etc. of the electrochemical device can be improved, thereby improving the overall performance of the electrochemical device.
  • the electrolyte includes a lithium salt additive, and the mass percentage e% of the lithium salt additive is 0.01% to 2% based on the mass of the electrolyte.
  • the lithium salt additive It includes at least one of lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium tetrafluoroborate, lithium tetraborate, lithium borate or lithium triflate.
  • the cycle performance, high temperature performance and safety performance of the electrochemical device can be improved, thereby improving the overall performance of the electrochemical device.
  • the positive electrode sheet includes a positive electrode material layer, and the positive electrode active material in the positive electrode material layer includes element A. Based on the mass of the positive electrode active material, the mass percentage of the element A The content is 0.001% to 2%, and the element A includes at least one of Al, B, Cr, Fe, Mg, Na, S, Ti, Zr, Y, Nb, Mo, W, F or P, which can be improved The cycle performance, high temperature performance and safety performance of the electrochemical device are improved, thereby improving the overall performance of the electrochemical device.
  • a second aspect of the present application provides an electronic device comprising the electrochemical device in any of the preceding embodiments.
  • the electrochemical device provided by this application has good comprehensive performance, and the obtained electronic device has a long service life.
  • the electrochemical device includes a positive electrode piece and an electrolyte.
  • the positive electrode piece includes a positive electrode tab, and the working length b of the positive electrode tab is 0.5m to 3m;
  • the electrolyte includes Cyclic carbonate, based on the quality of the electrolyte, the mass percentage of cyclic carbonate is a%, the cyclic carbonate includes ethylene carbonate and/or propylene carbonate; the electrochemical device satisfies 13 ⁇ a/b ⁇ 110.
  • Figure 1 is a schematic structural diagram of a positive electrode plate in some embodiments of the present application.
  • Figure 2 is a schematic structural diagram of a positive electrode plate in other embodiments of the present application.
  • a lithium-ion battery is used as an example of an electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to lithium-ion batteries.
  • Lithium-ion batteries usually include positive electrode plates, negative electrode plates, separators, electrolytes, etc., all of which are important factors affecting the performance of lithium-ion batteries.
  • the length-to-width ratio of the positive electrode piece and the negative electrode piece is large.
  • the number of positive electrode tabs provided on the positive electrode piece is small (such as one or two), it will affect the positive electrode tab.
  • the uniformity of current density and temperature distribution in different areas of the chip will affect the comprehensive performance of lithium-ion batteries, such as cycle performance, high temperature performance and safety performance. Based on the above problems, this application provides an electrochemical device and an electronic device to improve the overall performance of the electrochemical device.
  • the first aspect of the application provides an electrochemical device.
  • the electrochemical device includes a positive electrode piece and an electrolyte, wherein the positive electrode piece includes a positive electrode tab, and the working length b of the positive electrode tab is 0.5m to 3m; the electrolyte solution Including cyclic carbonates, the mass percentage of cyclic carbonates is a% based on the mass of the electrolyte, and the cyclic carbonates include ethylene carbonate (EC) and/or propylene carbonate (PC); electrochemistry
  • EC ethylene carbonate
  • PC propylene carbonate
  • electrochemistry satisfies 13 ⁇ a/b ⁇ 110, preferably 20 ⁇ a/b ⁇ 110.
  • the positive electrode piece 10 includes opposite first edges 11 and second edges 12 .
  • the working length b of the positive tab is equal to the maximum value of L1 and L2.
  • the positive electrode tab 20 close to the first edge 11 is the first positive electrode tab 21
  • the positive electrode tab 20 close to the second edge 12 is the first positive electrode tab 21
  • the pole tab 20 is the second positive pole tab 22
  • the distance between the first positive pole tab 21 and the first edge 11 is L3
  • the distance between the second positive pole tab 22 and the second edge 12 is L4
  • the distance between the second positive electrode tabs 22 is L5
  • the working length b of the positive electrode tab is equal to the maximum value among L3, L4, and 0.5 ⁇ L5.
  • the applicant of this application found that when the value of a/b is too small (for example, less than 13) or the working length b of the positive electrode tab is too large (for example, greater than 3m), the current density and heat on the positive electrode tab are uneven, and for In the area close to the cathode tab, the current density is larger, the heat accumulation is greater, and the temperature is higher, which increases the delithiation content, easily leading to lithium precipitation in the negative electrode piece, and intensifying the structural decay of the positive active material in the positive electrode piece. , which in turn aggravates the side reaction between the positive active material and the electrolyte, affects the cycle performance and safety performance of the electrochemical device, and even causes the failure of the electrochemical device.
  • the working length b of the positive electrode tab can be 0.5m, 1m, 1.5m, 2m, 2.5m, 3m or anything in between.
  • the value of a/b can be 13, 20, 30, 40, 50, 60, 70, 80, 90, 10, 110 or any range in between, and the above-mentioned selection has good chemical stability and thermal stability
  • the cyclic carbonate is conducive to the synergy between the positive electrode plate and the electrolyte to improve the cycle performance, high temperature performance and safety performance of the electrochemical device. It will not affect the kinetic performance of the electrochemical device, thereby improving Overall performance of electrochemical devices.
  • the mass ratio of EC and PC is not particularly limited in this application, as long as the purpose of this application can be achieved.
  • the mass ratio of EC and PC can be 1:5 to 4:1. .
  • the value of a/b is within the above range, the value of a is too small (for example, less than 25), that is, the mass percentage of cyclic carbonate is too low, which is not conducive to forming good protection on the surface of the positive electrode sheet.
  • the interface is used to reduce side reactions between the positive active material and the electrolyte, thereby affecting the cycle performance of the electrochemical device, and is not conducive to improving the high-temperature performance of the electrochemical device.
  • the value of a is too large (for example, greater than 60), that is, the mass percentage of cyclic carbonate is too high, the viscosity of the electrolyte increases, which affects the transmission of lithium ions and easily causes lithium precipitation in the negative electrode, thus affecting the Kinetic performance and safety performance of electrochemical devices.
  • the cyclic carbonate has a suitable mass percentage, as follows It is conducive to forming a suitable protective interface on the surface of the positive electrode piece to reduce side reactions between the positive electrode active material and the electrolyte. It can also passivate the interface of the lithium ionizing part of the negative electrode piece, which can improve the safety performance of the electrochemical device and also does not It will affect the kinetic performance of the electrochemical device and thereby improve the overall performance of the electrochemical device.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer disposed on at least one surface of the positive electrode current collector.
  • the coating quality of the positive electrode material layer is C g/1540.25mm 2 , and the electrochemical device satisfies 50 ⁇ a/C ⁇ 300.
  • the electrochemical device can improve the concentration polarization of the cathode material layer between the cathode current collector side and the separator side without losing energy density, thereby reducing the thickness of the cathode plate. , local overheating, material phase change and lithium evolution of the negative electrode sheet caused by locally large current density and polarization problems, thereby improving the safety performance, cycle performance and high temperature performance of the electrochemical device.
  • the value of a/C can be 50, 100, 150, 175, 200, 250, 300 or any range in between, the cycle performance of the electrochemical device can be improved. High temperature performance and safety performance will not affect the kinetic performance and energy density of the electrochemical device, thereby improving the overall performance of the electrochemical device.
  • the above-mentioned at least one surface of the positive electrode current collector refers to at least one of the two surfaces along the thickness direction of the positive electrode current collector.
  • the positive electrode piece can maintain the transmission efficiency of ions and electrons in the positive electrode material layer while ensuring the energy density.
  • the value of C can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or any range in between, the cathode material layer has appropriate coating quality and can improve the electrical conductivity. The safety performance of the chemical device will not affect the energy density of the electrochemical device, thereby improving the overall performance of the electrochemical device.
  • the electrolyte solution includes polynitrile compounds. Based on the mass of the electrolyte solution, the mass percentage content d% of the polynitrile compounds is 0.5% to 5%.
  • the polynitrile compounds include glutaronitrile and adiponitrile. (ADN), succinonitrile (SN), butenenitrile, 3-methylbutenenitrile, 1,2-bis(cyanoethoxy)ethane (DENE), 1,3,5-hexanetrinitrile , at least one of 1,3,6-hexanetrinitrile (HTCN), 1,2,3-tris(2-cyanoethoxy)propane or 1,3,4,6-hexanetetranitrile.
  • ADN glutaronitrile and adiponitrile.
  • SN succinonitrile
  • DENE 1,2-bis(cyanoethoxy)ethane
  • DENE 1,3,5-hexanetrinitrile
  • HTCN 1,3,6-hexanetrinitrile
  • the electrolyte includes: at least one of glutaronitrile, adiponitrile, succinonitrile or 1,2-bis(cyanoethoxy)ethane; and, 1,3,5-hexane At least one of trinitrile, 1,3,6-hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane or 1,3,4,6-hexanetetranitrile.
  • Adding the above-mentioned polynitrile compounds to the electrolyte is beneficial to inhibiting the phase change of the positive active material, thereby reducing side reactions between the positive active material and the electrolyte to further improve the safety performance and cycle performance of the electrochemical device, thereby improving electrochemistry overall performance of the device.
  • the cycle performance and safety performance of the electrochemical device are not significantly improved.
  • the mass percentage of the polynitrile compound is too low (for example, less than 0.5%), the cycle performance and safety performance of the electrochemical device are not significantly improved.
  • the mass percentage of polynitrile compounds is too high (for example, higher than 5%), the viscosity of the electrolyte increases, which affects the transmission of lithium ions and easily causes lithium precipitation in the negative electrode sheet, thereby affecting the dynamics of the electrochemical device. performance and safety features.
  • the mass percentage of the polynitrile compound can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% , 4.5%, 5% or any range in between, which is beneficial to improving the safety performance and cycle performance of the electrochemical device without affecting the kinetic performance of the electrochemical device.
  • the mass percentage of the polynitrile compound can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% , 4.5%, 5% or any range in between, which is beneficial to improving the safety performance and cycle performance of the electrochemical device without affecting the kinetic performance of the electrochemical device.
  • the positive electrode sheet includes a positive electrode active material, and the Dv10 of the positive electrode active material and the mass percentage d% of the polynitrile compound satisfy numerically: 0.2 ⁇ d/Dv10 ⁇ 4, 1 ⁇ m ⁇ Dv10 ⁇ 5 ⁇ m.
  • the value of d/Dv10 can be 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, 2.5, 3.0, 3.5, 4.0 or any range in between, Dv10
  • the value can be 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m or any range in between, which is conducive to the synergy between the electrolyte and the positive electrode plate to improve the cycle performance, high temperature performance and safety performance of the electrochemical device, and then Improve the overall performance of electrochemical devices.
  • Dv10 refers to the particle size corresponding to when the cumulative volume distribution percentage of the positive active material reaches 10%.
  • the electrolyte includes a sulfur-oxygen double bond-containing compound. Based on the mass of the electrolyte, the mass percentage of the sulfur-oxygen double bond-containing compound is 0.01% to 8%.
  • the sulfur-oxygen double bond-containing compound includes 1,3-propane sultone (PS), ethylene sulfate (DTD), methylmethane disulfonate (MMDS), propenyl-1,3-sultone (PES), tetrafluoroethane -At least one of beta-sultone, 2,4-butanesultone, 1,4-butanesultone, 1,8-naphthalenesultone or ethylene sulfite.
  • PS 1,3-propane sultone
  • DTD ethylene sulfate
  • MMDS methylmethane disulfonate
  • PES propenyl-1,3-sultone
  • Adding the above-mentioned sulfur-oxygen double bond-containing compounds to the electrolyte can improve the stability of the protective interface on the surface of the cathode plate, and can also improve the stability of the cathode active material to inhibit the phase change of the cathode active material and the interaction with the electrolyte. side reactions, further improving the safety performance and cycle performance of the electrochemical device, thereby improving the overall performance of the electrochemical device. Specifically, when the mass percentage of the sulfur-oxygen double bond-containing compound is low (for example, less than 0.01%), the cycle performance and safety performance of the electrochemical device are not significantly improved.
  • the mass percentage of the sulfur-oxygen double bond-containing compound can be 1%, 2%, 3%, 4%, 4.5%, 5% , 6%, 7%, 8% or any range in between, which is beneficial to improving the safety performance and cycle performance of the electrochemical device without affecting the kinetic performance of the electrochemical device.
  • the electrolyte includes a sulfur-oxygen double bond-containing compound, and the mass percentage of the sulfur-oxygen double bond-containing compound is 0.5% to 5% based on the mass of the electrolyte.
  • the sulfur-oxygen double bond-containing compound includes propenyl-1,3-sultone (PES). Based on the mass of the electrolyte, the mass percentage of propenyl-1,3-sultone is 0.5% to 2%. .
  • PES propenyl-1,3-sultone
  • the electrolyte includes a lithium salt additive. Based on the mass of the electrolyte, the mass percentage e% of the lithium salt additive is 0.01% to 2%, preferably 0.01% to 1%.
  • the lithium salt additive Including lithium difluorophosphate (LiPO 2 F 2 ), lithium difluoroborate (LiDFOB), lithium dioxaloborate (LiBOB), lithium tetrafluoroborate (LiBF 4 ), lithium tetraborate (B 4 Li 2 O 7 ), At least one of lithium borate (Li 3 BO 3 ) or lithium triflate (CF 3 LiO 3 S).
  • adding the above-mentioned lithium salt additive to the electrolyte can improve the stability of the positive electrolyte interface on the surface of the positive electrode piece, and can also improve the stability of the positive active material.
  • adding the above-mentioned lithium salt additive to the electrolyte can improve the stability of the positive electrolyte interface on the surface of the positive electrode piece, and can also improve the stability of the positive active material.
  • To suppress the phase change of the positive active material in the long positive electrode piece and the side reaction with the electrolyte. It can also form a stable solid electrolyte interface on the surface of the negative electrode plate, inhibit side reactions between the electrolyte and the negative active material, further improve the safety performance and cycle performance of the electrochemical device, and thereby improve the overall performance of the electrochemical device.
  • the mass percentage of the lithium salt additive when the mass percentage of the lithium salt additive is low (for example, less than 0.01%), the cycle performance and safety performance of the electrochemical device are not significantly improved.
  • the mass percentage of lithium salt additive is high (for example, higher than 2%), the density of the solid electrolyte interface formed on the surface of the negative electrode sheet is too high, which affects the transmission of lithium ions and thus affects the dynamics of the electrochemical device. performance.
  • the mass percentage of the lithium salt additive can be 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, or somewhere in between Any range is beneficial to improving the safety performance and cycle performance of the electrochemical device without affecting the kinetic performance of the electrochemical device.
  • lithium salt additive it is more conducive to improving the stability of the cathode active material and the stability of the solid electrolyte interface, and forming a synergistic effect with the cyclic carbonate to improve the cycle performance, high temperature performance and safety of the electrochemical device performance, etc., thereby improving the overall performance of the electrochemical device.
  • the positive electrode sheet includes a positive electrode material layer, and the positive electrode active material in the positive electrode material layer includes element A. Based on the mass of the positive electrode active material, the mass percentage of element A is 0.001% to 2%, Preferably, it is 0.05% to 0.5%.
  • Element A includes at least one of Al, B, Cr, Fe, Mg, Na, S, Ti, Zr, Y, Nb, Mo, W, F or P.
  • the positive electrode active material may include but is not limited to lithium cobalt oxide, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and manganate. At least one of lithium, lithium nickel manganate or lithium iron phosphate.
  • the above-mentioned element A may be included in the above-mentioned cathode active material.
  • This application has no special restrictions on the Dv50 and Dv90 of the positive active material, as long as the purpose of this application can be achieved.
  • the Dv50 of the positive active material is 0.4 ⁇ m to 20 ⁇ m, and the Dv90 is 2 ⁇ m to 40 ⁇ m.
  • Dv50 refers to the cumulative total of the positive active material.
  • Dv90 refers to the particle size corresponding to the cumulative volume distribution percentage of the cathode active material reaching 90%.
  • the preparation method of the cathode active material containing element A may include but is not limited to the following steps: prepare The raw materials of the cathode active material containing the element A are mixed and then calcined to obtain the cathode active material containing the element A.
  • the element A is introduced by adding the oxide of the element A as the raw material.
  • the oxide of the element A can be mixed with other elements at the beginning.
  • the raw materials are mixed together or added during the calcination process. Among them, the mass percentage of element A in the cathode active material is achieved by regulating the amount of oxide of element A added.
  • the amount of oxide of element A increases, the amount of element A in the cathode active material increases.
  • the mass percentage content of element A also increases; the addition amount of the oxide of element A decreases, and the mass percentage content of element A in the cathode active material also decreases.
  • the above-mentioned raw materials for preparing the cathode active material containing element A and the content ratio of each raw material can be selected according to the actual required cathode active material containing element A, which is not limited in this application.
  • the temperature and time for the above-mentioned calcination can be those known in the art for preparing cathode active materials, and are not limited in this application.
  • Oxides of element A are the most commonly used oxides among all oxides of element A in preparing cathode active materials.
  • the positive electrode material layer is provided on at least one of the two surfaces in the thickness direction of the positive electrode current collector.
  • the "surface" here can be the entire area of the positive electrode current collector, or it can be the entire area of the positive electrode current collector.
  • the partial area of the fluid is not particularly limited in this application, as long as the purpose of this application can be achieved.
  • the positive electrode current collector is not particularly limited as long as it can achieve the purpose of this application.
  • it can include but is not limited to aluminum foil, aluminum alloy foil, composite current collector, etc., and is preferably aluminum foil.
  • the thickness of the positive electrode current collector there is no particular limitation on the thickness of the positive electrode current collector, as long as the purpose of this application can be achieved, for example, the thickness is 1 ⁇ m to 30 ⁇ m, preferably 5 ⁇ m to 12 ⁇ m.
  • the positive electrode material layer may also include a binder.
  • the binder is not particularly limited in this application, as long as it can achieve the purpose of this application.
  • it may include but is not limited to carboxymethylcellulose (CMC), polyethylene, etc.
  • CMC carboxymethylcellulose
  • the positive electrode material layer may also include a conductive agent.
  • a conductive agent may include but is not limited to natural graphite, flake graphite, artificial graphite, conductive graphite, etc.
  • the above-mentioned carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and/or multi-walled carbon nanotubes.
  • the above-mentioned carbon fibers may include, but are not limited to, vapor grown carbon fibers (VGCF) and/or nanocarbon fibers.
  • the above-mentioned metal material may include but is not limited to metal powder and/or metal fiber. Specifically, the metal may include but is not limited to at least one of copper, nickel, aluminum or silver.
  • the above-mentioned conductive polymer may include, but is not limited to, at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene or polypyrrole.
  • the cathode active material, conductive agent and binder in the cathode material layer has no special restrictions on the content of the cathode active material, conductive agent and binder in the cathode material layer. Contents known in the art can be used.
  • the mass ratio of the cathode active material, conductive agent and binder can be (78 ⁇ 99):(0.1 ⁇ 10):(0.1 ⁇ 10).
  • the positive electrode plate may further include a conductive layer located between the positive electrode current collector and the positive electrode material layer.
  • the composition of the conductive layer is not particularly limited in this application. It may be a conductive layer commonly used in the art, which may include, but is not limited to, the above-mentioned conductive agent and the above-mentioned adhesive.
  • the electrochemical device may include the above-mentioned negative electrode sheet.
  • the negative electrode sheet usually includes a negative electrode current collector and a negative electrode material layer.
  • the negative electrode material layer may be disposed on a surface in the thickness direction of the negative electrode current collector, or may be disposed on the negative electrode. on both surfaces in the thickness direction of the current collector.
  • the "surface" here can be the entire area of the negative electrode current collector, or it can be a partial area of the negative electrode current collector.
  • This application has no special restrictions on the negative electrode current collector, as long as it can achieve the purpose of this application.
  • the negative electrode current collector can include but is not limited to copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, carbon-based Current collector or composite current collector, etc.
  • the thickness of the negative electrode current collector is 4 ⁇ m to 12 ⁇ m.
  • the negative electrode material layer includes a negative electrode active material.
  • the negative electrode active material is not particularly limited as long as it can achieve the purpose of this application.
  • it can include but is not limited to graphite, hard carbon, silicon, silicon oxide or organic At least one of silicon.
  • the negative electrode material layer may also include a conductive agent.
  • a conductive agent This application has no special restrictions on the conductive agent, as long as it can achieve the purpose of this application. For example, it may include but is not limited to at least one of the above conductive agents.
  • the negative electrode material layer may also include a binder.
  • This application has no special restrictions on the binder, as long as it can achieve the purpose of this application.
  • it may include but is not limited to at least one of the above-mentioned binders. .
  • the negative active material, conductive agent and binder in the negative electrode material layer has no special restrictions on the contents of the negative active material, conductive agent and binder in the negative electrode material layer. Contents known in the art can be used. For example, the mass ratio of the negative active material, conductive agent and binder can be (78 ⁇ 98.5):(0.1 ⁇ 10):(0.1 ⁇ 10).
  • the negative electrode may further include a conductive layer located between the negative electrode current collector and the negative electrode material layer.
  • a conductive layer located between the negative electrode current collector and the negative electrode material layer.
  • This application has no special limitation on the composition of the conductive layer. It can be a conductive layer commonly used in this field.
  • the conductive layer can include but is not limited to the above-mentioned conductive agent and the above-mentioned adhesive agent.
  • the electrolyte may also include compounds containing P-O bonds.
  • the compounds containing P-O bonds may include, but are not limited to, tris(trimethylsilyl)phosphate (TMSP), tris(trimethylsilyl)phosphite (TTSPi), at least one of triallyl phosphate, tripropargyl phosphate, triallyl phosphite or tripropargyl phosphite. Based on the mass of the electrolyte, the mass percentage of the P-O bond-containing compound is 0.1% to 10%.
  • the electrolyte may also include non-aqueous solvents, and the non-aqueous solvents may include but are not limited to at least one of carbonate compounds, carboxylate compounds, ether compounds or other organic solvents.
  • Carbonate compounds may include, but are not limited to, chain carbonate compounds and/or fluorocarbonate compounds.
  • Chain carbonate compounds may include, but are not limited to, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), At least one of ethyl propyl carbonate (EPC) or methyl ethyl carbonate (MEC).
  • Fluorocarbonate compounds may include, but are not limited to, 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 -At least one of difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, or trifluoromethylethylene carbonate.
  • FEC fluoroethylene carbonate
  • 1,1-difluoroethylene carbonate 1,1,2-trifluoroethylene carbonate
  • Carboxylate compounds may include, but are not limited to, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate (EP), propyl propionate (PP), ⁇ - At least one of butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone or methyl formate.
  • Ether compounds may include, but are not limited to, dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxy At least one of methoxyethane, 2-methyltetrahydrofuran or tetrahydrofuran.
  • organic solvents may include, but are not limited to, dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone , at least one of formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate or phosphate ester.
  • the mass percentage of the above-mentioned non-aqueous solvent is 40% to 75%, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or somewhere in between. Any range.
  • the electrolyte may also include lithium salts.
  • This application has no special restrictions on lithium salts, as long as the purpose of this application can be achieved.
  • it may include but is not limited to LiPF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , at least one of LiCH 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , LiSiF 6 or lithium difluoroborate.
  • the lithium salt includes LiPF 6 .
  • the density of the electrolyte is 1.10g/mL to 1.35g/mL, preferably 1.15g/mL to 1.30g/mL.
  • the electrolyte density meets the above range, the electrolyte can better meet the transmission needs of lithium ions during the charge and discharge process of the electrochemical device.
  • the electrochemical device may include an isolation membrane, and the material of the isolation membrane may include, but is not limited to, polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide or aramid. At least one of them is preferably polyethylene and/or polypropylene.
  • polyethylene may include, but is not limited to, at least one of high density polyethylene, low density polyethylene, or ultra-high molecular weight polyethylene.
  • the isolation membrane of the present application may have a porous structure, and the size of the pore diameter is not particularly limited as long as the purpose of the present application can be achieved. For example, the size of the pore diameter may be 0.01 ⁇ m to 1 ⁇ m.
  • the thickness of the isolation film is not particularly limited as long as the purpose of this application can be achieved. For example, the thickness may be 5 ⁇ m to 500 ⁇ m.
  • the surface of the isolation film may further include a porous layer, and the porous layer may be provided on one surface of the isolation film in the thickness direction of the base material, or may be provided on both surfaces of the isolation film in the thickness direction.
  • the "surface” here can be the entire area of the isolation film, or it can be a partial area of the isolation film.
  • the porous layer includes inorganic particles and a porous layer binder.
  • the inorganic particles may include but are not limited to aluminum oxide (Al 2 O 3 ), silicon oxide (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), dioxide Hafnium (HfO 2 ), tin oxide (SnO 2 ), cerium dioxide (CeO 2 ), nickel oxide (NiO), zinc oxide (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y) 2 O 3 ), at least one of silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate.
  • the porous layer binder may include, but is not limited to, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethylcellulose , at least one of polyvinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the porous layer on the surface of the isolation membrane can improve the heat resistance, oxidation resistance and electrolyte wetting performance of the isolation membrane, and enhance the adhesion between the isolation membrane and the positive electrode or negative electrode.
  • the preparation process of the electrochemical device is well known to those skilled in the art, and the application is not particularly limited. For example, it may include but is not limited to the following steps: stack the positive electrode sheet, the isolation film and the negative electrode sheet in order, and stack them as needed. Winding, folding and other operations are performed to obtain an electrode assembly with a wound structure, the electrode assembly is placed in a packaging bag, the electrolyte is injected into the packaging bag and sealed to obtain an electrochemical device; or, the positive electrode sheet, isolation film and negative electrode are The pole pieces are stacked in order, and then the four corners of the entire stacked structure are fixed with tape to obtain the electrode assembly of the stacked structure.
  • the electrode assembly is placed in the packaging bag, the electrolyte is injected into the packaging bag and sealed, and the electrochemical device is obtained. .
  • overcurrent prevention components, guide plates, etc. can also be placed in the packaging bag as needed to prevent pressure rise inside the electrochemical device and overcharge and discharge.
  • a second aspect of the present application provides an electronic device comprising the electrochemical device in any of the preceding embodiments.
  • the electrochemical device provided by this application has good comprehensive performance, and the obtained electronic device has a long service life.
  • the electronic device of the present application is not particularly limited and may be used in any electronic device known in the prior art.
  • the electronic device may include but is not limited to notebook computers, pen input computers, mobile computers, e-book players, Portable phones, portable fax machines, portable copiers, portable printers, stereo headsets, video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable Recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • the lithium-ion battery that has reached constant temperature is charged with a constant current of 1C until the voltage is 4.35V, then charged with a constant voltage of 4.35V until the current is 0.05C, and then discharged with a constant current of 1C until the voltage is 2.8V.
  • This is a charge and discharge cycle. Taking the first discharge capacity as 100%, repeatedly perform charge and discharge cycles until the discharge capacity decays to 80%, stop the test, and record the number of cycles at this time as the number of 45°C cycles, as an indicator for evaluating the cycle performance of lithium-ion batteries. .
  • the lithium-ion battery Charge the lithium-ion battery at a constant current of 0.5C to 4.35V at 25°C, then charge it at a constant voltage of 4.35V until the current is less than or equal to 0.05C. Place the fully charged lithium-ion battery in a high and low temperature chamber at 5°C/ The temperature is raised to 130°C at a rate of min, and the temperature is maintained at 130°C for 1 hour. The lithium-ion battery is monitored. If the lithium-ion battery does not catch fire or explode, the test is deemed to have passed. Ten lithium-ion batteries were tested for each example and comparative example, and the number that passed was recorded.
  • the float thickness expansion rate during the float charge test of lithium-ion batteries is calculated as an indicator to evaluate the float charge performance of lithium-ion batteries.
  • Floating thickness expansion rate (thickness after 60 days of floating - initial thickness)/initial thickness ⁇ 100%.
  • the positive electrode slurry is evenly coated on one surface of the positive electrode current collector aluminum foil with a thickness of 10 ⁇ m, and the aluminum foil is dried at 85°C for 1 hour to obtain a positive electrode sheet coated with a positive electrode material layer on one side.
  • the coating mass is 0.3g/1540.25mm 2 .
  • a positive electrode sheet coated with a positive electrode material layer on both sides After drying under vacuum conditions at 85°C for 1 hour, and then cold pressing, cutting, and slitting, a positive electrode piece with a specification of 65 mm ⁇ 2010 mm was obtained. And weld a positive electrode tab on the positive electrode piece.
  • the working length b of the positive electrode tab is 2m.
  • the width of the positive electrode tab is 10mm.
  • the Dv10 of the positive electrode active material is 2.5 ⁇ m.
  • a porous polyethylene film with a thickness of 7 ⁇ m (provided by Celgard) was used.
  • the positive electrode piece, isolation film and negative electrode piece prepared above are stacked in order, so that the isolation film is between the positive electrode piece and the negative electrode piece to play an isolation role, and the electrode assembly is obtained by winding.
  • the electrode assembly is placed in an aluminum-plastic film packaging bag, dried and then injected with electrolyte. After vacuum packaging, standing, formation, degassing, trimming and other processes, a lithium-ion battery is obtained.
  • Example 1-1 Except for adjusting relevant preparation parameters according to Table 1, the rest is the same as Example 1-1. Among them, when b is 0.5m, 1m, and 3m, the size of the positive electrode piece is adjusted to 65mm ⁇ 510mm, 65mm ⁇ 1010mm, 65mm ⁇ 3010mm, and the size of the negative electrode piece is adjusted to 68mm ⁇ 515mm, 68mm ⁇ 1015mm, 68mm. ⁇ 3015mm.
  • the size of the positive electrode piece is 65mm ⁇ 2030mm
  • the size of the negative electrode piece is 65mm ⁇ 2040mm
  • L3 is 10mm
  • L4 is 1000mm
  • L5 is 1000mm
  • Example 2-1 Example 2-1, Example 2-2 and Example 2-4
  • Example 1-3 Except that the polynitrile compound is added as shown in Table 3 when preparing the electrolyte, the rest is the same as in Example 1-3.
  • Example 1-1 Except for adjusting relevant preparation parameters according to Table 1, the rest is the same as Example 1-1. Among them, when b is 4m, the size of the positive electrode piece is adjusted to 65mm ⁇ 4010mm, and the size of the negative electrode piece is adjusted to 68mm ⁇ 4015mm.
  • Example 1-1 to Example 1-16 and Comparative Example 1 to Comparative Example 3 that when b and a/b are within the scope of the present application, the number of cycles of the lithium ion battery increases, indicating that the lithium ion battery The cycle performance of the battery has been improved. At the same time, the number of passes of the overcharge test and hot box test has increased, and the storage thickness expansion rate has decreased, indicating that the safety performance and high temperature performance of lithium-ion batteries have been improved. Overall, compared with the lithium-ion battery in the comparative example, the overall performance of the lithium-ion battery in the present application is improved.
  • the mass percentage of cyclic carbonate usually affects the performance of lithium-ion batteries. It can be seen from Example 1-1 to Example 1-16 that when the mass percentage of cyclic carbonate is within the scope of this application , the obtained lithium-ion battery has better cycle performance, high temperature performance and safety performance, that is, it has better overall performance.
  • the coating quality C and the value of a/C of the cathode material layer usually also affect the performance of the lithium-ion battery. From Example 1-3, Example 2-1 to Example 2-4, it can be seen that when the cathode material layer The coating quality C and the value of a/C are within the scope of this application, and the obtained lithium-ion battery has good cycle performance, high temperature performance and safety performance, that is, it has good comprehensive performance.
  • Example 3-1 to Example 3-11 that adding polynitrile compounds to the electrolyte containing cyclic carbonate can further improve the cycle performance and high temperature performance of lithium-ion batteries. and safety performance, that is, improving the overall performance of lithium-ion batteries.
  • the type and content of polynitrile compounds, and the value of d/Dv10 usually also affect the performance of lithium-ion batteries. From Example 3-1 to Example 3-11, it can be seen that when the type and content of polynitrile compounds, and The value of d/Dv10 is within the scope of this application, and the obtained lithium-ion battery has good cycle performance, high temperature performance and safety performance, that is, it has good comprehensive performance.
  • Example 4-1 to Example 4-9 that adding a sulfur-oxygen double bond-containing compound to the electrolyte containing cyclic carbonate can further improve the cycle performance of lithium-ion batteries. , high temperature performance and safety performance, that is, improving the overall performance of lithium-ion batteries.
  • the type and content of sulfur-oxygen double bond-containing compounds usually also affect the performance of lithium-ion batteries. It can be seen from Example 4-1 to Example 4-9 that when the type and content of sulfur-oxygen double bond-containing compounds are determined in this application Within the range, the obtained lithium-ion battery has good cycle performance, high temperature performance and safety performance, that is, it has good overall performance.
  • Example 5-1 to Example 5-7 that adding lithium salt additives to the electrolyte containing cyclic carbonate can further improve the cycle performance and high temperature performance of lithium-ion batteries. and safety performance, that is, improving the overall performance of lithium-ion batteries.
  • the type and content of lithium salt additives usually also affect the performance of lithium ion batteries.
  • the obtained Lithium-ion batteries have good cycle performance, high temperature performance and safety performance, that is, they have good overall performance.
  • Example 6-1 to Example 6-4 that on the basis of the electrolyte containing cyclic carbonate, polynitrile compounds, sulfur-oxygen double bond-containing compounds and lithium salt additives are added. At least two of them can further improve the cycle performance, high temperature performance and safety performance of lithium-ion batteries, that is, improve the overall performance of lithium-ion batteries. It can be seen from Example 6-1 to Example 6-4 that polynitrile compounds, sulfur-oxygen double bond-containing compounds and lithium salt additives have good superposition, and the obtained lithium-ion battery has good cycle performance, high temperature performance and Safety performance, that is, good overall performance.
  • Example 7-1 to Example 7-9 it can be seen from Example 1-3, Example 7-1 to Example 7-9 that when the positive electrode active material contains element A, the cycle performance, high temperature performance and safety performance of the lithium ion battery can be further improved, that is, Improve the overall performance of lithium-ion batteries.
  • the type and content of element A usually also affects the performance of lithium-ion batteries. From Example 7-1 to Example 7-9, it can be seen that when the type and content of element A are within the scope of this application, the obtained lithium ion The battery has good cycle performance, high temperature performance and safety performance, that is, it has good overall performance.

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Abstract

一种电化学装置和电子装置，电化学装置包括正极极片(10)和电解液，其中，正极极片(10)包括正极极耳(20)，正极极耳(20)的工作长度b为0.5m至3m；电解液包括环状碳酸酯，基于电解液的质量，环状碳酸酯的质量百分含量为a％，环状碳酸酯包括碳酸亚乙酯和/或碳酸亚丙酯；电化学装置满足13≤a/b≤110。通过调控正极极耳(20)的工作长度b和a/b的值，以及选择环状碳酸酯，有利于正极极片(10)与电解液之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。

Description

一种电化学装置和电子装置
本申请要求于2022年5月11日提交中国专利局、申请号为202210506822.1、发明名称为“一种电化学装置和电子装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电化学技术领域，特别是涉及一种电化学装置和电子装置。
背景技术
锂离子电池具有储能密度大、开路电压高、自放电率低、循环寿命长、安全性好等优点，广泛应用于便携式电能储存、电子设备、电动汽车等各个领域，也已逐渐成为上述领域的主流电池。在锂离子电池飞速发展的过程中也对锂离子电池的综合性能提出更高的要求。例如，在保证锂离子电池具有较高能量密度和较低成本的基础上，如何提高锂离子电池的循环性能、高温性能和安全性能。因此，如何提高锂离子电池的综合性能已成为亟待解决的问题。
发明内容
本申请的目的在于提供一种电化学装置和电子装置，以提高电化学装置的综合性能。
本申请的第一方面提供了一种电化学装置，电化学装置包括正极极片和电解液，其中，所述正极极片包括正极极耳，所述正极极耳的工作长度b为0.5m至3m；所述电解液包括环状碳酸酯，基于所述电解液的质量，所述环状碳酸酯的质量百分含量为a％，所述环状碳酸酯包括碳酸亚乙酯和/或碳酸亚丙酯；所述电化学装置满足13≤a/b≤110，优选为20≤a/b≤110。通过调控正极极耳的工作长度b和a/b的值在上述范围内，以及选择上述环状碳酸酯，有利于正极极片与电解液之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。
其中，沿所述正极极片长度方向，所述正极极片包括相对的第一边缘和第二边缘；所述正极极耳为一个，所述正极极耳到所述第一边缘的距离为L1，所述正极极耳到所述第二边缘的距离为L2，所述工作长度b等于L1和L2中的最大值；或者，所述正极极耳为两个，其中，靠近所述第一边缘的正极极耳为第一正极极耳，靠近所述第二边缘的正极极耳为第二正极极耳，所述第一正极极耳到所述第一边缘的距离为L3，所述第二正极极耳到所 述第二边缘的距离为L4，所述第一正极极耳和所述第二正极极耳之间的距离为L5，所述工作长度b等于L3、L4、0.5×L5中的最大值。
在本申请的一些实施方案中，25≤a≤60，14.5≤a/b≤110。通过调控a和a/b的值在上述范围内，能够改善电化学装置的安全性能，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，所述正极极片包括正极集流体和设置于所述正极集流体至少一个表面上的正极材料层，所述正极材料层的涂布质量为C g/1540.25mm 2，所述电化学装置满足50≤a/C≤300。通过调控a/C的值在上述范围内，能够改善电化学装置的循环性能、高温性能和安全性能，同时也不会影响电化学装置的动力学性能和能量密度，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，0.2≤C≤0.5。通过调控C的值在上述范围内，能够改善电化学装置的安全性能，同时也不会影响电化学装置的能量密度，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，所述电解液包括多腈化合物，基于所述电解液的质量，所述多腈化合物的质量百分含量d％为0.5％至5％，所述多腈化合物包括戊二腈、己二腈、丁二腈、丁烯腈、3-甲基丁烯腈、1,2-双(氰乙氧基)乙烷、1,3,5-己烷三腈、1,3,6-己烷三腈、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。优选地，所述电解液包括：戊二腈、己二腈、丁二腈或1,2-双(氰乙氧基)乙烷中的至少一种；和，1,3,5-己烷三腈、1,3,6-己烷三腈、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。通过调控多腈化合物的质量百分含量在上述范围内，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述多腈化合物，可以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，所述正极极片包括正极活性材料，所述正极活性材料的Dv10和所述多腈化合物的质量百分含量d％在数值上满足：0.2≤d/Dv10≤4；1μm≤Dv10≤5μm。通过调控d/Dv10的值在上述范围内，有利于改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，所述电解液包括含硫氧双键化合物，基于所述电解液的质量，所述含硫氧双键化合物的质量百分含量为0.01％至8％，所述含硫氧双键化合物包括1,3-丙烷磺内酯、硫酸亚乙酯、甲烷二磺酸亚甲酯、丙烯基-1,3-磺酸内酯、四氟乙烷-beta- 磺内酯、2,4-丁烷磺内酯、1,4-丁磺酸内酯、1,8-萘磺酸内酯或亚硫酸亚乙酯中的至少一种。通过调控含硫氧双键化合物的质量百分含量在上述范围内，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述含硫氧双键化合物，可以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，所述电解液包括锂盐添加剂，基于所述电解液的质量，所述锂盐添加剂的质量百分含量e％为0.01％至2％，所述锂盐添加剂包括二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、四氟硼酸锂、四硼酸锂、硼酸锂或三氟甲磺酸锂中的至少一种。通过调控锂盐添加剂的质量百分含量在上述范围内，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述锂盐添加剂，可以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。在本申请的一些实施方案中，所述正极极片包括正极材料层，所述正极材料层中的正极活性材料包括元素A，基于所述正极活性材料的质量，所述元素A的质量百分含量为0.001％至2％，所述元素A包括Al、B、Cr、Fe、Mg、Na、S、Ti、Zr、Y、Nb、Mo、W、F或P中的至少一种，可以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
本申请的第二方面提供了一种电子装置，其包括前述任一实施方案中的电化学装置。本申请提供的电化学装置具有良好的综合性性能，得到的电子装置具有较长的使用寿命。
本申请提供了一种电化学装置和电子装置，电化学装置包括正极极片和电解液，其中，正极极片包括正极极耳，正极极耳的工作长度b为0.5m至3m；电解液包括环状碳酸酯，基于电解液的质量，环状碳酸酯的质量百分含量为a％，环状碳酸酯包括碳酸亚乙酯和/或碳酸亚丙酯；电化学装置满足13≤a/b≤110。通过调控正极极耳的工作长度b和a/b的值在上述范围内，以及选择上述环状碳酸酯，有利于正极极片与电解液之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。
当然，实施本申请的任一实施方案并不一定需要同时达到以上所述的所有优点。
附图说明
为了更清楚地说明本申请实施例和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实 施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请一些实施方案中的正极极片的结构示意图；
图2为本申请另一些实施方案中的正极极片的结构示意图。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照附图并举实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方案中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
锂离子电池中通常包括正极极片、负极极片、隔离膜和电解液等，均是影响锂离子电池性能的重要因素。对于具有卷绕结构的锂离子电池，正极极片和负极极片的长宽比较大，当在正极极片上设置的正极极耳的数量较少时(例如一个或两个)，会影响正极极片不同区域的电流密度和温度分布的均匀性，从而会影响锂离子电池的综合性能，例如，循环性能、高温性能和安全性能等。基于上述问题，本申请提供了一种电化学装置和电子装置，以提高电化学装置的综合性能。
本申请的第一方面提供了一种电化学装置，电化学装置包括正极极片和电解液，其中，正极极片包括正极极耳，正极极耳的工作长度b为0.5m至3m；电解液包括环状碳酸酯，基于电解液的质量，环状碳酸酯的质量百分含量为a％，环状碳酸酯包括碳酸亚乙酯(EC)和/或碳酸亚丙酯(PC)；电化学装置满足13≤a/b≤110，优选为20≤a/b≤110。
为了方便理解，以正极极片的长度方向为X方向、以正极极片的宽度方向为Y方向建立直角坐标系。如图1和图2所示，沿正极极片10长度方向(X方向)，正极极片10包括相对的第一边缘11和第二边缘12。具体地，如图1所示，当正极极片10的正极极耳20为一个时，正极极耳20到第一边缘11的距离为L1，正极极耳20到第二边缘12的距离为L2，正极极耳的工作长度b等于L1和L2中的最大值。或者，如图2所示，当正极极片10的正极极耳20为两个时，其中，靠近第一边缘11的正极极耳20为第一正极极耳21，靠近第二边缘12的正极极耳20为第二正极极耳22，第一正极极耳21到第一边缘11的距离为L3，第二正极极耳22到第二边缘12的距离为L4，第一正极极耳21和第二正极极耳 22之间的距离为L5，正极极耳的工作长度b等于L3、L4、0.5×L5中的最大值。
本申请的申请人发现，当a/b的值过小(例如小于13)或正极极耳的工作长度b过大(例如大于3m)时，使得正极极片上的电流密度和热量不均匀，对于靠近正极极耳的区域，电流密度较大、热量聚集较多、温度较高，使得脱锂含量增加，容易导致负极极片出现析锂现象，并导致正极极片中正极活性材料的结构衰变加剧，进而加剧正极活性材料与电解液的副反应，影响电化学装置的循环性能和安全性能，甚至导致电化学装置失效。当a/b的值过大时(例如大于110)，环状碳酸酯的相对含量较高，电解液对锂离子的传输的改善受限，容易引起负极极片的析锂现象，从而影响电化学装置的动力学性能(例如倍率性能)和安全性能。通过调控正极极耳的工作长度b和a/b的值在上述范围内，例如，正极极耳的工作长度b可以为0.5m、1m、1.5m、2m、2.5m、3m或为其间的任意范围，a/b的值可以为13、20、30、40、50、60、70、80、90、10、110或为其间的任意范围，以及选择上述具有良好的化学稳定性和热稳定性的环状碳酸酯，有利于正极极片与电解液之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。当电解液同时包含EC和PC时，本申请对EC和PC的质量比没有特别限定，只要能实现本申请的目的即可，例如，EC和PC的质量比可以为1:5至4:1。
在本申请的一些实施方案中，25≤a≤60，14.5≤a/b≤110。具体地，当a/b的值在上述范围内，a的值过小时(例如小于25)，也即环状碳酸酯的质量百分含量过低，不利于在正极极片表面形成良好的保护界面以减少正极活性材料与电解液之间的副反应，从而影响电化学装置的循环性能，同时也不利于改善电化学装置的高温性能。a的值过大时(例如大于60)，也即环状碳酸酯的质量百分含量过高，电解液的粘度增加，影响锂离子的传输，容易引起负极极片的析锂现象，从而影响电化学装置的动力学性能和安全性能。通过调控a的值在上述范围内，例如，a可以为25、30、35、40、45、50、55、60或为其间的任意范围，环状碳酸酯具有合适的质量百分含量，有利于在正极极片表面形成合适的保护界面以减少正极活性材料与电解液之间的副反应，同时还可以钝化负极极片析锂部分的界面，能够改善电化学装置的安全性能，也不会影响电化学装置的动力学性能，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，正极极片包括正极集流体和设置于正极集流体至少一个表面上的正极材料层，正极材料层的涂布质量为C g/1540.25mm 2，电化学装置满足50≤a/C ≤300。当a/C满足上述范围，电化学装置能够在不损失能量密度的同时，能够改善正极材料层在正极集流体侧和隔离膜侧之间的浓差极化，从而降低正极极片厚度方向上，局部较大的电流密度和极化问题带来的局部过热、材料相变和负极极片的析锂现象，从而改善电化学装置的安全性能、循环性能和高温性能。通过调控a/C的值在上述范围内，例如，a/C的值可以为50、100、150、175、200、250、300或为其间的任意范围，能够改善电化学装置的循环性能、高温性能和安全性能，同时也不会影响电化学装置的动力学性能和能量密度，进而改善电化学装置的综合性能。上述正极集流体至少一个表面是指沿正极集流体厚度方向的两个表面中的至少一个表面。
在本申请的一些实施方案中，0.2≤C≤0.5。具体地，满足0.2≤C≤0.5，正极极片能够在保证能量密度的同时，维持正极材料层中的离子及电子的传输效率。通过调控C的值在上述范围内，例如，C的值可以为0.2、0.25、0.3、0.35、0.4、0.45、0.5或为其间的任意范围，正极材料层具有合适的涂布质量，能够改善电化学装置的安全性能，同时也不会影响电化学装置的能量密度，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，电解液包括多腈化合物，基于电解液的质量，多腈化合物的质量百分含量d％为0.5％至5％，多腈化合物包括戊二腈、己二腈(ADN)、丁二腈(SN)、丁烯腈、3-甲基丁烯腈、1,2-双(氰乙氧基)乙烷(DENE)、1,3,5-己烷三腈、1,3,6-己烷三腈(HTCN)、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。优选地，所述电解液包括：戊二腈、己二腈、丁二腈或1,2-双(氰乙氧基)乙烷中的至少一种；和，1,3,5-己烷三腈、1,3,6-己烷三腈、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。在电解液中加入上述多腈化合物，有利于抑制正极活性材料的相变，从而减少正极活性材料与电解液之间的副反应以进一步提高电化学装置的安全性能和循环性能，进而改善电化学装置的综合性能。具体地，当多腈化合物的质量百分含量过低时(例如低于0.5％)，对电化学装置的循环性能和安全性能改善不明显。当多腈化合物的质量百分含量过高时(例如高于5％)，电解液的粘度增加，影响锂离子的传输，容易引起负极极片的析锂现象，从而影响电化学装置的动力学性能和安全性能。通过调控多腈化合物的质量百分含量在上述范围内，例如，多腈化合物的质量百分含量可以为0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％或为其间的任意范围，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述多腈化合物，更有利于提高正极活性材料的稳定性，并与环状碳酸酯之间形成协同作用，以改善电化学装置的循环性能、高温性 能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，正极极片包括正极活性材料，正极活性材料的Dv10和多腈化合物的质量百分含量d％在数值上满足：0.2≤d/Dv10≤4，1μm≤Dv10≤5μm。通过调控d/Dv10和Dv10的值在上述范围内，例如，d/Dv10的值可以为0.2、0.4、0.8、1.2、1.6、2.0、2.5、3.0、3.5、4.0或为其间的任意范围，Dv10的值可以为1μm、2μm、3μm、4μm、5μm或为其间的任意范围，有利于电解液与正极极片之前形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。Dv10是指正极活性材料累计体积分布百分数达到10％时所对应的粒径。
在本申请的一些实施方案中，电解液包括含硫氧双键化合物，基于电解液的质量，含硫氧双键化合物的质量百分含量为0.01％至8％，含硫氧双键化合物包括1,3-丙烷磺内酯(PS)、硫酸亚乙酯(DTD)、甲烷二磺酸亚甲酯(MMDS)、丙烯基-1,3-磺酸内酯(PES)、四氟乙烷-beta-磺内酯、2,4-丁烷磺内酯、1,4-丁磺酸内酯、1,8-萘磺酸内酯或亚硫酸亚乙酯中的至少一种。在电解液中加入上述含硫氧双键化合物，能够提高正极极片表面的保护界面的稳定性，同时也可以提高正极活性材料的稳定性，以抑制正极活性材料的相变以及与电解液之间的副反应，进一步提高电化学装置的安全性能和循环性能，进而改善电化学装置的综合性能。具体地，当含硫氧双键化合物的质量百分含量较低时(例如低于0.01％)，对电化学装置的循环性能和安全性能改善不明显。当含硫氧双键化合物的质量百分含量较高时(例如高于8％)，在正极极片表面和负极极片表面形成的保护界面的致密性过高，影响锂离子的传输，从而影响电化学装置的动力学性能。通过调控含硫氧双键化合物的质量百分含量在上述范围内，例如，含硫氧双键化合物的质量百分含量可以为1％、2％、3％、4％、4.5％、5％、6％、7％、8％或为其间的任意范围，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述含硫氧双键化合物，更有利于提高正极活性材料的稳定性，并与环状碳酸酯之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，电解液包括含硫氧双键化合物，基于电解液的质量，含硫氧双键化合物的质量百分含量为0.5％至5％。含硫氧双键化合物包括丙烯基-1,3-磺酸内酯(PES)，基于电解液的质量，丙烯基-1,3-磺酸内酯的质量百分含量为0.5％至2％。当电化学装置满足13≤a/b≤110时，在电解液中加入包括丙烯基-1,3-磺酸内酯(PES)，对于正极极片中局部较高的电流密度、极化作用造成的正极活性材料相变有显著的抑制作用，从而 进一步改善了电化学装置的循环性能、高温存储性能及浮充膨胀率。
在本申请的一些实施方案中，电解液包括锂盐添加剂，基于电解液的质量，锂盐添加剂的质量百分含量e％为0.01％至2％，优选为0.01％至1％，锂盐添加剂包括二氟磷酸锂(LiPO 2F 2)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、四氟硼酸锂(LiBF 4)、四硼酸锂(B 4Li 2O 7)、硼酸锂(Li 3BO 3)或三氟甲磺酸锂(CF 3LiO 3S)中的至少一种。当电化学装置满足13≤a/b≤110时，在电解液中加入上述锂盐添加剂，能够提高正极极片表面的正极电解液界面的稳定性，同时也可以提高正极活性材料的稳定性，以抑制长正极极片中正极活性材料的相变以及与电解液之间的副反应。也可以在负极极片表面形成稳定的固体电解质界面，抑制电解液与负极活性材料的副反应，进一步提高电化学装置的安全性能和循环性能，进而改善电化学装置的综合性能。具体地，当锂盐添加剂的质量百分含量较低时(例如低于0.01％)，对电化学装置的循环性能和安全性能改善不明显。当锂盐添加剂的质量百分含量较高时(例如高于2％)，在负极极片表面形成的固体电解质界面的致密性过高，影响锂离子的传输，从而影响电化学装置的动力学性能。通过调控锂盐添加剂的质量百分含量在上述范围内，例如，锂盐添加剂的质量百分含量可以为0.01％、0.05％、0.1％、0.5％、1％、1.5％、2％或为其间的任意范围，有利于改善电化学装置的安全性能和循环性能，且不会影响电化学装置的动力学性能。通过选择上述锂盐添加剂，更有利于提高正极活性材料的稳定性及固体电解质界面的稳定性，并与环状碳酸酯之间形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。
在本申请的一些实施方案中，正极极片包括正极材料层，正极材料层中的正极活性材料包括元素A，基于正极活性材料的质量，元素A的质量百分含量为0.001％至2％，优选为0.05％至0.5％，元素A包括Al、B、Cr、Fe、Mg、Na、S、Ti、Zr、Y、Nb、Mo、W、F或P中的至少一种。在正极活性材料中引入上述元素A且调控元素A的质量百分含量在上述范围内，有利于与上述任一实施方案中的电解液形成协同作用，以改善电化学装置的循环性能、高温性能和安全性能等，进而改善电化学装置的综合性能。其中，本申请对正极活性材料没有特别限制，只要能实现本申请的目的即可，例如，正极活性材料可以包括但不限于钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、镍锰酸锂或磷酸铁锂中的至少一种。可以理解的是，上述正极活性材料中可以包含上述元素A。本申请对正极活性材料的Dv50和Dv90没有特别限制，只要能实现本申请的目的即可，例如，正极活性材料的Dv50为0.4μm至20μm，Dv90为2μm至40μm，Dv50是指正极活性材料累计体积分布百分数达到 50％时所对应的粒径；Dv90是指正极活性材料累计体积分布百分数达到90％时所对应的粒径。
本申请对含有元素A的正极活性材料的制备方法没有特别的限制，只要能实现本申请的目的即可，例如，含有元素A的正极活性材料的制备方法可以包括但不限于以下步骤：将制备含有元素A的正极活性材料的原料混合后进行煅烧得到含有元素A的正极活性材料，其中元素A的引入方式是以元素A的氧化物作为原料加入，元素A的氧化物可以在最开始与其它原料一起混合加入，也可以在煅烧过程中加入。其中，元素A在正极活性材料中的质量百分含量是通过调控元素A的氧化物的加入量来实现的，通常情况下，元素A的氧化物的加入量增加，元素A在正极活性材料中的质量百分含量也随之增加；元素A的氧化物的加入量减少，元素A在正极活性材料中的质量百分含量也随之减少。上述制备含有元素A的正极活性材料的原料和各原料之间的含量比例可以根据实际所需的含有元素A的正极活性材料进行选择，本申请对此不作限定。上述煅烧的温度和时间可以采用本领域已知的制备正极活性材料的温度和时间，本申请对此不作限定。元素A的氧化物为元素A所有氧化物中在制备正极活性材料时最常用的氧化物。
在本申请中，正极材料层设置在正极集流体厚度方向的两个表面中的至少一个表面上，可以理解的是，这里的“表面”可以是正极集流体的全部区域，也可以是正极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。在本申请中，正极集流体没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于铝箔、铝合金箔或复合集流体等，优选为铝箔。在本申请中，对正极集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为1μm至30μm，优选为5μm至12μm。
在本申请中，正极材料层还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于羧甲基纤维素(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。
在本申请中，正极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于天然石墨、片层石墨、人造石墨、导电炭黑(Super P)、碳纳米管(CNTs)、碳纤维、鳞片石墨、科琴黑、石墨烯、金属材料或导电聚合物中的至少一种。上述碳纳米管可以包括但不限于单壁碳纳米管和/或多壁碳纳米管。上述碳纤维可以包括但不限于气相生长碳纤维(VGCF)和/或纳米碳纤维。上述金属材料 可以包括但不限于金属粉和/或金属纤维，具体地，金属可以包括但不限于铜、镍、铝或银中的至少一种。上述导电聚合物可以包括但不限于聚亚苯基衍生物、聚苯胺、聚噻吩、聚乙炔或聚吡咯中的至少一种。
本申请对正极材料层中的正极活性材料、导电剂和粘结剂的含量没有特别限制，可以采用本领域已知的含量，例如，正极活性材料、导电剂和粘结剂的质量比可以为(78～99):(0.1～10):(0.1～10)。
任选地，正极极片还可以包括导电层，导电层位于正极集流体和正极材料层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，例如可以包括但不限于上述导电剂和上述粘结剂。
在本申请中，电化学装置可以包括上述负极极片，负极极片通常包括负极集流体和负极材料层，负极材料层可以设置于负极集流体厚度方向上的一个表面上，也可以设置于负极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是负极集流体的全部区域，也可以是负极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。本申请对负极集流体没有特别限制，只要能够实现本申请目的即可，例如，可以包括但不限于铜箔、铜合金箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、碳基集流体或复合集流体等。在本申请中，对负极集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为4μm至12μm。
在本申请中，负极材料层包括负极活性材料，其中，负极活性材料没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于石墨、硬碳、硅、氧化亚硅或有机硅中的至少一种。
在本申请中，负极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述导电剂中的至少一种。
在本申请中，负极材料层中还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述粘结剂中的至少一种。
本申请对负极材料层中的负极活性材料、导电剂和粘结剂的含量没有特别限制，可以采用本领域已知的含量，例如，负极活性材料、导电剂和粘结剂的质量比可以为(78～98.5):(0.1～10):(0.1～10)。
任选地，负极还可以包括导电层，导电层位于负极集流体和负极材料层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，导电层可以包括但不限于上 述导电剂和上述粘结剂。
在一些实施例中，电解液还可以包括含P-O键的化合物，含P-O键的化合物可以包括但不限于三(三甲基硅烷)磷酸酯(TMSP)、三(三甲硅烷基)亚磷酸酯(TTSPi)、磷酸三烯丙酯、磷酸三炔丙酯、亚磷酸三烯丙酯或亚磷酸三炔丙酯中的至少一种。基于电解液的质量，含P-O键的化合物的质量百分含量为0.1％至10％。
在本申请中，电解液还可以包括非水溶剂，非水溶剂可以包括但不限于碳酸酯化合物、羧酸酯化合物、醚化合物或其它有机溶剂中的至少一种。碳酸酯化合物可以包括但不限于链状碳酸酯化合物和/或氟代碳酸酯化合物。链状碳酸酯化合物可以包括但不限于碳酸甲乙酯(EMC)、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)或碳酸甲乙酯(MEC)中的至少一种。氟代碳酸酯化合物可以包括但不限于碳酸氟代亚乙酯(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-甲基亚乙酯或碳酸三氟甲基亚乙酯中的至少一种。羧酸酯化合物可以包括但不限于乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯(EP)、丙酸丙酯(PP)、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯或甲酸甲酯中的至少一种。醚化合物可以包括但不限于二丁醚、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-甲基四氢呋喃或四氢呋喃中的至少一种。其它有机溶剂可以包括但不限于二甲亚砜、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、磷酸三辛酯或磷酸酯中的至少一种。基于电解液的质量，上述非水溶剂的质量百分含量为40％至75％，例如40％、45％、50％、55％、60％、65％、70％、75％或为其间的任意范围。
在本申请中，电解液中还可以包括锂盐，本申请对锂盐没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于LiPF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6或二氟硼酸锂中的至少一种。优选地，锂盐包括LiPF 6。
本申请中，电解液的密度为1.10g/mL至1.35g/mL，优选1.15g/mL至1.30g/mL。当电解液密度满足上述范围时，电解液能够更好地满足电化学装置充放电过程中锂离子的传输需求。
在本申请中，电化学装置可以包括隔离膜，隔离膜的材料可以包括但不限于聚乙烯、 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，优选为聚乙烯和/或聚丙烯。例如，聚乙烯可以包括但不限于高密度聚乙烯、低密度聚乙烯或超高分子量聚乙烯中的至少一种。本申请的隔离膜可以具有多孔结构，孔径的尺寸没有特别限制，只要能实现本申请的目的即可，例如，孔径的尺寸可以为0.01μm至1μm。在本申请中，隔离膜的厚度没有特别限制，只要能实现本申请的目的即可，例如厚度可以为5μm至500μm。
任选地，隔离膜的表面还可以包括多孔层，多孔层设置于隔离膜的基材厚度方向上的一个表面上，也可以设置于隔离膜厚度方向上的两个表面上。需要说明，这里的“表面”可以是隔离膜的全部区域，也可以是隔离膜的部分区域，本申请没有特别限制，只要能实现本申请目的即可。多孔层包括无机颗粒和多孔层粘结剂，无机颗粒可以包括但不限于氧化铝(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。多孔层粘结剂可以包括但不限于聚偏氟乙烯、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高隔离膜的耐热性能、抗氧化性能和电解质浸润性能，增强隔离膜与正极极片或负极极片之间的粘结性。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制，例如，可以包括但不限于以下步骤：将正极极片、隔离膜和负极极片按顺序堆叠，并根据需要将其卷绕、折叠等操作得到卷绕结构的电极组件，将电极组件放入包装袋内，将电解液注入包装袋并封口，得到电化学装置；或者，将正极极片、隔离膜和负极极片按顺序堆叠，然后用胶带将整个叠片结构的四个角固定好得到叠片结构的电极组件，将电极组件置入包装袋内，将电解液注入包装袋并封口，得到电化学装置。此外，也可以根据需要将防过电流元件、导板等置于包装袋中，从而防止电化学装置内部的压力上升、过充放电。
本申请的第二方面提供了一种电子装置，其包括前述任一实施方案中的电化学装置。本申请提供的电化学装置具有良好的综合性性能，得到的电子装置具有较长的使用寿命。
本申请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，例如，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。
实施例
以下，举出实施例及对比例来对本申请的实施方案进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“％”为质量百分含量。
测试方法和设备：
循环性能测试：
将锂离子电池置于45℃恒温箱中，静置30min，使锂离子电池达到恒温。将达到恒温的锂离子电池以1C恒流充电至电压为4.35V，然后以4.35V恒压充电至电流为0.05C，接着以1C恒流放电至电压为2.8V，此为一个充放电循环。以首次放电的容量为100％，反复进行充放电循环，至放电容量衰减至80％时，停止测试，记录此时的循环圈数为45℃循环圈数，作为评价锂离子电池循环性能的指标。
高温存储性能测试：
将锂离子电池置于25℃恒温箱中，静置30min，使锂离子电池达到恒温。以1C恒流充电至4.35V，恒压充电至电流为0.05C，然后用1C恒流放电至2.8V。之后以0.5C恒流充电至4.35V，恒压充电至电流为0.05C，用千分尺测试并记录电池的厚度记为初始厚度。将测试锂离子电池转至70℃恒温箱中进行存储48h，期间每隔6h测试并记录锂离子电池的厚度一次，48h存储结束后将锂离子电池转移至25℃恒温箱中，静置60min，以1C恒流放电至2.8V，记录放电容量，作为锂离子电池的剩余容量。以1C恒流充电至4.35V，恒压充电至电流为0.05C，然后用1C恒流放电至2.8V，记录放电容量，作为锂离子电池可恢复容量，并测试此时锂离子电池的厚度记为测试后厚度，计算存储厚度膨胀率作为评价锂离子电池高温存储产气量的指标。存储厚度膨胀率＝(测试后厚度-初始厚度)/初始厚度×100％。
过充测试：
(1)3C 4.6V过充测试：
将锂离子电池在25℃下以0.5C放电至2.8V，再以3C恒流充电至4.6V，再恒压充电 2h，监控锂离子电池表面温度变化，锂离子电池不起火、不燃烧、不爆炸则记为测试通过。每个实施例和对比例测试10个锂离子电池，记录通过的个数。
(2)3C 4.8V过充测试：
将锂离子电池在25℃下以0.5C放电至2.8V，在以3C恒流充电至4.8V，再恒压充电2h，监控锂离子电池表面温度变化，锂离子电池不起火、不燃烧、不爆炸则记为测试通过。每个实施例和对比例测试10个锂离子电池，记录通过的个数。
(3)3C 5.4V过充测试：
将锂离子电池在25℃下以0.5C放电至2.8V，在以3C恒流充电至5.4V，再恒压充电2h，监控锂离子电池表面温度变化，锂离子电池不起火、不燃烧、不爆炸则记为测试通过。每个实施例和对比例测试10个锂离子电池，记录通过的个数。
热箱测试：
将锂离子电池在25℃下0.5C恒流充电至4.35V，再以4.35V恒压充电至电流小于等于0.05C，将满充后的锂离子电池放置到高低温箱中，以5℃/min的速率升温至130℃，在130℃条件下恒温保持1h，监控锂离子电池，锂离子电池不起火、不爆炸则记为测试通过。每个实施例和对比例测试10个锂离子电池，记录通过的个数。
浮充测试：
将锂离子电池置于25℃恒温箱中，静置30min，使锂离子电池达到恒温。以1C恒流充电至电压为4.35V，恒压充电至电流为0.05C，用千分尺测试并记录锂离子电池的初始厚度。将测试锂离子电池转至45℃恒温箱中以1C的电流持续充电60天，结束后将锂离子电池转移至25℃恒温箱中，测试并记录锂离子电池的厚度为浮充60天厚度。计算锂离子电池浮充测试过程中浮充厚度膨胀率，作为评价锂离子电池浮充性能的指标。浮充厚度膨胀率＝(浮充60天厚度-初始厚度)/初始厚度×100％。
粒径的测试：
参照国家标准GB/T 19077-2016(《粒度分布激光衍射法》)，使用激光粒度分析仪(如Malvern Master Size 3000)测定正极活性材料的Dv10。
实施例1-1
<正极极片的制备>
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2、导电剂导电炭黑、粘结剂聚偏氟乙烯按照质量比为97:1.4:1.6进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀， 获得正极浆料，其中正极浆料的固含量为70wt％。将正极浆料均匀涂覆于厚度为10μm的正极集流体铝箔的一个表面上，将铝箔在85℃下烘干处理1h，得到单面涂覆有正极材料层的正极极片，正极材料层的涂布质量为0.3g/1540.25mm 2。在铝箔的另一个表面上重复以上步骤，即得到双面涂布正极材料层的正极极片。在85℃的真空条件下干燥1h，然后经过冷压、裁片、分切后，得到规格为65mm×2010mm的正极极片。并在正极极片上焊接一个正极极耳，正极极耳的工作长度b为2m，沿正极极片的长度方向，正极极耳的宽度为10mm。其中，正极活性材料的Dv10为2.5μm。
<负极极片的制备>
将负极活性材料人造石墨、导电剂导电炭黑、增稠剂羧甲基纤维素钠、粘结剂丁苯橡胶按照质量比为96.4:1.5:0.5:1.6进行混合，加入去离子水，在真空搅拌机作用下搅拌均匀，获得负极浆料，其中负极浆料的固含量为54wt％。将负极浆料均匀涂覆于厚度为7μm的负极集流体铜箔的一个表面上，将铜箔在85℃下烘干，得到单面涂覆有厚度为50μm的负极材料层的负极极片。在铜箔的另一个表面上重复以上步骤，即得到双面涂覆负极材料层的负极极片。在85℃的真空条件下干燥1h，然后经过冷压、裁片、分切后，得到规格为68mm×2015mm的负极极片，沿负极极片的长度方向(与正极极片的长度方向相同)，负极极耳的宽度为15mm。
<电解液的制备>
在含水量小于10ppm的氩气气氛手套箱中，将EC、PC、EMC和DEC按照质量比为10:20:20:50混合得到有机溶剂，然后向有机溶剂中加入锂盐LiPF 6，得到电解液。其中，锂盐的质量百分含量为12.5％。
<隔离膜的制备>
采用厚度为7μm的多孔聚乙烯薄膜(Celgard公司提供)。
<锂离子电池的制备>
将上述制备得到的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片中间以起到隔离的作用，卷绕得到电极组件。将电极组件置于铝塑膜包装袋中，干燥后注入电解液，经过真空封装、静置、化成、脱气、切边等工序得到锂离子电池。
实施例1-2至实施例1-11、实施例1-13和实施例1-14
除了按照表1调整相关制备参数以外，其余与实施例1-1相同。其中，当b为0.5m、1m、3m时，正极极片的尺寸依次调整为65mm×510mm、65mm×1010mm、65mm×3010mm， 负极极片的尺寸依次调整为68mm×515mm、68mm×1015mm、68mm×3015mm。
实施例1-12
除了在正极极片和负极极片上焊接两个极耳、正极极片的尺寸为65mm×2030mm、负极极片的尺寸为65mm×2040mm、L3为10mm、L4为1000mm、L5为1000mm以外，其余与实施例1-1相同。
实施例1-15和实施例1-16
除了将正极活性材料变更为钴酸锂，并按照表1调整相关制备参数以外，其余与实施例1-1相同。
实施例2-1、实施例2-2和实施例2-4
除了按照表2所示调整相关制备参数以外，其余与实施例1-3相同。
实施例2-3
除了按照表2调整相关制备参数以外，其余与实施例1-8相同。
实施例3-1至实施例3-11
除了在制备电解液时按照表3所示加入多腈化合物以外，其余与实施例1-3相同。
实施例4-1至实施例4-9
除了在制备电解液时按照表4所示加入含硫氧双键化合物以外，其余与实施例1-3相同。
实施例5-1至实施例5-7
除了在制备电解液时按照表5所示加入锂盐添加剂以外，其余与实施例1-3相同。
实施例6-1至实施例6-4
除了在制备电解液时按照表6所示加入多腈化合物、含硫氧双键化合物和锂盐添加剂中的至少两种以外，其余与实施例1-3相同。
实施例7-1至实施例7-9
除了按照表7所示调整相关制备参数以外，其余与实施例1-3相同。
对比例1至对比例3
除了按照表1调整相关制备参数以外，其余与实施例1-1相同。其中，当b为4m时，正极极片的尺寸调整为65mm×4010mm，负极极片的尺寸调整为68mm×4015mm。
各实施例和对比例的制备参数和性能测试如表1至表7所示。
表1
Figure PCTCN2022117005-appb-000001
从实施例1-1至实施例1-16、对比例1至对比例3可以看出，当b和a/b在本申请的范围内时，锂离子电池的循环圈数增加，说明锂离子电池的循环性能得到提高，同时过充测试和热箱测试的通过个数增加、存储厚度膨胀率降低，说明锂离子电池的安全性能和高温性能都得到了提高。整体而言，相比于对比例中的锂离子电池，本申请中的锂离子电池的综合性能得到了提高。环状碳酸酯的质量百分含量通常会影响锂离子电池的性能，从实施例1-1至实施例1-16可以看出，当环状碳酸酯的质量百分含量在本申请的范围内，得到 的锂离子电池具有更好的循环性能、高温性能和安全性能，也即具有更好的综合性能。
表2
Figure PCTCN2022117005-appb-000002
正极材料层的涂布质量C以及a/C的值通常也会影响锂离子电池的性能，从实施例1-3、实施例2-1至实施例2-4可以看出，当正极材料层的涂布质量C以及a/C的值在本申请的范围内，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
表3
Figure PCTCN2022117005-appb-000003
Figure PCTCN2022117005-appb-000004
注：表3中的“/”表示不存在对应的参数或物质。
从实施例1-3、实施例3-1至实施例3-11可以看出，在电解液含有环状碳酸酯的基础上加入多腈化合物，可以进一步提高锂离子电池的循环性能、高温性能和安全性能，也即提高锂离子电池的综合性能。多腈化合物的种类及含量，以及d/Dv10的值通常也会影响锂离子电池的性能，从实施例3-1至实施例3-11可以看出，当多腈化合物的种类及含量，以及d/Dv10的值在本申请的范围内，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
表4
Figure PCTCN2022117005-appb-000005
注：表4中的“/”表示不存在对应的参数或物质。
从实施例1-3、实施例4-1至实施例4-9可以看出，在电解液含有环状碳酸酯的基础上加入含硫氧双键化合物，可以进一步提高锂离子电池的循环性能、高温性能和安全性能，也即提高锂离子电池的综合性能。含硫氧双键化合物的种类及含量通常也会影响锂离子电池的性能，从实施例4-1至实施例4-9可以看出，当含硫氧双键化合物的种类及含量在本申请的范围内，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
表5
Figure PCTCN2022117005-appb-000006
注：表5中的“/”表示不存在对应的参数或物质。
从实施例1-3、实施例5-1至实施例5-7可以看出，在电解液含有环状碳酸酯的基础上加入锂盐添加剂，可以进一步提高锂离子电池的循环性能、高温性能和安全性能，也即提高锂离子电池的综合性能。锂盐添加剂的种类及含量通常也会影响锂离子电池的性能，从实施例5-1至实施例5-7可以看出，当锂盐添加剂的种类及含量在本申请的范围内，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
表6
Figure PCTCN2022117005-appb-000007
注：表6中的“/”表示不存在对应的参数或物质。
从实施例1-3、实施例6-1至实施例6-4可以看出，在电解液含有环状碳酸酯的基础上加入多腈化合物、含硫氧双键化合物和锂盐添加剂中的至少两种，可以进一步提高锂离子电池的循环性能、高温性能和安全性能，也即提高锂离子电池的综合性能。从实施例6-1 至实施例6-4可以看出，多腈化合物、含硫氧双键化合物和锂盐添加剂具有良好的叠加性，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
表7
Figure PCTCN2022117005-appb-000008
注：表7中的“/”表示不存在对应的参数或物质。
从实施例1-3、实施例7-1至实施例7-9可以看出，当正极活性材料中含有元素A时，可以进一步提高锂离子电池的循环性能、高温性能和安全性能，也即提高锂离子电池的综合性能。元素A的种类及含量通常也会影响锂离子电池的性能，从实施例7-1至实施例7-9可以看出，当元素A的种类及含量在本申请的范围内，得到的锂离子电池具有良好的循环性能、高温性能和安全性能，也即具有良好的综合性能。
需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体与另一个实体区分开来，而不一定要求或者暗示这些实体之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其它变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其它要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。
本说明书中的各个实施方案均采用相关的方式描述，各个实施方案之间相同相似的部分互相参见即可，每个实施方案重点说明的都是与其它实施例的不同之处。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (12)

  1. 一种电化学装置，其包括正极极片和电解液，其中，
    所述正极极片包括正极极耳，所述正极极耳的工作长度b为0.5m至3m；
    所述电解液包括环状碳酸酯，基于所述电解液的质量，所述环状碳酸酯的质量百分含量为a％，所述环状碳酸酯包括碳酸亚乙酯和/或碳酸亚丙酯；
    所述电化学装置满足13≤a/b≤110；
    沿所述正极极片长度方向，所述正极极片包括相对的第一边缘和第二边缘；
    所述正极极耳为一个，所述正极极耳到所述第一边缘的距离为L1，所述正极极耳到所述第二边缘的距离为L2，所述工作长度b等于L1和L2中的最大值；
    或者，所述正极极耳为两个，其中，靠近所述第一边缘的正极极耳为第一正极极耳，靠近所述第二边缘的正极极耳为第二正极极耳，所述第一正极极耳到所述第一边缘的距离为L3，所述第二正极极耳到所述第二边缘的距离为L4，所述第一正极极耳和所述第二正极极耳之间的距离为L5，所述工作长度b等于L3、L4、0.5×L5中的最大值。
  2. 根据权利要求1所述的电化学装置，其中，25≤a≤60，14.5≤a/b≤110。
  3. 根据权利要求1所述的电化学装置，其中，20≤a/b≤110。
  4. 根据权利要求1所述的电化学装置，其中，所述正极极片包括正极集流体和设置于所述正极集流体至少一个表面上的正极材料层，所述正极材料层的涂布质量为C g/1540.25mm 2，所述电化学装置满足50≤a/C≤300。
  5. 根据权利要求4所述的电化学装置，其中，0.2≤C≤0.5。
  6. 根据权利要求1所述的电化学装置，其中，所述电解液包括多腈化合物，基于所述电解液的质量，所述多腈化合物的质量百分含量d％为0.5％至5％，所述多腈化合物包括戊二腈、己二腈、丁二腈、丁烯腈、3-甲基丁烯腈、1,2-双(氰乙氧基)乙烷、1,3,5-己烷三腈、1,3,6-己烷三腈、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。
  7. 根据权利要求6所述的电化学装置，其中，所述电解液包括：
    戊二腈、己二腈、丁二腈或1,2-双(氰乙氧基)乙烷中的至少一种；和，
    1,3,5-己烷三腈、1,3,6-己烷三腈、1,2,3-三(2-氰乙氧基)丙烷或1,3,4,6-己烷四腈中的至少一种。
  8. 根据权利要求6所述的电化学装置，其中，所述正极极片包括正极活性材料，所述正极活性材料的Dv10和所述多腈化合物的质量百分含量d％满足：0.2≤d/Dv10≤4；1μm ≤Dv10≤5μm。
  9. 根据权利要求1所述的电化学装置，其中，所述电解液包括含硫氧双键化合物，基于所述电解液的质量，所述含硫氧双键化合物的质量百分含量为0.01％至8％，所述含硫氧双键化合物包括1,3-丙烷磺内酯、硫酸亚乙酯、甲烷二磺酸亚甲酯、丙烯基-1,3-磺酸内酯、四氟乙烷-beta-磺内酯、2,4-丁烷磺内酯、1,4-丁磺酸内酯、1,8-萘磺酸内酯或亚硫酸亚乙酯中的至少一种。
  10. 根据权利要求1所述的电化学装置，其中，所述电解液包括锂盐添加剂，基于所述电解液的质量，所述锂盐添加剂的质量百分含量e％为0.01％至2％，所述锂盐添加剂包括二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、四氟硼酸锂、四硼酸锂、硼酸锂或三氟甲磺酸锂中的至少一种。
  11. 根据权利要求1至10中任一项所述的电化学装置，其中，所述正极极片包括正极材料层，所述正极材料层中的正极活性材料包括元素A，基于所述正极活性材料的质量，所述元素A的质量百分含量为0.001％至2％，所述元素A包括Al、B、Cr、Fe、Mg、Na、S、Ti、Zr、Y、Nb、Mo、W、F或P中的至少一种。
  12. 一种电子装置，其包括权利要求1至11中任一项所述的电化学装置。
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