WO2024017064A1 - 电池单体、电池及用电装置 - Google Patents

电池单体、电池及用电装置 Download PDF

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Publication number
WO2024017064A1
WO2024017064A1 PCT/CN2023/105973 CN2023105973W WO2024017064A1 WO 2024017064 A1 WO2024017064 A1 WO 2024017064A1 CN 2023105973 W CN2023105973 W CN 2023105973W WO 2024017064 A1 WO2024017064 A1 WO 2024017064A1
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Prior art keywords
battery cell
active material
electrolyte
battery
cell according
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PCT/CN2023/105973
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English (en)
French (fr)
Inventor
张翠平
韩昌隆
张哲�
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宁德时代新能源科技股份有限公司
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Publication of WO2024017064A1 publication Critical patent/WO2024017064A1/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
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • 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
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This application relates to the field of battery technology, specifically to a battery cell, a battery and an electrical device.
  • Batteries are used in consumer electronics, electric transportation, aerospace and other fields due to their high energy density, good cycle performance, low self-discharge, and good safety performance. Among them, the energy density and cycle performance of batteries are in the above fields. attracted much attention.
  • the improvement of battery energy density may lead to a decrease in its cycle performance, that is, there is a problem in the battery that it is difficult to balance energy density and cycle performance.
  • This application provides a battery cell, a battery and an electrical device that can take into account both energy density and cycle performance.
  • this application provides a battery cell, including: a casing, an electrode assembly and an electrolyte.
  • the housing has a receiving cavity.
  • the electrode assembly is arranged in the containing cavity.
  • the electrolyte is disposed in the containing cavity.
  • the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell satisfy the following relationship: 2 ⁇ a/b ⁇ 3, and the unit of the liquid retention coefficient a is g/Ah.
  • the ratio of the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell is set within the above-mentioned appropriate range, which enables the battery cell to have high energy density and good cycle performance. performance.
  • the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell satisfy the following relationship: 2.25 ⁇ a/b ⁇ 2.90. Setting the ratio of a/b within the above-mentioned appropriate range can further enable the battery cell to achieve both higher energy density and better cycle performance.
  • the liquid retention coefficient a of the electrolyte ranges from 1.4g/Ah to 2.97g/Ah.
  • the liquid retention coefficient a of the electrolyte is set within the above-mentioned appropriate range, which can help to increase the energy density of the battery cell and at the same time enable the battery cell to have a suitable amount of electrolyte, thereby improving the cycle of the battery cell. performance purposes.
  • the liquid retention coefficient a of the electrolyte ranges from 1.8g/Ah to 2.3g/Ah. Setting the liquid retention coefficient a of the electrolyte within the above-mentioned appropriate range can help improve the energy density of the battery cell and further improve the cycle performance of the battery cell.
  • the group margin b of the battery cell ranges from 80% to 99%. Setting the group margin b of the battery cell within the above-mentioned appropriate range allows the battery cell to have better cycle performance while also helping to increase the energy density of the battery cell.
  • the group margin b of the battery cell ranges from 85% to 95%. Setting the group margin b of the battery cell within the above-mentioned appropriate range can not only help improve the cycle performance of the battery cell, but also help further improve the energy density of the battery cell.
  • the electrode assembly includes a positive electrode piece, a negative electrode piece and a separation film.
  • the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector.
  • the positive active material layer includes a positive active material.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode active material layer includes a negative electrode active material.
  • a separation film is disposed between the positive electrode piece and the negative electrode piece.
  • the positive active material is selected from the group consisting of lithium cobalt oxide positive active material, lithium iron phosphate positive active material, lithium manganate positive active material, and lithium-rich positive active material.
  • the negative active material is selected from at least one of a carbon-containing negative active material, a silicon-containing negative active material, an alloy negative active material, a lithium-containing negative active material, and a tin-containing negative active material.
  • the ternary cathode active material has the following chemical formula: LiNix Co y N z M 1-xyz O 2 , where N is selected from Mn and Al, and M is selected from Co, Ni, Mn , at least one of Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, x+y+ z ⁇ 1.
  • the ternary cathode active material has the above chemical formula, which can further increase the energy density of the battery cell.
  • the lithium-rich cathode active material has the following chemical formula: Li 2 MnO 3 ⁇ (1-c)LiAO 2 , where A is selected from at least one of Ni, Co and Mn, 0 ⁇ c ⁇ 1. Lithium-rich cathode active materials with the above chemical formula can also further increase the energy density of battery cells.
  • the electrolyte solution includes an organic solvent and an electrolyte salt, wherein the organic solvent is selected from at least one of ester compounds and ether compounds.
  • the organic solvent is selected from at least one type of ester compounds and ether compounds, which can help improve the cycle performance of the battery cells.
  • the ester compound is selected from the group consisting of dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate and carbonic acid. At least one vinyl ester.
  • the ester compound is selected from any one or more of the above ester compounds, which can further improve the cycle performance of the battery cell.
  • the ether compound is selected from tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2, 3-Dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzene and at least one of furan and 2-(2-nitrovinyl)furan.
  • the ether compound is selected from any one or more of the above ether compounds, which can further improve the cycle performance of the battery cell.
  • the concentration of the electrolyte salt in the electrolyte solution is 0.6 mol/L-2.0 mol/L.
  • the concentration of the electrolyte in the electrolyte solution is set within the above-mentioned appropriate range, which helps to improve the cycle performance of the battery cells.
  • the electrolyte salt is selected from at least one of lithium hexafluorophosphate and lithium bisfluorosulfonimide.
  • the electrolyte is selected from the above-mentioned lithium salts, which can improve the high-temperature storage performance of the battery cells.
  • embodiments of the present application provide a battery, including the battery cell described in any of the above embodiments. Since the battery includes the battery cell in any of the above embodiments, the battery has the technical effects of the above-mentioned battery cell, which will not be described again here.
  • an embodiment of the present application provides an electrical device, including the battery described in the above embodiment.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • Figure 2 shows an exploded view of a battery provided by some embodiments of the present application
  • Figure 3 shows a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • Figure 4 shows an exploded view of a battery cell provided by some embodiments of the present application.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.
  • multiple refers to more than two (including two).
  • multiple groups refers to two or more groups (including two groups), and “multiple pieces” refers to It is more than two pieces (including two pieces).
  • the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-ion battery cell or a magnesium-ion battery cell, etc.
  • the embodiments of the present application do not refer to this. Not limited.
  • the battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this. Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.
  • the battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack.
  • Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly consists of a positive electrode plate, a negative electrode plate and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector.
  • the positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode collector that is coated with the positive electrode active material layer. Fluid, the cathode current collector without coating the cathode active material layer serves as the cathode tab.
  • Indicators of battery performance include energy density and cycle performance.
  • Energy density refers to the electrical energy released by the average unit volume or mass of the battery.
  • Cycle performance refers to the number of cycles of a rechargeable battery, which indicates how many complete charge and discharge processes the battery can undergo before it fails or begins to lose capacity. Therefore, high energy density and cycle performance can help improve the cruising range and service life of electrical devices containing the battery.
  • the content of active materials and the amount of electrolyte in the battery are usually increased.
  • the inventor found that in the limited space of the battery case, if the active material content in the battery is increased, the space occupied by the active material will increase and the space left for the electrolyte will decrease, which will lead to the electrolyte in the battery. The capacity will decrease, thus affecting the battery's cycle performance. If the amount of electrolyte in the battery is increased, the energy density of the battery may decrease, and it may even cause more side reactions and worsen the service life of the battery. It can be seen that there is a problem in the battery that it is difficult to balance energy density and cycle performance.
  • embodiments of the present application provide a battery cell, a battery, and a power device that enable the battery to take into account both energy density and cycle performance.
  • the battery cells, batteries, etc. disclosed in this application can be assembled into a power supply system for an electrical device, which can help ensure the cruising range and service life of the electrical device.
  • the electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc.
  • electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.
  • an electrical device is a vehicle.
  • Figure 1 shows a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • a battery 100 is disposed inside a vehicle 1000 .
  • the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 .
  • the battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may serve as an operating power source for the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300 .
  • the controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .
  • Figure 2 shows a schematic structural diagram of a battery provided by some embodiments of the present application.
  • the battery 100 includes a case 10 and a battery cell 20 .
  • the case 10 is used to accommodate the battery cell 20 .
  • the box 10 is a component that accommodates the battery cells 20.
  • the box 10 provides a storage space for the battery cells 20.
  • the box 10 can adopt a variety of structures.
  • the box 10 may include a first part 11 and a second part 12 , and the first part 11 and the second part 12 cover each other to define an accommodation space for accommodating the battery cells 20 .
  • the first part 11 and the second part 12 can be in various shapes, such as cuboid, cylinder, etc.
  • the first part 11 may be a hollow structure open on one side, and the second part 12 may also be a hollow structure open on one side.
  • the open side of the second part 12 is covered with the open side of the first part 11 to form a box with accommodating space.
  • the first part 11 may be a hollow structure with one side open
  • the second part 12 may be a plate-like structure
  • the second part 12 covers the open side of the first part 11 to form a box 10 with an accommodation space.
  • the first part 11 and the second part 12 can be sealed by sealing elements, which can be sealing rings, sealants, etc.
  • the battery 100 there may be one battery cell 20 or a plurality of battery cells 20. If there are multiple battery cells 20 , the multiple battery cells 20 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. Multiple battery cells 20 may be first connected in series, parallel, or mixed to form a battery module, and then multiple battery modules may be connected in series, parallel, or mixed to form a whole, and be accommodated in the box 10 . It is also possible that all the battery cells 20 are directly connected in series or in parallel or mixed together, and then the entire battery cell 20 is accommodated in the box 10 .
  • Figure 3 shows a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • Figure 4 shows an exploded view of a battery cell provided by some embodiments of the present application.
  • the battery cell 20 includes a case 21, an electrode assembly 22 and an electrolyte.
  • the housing 21 has a receiving cavity.
  • the electrode assembly 22 is disposed in the accommodation cavity.
  • the electrolyte is arranged in the containing cavity.
  • the liquid retention coefficient a of the electrolyte and the group margin b of the secondary battery satisfy the following relationship: 2 ⁇ a/b ⁇ 3, and the unit of the liquid retention coefficient a is g/Ah.
  • the housing 21 is a component for accommodating the electrode assembly 22.
  • the housing 21 has a hollow structure with an opening formed at one end, that is, a receiving cavity.
  • the housing 21 can be in various shapes, such as a cylinder, a cuboid, etc., which are not particularly limited in the embodiments of the present application.
  • the housing 21 can be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc., and this application is not particularly limited.
  • there may be a plurality of electrode assemblies 22 and the plurality of electrode assemblies 22 are arranged in a stack.
  • the electrode assembly 22 is a component that undergoes electrochemical reactions in the battery cell 20 and can be formed into a rolled structure by winding or a stacked structure formed by a stacked arrangement, which is not particularly limited in the embodiments of the present application.
  • the liquid retention coefficient a refers to the ratio of the liquid retention capacity of the electrolyte to the discharge capacity of the battery cell 20 in the first cycle.
  • the group margin b refers to the ratio of the volume of the electrode assembly 22 in the battery to the volume of the accommodation cavity in the casing 21 .
  • the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell 20 satisfy the following relationship: 2.25 ⁇ a/b ⁇ 2.90.
  • the ratio a/b of the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell 20 is set within the above-mentioned appropriate range, which can further enable the battery cell 20 to take into account a higher energy density. and better cycle performance.
  • the ratio a/b of the liquid retention coefficient a of the electrolyte and the group margin b of the battery cell 20 may be, but is not limited to, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95, 3.
  • the liquid retention coefficient a of the electrolyte ranges from 1.4g/Ah to 2.97g/Ah.
  • the liquid retention coefficient a of the electrolyte and the group margin b of the battery cells 20 satisfy 2 ⁇ a/b ⁇ 3
  • the liquid retention coefficient a of the electrolyte is set in the above-mentioned appropriate range.
  • it can help to improve the energy density of the battery cell 20 and at the same time, it can provide the battery cell 20 with an appropriate amount of electrolyte to improve the cycle performance of the battery cell 20.
  • the battery cell 20 is The capacity retention rate after 1000 cycles at 25°C is in the range of 80%-92%.
  • it can also help to improve the storage performance of the battery cell 20 at high temperatures.
  • the capacity retention rate of the battery cell 20 after being stored in an environment of 60°C for 90 days is between 86% and 96%.
  • the liquid retention coefficient a of the electrolyte ranges from 1.8g/Ah to 2.3g/Ah.
  • the liquid retention coefficient a of the electrolyte and the group margin b of the battery cells 20 satisfy 2 ⁇ a/b ⁇ 3
  • the liquid retention coefficient a of the electrolyte is set in the above-mentioned appropriate range.
  • it can not only help to increase the energy density of the battery cell 20, but also help to further improve the cycle performance of the battery cell 20.
  • it can also help to further improve the storage performance of the battery cell 20 at high temperatures.
  • the capacity retention rate of the battery cell 20 after being stored in an environment of 60°C for 90 days is between 90% and 96%.
  • the liquid retention coefficient a of the electrolyte can be, but is not limited to, 1.4g/Ah, 1.41g/Ah, 1.42g/Ah, 1.43g/Ah, 1.44g/Ah, 1.45g/Ah, 1.46g/ Ah, 1.47g/Ah, 1.48g/Ah, 1.49g/Ah, 1.50g/Ah, 1.51g/Ah, 1.52g/Ah, 1.53g/Ah, 1.54g/Ah, 1.55g/Ah, 1.56g/ Ah, 1.57g/Ah, 1.58g/Ah, 1.59g/Ah, 1.60g/Ah, 1.61g/Ah, 1.62g/Ah, 1.63g/Ah, 1.64g/Ah, 1.65g/Ah, 1.66g/ Ah, 1.67g/Ah, 1.68g/Ah, 1.69g/Ah, 1.70g/Ah, 1.71g/Ah, 1.72g/Ah, 1.73g
  • the group margin b of the battery cell 20 ranges from 80% to 99%.
  • the group margin b of the battery cell 20 is set at the above-mentioned within an appropriate range, it can not only help improve the cycle performance of the battery cell 20, but also help improve the energy density of the battery cell 20.
  • the mass energy density of the battery cell 20 is between 190Wh/g-213Wh/g. within the range.
  • the group margin b of the battery cell 20 ranges from 85% to 95%.
  • the group margin b of the battery cell 20 is set at the above-mentioned within a suitable range, it can not only help to improve the cycle performance of the battery cell 20, but also help to further improve the energy density of the battery cell 20.
  • the mass energy density of the battery cell 20 is between 196Wh/g-213Wh/ g range.
  • the group margin b of the battery cell 20 may be, but is not limited to, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90 %, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%.
  • the electrode assembly 22 includes a positive electrode piece, a negative electrode piece, and a separator.
  • the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector.
  • the positive active material layer includes a positive active material.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode active material layer includes a negative electrode active material.
  • the isolation film is disposed between the positive electrode piece and the negative electrode piece.
  • the cathode active material is selected from at least one of lithium cobalt oxide cathode active material, lithium iron phosphate cathode active material, lithium manganate cathode active material, lithium-rich cathode active material and ternary cathode active material.
  • the negative active material is selected from at least one of a carbon-containing negative active material, a silicon-containing negative active material, an alloy negative active material, a lithium-containing negative active material, and a tin-containing negative active material.
  • the positive current collector can be made of metal foil or porous metal plate.
  • the material of the positive electrode current collector may be, but is not limited to, foil or porous plate made of metals such as copper, nickel, titanium, silver, or their alloys.
  • foil or porous plate made of metals such as copper, nickel, titanium, silver, or their alloys.
  • aluminum foil is used as the positive electrode current collector.
  • the negative electrode current collector can be made of metal foil or porous metal plate.
  • the material of the negative electrode current collector may be, but is not limited to, foil or porous plate made of metals such as copper, nickel, titanium, iron, or their alloys.
  • the negative electrode current collector is made of copper foil.
  • rational selection of the positive electrode active material and the negative electrode active material can help improve the energy density and cycle performance of the battery cell 20 .
  • the ternary cathode active material has the following chemical formula: LiNix Co y N z M 1-xyz O 2 , where N is selected from Mn and Al, and M is selected from Co, Ni, Mn, Mg , at least one of Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, x+y+z ⁇ 1.
  • the ternary cathode active material has the above chemical formula, which can further increase the energy density of the battery cell 20 .
  • the lithium-rich cathode active material has the following chemical formula: Li 2 MnO 3 ⁇ (1-c)LiAO 2 , where A is selected from at least one of Ni, Co and Mn, 0 ⁇ c ⁇ 1.
  • the lithium-rich cathode active material having the above chemical formula can also further increase the energy density of the battery cell 20 .
  • a conductive agent and a binder may also be included in the cathode active material layer.
  • This application does not impose specific restrictions on the types of conductive agents and binders in the positive active material layer, and can be selected according to actual needs.
  • the conductive agent may be, but is not limited to, one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers; bonding
  • the agent can be, but is not limited to, styrene-butadiene rubber (SBR), water-based acrylic resin, carboxymethylcellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoroethylene
  • fluoropropylene copolymer fluorine-containing acrylic resin and
  • the positive electrode active material, conductive agent, and binder are fully stirred and mixed in an appropriate amount of NMP according to a certain mass ratio to form a uniform positive electrode slurry; the positive electrode slurry is coated on the positive electrode After drying and cold pressing on the surface of the current collector aluminum foil, the positive electrode piece is obtained.
  • the negative active material may include natural graphite, artificial graphite, mesophase microcarbon balls (MCMB for short), hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, At least one of Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithiated TiO 2 -Li 4 Ti 5 O 12 , and Li-Al alloy.
  • MCMB mesophase microcarbon balls
  • the negative active material layer may further include a conductive agent and a binder.
  • a conductive agent and a binder This application does not impose specific restrictions on the types of conductive agents and binders in the negative active material layer, and can be selected according to actual needs.
  • the conductive agent may be, but is not limited to, one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers; adhesive
  • the binder can be, but is not limited to, styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin and carboxymethyl fiber One or more elements (CMC).
  • the negative active material, conductive agent, and binder are mixed according to a certain mass ratio, and fully stirred in an appropriate amount of deionized water to form a uniform negative electrode slurry; the negative electrode slurry is coated Cover the surface of the negative electrode current collector copper foil, dry and cold press to obtain the negative electrode piece.
  • the electrode assembly 22 has a positive electrode tab 221 and a negative electrode tab 222.
  • the positive electrode tab 221 may be a portion of the positive electrode piece that is not coated with a positive electrode active material layer
  • the negative electrode tab 222 may be a portion of the negative electrode piece that is not coated with a negative electrode active material layer. layer part.
  • isolation membrane there is no particular restriction on the type of isolation membrane. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane may be selected from one or more of fiberglass, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different.
  • the battery cell 20 may further include an end cover 23 .
  • the end cover 23 covers the opening of the housing 21 to separate the internal environment of the battery cell 20 from the external environment. Parts isolated.
  • the end cap 23 covers the opening of the housing 21 , and the end cap 23 and the housing 21 jointly define a sealed space for accommodating the electrode assembly 22 , the electrolyte, and other components.
  • the shape of the end cover 23 can be adapted to the shape of the housing 21.
  • the housing 21 has a rectangular parallelepiped structure
  • the end cover 23 is a rectangular plate-shaped structure that is adapted to the housing 21 .
  • the housing 21 is a cylindrical structure
  • the end cover 23 is a circular plate-shaped structure that is adapted to the housing 21 .
  • the end cap 23 can also be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.
  • the material of the end cap 23 and the housing 21 can be the same or different.
  • Electrode terminals may be provided on the end cap 23 , and the electrode terminals are used to electrically connect with the electrode assembly 22 to output the electric energy of the battery cell 20 .
  • the electrode terminals may include a positive electrode terminal 231 for electrical connection with the positive electrode tab 221 and a negative electrode terminal 232 for electrical connection with the negative electrode tab 222 .
  • the positive electrode terminal 231 and the positive electrode tab 221 may be connected directly or indirectly, and the negative electrode terminal 232 and the negative electrode tab 222 may be connected directly or indirectly.
  • the electrolyte solution includes an organic solvent and an electrolyte salt, wherein the organic solvent is selected from at least one of ester compounds and ether compounds.
  • the organic solvent is selected from at least one of ester compounds and ether compounds, which can help improve the cycle performance of the battery cell 20 .
  • the ester compound is selected from the group consisting of dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate and ethylene carbonate. at least one of them.
  • the ester compound is selected from any one or more of the above ester compounds, which can further improve the cycle performance of the battery cell 20 .
  • the ether compound is selected from tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3- Dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran and at least one of 2-(2-nitrovinyl)furan.
  • the ether compound is selected from any one or more of the above ether compounds, which can further improve the cycle performance of the battery cell 20 .
  • the electrolyte further includes additives.
  • the additive may be selected from the group consisting of ethylene carbonate, vinyl sulfate, lithium difluoroxalate borate, lithium difluorophosphate, lithium tetrafluoroborate, 1,3 propane At least one of sultone, lithium trifluoromethanesulfonate, and lithium diacetate borate.
  • the concentration of the electrolyte salt in the electrolyte solution is 0.6 mol/L-2.0 mol/L.
  • the concentration of the electrolyte salt in the electrolyte solution is set within the above-mentioned appropriate range, It can help to improve the ionic conductivity of the electrolyte and the mobility of metal ions in the electrolyte, thereby achieving the purpose of improving the cycle performance of the battery cell 20 .
  • the concentration of the electrolyte salt in the electrolyte solution may be, but is not limited to, 0.6M, 0.7M, 0.8M, 0.9M, 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M , 1.7M, 1.8M, 1.9M, 2.0M.
  • the electrolyte salt can be a lithium salt.
  • the lithium salt can be LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiFSI, LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, ( SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi.
  • the electrolyte salt is selected from at least one of LiPF 6 and LiFSI.
  • the electrolyte is selected from the above-mentioned lithium salts and can improve the high-temperature storage performance of the battery cell 20 .
  • Embodiments of the present application provide a battery, including the battery cell in any of the above embodiments. Since the battery includes the battery cell in any of the above embodiments, the battery has the technical effects of the above-mentioned battery cell, which will not be described again here.
  • the embodiment of the present application provides an electrical device, including the battery in the above embodiment.
  • PE polyethylene film
  • the preparation method is similar to Example 1, except that the parameters for controlling the liquid retention coefficient and group margin are shown in Table 1 for details.
  • the battery cells to be disassembled are weighed to obtain M 1 .
  • Disassemble the battery cells pour out the free electrolyte, add dimethyl carbonate (DMC) to the shell for extraction three times, pour out the DMC residue Keep the liquid, put the electrode assembly, shell and other components into the oven, fully remove DMC, and weigh to obtain M 2 .
  • the liquid retention capacity is equal to M 1 -M 2
  • the liquid retention coefficient a of the electrolyte is equal to (M 1 -M 2 )/D 1 .
  • the volume of the regular shell can be calculated to get V 2
  • the volume inside the irregular shell can be calculated by adding Calculating the volume of water, the group margin b of the battery cell is equal to V 1 /V 2 .
  • the battery cell In an environment of 25°C, the battery cell was charged to 4.25V at 1C, then charged to 0.05C at a constant voltage, left to stand for 30 minutes, discharged to 2.8V at 1C, and the discharge capacity was recorded as C 3 . Charge the battery cell to 4.25V at 1C and charge to 0.05C at constant voltage. Then place the battery cell in a constant temperature box at 60°C for 90 days. After the surface temperature of the battery cell returns to 25°C, discharge it to 1C.
  • the discharge voltage platform of the battery cell is P
  • the mass energy density (Wh/g) of the battery cell is D 1 *P/m.
  • the test results are shown in Table 1.

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Abstract

本申请提供了一种电池单体、电池及用电装置，该电池单体包括：壳体、电极组件和电解液。壳体具有容纳腔。电极组件设置于所述容纳腔内。电解液设置于所述容纳腔内。其中，所述电解液的保液系数a和所述电池单体的群裕度b满足如下关系：2≤a/b≤3，所述保液系数a的单位为g/Ah。电解液的保液系数a和电池单体的群裕度b的比值设置在上述的合适范围内，能够使电池单体具有高能量密度的同时，还具有较好的循环性能。

Description

电池单体、电池及用电装置
相关申请的交叉引用
本申请要求享有于2022年07月19日提交的名称为“电池单体、电池及用电装置”的中国专利申请202210854949.2的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，具体涉及一种电池单体、电池及用电装置。
背景技术
电池由于具有能量密度高、循环性能好、自放电少、安全性能好等特点，而被应用于消费电子、电动交通、航空航天等领域中，其中，电池的能量密度和循环性能在上述各领域中备受关注。
然而，在相关技术中，电池能量密度的提升可能会致使其循环性能下降，即电池中存在能量密度和循环性能难以兼顾的问题。
发明内容
本申请提供了一种电池单体、电池及用电装置，能够兼顾能量密度和循环性能。
第一方面，本申请提供了一种电池单体，包括：壳体、电极组件和电解液。壳体具有容纳腔。电极组件设置于所述容纳腔内。电解液设置于所述容纳腔内。其中，所述电解液的保液系数a和所述电池单体的群裕度b满足如下关系：2≤a/b≤3，所述保液系数a的单位为g/Ah。
在上述实施例中，电解液的保液系数a和电池单体的群裕度b的比值设置在上述的合适范围内，能够使电池单体具有高能量密度的同时，还具有较好的循环性能。
在本申请的一些实施例中，所述电解液的保液系数a和所述电池单体的群裕度b满足如下关系：2.25≤a/b≤2.90。a/b的比值设置在上述的合适范围内，能够进一步使电池单体兼顾较高的能量密度和较好的循环性能。
在本申请的一些实施例中，所述电解液的保液系数a的取值范围为1.4g/Ah-2.97g/Ah。电解液的保液系数a设置在上述的合适范围内，可有助于提高电池单体的能量密度的同时，能够使电池单体具有合适的电解液量，从而有实现提升电池单体的循环性能的目的。
在本申请的一些实施例中，所述电解液的保液系数a的取值范围为1.8g/Ah-2.3g/Ah。电解液的保液系数a设置在上述的合适范围内，可有助于提高电池单体的能量密度的同时，还可有助于进一步提升电池单体的循环性能。
在本申请的一些实施例中，所述电池单体的群裕度b的取值范围为80％-99％。电池单体的群裕度b设置在上述的合适范围内，可使电池单体在具有较好的循环性能的同时，还可有助于提高电池单体的能量密度。
在本申请的一些实施例中，所述电池单体的群裕度b的取值范围为85％-95％。电池单体的群裕度b设置在上述的合适范围内，可有助于提升电池单体的循环性能的同时，还可有助于进一步提高电池单体的能量密度。
在本申请的一些实施例中，所述电极组件包括正极极片、负极极片和隔离膜。正极极片包括正极集流体及设置于所述正极集流体的至少一个表面的正极活性材料层，所述正极活性材料层包括正极活性材料。负极极片包括负极集流体及设置于所述负极集流体的至少一个表面的负极活性材料层，所述负极活性材料层包括负极活性材料。隔离膜设置于所述正极极片和所述负极极片之间。其中，所述正极活性材料选自钴酸锂正极活性材料、磷酸铁锂正极活性材料、锰酸锂正极活性材料、富锂正极活性材料 和三元正极活性材料中的至少一种。所述负极活性材料选自含碳的负极活性材料、含硅的负极活性材料、合金负极活性材料、含锂的负极活性材料和含锡的负极活性材料中的至少一种。在上述电极组件中，合理选择正极活性材料和负极活性材料，能够有助于提高电池单体的能量密度及循环性能。
在本申请的一些实施例中，所述三元正极活性材料具有如下化学式：LiNixCoyNzM1-x-y-zO2，其中，N选自Mn和Al，M选自Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V和Ti中的至少一种，0≤x＜1，0≤y≤1，0≤z≤1，x+y+z≤1。三元正极活性材料具有上述化学式，可进一步提高电池单体的能量密度。
在本申请的一些实施例中，所述富锂正极活性材料具有如下化学式：Li2MnO3·(1-c)LiAO2，其中，A选自Ni、Co和Mn中的至少一种，0≤c＜1。富锂正极活性材料具有上述化学式，也可进一步提高电池单体的能量密度。
在本申请的一些实施例中，所述电解液包括有机溶剂和电解质盐，其中，所述有机溶剂选自酯类化合物和醚类化合物中的至少一种。有机溶剂选自酯类化合物和醚类化合物中的至少一种，能够有助于提升电池单体的循环性能。
在本申请的一些实施例中，所述酯类化合物选自碳酸二甲酯、碳酸二乙酯、碳酸丙烯酯、碳酸甲乙酯、氟代碳酸乙烯酯、甲酸乙酯、乙酸乙酯和碳酸乙烯酯中的至少一种。酯类化合物选自上述任意一种或多种的酯类化合物，可进一步提升电池单体的循环性能。
在本申请的一些实施例中，所述醚类化合物选自四氢呋喃、2-甲基呋喃、3-甲基呋喃、2-乙基呋喃、2-丙基呋喃、2-丁基呋喃、2，3-二甲基呋喃、2，4-二甲基呋喃、2，5-二甲基呋喃、吡喃、2-甲基吡喃、3-甲基吡喃、4-甲基吡喃、苯并呋喃和2-(2-硝基乙烯基)呋喃中的至少一种。醚类化合物选自上述任意一种或多种的醚类化合物，可进一步提升电池单体的循环性能。
在本申请的一些实施例中，所述电解质盐在所述电解液中的浓度为0.6mol/L-2.0mol/L。电解质在电解液的浓度设置在上述的合适范围内，有助于提高电池单体的循环性能。
在本申请的一些实施例中，所述电解质盐选自六氟磷酸锂和双氟磺酰亚胺锂中的至少一种。电解质选自上述锂盐，能够提高电池单体的高温存储性能。
第二方面，本申请实施例提供了一种电池，包括上述任一项实施例中所述的电池单体。由于该电池包含上述任一项实施例中的电池单体，因此，该电池具有上述电池单体所具有的技术效果，在此不再赘述。
第三方面，本申请实施例提供了一种用电装置，包括上述实施例中所述的电池。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读对下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1为本申请一些实施例提供的车辆的结构示意图；
图2示出了本申请一些实施例提供的电池的爆炸图；
图3示出了本申请一些实施例提供的电池单体的结构示意图；
图4示出了本申请一些实施例提供的电池单体的爆炸图。
具体实施方式中的附图标号如下：
1000-车辆；
100-电池，200-控制器，300-马达；
10-箱体，11-第一部分，12-第二部分；
20-电池单体；
21-壳体；
22-电极组件，221-正极极耳，222-负极极耳；
23-端盖，231-正极电极端子，232-负极电极端子。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”、“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”“底”、“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。
本申请中，电池单体可以包括锂离子二次电池单体、锂离子一次电池单体、锂硫电池单体、钠离子电池单体或镁离子电池单体等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极极片、负极极片和隔离膜组成。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性材料层，正极活性材料层涂覆于正极集流体的表面，未涂敷正极活性材料层的正极集流体凸出于已涂覆正极活性材料层的正极集流体，未涂敷正极活性材料层的正极集流体作为正极极耳。
电池性能的指标包括能量密度和循环性能，能量密度是指电池平均单位体积或质量所释放出的电能。循环性能是是指可充电电池的循环次数，其指示在电池失效或开始容量衰减之前电池可经历多少次完全的充放电过程。因此，高能量密度和循环性能，可以有助于提高包含该电池的用电装置的续航里程和使用寿命。目前，为了提高电池的能量密度和循环性能，通常会增加电池内的活性材料含量和电解液量。
然而，发明人发现，在电池壳体有限的空间内，若增加电池内的活性材料含量，则活性材料所占用的空间会增加，留给电解液的空间会减少，这样导致电池内的电解液量会下降，从而影响电池的循环性能。若增加电池内的电解液量，可能会导致电池的能量密度下降，甚至可能还会导致更多的副反应，恶化电池的使用寿命。由此可知，电池中存在能量密度和循环性能难以兼顾的问题。
鉴于此，本申请实施例提供了一种电池单体、电池及用电装置，能够使电池兼顾能量密度和循环性能。
本申请公开的电池单体、电池等可以组装为用电装置的电源系统，能够有利于保证用电装置的续航里程和使用寿命。
在本申请中，用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆为例进行说明。
图1示出了本申请一些实施例提供的车辆的结构示意图。
请参照图1，车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
图2示出了本申请一些实施例提供的电池的结构示意图。
请参照图2，电池100包括箱体10和电池单体20，箱体10用于容纳电池单体20。
其中，箱体10是容纳电池单体20的部件，箱体10为电池单体20提供容纳空间，箱体10可以采用多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，以限定出用于容纳电池单体20的容纳空间。第一部分11和第二部分12可以是多种形状，比如，长方体、圆柱体等。第一部分11可以是一侧开放的空心结构，第二部分12也可以是一侧开放的空心结构，第二部分12的开放侧盖合于第一部分11的开放侧，则形成具有容纳空间的箱体10。也可以是第一部分11为一侧开放的空心结构，第二部分12为板状结构，第二部分12盖合于第一部分11的开放侧，则形成具有容纳空间的箱体10。第一部分11与第二部分12可以通过密封元件来实现密封，密封元件可以是密封圈、密封胶等。
在电池100中，电池单体20可以是一个、也可以是多个。若电池单体20为多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。可以是多个电池单体20先串联或并联或混联组成电池模块，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。也可以是所有电池单体20之间直接串联或并联或混联在一起，再将所有电池单体20构成的整体容纳于箱体10内。
图3示出了本申请一些实施例提供的电池单体的结构示意图。图4示出本申请一些实施例提供的电池单体的爆炸图。
请参照图3和4，电池单体20包括壳体21、电极组件22和电解液。壳体21具有容纳腔。电极组件22设置于容纳腔内。电解液设置于容纳腔内。其中，电解液的保液系数a和二次电池的群裕度b满足如下关系：2≤a/b≤3，保液系数a的单位为g/Ah。
壳体21是用于容纳电极组件22的部件，壳体21具有一端形成开口的空心结构，即容纳腔。壳体21可以是多种形状，比如，圆柱体、长方体等，本申请实施例对此不做特别限定。壳体21的材质可以是多种，比如，铜、铁、铝、钢、铝合金等，本申请对此也不做特别限定。
继续参照图4，壳体21内的电极组件22可以是一个，也可以是多个。例如，如图4所示，电极组件22为多个，多个电极组件22层叠布置。
电极组件22是电池单体20中发生电化学反应的部件，可以通过卷绕形成的卷绕式结构，也可以通过层叠布置形成的层叠式结构，本申请实施例对此不做特别限定。
在本申请的实施例中，保液系数a是指电解液的保液量与电池单体20首圈的放电容量的比值。群裕度b是指电池中电极组件22的体积与壳体21内的容纳腔体积的比值。当电解液的保液系数a和电池单体20的群裕度b的比值a/b设置在上述的合适范围内时，能够使电池单体20具有高能量密度的同时，还具有较好的循环性能。
在本申请的一些实施例中，电解液的保液系数a和电池单体20的群裕度b满足如下关系：2.25≤a/b≤2.90。
在上述这些实施例中，电解液的保液系数a和电池单体20的群裕度b的比值a/b设置在上述的合适范围内，能够进一步使电池单体20兼顾较高的能量密度和较好的循环性能。
示例性的，电解液的保液系数a和电池单体20的群裕度b的比值a/b可以但不局限于为2、2.05、2.1、2.15、2.2、2.25、2.3、2.35、2.4、2.45、2.5、2.55、2.6、2.65、2.7、2.75、2.8、2.85、2.9、2.95、3。
在本申请的一些实施例中，电解液的保液系数a的取值范围为1.4g/Ah-2.97g/Ah。
在上述这些实施例中，在电解液的保液系数a和电池单体20的群裕度b满足2≤a/b≤3的前提下，电解液的保液系数a设置在上述的合适范围内，能够有助于提高电池单体20的能量密度的同时，能够使电池单体20具有合适的电解液量，以提升电池单体20的循环性能，该电池单体20在 25℃环境下循环1000圈后的容量保持率在80％-92％的范围内。此外，还能够有助于提高电池单体20在高温下的存储性能，电池单体20在60℃环境下存储90d后的容量保持率在86％-96％。
在本申请的一些实施例中，电解液的保液系数a的取值范围为1.8g/Ah-2.3g/Ah。
在上述这些实施例中，在电解液的保液系数a和电池单体20的群裕度b满足2≤a/b≤3的前提下，电解液的保液系数a设置在上述的合适范围内，可有助于提高电池单体20的能量密度的同时，还可有助于进一步提升电池单体20的循环性能，该电池单体20在25℃环境下循环1000圈后的容量保持率在85％-92％的范围内。此外，还能够有助于进一步提高电池单体20在高温下的存储性能，电池单体20在60℃环境下存储90d后的容量保持率在90％-96％。
示例性的，电解液的保液系数a可以但不局限于为1.4g/Ah、1.41g/Ah、1.42g/Ah、1.43g/Ah、1.44g/Ah、1.45g/Ah、1.46g/Ah、1.47g/Ah、1.48g/Ah、1.49g/Ah、1.50g/Ah、1.51g/Ah、1.52g/Ah、1.53g/Ah、1.54g/Ah、1.55g/Ah、1.56g/Ah、1.57g/Ah、1.58g/Ah、1.59g/Ah、1.60g/Ah、1.61g/Ah、1.62g/Ah、1.63g/Ah、1.64g/Ah、1.65g/Ah、1.66g/Ah、1.67g/Ah、1.68g/Ah、1.69g/Ah、1.70g/Ah、1.71g/Ah、1.72g/Ah、1.73g/Ah、1.74g/Ah、1.75g/Ah、1.76g/Ah、1.77g/Ah、1.78g/Ah、1.79g/Ah、1.80g/Ah、1.81g/Ah、1.82g/Ah、1.83g/Ah、1.84g/Ah、1.85g/Ah、1.86g/Ah、1.87g/Ah、1.88g/Ah、或1.90g/Ah-2.0g/Ah、2.01g/Ah、2.02g/Ah、2.03g/Ah、2.04g/Ah-2.19g/Ah、2.20g/Ah、2.21g/Ah-2.29g/Ah、2.30g/Ah、2.31g/Ah-2.69g/Ah、2.70g/Ah、2.71g/Ah、2.72g/Ah、2.73g/Ah、2.74g/Ah、2.75g/Ah、2.76g/Ah、2.77g/Ah、2.78g/Ah、2.79g/Ah、2.80g/Ah、2.81g/Ah、2.82g/Ah、2.83g/Ah、2.84g/Ah、2.85g/Ah、2.86g/Ah、2.87g/Ah、2.88g/Ah、2.89g/Ah、2.90g/Ah、2.91g/Ah、2.92g/Ah、2.93g/Ah、2.94g/Ah、2.95g/Ah、2.96g/Ah、2.97g/Ah。
在本申请的一些实施例中，电池单体20的群裕度b的取值范围为80％-99％。
在上述这些实施例中，在电解液的保液系数a和电池单体20的群裕度b满足2≤a/b≤3的前提下，电池单体20的群裕度b设置在上述的合适范围内，能够有助于提高电池单体20的循环性能的同时，还可有助于提高电池单体20的能量密度，该电池单体20的质量能量密度在190Wh/g-213Wh/g范围内。
在本申请的一些实施例中，电池单体20的群裕度b的取值范围为85％-95％。
在上述这些实施例中，在电解液的保液系数a和电池单体20的群裕度b满足2≤a/b≤3的前提下，电池单体20的群裕度b设置在上述的合适范围内，可有助于提升电池单体20的循环性能的同时，还可有助于进一步提高电池单体20的能量密度，该电池单体20的质量能量密度在196Wh/g-213Wh/g范围内。
示例性的，电池单体20的群裕度b可以但不局限于为80％、81％、82％、83％、84％、85％、86％、87％、88％、89％、90％、91％、92％、93％、94％、95％、96％、97％、98％、99％。
在本申请的一些实施例中，电极组件22包括正极极片、负极极片和隔离膜。正极极片包括正极集流体及设置于正极集流体的至少一个表面的正极活性材料层，正极活性材料层包括正极活性材料。负极极片包括负极集流体及设置于负极集流体的至少一个表面的负极活性材料层，负极活性材料层包括负极活性材料。隔离膜设置于正极极片和所述负极极片之间。其中，正极活性材料选自钴酸锂正极活性材料、磷酸铁锂正极活性材料、锰酸锂正极活性材料、富锂正极活性材料和三元正极活性材料中的至少一种。负极活性材料选自含碳的负极活性材料、含硅的负极活性材料、合金负极活性材料、含锂的负极活性材料和含锡的负极活性材料中的至少一种。
正极集流体可以采用金属箔材或多孔金属板等材质。示例性的，正极集流体的材质可以但不限于为铜、镍、钛或银等金属或它们的合金的箔材或多孔板。进一步的，在本申请的一些具体实施例中，正极集流体采用铝箔。
负极集流体可以采用金属箔材或多孔金属板等材质。示例性的，负极集流体的材质可以但不限于为铜、镍、钛或铁等金属或它们的合金的箔材或多孔板。进一步的，在本申请的一些具体实施例中，负极集流体采用铜箔。
在上述这些实施例中，合理选择正极活性材料和负极活性材料，能够有助于提高电池单体20的能量密度及循环性能。
在本申请的一些实施例中，三元正极活性材料具有如下化学式：LiNixCoyNzM1-x-y-zO2，其中，N选自Mn和Al，M选自Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V和Ti中的至少一种，0≤x＜1，0≤y≤1，0≤z≤1，x+y+z≤1。三元正极活性材料具有上述化学式，可进一步提高电池单体20的能量密度。
在本申请的一些实施例中，富锂正极活性材料具有如下化学式：Li2MnO3·(1-c)LiAO2，其中，A选自Ni、Co和Mn中的至少一种，0≤c＜1。富锂正极活性材料具有上述化学式，也可进一步提高电池单体20的能量密度。
在本申请的一些实施例中，正极活性材料层中还可以包括导电剂和粘结剂。本申请对正极活性材料层中导电剂及粘结剂的种类不做具体限制，可以根据实际需求进行选择。
示例性的，导电剂可以但不局限于为石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或多种；粘结剂可以但不局限于为丁苯橡胶(SBR)、水性丙烯酸树脂、羧甲基纤维素(CMC)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、乙烯-醋酸乙烯酯共聚物(EVA)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物、含氟丙烯酸树脂及聚乙烯醇(PVA)中的一种或多种。
在本申请得实施例中，将正极活性材料、导电剂、粘结剂按一定得质量比在适量的NMP中充分搅拌混合，使其形成均匀的正极浆料；将正极浆料涂覆于正极集流体铝箔的表面上，经干燥、冷压后，得到正极极片。
在本申请的一些实施例中，负极活性材料可以包括天然石墨、人造石墨、中间相微碳球(简称为MCMB)、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO2、尖晶石结构的锂化TiO2-Li4Ti5O12、Li-Al合金中的至少一种。
在本申请得一些实施例中，负极活性材料层还可以包括导电剂和粘结剂。本申请对负极活性材料层中的导电剂和粘结剂的种类不做具体限制，可以根据实际需求进行选择。
示例性的，导电剂可以但不局限于为石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种或多种；粘结剂可以但不局限于为丁苯橡胶(SBR)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、水性丙烯酸树脂及羧甲基纤维素(CMC)中的一种或多种。
在本申请得实施例中，将负极活性材料、导电剂、粘结剂按一定得质量比混合，并在适量的去离子水中充分搅拌，使其形成均匀的负极浆料；将负极浆料涂覆于负极集流体铜箔的表面上，经干燥、冷压后，得到负极极片。
此外，电极组件22具有正极极耳221和负极极耳222，正极极耳221可以是正极极片上未涂覆正极活性材料层的部分，负极极耳222可以是负极极片上未涂覆负极活性材料层的部分。
本申请实施例对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。在一些实施例中，隔离膜的材质可以选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的一种或几种。隔离膜可以是单层薄膜，也可以是多层复合薄膜。隔离膜为多层复合薄膜时，各层的材料可以相同或不同。
可继续参照图4，在本申请的一些实施例中，电池单体20可以还包括端盖23，端盖23是盖合于壳体21的开口以将电池单体20的内部环境与外部环境隔绝的部件。端盖23盖合于壳体21的开口，端盖23与壳体21共同限定出用于容纳电极组件22、电解液以及其他部件的密封空间。端盖23的形状可以与壳体21的形状适配，比如，壳体21为长方体结构，端盖 23为与壳体21相适配的矩形板状结构，再如，壳体21为圆柱体结构，端盖23为与壳体21相适配的圆形板状结构。端盖23的材质也可以是多种，比如，铜、铁、铝、钢、铝合金等，端盖23的材质与壳体21的材质可以相同，也可以不同。
端盖23上可以设置电极端子，电极端子用于与电极组件22电连接，以输出电池单体20的电能。电极端子可以包括正极电极端子231和负极电极端子232，正极电极端子231用于与正极极耳221电连接，负极电极端子232用于与负极极耳222电连接。正极电极端子231与正极极耳221可以直接连接，也可以间接连接，负极电极端子232与负极极耳222可以直接连接，也可以间接连接。
在本申请的一些实施例中，电解液包括有机溶剂和电解质盐，其中，有机溶剂选自酯类化合物和醚类化合物中的至少一种。
在上述这些实施例中，有机溶剂选自酯类化合物和醚类化合物中的至少一种，能够有助于提升电池单体20的循环性能。
在本申请的一些实施例中，酯类化合物选自碳酸二甲酯、碳酸二乙酯、碳酸丙烯酯、碳酸甲乙酯、氟代碳酸乙烯酯、甲酸乙酯、乙酸乙酯和碳酸乙烯酯中的至少一种。酯类化合物选自上述任意一种或多种的酯类化合物，可进一步提升电池单体20的循环性能。
在本申请的一些实施例中，醚类化合物选自四氢呋喃、2-甲基呋喃、3-甲基呋喃、2-乙基呋喃、2-丙基呋喃、2-丁基呋喃、2，3-二甲基呋喃、2，4-二甲基呋喃、2，5-二甲基呋喃、吡喃、2-甲基吡喃、3-甲基吡喃、4-甲基吡喃、苯并呋喃和2-(2-硝基乙烯基)呋喃中的至少一种。醚类化合物选自上述任意一种或多种的醚类化合物，可进一步提升电池单体20的循环性能。
在本申请的一些实施例中，电解液还包括添加剂，例如该添加剂可以选自碳酸亚乙酯、硫酸乙烯酯、二氟草酸硼酸锂、二氟磷酸锂、四氟硼酸锂、1，3丙磺酸内酯、三氟甲基磺酸锂、双乙酸硼酸锂中至少一种。
在本申请的一些实施例中，电解质盐在电解液中的浓度为0.6mol/L-2.0mol/L。电解质盐在电解液的浓度设置在上述的合适范围内， 能够有助于提高电解液的离子传导性以及金属离子在电解液中的迁移率，从而实现提高电池单体20的循环性能的目的。
示例性的，电解质盐在电解液中的浓度可以但不局限于为0.6M、0.7M、0.8M、0.9M、1.0M、1.1M、1.2M、1.3M、1.4M、1.5M、1.6M、1.7M、1.8M、1.9M、2.0M。
在上述这些实施例中，电解质盐可以为锂盐，例如，该锂盐可以为LiCl、LiBr、LiI、LiClO4、LiBF4、LiB10Cl10、LiPF6、LiFSI、LiCF3SO3、LiCF3CO2、LiC4BO8、LiAsF6、LiSbF6、LiAlCl4、CH3SO3Li、CF3SO3Li、(CF3SO2)2NLi、(C2F5SO2)2NLi、(SO2F)2NLi、(CF3SO2)3CLi。
在本申请的一些实施例中，电解质盐选自LiPF6和LiFSI中的至少一种。电解质选自上述锂盐，能够提高电池单体20的高温存储性能。
本申请实施例提供了一种电池，包括上述任一项实施例中的电池单体。由于该电池包含上述任一项实施例中的电池单体，因此，该电池具有上述电池单体所具有的技术效果，在此不再赘述。
本申请实施例提供了一种用电装置，包括上述实施例中的电池。
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比、和比值都是基于重量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1
正极极片的制备
将正极活性材LiNi0.8Co0.1Mn0.1O2、导电剂Super P、粘结剂聚偏二氟乙烯(PVDF)按95:3:2的质量比在N-甲基吡咯烷酮(NMP)中充分搅拌混合，使其形成均匀的正极浆料，其中，正极浆料中固体含量为50wt％；将正极浆料涂布在集流体铝箔的表面上，并在85℃下烘干，然后进行冷压、切边、裁片、分条后，在85℃的真空条件下烘干4h，得到正极极片。
负极极片的制备
将负极活性材料石墨、导电剂Super P、增稠剂CMC、粘结剂丁苯橡胶(SBR)按92：3：2.5：2.5的质量比在去离子水中充分搅拌，使其形成均匀的负极浆料，其中，负极浆料中固体含量为30wt％；将负极浆料涂布在集流体铜箔的表面上，并在85℃下烘干，然后进行冷压、切边、裁片、分条后，在120℃真空条件下烘干12h，得到负极极片。
隔离膜
使用厚度为16μm的聚乙烯薄膜(PE)。
电解液的制备
在充满氩气的手套箱中(水含量＜10ppm，氧气含量＜1ppm)，将碳酸亚乙酯(EC)和碳酸甲乙酯(EMC)按照3:7W％/W％混合，然后加入2％碳酸亚乙烯酯，混合均匀后，向上述溶液中缓慢加入1mol的LiFP6，待LiFP6完全溶解后，得到电解液。
电池单体的制备
将上述正极极片、隔离膜、负极极片按顺序堆叠并卷绕，得到电极组件；将电极组件放入外包装中，加入上述制备的电解液，经封装、静置、化成、老化等工序后，得到电池单体。
实施例2～10及对比例1～2
制备方法与实施例1类似，不同的是：调控保液系数和群裕度的参数，详见表1。
测试部分
1)电池单体的容量测试
将电池置于25℃环境下静置60min，随后1C充电到4.25V，恒压充电到0.05C，静置30min，随后1C放电到2.8V，静置30min，记录放电容量D1。
2)保液量的测试
对待拆解的电池单体进行称重，得到M1。将电池单体拆解，倒出游离电解液，壳体中加入碳酸二甲酯(DMC)萃取3次，倒出DMC残 留液，将电极组件和壳体等部件放入烘箱，充分去除DMC，称重得到M2。保液量等于M1-M2，则电解液的保液系数a等于(M1-M2)/D1。
3)电池单体的群裕度测试
将电极组件浸泡到水中，利用阿基米德原理，采用排水发即可测试出电极组件的体积V1，规则壳体的体积可以通过计算得到V2，不规则壳体内部的体积可以通过加入水的体积计算，则电池单体的群裕度b等于V1/V2。
4)电池单体循环性能的测试
在25℃环境下，将电池单体以0.5C恒流充电至4.25V，然后以4.25V恒压充电至电流为0.05C，然后用1C恒流放电至2.8V，记录放电容量为C1。电池单体在循环1000次后的放电容量记录为C2。则电池单体循环1000次后的容量保持率(％)＝C2/C1×100％，测试结果如表1所示。
5)电池单体的高温存储性能测试
在25℃环境下，将电池单体以1C充电至4.25V，随后恒压充电到0.05C，静置30min，1C放电到2.8V，记录放电容量为C3。将电池单体以1C充电到4.25V，恒压充电到0.05C，随后将电池单体置于60℃的恒温箱中存放90d，待电池单体的表面温度恢复至25℃后，1C放电到2.8V，静置30min，1C充电到4.25V，恒压充电到0.05C，静置30min，随后1C放电到2.8V，记录放电容量为C4，该电池单体在60℃下存储90d时的可逆容量保持率(％)＝C4/C3×100％，测试结果如表1所示。
6)电池单体的能量密度测试
对电池单体进行称重，得到m。电池单体的放电电压平台为P，则电池单体的质量能量密度(Wh/g)为D1*P/m，测试结果如表1所示。
表1

从表1可看出，由实施例1-10与对比例1-2的比较结果可以看出，在本申请实施例提供的电池单体中，电解液的保液系数a和电池单体的群裕度b满足2≤a/b≤3时，能够使电池单体具有高能量密度的同时，还具有较好的循环性能。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (16)

  1. 一种电池单体，包括：
    壳体，具有容纳腔；
    电极组件，设置于所述容纳腔内；
    电解液，设置于所述容纳腔内；
    其中，所述电解液的保液系数a和所述电池单体的群裕度b满足如下关系：2≤a/b≤3，所述保液系数a的单位为g/Ah。
  2. 根据权利要求1所述的电池单体，其中，所述电解液的保液系数a和所述电池单体的群裕度b满足如下关系：2.25≤a/b≤2.90。
  3. 根据权利要求1或2所述的电池单体，其中，所述电解液的保液系数a的取值范围为1.4g/Ah-2.97g/Ah。
  4. 根据权利要求1-3中任一项所述的电池单体，其中，所述电解液的保液系数a的取值范围为1.8g/Ah-2.3g/Ah。
  5. 根据权利要求1-4中任一项所述的电池单体，其中，所述电池单体的群裕度b的取值范围为80％-99％。
  6. 根据权利要求1-5中任一项所述的电池单体，其中，所述电池单体的群裕度b的取值范围为85％-95％。
  7. 根据权利要求1-6中任一项所述的电池单体，其中，所述电极组件包括：
    正极极片，包括正极集流体及设置于所述正极集流体的至少一个表面的正极活性材料层，所述正极活性材料层包括正极活性材料；
    负极极片，包括负极集流体及设置于所述负极集流体的至少一个表面的负极活性材料层，所述负极活性材料层包括负极活性材料；
    隔离膜，设置于所述正极极片和所述负极极片之间；
    其中，所述正极活性材料选自钴酸锂正极活性材料、磷酸铁锂正极活性材料、锰酸锂正极活性材料、富锂正极活性材料和三元正极活性材料中的至少一种；
    所述负极活性材料选自含碳的负极活性材料、含硅的负极活性材料、合金负极活性材料、含锂的负极活性材料和含锡的负极活性材料中的至少一种。
  8. 根据权利要求7所述的电池单体，其中，所述三元正极活性材料具有如下化学式：LiNixCoyNzM1-x-y-zO2，其中，N选自Mn和Al，M选自Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V和Ti中的至少一种，0≤x＜1，0≤y≤1，0≤z≤1，x+y+z≤1。
  9. 根据权利要求7或8所述的电池单体，其中，所述富锂正极活性材料具有如下化学式：Li2MnO3·(1-c)LiAO2，其中，A选自Ni、Co和Mn中的至少一种，0≤c＜1。
  10. 根据权利要求1-9中任一项所述的电池单体，其中，所述电解液包括有机溶剂和电解质盐，其中，所述有机溶剂选自酯类化合物和醚类化合物中的至少一种。
  11. 根据权利要求10所述的电池单体，其中，所述酯类化合物选自碳酸二甲酯、碳酸二乙酯、碳酸丙烯酯、碳酸甲乙酯、氟代碳酸乙烯酯、甲酸乙酯、乙酸乙酯和碳酸乙烯酯中的至少一种。
  12. 根据权利要求10所述的电池单体，其中，所述醚类化合物选自四氢呋喃、2-甲基呋喃、3-甲基呋喃、2-乙基呋喃、2-丙基呋喃、2-丁基呋喃、2，3-二甲基呋喃、2，4-二甲基呋喃、2，5-二甲基呋喃、吡喃、2-甲基吡喃、3-甲基吡喃、4-甲基吡喃、苯并呋喃和2-(2-硝基乙烯基)呋喃中的至少一种。
  13. 根据权利要求10-12中任一项所述的电池单体，其中，所述电解质 盐在所述电解液中的浓度为0.6mol/-2.0mol/L。
  14. 根据权利要求10-13中任一项所述的电池单体，其中，所述电解质盐选自六氟磷酸锂和双氟磺酰亚胺锂中的至少一种。
  15. 一种电池，包括权利要求1-14中任一项所述的电池单体。
  16. 一种用电装置，包括权利要求15中所述的电池。
PCT/CN2023/105973 2022-07-19 2023-07-05 电池单体、电池及用电装置 WO2024017064A1 (zh)

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