WO2021004151A1 - 锂离子电池及包含其的用电设备 - Google Patents

锂离子电池及包含其的用电设备 Download PDF

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WO2021004151A1
WO2021004151A1 PCT/CN2020/090079 CN2020090079W WO2021004151A1 WO 2021004151 A1 WO2021004151 A1 WO 2021004151A1 CN 2020090079 W CN2020090079 W CN 2020090079W WO 2021004151 A1 WO2021004151 A1 WO 2021004151A1
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electrolyte
lithium ion
ion battery
positive electrode
carbon atoms
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PCT/CN2020/090079
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English (en)
French (fr)
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邹海林
张明
韩昌隆
张翠平
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宁德时代新能源科技股份有限公司
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Priority to PL20816372.5T priority Critical patent/PL3793013T3/pl
Priority to EP20816372.5A priority patent/EP3793013B1/en
Priority to KR1020207033409A priority patent/KR102471591B1/ko
Priority to EP22181628.3A priority patent/EP4087006B1/en
Priority to JP2020564740A priority patent/JP7047138B2/ja
Priority to US17/135,600 priority patent/US11329319B2/en
Publication of WO2021004151A1 publication Critical patent/WO2021004151A1/zh

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    • H—ELECTRICITY
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    • 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
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    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
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    • 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
    • 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

  • This application relates to the field of batteries, in particular to a lithium ion battery and electrical equipment containing the same.
  • Lithium-ion batteries have become the most popular energy storage system due to their high working potential, long life, and environmental friendliness. They have been widely used in pure electric vehicles, hybrid electric vehicles, smart grids and other fields.
  • the current lithium-ion battery based on LiFePO 4 cathode material cannot meet people's higher demand for endurance. To eliminate people's "range anxiety" problem for electric vehicles, it is urgent to develop a lithium-ion battery system with higher energy density.
  • high energy density cathode materials such as high voltage LiNi 0.5 Mn 1.5 O 4 , high capacity high nickel ternary NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) and lithium-rich ternary materials can Improve the energy density of the battery.
  • these materials have high lithium content on the surface and strong side reaction activity between the surface of the particles and the electrolyte, resulting in a large high-temperature gas production of lithium-ion batteries using the above-mentioned cathode materials, resulting in cycle deterioration, and even safety risks.
  • the current industrialized method of increasing its energy density is to increase the energy density by increasing the space utilization rate of packaging materials.
  • the inventors have conducted a lot of research, and the first purpose of this application is to provide a lithium-ion battery to solve the problem that the current wound-type batteries cannot have both high energy density and high cycle performance.
  • the second objective of the present application is to provide an electrical equipment containing the lithium ion battery of the present invention.
  • a lithium ion battery including:
  • An electrode assembly and an electrolyte infiltrated in the electrode assembly; wherein,
  • the electrode assembly includes an electrode body, a positive electrode tab, and a negative electrode tab.
  • the electrode body includes a positive pole piece, a negative pole piece, and a positive pole piece wound together around an axis.
  • the positive electrode tab includes a positive electrode current collector and a positive electrode material layer provided on at least one surface of the positive electrode current collector, the positive electrode tab is connected to the positive electrode tab, and the negative electrode tab is connected to The negative pole piece;
  • the electrode main body has two oppositely arranged two sides, and the positive electrode tab and the negative electrode tab respectively extend from both sides of the electrode main body;
  • the electrolyte contains additive A, and the additive A includes at least one of a phosphate compound containing an unsaturated bond, a cyclic compound containing a -SO 2 -bond, and a cyclic siloxane compound containing an unsaturated bond,
  • the diffusion rate v of the electrolyte in the electrode body is 0.01 ⁇ g/s to 5 ⁇ g/s, preferably 0.2 ⁇ g/s to 2 ⁇ g/s,
  • the ⁇ is the liquid absorption rate of the positive pole piece to the electrolyte, in ⁇ g/s,
  • the H is the maximum length of the side portion along the width direction (Z) of the electrode body, and the unit is mm,
  • the L is the length of the electrode body along the axis direction (X), and the unit is mm.
  • An electrical equipment includes the lithium ion battery of the present application.
  • the lithium ion battery of the present application is a wound lithium ion battery.
  • the utilization rate of the internal space of the single battery can be effectively increased, and the battery's Volume energy density.
  • the electrolyte containing the additive A is controlled
  • the diffusion rate of the electrode body is in the range of 0.01 ⁇ g/s ⁇ 5 ⁇ g/s, thus ensuring that the electrolyte can quickly infiltrate or reflow into the wound cell during the cycle, and form new ones on the surface of the positive pole piece in time
  • the SEI film can improve the cycle performance and safety of lithium-ion batteries, and suppress the gas generation problems of high-capacity lithium-ion batteries.
  • the lithium ion battery provided by the present application has the characteristics of high energy density, high cycle stability and high safety. More preferably, the lithium ion battery can also have higher high-temperature storage performance.
  • the electrical equipment of the present application includes the lithium-ion battery, and therefore has at least the same advantages.
  • FIG. 1 is a schematic diagram of an electrode assembly provided by an embodiment of the application.
  • FIG. 2 is an exploded schematic diagram of a hard-shell lithium ion battery provided by an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of a soft-packed lithium-ion battery provided by an embodiment of the application.
  • Fig. 4 is a schematic diagram of an embodiment of a battery module.
  • Fig. 5 is a schematic diagram of an embodiment of a battery pack.
  • Fig. 6 is an exploded view of Fig. 5.
  • FIG. 7 is a schematic diagram of an embodiment of an electric device in which a lithium ion battery is used as a power source.
  • any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and any upper limit may be combined with any other upper limit to form an unspecified range.
  • every point or single value between the end points of the range is included in the range. Therefore, each point or single numerical value can be used as its own lower limit or upper limit in combination with any other point or single numerical value or in combination with other lower or upper limits to form an unspecified range.
  • FIG. 2 shows a lithium ion battery 10 as an example.
  • the lithium ion battery 10 includes:
  • the electrode assembly 1 (shown in Figure 1) and the electrolyte infiltrated in the electrode assembly 1.
  • the electrode assembly 1 includes an electrode body 11, a positive electrode tab 12, and a negative electrode tab 13.
  • the electrode body 11 includes The positive pole piece, the negative pole piece, and the separator arranged between the positive pole piece and the negative pole piece together.
  • the positive pole piece includes a positive electrode current collector and a positive electrode material layer provided on at least one surface of the positive electrode current collector;
  • the lug 12 is connected to the positive pole piece, and the negative electrode lug 13 is connected to the negative pole piece; along the axis direction (X), the electrode body has two opposite sides 14 opposite to each other. In this lithium ion battery, the two sides of the electrode body 11 14 respectively extend the positive electrode tab 12 and the negative electrode tab 13.
  • the X direction is the axis direction of the winding of the positive pole piece, the negative pole piece and the separator provided between the positive pole piece and the negative pole piece of the electrode body 11, and is also the direction of the electrolyte in the electrode body 11
  • the positive electrode tab 12 and the negative electrode tab 13 are respectively arranged on both sides 14 of the electrode body 11.
  • the electrode body in the battery case The increase in the volume occupancy rate of the battery is beneficial to increase the active material content in the internal space of the battery, thereby effectively increasing the volume energy density of the lithium ion battery.
  • the electrolyte can only diffuse and enter from the two sides of the electrode body to the middle of the electrode body.
  • the tabs are further bent in the thickness direction (Y) of the electrode body, it is easy to cause partial The diffusion path of the electrolyte is blocked, making it more difficult for the electrolyte to infiltrate the electrode body.
  • the active material layer of the positive and negative electrodes will expand in volume, the distance between the pole pieces will be shortened, and part of the electrolyte in the middle of the battery core will be squeezed out.
  • the active material layer of the sheet will shrink in volume again, the distance between the pole pieces will increase, and the free electrolyte needs to be refilled into the positive and negative pole pieces.
  • the electrolyte contains additive A.
  • Additive A includes at least one of a phosphate compound containing an unsaturated bond, a cyclic compound containing a -SO 2 -bond, and a cyclic siloxane compound containing an unsaturated bond.
  • the diffusion rate of the electrolyte in the electrode body v It is 0.01 ⁇ g/s to 5 ⁇ g/s, preferably 0.2 ⁇ g/s to 2 ⁇ g/s.
  • the additive A By introducing the additive A to preferentially form a film on the surface of the positive electrode, a dense and stable passivation layer is formed, blocking the direct contact between the positive electrode and the solvent, and effectively inhibiting the oxidation and gas generation of the solvent.
  • the above-mentioned film-forming additives are especially suitable for high-capacity battery systems with serious gas production problems.
  • adjust the electrolyte diffusion rate v in the electrode body to 0.01 ⁇ g/s ⁇ 5 ⁇ g/s, preferably 0.2 ⁇ g/s ⁇ 2 ⁇ g/s.
  • the electrolyte has good wettability in the electrode body and can quickly Enter the inside of the electrode body, and form a new SEI film on the surface of the positive electrode in time, thereby improving the cycle performance and safety of the lithium-ion battery, and improving the gas generation problem during the cycle. Furthermore, lithium-ion batteries can also have higher high-temperature storage performance.
  • the diffusion rate of the electrolyte in the electrode body v ⁇ H/L, where ⁇ is the rate of absorption of the electrolyte by the positive pole piece ( ⁇ g/s), and H is the width direction along the electrode body (Z ) The maximum length (mm) of the side portion, and L is the length (mm) of the electrode body along the axial direction (X).
  • the diffusion rate v is measured based on the absorption rate of the positive pole piece to the electrolyte in the electrode body as the main influencing factor, mainly based on the following reasons: the additive A in the electrolyte mainly acts on the surface of the active material particles of the positive pole piece.
  • the dense passivation film improves the gas production performance of lithium-ion batteries.
  • the compaction density of the positive pole piece is usually higher than that of the negative pole piece.
  • the internal structure of the positive pole piece is tighter and the electrolyte diffuses in the positive pole piece. The impact on battery cycle performance is more significant.
  • the liquid absorption rate ⁇ of the positive pole piece to the electrolyte can be determined by the following method: fill the electrolyte with a dropper with a certain inner diameter and a standard scale, and the diameter of the lower mouth of the dropper is 0.2mm; Fully dry (for example, drying at 70°C ⁇ 90°C for 10h ⁇ 15h), then cut out the square positive pole piece of 5cm ⁇ 5cm; in the drying room with humidity lower than 2%, make the lower mouth of the dropper and the square positive pole piece Make sure that the dropper is perpendicular to the surface of the positive pole piece.
  • the electrolyte in the dropper gradually infiltrates the inside of the positive pole piece. Record the quality of the electrolyte infiltrated into the positive pole piece per second, which is the absorption of the electrolyte by the positive pole piece rate.
  • the diffusion rate v of the electrolyte in the electrode body is also affected by the structure of the electrode body.
  • H is the maximum length (mm) of the side portion along the width direction (Z) of the electrode body
  • L is the length (mm) of the electrode body along the axial direction (X).
  • the electrolyte diffusion rate v in the electrode body may be 0.25 ⁇ g/s, 0.37 ⁇ g/s, 0.58 ⁇ g/s, 0.68 ⁇ g/s, 0.75 ⁇ g/s, 1.08 ⁇ g/s, 1.55 ⁇ g/s, 1.97 ⁇ g/s, 2.5 ⁇ g/s, 3 ⁇ g/s, 4 ⁇ g/s or 4.97 ⁇ g/s etc.
  • the liquid absorption rate ⁇ of the positive pole piece to the electrolyte may be 0.15 ⁇ g/s to 7.25 ⁇ g/s, further 0.45 ⁇ g/s to 3.58 ⁇ g/s.
  • the absorption rate ⁇ of the positive pole piece to the electrolyte is 0.71 ⁇ g/s, 0.82 ⁇ g/s, 0.96 ⁇ g/s, 1.08 ⁇ g/s, 2.24 ⁇ g/s, 2.48 ⁇ g/s, 2.57 ⁇ g/s, 3.12 ⁇ g/s, 4 ⁇ g/s, 5 ⁇ g/s, 6 ⁇ g/s, or 6.51 ⁇ g/s, etc.
  • the maximum length H (mm) of the side portion along the width direction (Z) of the electrode body and the length L (mm) of the electrode body along the axis direction (X) satisfy: 0.05 ⁇ H/L ⁇ 0.8.
  • H/L is 0.1-0.6.
  • H/L is 0.15 to 0.5.
  • the value of H/L may be 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.1, or 0.05.
  • the main structure of the electrode with a smaller H/L ratio minimizes the proportion of the positive pole tab and the negative pole tab in the positive pole piece and the negative pole piece, and relatively increases
  • the space utilization rate of the lithium ion battery further increases the energy density of the lithium ion battery.
  • the tabs are respectively arranged at both ends of the electrode body, the circuit design during module assembly can be simplified, and the assembly efficiency can be improved while the cost can be reduced.
  • the maximum length H of the side portion along the width direction (Z) of the electrode body may be 10 mm to 280 mm, further 30 mm to 160 mm, and still further 45 mm to 150 mm.
  • H is 90mm, 91mm, 100mm, 120mm, 150mm, or 160mm.
  • the length L of the electrode body along the axial direction (X) may be 50 mm to 500 mm, further 100 mm to 400 mm, and still further 200 mm to 350 mm.
  • L is 200mm, 300mm, 301mm, 350mm, etc.
  • the axial direction (X) of the electrode body is a horizontal direction.
  • the winding axis direction of the electrode body is substantially parallel to the horizontal direction, and the electrolyte can infiltrate and diffuse into the inside of the electrode body from both ends of the electrode body, which is more conducive to the rapid infiltration of the electrolyte.
  • the winding axis direction of the electrode assembly is a horizontal direction
  • the electrode assembly is placed in the battery casing and sealed with a top cover to assemble a lithium ion battery, as shown in FIG. 2 for example.
  • the lithium ion battery can be placed vertically (that is, the Z direction is parallel to the direction of gravity), or it can be placed flat (that is, the Y direction is parallel to the direction of gravity).
  • the winding axis of the electrode assembly is in the horizontal direction
  • the electrode assembly is packaged by aluminum-plastic film
  • the edge of the packaging bag is sealed by hot pressing, glue fixing, etc., to assemble a lithium ion battery, as shown in the figure 3 shown.
  • the lithium ion battery can be placed vertically (that is, the Z direction is parallel to the direction of gravity), or it can be placed flat (that is, the Y direction is parallel to the direction of gravity).
  • the mass percentage w (%) and diffusion rate v ( ⁇ g/s) of the additive A in the electrolyte satisfy: 0.01 ⁇ w ⁇ v ⁇ 10, preferably 0.1 ⁇ w ⁇ v ⁇ 10 .
  • w ⁇ v is 0.43, 0.50, 0.65, 0.74, 1.15, 1.35, 1.50, 2.16, 3.11, 3.94, 4.97, 6.74, 9.84, etc.
  • the mass percentage w (%) of the additive A in the electrolyte and the diffusion rate v ( ⁇ g/s) satisfy: 0.4 ⁇ w ⁇ v ⁇ 5.
  • the inventor found through research that the relationship between the mass percentage w of the additive A in the electrolyte and the diffusion rate v of the electrolyte in the electrode body has a greater impact on the film formation quality and interface impedance of the positive pole piece, thereby affecting the gas production of the battery And cycle performance.
  • the mass ratio w of the additive A in the electrolyte and the diffusion rate v satisfy the above relationship, it can ensure that the electrolyte has a high infiltration or reflow rate, and it can also ensure that there is enough additive A to form a stable protection Membrane to suppress gas production, while the amount of additive A is moderate to ensure good cycle performance of the lithium ion battery.
  • the weight percentage w of the additive A in the electrolyte may be 0.1 wt% to 5 wt%, further 0.1 wt% to 3 wt%, and still further 1 wt% to 2 wt%.
  • the unsaturated bond-containing phosphate compound is at least one of the compounds of formula 1,
  • R 1 , R 2 and R 3 are each independently selected from alkyl groups having 1 to 6 carbon atoms, alkenyl groups, alkynyl groups, halogenated alkyl groups, halogenated alkenyl groups, halogenated alkynyl groups, and 6 carbon atoms.
  • R 1 , R 2 and R 3 may each independently be methyl, ethyl, propyl, isopropyl, butyl, vinyl, allyl, 3-butanol Alkenyl, isobutenyl, 4-pentenyl, ethynyl, propargyl, 3-butynyl, 1-methyl-2-propynyl or halogenated derivatives thereof, and R 1 , R 2 and R At least one of 3 contains a double bond or a triple bond.
  • halogenated derivatives include but are not limited to monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, 2 ,2-Difluoroethyl, 2,2,2-trifluoroethyl, 3,3-difluoropropyl, 3,3,3-trifluoropropyl and hexafluoroisopropyl, etc.
  • R 1 , R 2 and R 3 can each independently be one of ethyl, propyl, isopropyl, vinyl, allyl, ethynyl, propargyl, and fluoro derivatives thereof, And at least one of R 1 , R 2 and R 3 contains a double bond or a triple bond.
  • the terminal of at least one branch of R 1 , R 2 and R 3 of the phosphorus-oxygen bond-containing compound is a carbon-carbon unsaturated bond. More preferably, the ends of at least two branches of R 1 , R 2 and R 3 are carbon-carbon unsaturated bonds. Particularly preferably, all of the R 1 , R 2 and R 3 branch ends of the phosphorus-oxygen bond-containing compound are carbon-carbon unsaturated bonds.
  • the phosphate compound containing unsaturated branch chains shown in Formula 1 can be selected from one or more of the following compounds:
  • the cyclic compound containing -SO 2 -bond includes at least one of the compounds of formula 2 to formula 4,
  • R 4 is an alkylene group having 1 to 4 carbon atoms, a fluoroalkylene group having 1 to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and a carbon atom
  • a fluoroalkenylene group having 2 to 4 an arylene group having 6 to 14 carbon atoms
  • a fluoroarylene group having 6 to 10 carbon atoms
  • R 5 , R 6 , R 7 and R 8 are each independently H, an alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, halo One of an alkynyl group, an aryl group having 6 to 10 carbon atoms, or a halogenated aryl group, and n is 1, 2, or 3.
  • the alkylene group having 1 to 4 carbon atoms is a linear or branched alkylene group.
  • alkylene groups include: methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, 1-methylpropylene, 2-Methylpropylene and so on.
  • the number of fluorine atoms and the substitution position are not particularly limited.
  • the fluorine atom can be selected according to actual needs. Part of hydrogen atoms or all hydrogen atoms are substituted.
  • the number of fluorine atoms may be 1, 2, 3, 4 or more.
  • fluoroalkylene groups include: 1-fluoromethylene, 1-fluoroethylene, 1,1,2,2-tetrafluoroethylene, 1-fluoropropylene, 2 -Fluoropropylene, 1,1,1-trifluoropropylene, 1-fluoroisopropylidene, 1-fluorobutylene, 1-fluoroisobutylene, 1-fluorosec-butylene, etc.
  • the alkenylene group having 2 to 4 carbon atoms is a straight chain or branched chain alkenylene group, preferably a straight chain alkenylene group, and the number of double bonds in the alkenyl group may be one or two.
  • alkenylene groups include vinylene, allylylene, isopropenylene, butenylene, butadienylene, 1-methylvinylene, and 1-methylpropenylene. , 2-Methylpropenylene, etc.
  • the number of fluorine atoms and the substitution position are not particularly limited, and the fluorine atoms can be selected according to actual needs. Part of hydrogen atoms or all hydrogen atoms are substituted.
  • the number of fluorine atoms may be one, two or more.
  • fluoroalkenylene groups examples include 1-fluorovinylidene, 1,2-difluorovinylidene, 1-fluoroallyl, 1-fluoroisopropenylene, 1-fluoro Butenylene, 1-fluorobutadienyl, 1,2,3,4-tetrafluorobutadienyl, etc.
  • the specific type of the aryl group is not particularly limited, and can be selected according to actual needs, such as phenylene, naphthylene, and benzylidene , Wherein other substituent groups may be attached to the phenyl group, such as an alkyl group.
  • arylene group specific examples include: phenylene, benzylidene, 1-naphthylene, 2-naphthylene, o-methylphenylene, m-methylphenylene, p-methylene Phenyl, p-ethylphenylene, m-ethylphenylene, o-ethylphenylene, 1-tetrahydronaphthylene, 2-tetrahydronaphthylene, 4-vinylphenylene, 3- Isopropylphenylene, 4-isopropylphenylene, 4-butylphenylene, 4-isobutylphenylene, 4-tert-butylphenylene, 2,3-dimethylphenylene Phenyl, 2,4-dimethylphenylene, 2,5-dimethylphenylene, 2,6-dimethylphenylene, 3,4-dimethylphenylene, 3,5 -Dimethylphenylene, 2,4,5-tri
  • the number of substitutions of fluorine atoms and their substitution positions are not particularly limited, and the number of halogen atoms can be 1, 2, 3, 4, 5 or more.
  • fluoroarylene groups include: 2-fluorophenylene, 3-fluorophenylene, 4-fluorophenylene, 2-fluoro-4-methylphenylene, 3-fluorophenylene -4-methylphenylene, 4-fluoro-2-methylphenylene, 2,4-difluorophenylene, 3,4-difluorophenylene, 2,6-difluoro-4- Methylphenylene, 2,6-difluoro-3-methylphenylene, 2-fluoro-naphthylene, 4-fluoro-naphthylene, 2,4,6-trifluorophenylene, 2 ,3,4,6-tetrafluorophenylene, 4-trifluoromethylphenylene, 2,3,4,5-tetrafluorophenylene, pentafluorophenylene, 3,5-bis(trifluorophenylene) Fluoromethyl)phenylene and the like.
  • the compound of formula 2 is selected from one or more of the following compounds:
  • R 5 , R 6 , R 7 and R 8 are each independently H, methyl, ethyl, propyl, isopropyl, butyl, vinyl, allyl Group, 3-butenyl, isobutenyl, 4-pentenyl, ethynyl, propargyl, 3-butynyl, 1-methyl-2-propynyl or halogenated derivatives thereof.
  • halogenated derivatives include, but are not limited to, monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl Group, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 3,3-difluoropropyl, 3,3,3-trifluoropropyl and hexafluoroisopropyl, etc. More preferably, the compound of formula 3 is 1,3-propene sultone (PST), 1,4-butene sultone, 1-methyl-1,3-propene sultone and its halogens. One or more of substituted derivatives (such as fluoro derivatives).
  • the cyclic compound containing —SO 2 — bond includes the compound of Formula 4.
  • the compound of formula 4 is 1,3-propane sultone (PS).
  • the cyclic compound containing —SO 2 — bond may also be selected from at least one compound of Formula 5.
  • R 17 and R 18 are each independently selected from alkylene groups having 1 to 4 carbon atoms, fluoroalkylene groups having 1 to 4 carbon atoms, and alkenylene having 2 to 4 carbon atoms.
  • alkylene groups having 1 to 4 carbon atoms fluoroalkylene groups having 1 to 4 carbon atoms, and alkenylene having 2 to 4 carbon atoms.
  • an alkylene group having 1 to 4 carbon atoms, a fluoroalkylene group having 1 to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and an alkenylene group having 2 to 4 carbon atoms are independently selected from alkylene groups having 1 to 4 carbon atoms, fluoroalkylene groups having 1 to 4 carbon atoms, and al
  • the fluoroalkenylene group 4, the arylene group having 6 to 14 carbon atoms, and the fluoroarylene group having 6 to 10 carbon atoms may be as described above, respectively.
  • R 17 and R 18 are each independently selected from methylene, ethylene, propylene, isopropylene, vinylene, allyl, isopropenylene, and fluoro derivatives thereof One of the things.
  • the compound of formula 5 is methylene disulfonate and the like.
  • the cyclic compound containing —SO 2 — bond may include at least one compound of Formula 2 to Formula 5.
  • the cyclic siloxane compound containing unsaturated bonds includes at least one of the compounds of formula 6:
  • R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , and R 16 are each independently selected from substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms, and R 9 At least one of R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , and R 16 has a double bond or a triple bond, and the substituent is a halogen element.
  • R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , and R 16 are each independently selected from methyl, ethyl, propyl, isopropyl, vinyl, Allyl, ethynyl, propargyl and one of its fluorinated derivatives, and at least one of R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , and R 16 contains double Key or triple key.
  • the compound of formula 6 is selected from one or more of the following compounds:
  • additive A includes but is not limited to 1,3-propane sultone, propene sultone, methylene disulfonate, triallyl phosphate, tetramethyltetraethylene At least one of cyclotetrasiloxane.
  • the additive A is at least one of methylene methanedisulfonate, triallyl phosphate or tetramethyltetravinylcyclotetrasiloxane.
  • the viscosity of the electrolyte at 25 ⁇ 3° C. is 0.5 mPa ⁇ s to 5.0 mPa ⁇ s.
  • the flow rate of the electrolyte is relatively high, which can effectively increase the infiltration rate of the electrolyte in the positive electrode piece and the diffusion rate of the electrolyte in the electrode body.
  • the viscosity of the above-mentioned electrolyte at 0° C. is 1 mPa ⁇ s to 6.0 mPa ⁇ s. This can ensure that the electrolyte has good fluidity at room temperature and low temperature, and ensure that the battery has good kinetic performance at high and low temperatures.
  • the electrolyte includes a low-viscosity solvent, and a certain amount of wetting agent can be optionally added; wherein the viscosity of the low-viscosity solvent at 25 ⁇ 3°C is ⁇ 0.65mPa ⁇ s.
  • a low-viscosity solvent or selectively adding a wetting agent to the electrolyte, so that the electrolyte can obtain a specific flow rate, thereby increasing the infiltration rate of the electrolyte in the positive pole piece.
  • low viscosity solvents include but are not limited to dimethyl carbonate DMC, methyl formate MF, ethyl formate EF, methyl acetate MA, ethyl acetate EA, ethyl propionate EP, butyric acid Ethyl EB, tetrahydrofuran THF, 2 methyl tetrahydrofuran, dioxolane DOL, 1,2-dimethoxyethane DME, acetonitrile AN, methyl nonafluorobutyl ether MFE and ethyl nonafluorobutyl ether EFE At least one.
  • the mass fraction of the low-viscosity solvent in the electrolyte may be 10% to 80%, preferably 20% to 60%.
  • the percentage of the mass fraction may be, for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80%.
  • the electrolyte contains a wetting agent, which includes but is not limited to 1,1,2,2-tetrafluoroethyl-2,2,3,3 tetrafluoropropyl ether, 1H, At least one of 1H,5H-octafluoropentyl-1,1,2,2 tetrafluoroethyl ether or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl etherkind.
  • a wetting agent which includes but is not limited to 1,1,2,2-tetrafluoroethyl-2,2,3,3 tetrafluoropropyl ether, 1H, At least one of 1H,5H-octafluoropentyl-1,1,2,2 tetrafluoroethyl ether or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl etherkind.
  • the mass fraction of the infiltrant in the electrolyte is, for example, 0.1% to 10%. Specifically, for example, it may be 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 5%, 7%, 9%, or 10%.
  • the solvent of the electrolyte may further include other solvents.
  • Other solvents can be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate ( MPC), ethylene propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), propyl acetate (PA), methyl propionate (MP), propyl propionate (PP) , Methyl butyrate (MB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE) one or several Kind.
  • EC ethylene carbonate
  • PC propylene carbonate
  • EMC diethyl carbonate
  • DPC diethyl carbonate
  • the electrolyte salt of the electrolyte may be selected from LiPF 6 (lithium hexafluorophosphate), LiBF 4 (lithium tetrafluoroborate), LiClO 4 (lithium perchlorate), LiAsF 6 (hexafluoroarsenic) Lithium oxide), LiFSI (lithium bisfluorosulfonimide), LiTFSI (lithium bistrifluoromethanesulfonimide), LiTFS (lithium trifluoromethanesulfonate), LiDFOB (lithium difluorooxalate borate), LiBOB (two One or more of lithium oxalate borate), LiPO 2 F 2 (lithium difluorophosphate), LiDFOP (lithium difluorodioxalate phosphate) and LiTFOP (lithium tetrafluorooxalate phosphate).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluo
  • the positive electrode active material in the positive electrode material layer of the lithium ion battery of the present application is typically but not limitedly selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide , Lithium nickel cobalt aluminum oxide or olivine structured lithium-containing phosphate, etc., but this application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for lithium ion batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • the positive active material includes at least one of the compounds represented by formula (1) to formula (3):
  • M includes Mn, Fe, Cr, Ti One or more of Zn, V, Al, Zr and Ce
  • A includes one or more of S, N, F, Cl, Br and I.
  • M" is Ni, Co and Mn, or Ni, Co and Mn, and Fe, Cr, Ti, Zn, V, Al, Zr and Ce
  • A" includes one or more of S, N, F, Cl, Br and I.
  • the positive electrode active material is selected from the compounds represented by formula (1) to formula (3)
  • the positive electrode active material has a higher Ni content or a higher working voltage, so that the surface of the positive electrode active material particles The probability of side reactions in the electrolyte increases, which is more likely to cause gas problems.
  • the electrolyte diffusion rate in the electrode body is between 0.01 ⁇ g/s and 5 ⁇ g/s, a SEI film with good film quality can be formed on the surface of the above-mentioned cathode material in time, which effectively improves the gas production problem of the lithium ion battery using the above-mentioned cathode material .
  • the positive electrode active material may be selected from LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.55 Co 0.05 Mn 0.4 O 2 , LiNi 0.55 Co 0.1 Mn 0.35 O 2 , LiNi 0.55 Co 0.12 Mn 0.33 O 2 , LiNi 0.55 Co 0.15 Mn 0.3 O 2 , LiNi 0.6 Co 0.15 Mn 0.25 O 2 , LiNi 0.6 Co 0.18 Mn 0.22 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.65 Co 0.05 Mn 0.3 O 2 , LiNi 0.65 Co 0.09 Mn 0.26 O 2 , LiNi 0.65 Co 0.12 Mn 0.23 O 2 , LiNi 0.65 Co 0.15 Mn 0.2 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), LiNi 0.85 Co 0.15 Al 0.05 O 2 , LiNi 0.8 Co 0.1 Mn
  • the positive electrode material layer further includes a conductive agent and a binder.
  • the types of the conductive agent and the binder are not specifically limited, and can be selected according to actual needs.
  • the inventor of the present application discovered through research that the porosity, specific surface area, and OI value of the positive electrode material layer also have a greater impact on the diffusion rate of the electrolyte.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer coated on the surface of the positive electrode current collector, and the porosity of the positive electrode material layer is 10%-50%, preferably 20% ⁇ 40%.
  • the greater the porosity of the positive electrode material layer the more and smoother the path for the electrolyte to enter the positive pole piece, so that the electrolyte can infiltrate the positive pole piece more quickly.
  • the porosity of the positive electrode material layer By limiting the porosity of the positive electrode material layer to 10% to 50%, the electrolyte can infiltrate the positive electrode pieces faster and better, and the filling amount of the electrolyte can be kept in a reasonable range.
  • the electrode body has a relatively high High volume energy density and mass energy density.
  • the specific surface area of positive electrode material layer is 0.5m 2 /g ⁇ 1.5m 2 / g.
  • the electrolyte can quickly infiltrate the positive pole piece, and the contact area between the positive electrode material layer and the electrolyte can be controlled at a reasonable level. Within the range, it can effectively prevent side reactions between the electrolyte and the positive pole pieces.
  • the specific surface area of the positive electrode material layer is 0.53m 2 /g,0.62m 2 /g,0.8m 2 /g,0.92m 2 / g, 1m 2 / g or 1.2m 2 / g and the like.
  • the grain orientation OI value of the positive electrode material layer is 5 to 120.
  • the OI value of the positive electrode material layer is 30-70.
  • the OI value of the positive electrode material layer is the ratio of the peak area of the (003) diffraction peak to the (110) diffraction peak in the X-ray diffraction pattern of the positive pole piece.
  • the OI value of the positive electrode material layer can reflect the degree of stacking orientation of the lithium-containing compound particles in the layered structure. The surface energy of each crystal face of the positive electrode particles in the positive electrode sheet is different, and the affinity to the electrolyte is different.
  • Adjusting the OI value of the positive electrode material layer to the above range can improve the wettability of the electrolyte and the positive electrode piece to a certain extent, thereby increasing the diffusion rate of the electrolyte in the electrode body.
  • the OI value of the positive electrode material layer is 32, 37, 40, 50, 62, 75, 80, 90, or 100.
  • the viscosity of the electrolyte is a well-known meaning in the art, and can be tested by a method known in the art.
  • the test reference standard is GB/T 10247-2008, and the equipment used is Brookfield DV2T viscometer.
  • An exemplary test method is as follows: first, seal the electrolyte sample, put it in a constant temperature water bath, and start the test after reaching the temperature to be tested ⁇ 0.1°C, using 18# rotor during the test.
  • the porosity of the positive electrode material layer has a well-known meaning in the art, and can be tested using methods known in the art.
  • the test reference standard is GB/T24586-2009
  • the equipment used is AccuPyc II 1340
  • the range is 0.1cm 3 ⁇ 3.5cm 3 .
  • Test sample preparation punch the positive pole piece into a disc with a diameter of 1.6 cm, the number is greater than 20 pieces (such as 30 pieces), and record the number of samples and thickness in detail.
  • the specific surface area of the positive electrode material layer has a well-known meaning in the art, and can be tested by methods known in the art.
  • the test reference standard is GB/T 19587-2017
  • the equipment used is TriStar II 3020
  • the range is ⁇ 0.01m 2 /g
  • the heating range is 40°C ⁇ 350°C.
  • the OI value of the positive electrode material layer is the ratio of the peak area of the (003) diffraction peak to the (110) diffraction peak in the X-ray diffraction pattern of the positive pole piece.
  • the X-ray diffraction pattern of the positive pole piece can be tested using methods known in the art. For example, the test refers to JIS K 0131-1996, the equipment used is BruKer D8 Discover, and the pole piece sample area is not less than 30mm*30mm.
  • the 2 ⁇ angle corresponding to the 003 crystal plane of the layered lithium transition metal oxide is 17°-20°; the 2 ⁇ angle corresponding to the 110 crystal plane of the layered lithium transition metal oxide is 63° ⁇ 67°.
  • the negative electrode sheet may include a negative electrode current collector and a negative electrode material layer disposed on the negative electrode current collector and containing a negative electrode active material.
  • the type of the negative electrode active material is not specifically limited, and can be selected according to actual needs.
  • the negative electrode active material is a material capable of reversibly releasing lithium, including graphite, silicon, tin, metal oxide, silicon oxide, tin oxide, silicon alloy, tin alloy, silicon-carbon composite, tin-carbon One or more of composites, lithium titanate, etc.
  • the negative electrode active material is selected from natural graphite, artificial graphite or a mixture of the two.
  • the negative electrode material layer may also optionally include a conductive agent and a binder. The types of the conductive agent and the binder are not specifically limited, and can be selected according to actual requirements.
  • the negative pole piece can also be a metal lithium piece directly.
  • the material of the isolation film is not limited, and can be selected according to actual needs.
  • Fig. 2 shows a lithium ion battery 10 with a square structure as an example.
  • the lithium ion battery 10 also includes an outer package for packaging the electrode assembly 1 and electrolyte (not shown).
  • the outer packaging of the lithium ion battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the lithium ion battery can also be a soft bag, such as a pouch type soft bag.
  • the soft package can be aluminum-plastic film packaging or plastic film packaging, which can include one or more of polypropylene PP, polybutylene terephthalate PBT, polybutylene succinate PBS, and the like.
  • the outer package may include a housing 2 and a cover 3.
  • the housing 2 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a containing cavity.
  • the housing 2 has an opening communicating with the containing cavity, and a cover plate 3 can cover the opening to close the containing cavity.
  • the electrode assembly 1 is packaged in the containing cavity.
  • the number of electrode assemblies 1 contained in the lithium ion battery 10 can be one or several, which can be adjusted according to requirements.
  • lithium ion batteries can be assembled into battery modules, and the number of lithium ion batteries contained in the battery modules can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 4 is a battery module 20 as an example. 4, in the battery module 20, a plurality of lithium ion batteries 10 may be arranged in order along the length direction of the battery module 20. Of course, it can also be arranged in any other manner. Furthermore, the plurality of lithium ion batteries 10 can be fixed by fasteners.
  • the battery module 20 may further include a housing having an accommodation space, and a plurality of lithium ion batteries 10 are accommodated in the accommodation space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 30 may include a battery box and a plurality of battery modules 20 provided in the battery box.
  • the battery box includes an upper box body 31 and a lower box body 32.
  • the upper box body 31 can be covered on the lower box body 32 to form a closed space for accommodating the battery module 20.
  • a plurality of battery modules 20 may be arranged in the battery box in any manner.
  • this application provides an electrical equipment containing the lithium-ion battery of this application.
  • the lithium ion battery can be used as a power source for the electrical equipment, and can also be used as an energy storage unit of the electrical equipment.
  • the electrical equipment including the lithium ion battery of the present application also has the above advantages, which will not be repeated here.
  • the electrical equipment in this application can be, for example, new energy vehicles, electronic devices, electric tools, and power storage facilities. Further, the electrical equipment may be, but not limited to, mobile equipment (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric pedals Cars, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • mobile equipment such as mobile phones, laptop computers, etc.
  • electric vehicles such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric pedals Cars, electric golf carts, electric trucks, etc.
  • electric trains ships and satellites, energy storage systems, etc.
  • the electric equipment can select lithium ion batteries, battery modules or battery packs according to its usage requirements.
  • Figure 7 is an example of electrical equipment.
  • the electrical equipment is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • battery packs or battery modules can be used.
  • This embodiment is a lithium ion battery, which includes an electrode body formed by winding a positive pole piece, a separator film, and a negative pole piece in sequence, and the positive electrode tab and the negative electrode tab are separately provided at both ends of the electrode body.
  • the preparation process of the lithium ion battery of this embodiment is as follows:
  • the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 94:3:3 and added to the solvent N-methylpyrrolidone (NMP), stir under the action of a vacuum mixer until the system is uniform, to obtain a positive electrode slurry, wherein the solid content of the positive electrode slurry is 77wt%; the positive electrode slurry is uniformly coated on the positive electrode current collector aluminum foil with a thickness of 14 ⁇ m and Dry at 85°C, then go through cold pressing, trimming, cutting, slitting, and finally drying at 85°C for 4 hours under vacuum conditions to obtain positive pole pieces.
  • NMP solvent N-methylpyrrolidone
  • the negative active material graphite, the conductive agent Super P, the thickener sodium carboxymethyl cellulose CMC-Na, and the binder styrene butadiene rubber emulsion SBR are mixed in a mass ratio of 94:2:2:2, and added to the solvent to deionize
  • the negative electrode slurry is obtained under the action of a vacuum mixer, wherein the solid content in the negative electrode slurry is 54wt%; the negative electrode slurry is uniformly coated on the copper foil of the negative electrode current collector with a thickness of 8 ⁇ m and dried at 85°C, Then, after cold pressing, trimming, cutting, slitting, and finally drying at 120°C for 12 hours under vacuum conditions, the negative pole piece is obtained.
  • EC, EMC, and EA are mixed at a mass ratio of 30:60:10 as an organic solvent, and then the fully dried lithium salt LiPF 6 is dissolved in the mixed organic solvent Then, 2wt% of additive A triallyl phosphate is added, and the electrolyte is obtained after uniform mixing.
  • the concentration of LiPF 6 is 1 mol/L
  • a polyethylene film PE with a thickness of 16 ⁇ m is used as a base film, and a coating containing ceramic particles is coated on at least one surface of the PE porous film to form an isolation film.
  • Examples 2-18 and Comparative Examples 1-3 are respectively a lithium ion battery, and the differences from Example 1 are listed in Table 1.
  • Table 1 the addition amount of each solvent and additive A is the mass percentage calculated based on the total mass of the electrolyte. Others are the same as in Example 1.
  • the capillary with the electrolyte is in vertical contact with the positive pole piece, and the liquid level of the capillary drops while using a stopwatch. When the liquid level drops, read the suction time t.
  • the capacity retention rate of the lithium ion battery after 400 cycles of 1C/1C at 25°C (%) discharge capacity at the 800th cycle/discharge capacity at the first cycle ⁇ 100%.
  • the volume expansion rate (%) of the lithium ion battery after storage at 80°C for 10 days (V 3 -V 2 )/V 2 ⁇ 100%.
  • the electrolyte solution containing additive A was used and the diffusion rate of the electrolyte solution in the electrode body was limited within the range of 0.01 ⁇ g/s to 5 ⁇ g/s. Due to the film formation quality of the positive electrode passivation film High, it can effectively inhibit the side reaction of the electrolyte on the surface of the positive electrode active material. At the same time, the electrolyte has good wettability, which can effectively alleviate the obstacles caused by the high energy density design to the electrolyte diffusion and ensure that the additive A is in the circulation process.
  • the diffusion rate v of the electrolyte in the electrode body is significantly smaller than the diffusion rate defined in this application. It can be seen from the experimental data that when the diffusion rate v of the electrolyte in the cell is small, the effective wetting rate cannot be reached, and therefore, the cycle performance of the lithium ion battery will be affected.
  • the diffusion rate v of the electrolyte in the electrode body is significantly greater than the diffusion rate defined in this application. It can be seen from the experimental data that when the electrolyte diffusion rate v in the cell is large, the cycle performance of the lithium ion battery will be reduced. This is because the solvent (such as ethylene carbonate EC) and lithium salt in the electrolyte will worsen the electrolyte infiltration rate on the positive electrode, and a certain amount of ethylene carbonate EC is required in the electrolyte to dissociate the lithium salt , Increase conductivity, and need a certain amount of lithium salt to provide lithium ions. Too high a diffusion rate of the electrolyte will affect the dissociation and conductivity of the electrolyte to the lithium salt.
  • the solvent such as ethylene carbonate EC

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Abstract

本申请提供了一种锂离子电池及包含其的用电设备，涉及电池领域。锂离子电池包括：电极组件；以及浸润于所述电极组件的电解液；其中，所述电极组件包括电极主体、正极极耳和负极极耳，所述电极主体包括围绕轴线卷绕在一起的正极极片、负极极片以及设置在所述正极极片和所述负极极片之间的隔离膜；所述正极极耳连接于所述正极极片，所述负极极耳连接于所述负极极片；沿轴线方向(X)，所述电极主体具有相对设置的两侧部，所述正极极耳和所述负极极耳分别从所述电极主体的两侧部延伸出；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的正极材料层；所述电解液含有添加剂A，所述电解液在所述电极主体中的扩散速率v为0.01μg/s～5μg/s。

Description

锂离子电池及包含其的用电设备
相关申请的交叉引用
本申请要求享有于2019年07月10日提交的名称为“锂离子电池及包含其的用电设备”的中国专利申请201910618619.1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
本申请涉及电池领域，具体涉及一种锂离子电池及包含其的用电设备。
背景技术
锂离子电池因其工作电位高，寿命长，环境友好的特点成为最受欢迎的能量存储系统，现已被广泛应用于纯电动汽车，混合电动汽车，智能电网等领域。但目前基于LiFePO 4正极材料的锂离子电池难以满足人们对续航能力的更高需求，要破除人们对电动汽车“里程焦虑”的问题，就迫切需要开发具有更高能量密度的锂离子电池体系。
发明内容
然而，本发明人发现，采用高能量密度的正极材料如高电压LiNi 0.5Mn 1.5O 4、高容量的高镍三元NCM811(LiNi 0.8Co 0.1Mn 0.1O 2)和富锂三元材料，可以提高电池的能量密度。但是这些材料表面杂锂含量高，颗粒表面与电解液的副反应活性较强，导致使用上述正极材料的锂离子电池的高温产气量较大，造成循环恶化，甚至带来安全风险。另外，对于卷绕式电池来说，目前产业化的提高其能量密度的方法是通过提高包装材料的空间利用率来提高能量密度。例如，将电芯长度方向加长，降低用于引出正、负极片电流的极耳所占的空间。但是，根据研发经验，增加空间利用率将会使得电解液更难进入卷绕式电芯，尤其在循环过程中，由于正极极片表面的SEI(solid electrolyte interphase，固体电解质界面)膜的形成与消耗是一个动态过程， 电芯内部的体积膨胀-收缩会将游离态的电解液挤出至卷绕式电芯两端，如果电解液不能及时回流至电芯中部，会造成卷绕式电芯在循环过程中由于动力学不足导致析锂发生；同时，由于正极极片表面的SEI被消耗完而不能及时形成新的SEI膜，不仅电芯的产气性能和循环寿命会发生恶化，甚至可能还有严重的安全风险。因此，如何使锂离子电池同时兼顾高能量密度和高循环寿命是电池设计的关键挑战所在。
因此，本发明人进行了大量的研究，本申请的第一目的在于提供一种锂离子电池，以解决目前卷绕式电芯高能量密度和高循环性能不能兼具的问题。
本申请的第二目的在于提供一种包含本发明锂离子电池的用电设备。
为实现上述目的，本申请采用以下技术方案：
一种锂离子电池，包括：
电极组件；以及浸润于所述电极组件的电解液；其中，
所述电极组件包括电极主体、正极极耳和负极极耳，所述电极主体包括围绕轴线卷绕在一起的正极极片、负极极片以及设置在所述正极极片和所述负极极片之间的隔离膜，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的正极材料层，所述正极极耳连接于所述正极极片，所述负极极耳连接于所述负极极片；
沿所述轴线方向(X)，所述电极主体具有相对设置的两侧部，所述正极极耳和所述负极极耳分别从所述电极主体的两侧部延伸出；
所述电解液含有添加剂A，所述添加剂A包括含不饱和键的磷酸酯化合物、含-SO 2-键的环状化合物、含不饱和键的环状硅氧烷化合物中的至少一种，所述电解液在所述电极主体中的扩散速率v为0.01μg/s～5μg/s，优选为0.2μg/s～2μg/s，
所述v＝γ×H/L，
所述γ为所述正极极片对所述电解液的吸液速率，单位为μg/s，
所述H为沿所述电极主体的宽度方向(Z)所述侧部的最大长度，单位为mm，
所述L为沿所述轴线方向(X)所述电极主体的长度，单位为mm。
一种用电设备，包括本申请的锂离子电池。
本申请提供的技术方案至少可以达到以下有益效果：
本申请的锂离子电池为卷绕式锂离子电池，通过将正、负极极耳分别设置在沿轴线方向的电极主体的两个侧部，能够有效提高单体电池内部空间利用率，提高电 池的体积能量密度。同时，通过在电解液中加入能够在正极极片表面形成致密SEI膜的添加剂A，并且将电解液的浸润性与正极极片微观结构、电极主体的结构相匹配，控制含有添加剂A的电解液在电极主体的扩散速率在0.01μg/s～5μg/s的范围内，由此保证循环过程中电解液能够快速浸润或回流进入卷绕式电芯内部，并且在正极极片表面及时形成新的SEI膜，从而能提高锂离子电池的循环性能和安全性、并抑制高容量锂离子电池的产气问题。因此，本申请提供的锂离子电池兼具高能量密度、高循环稳定性和高安全性的特点。更优选地，所述锂离子电池还可具有较高的高温存储性能。本申请的用电设备包含所述的锂离子电池，因而至少具有相同的优势。
附图说明
为了更清楚地说明本实用新型实施例的技术方案，下面将对实施例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实用新型的一些实施例，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它的附图。
图1为本申请实施例提供的一种电极组件示意图。
图2为本申请实施例提供的一种硬壳锂离子电池的分解示意图。
图3为本申请实施例提供的一种软包锂离子电池的结构示意图。
图4是电池模块的一实施方式的示意图。
图5是电池包的一实施方式的示意图。
图6是图5的分解图。
图7是锂离子电池用作电源的用电设备的一实施方式的示意图。
具体实施方式
为了使本申请的发明目的、技术方案和有益技术效果更加清晰，以下结合具体实施例对本申请进行详细说明。应当理解的是，本说明书中描述的实施例仅仅是为了解释本申请，并非为了限定本申请。
为了简便，本文仅明确地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，尽 管未明确记载，但是范围端点间的每个点或单个数值都包含在该范围内。因而，每个点或单个数值可以作为自身的下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种以上。
本申请的上述发明内容并不意欲描述本申请中的每个公开的实施方式或每种实现方式。如下描述更具体地举例说明示例性实施方式。在整篇申请中的多处，通过一系列实施例提供了指导，这些实施例可以以各种组合形式使用。在各个实例中，列举仅作为代表性组，不应解释为穷举。
一方面，本申请提供了一种锂离子电池。图2示出作为一个示例的锂离子电池10。参照图2，锂离子电池10包括：
电极组件1(如图1所示)，以及浸润于所述电极组件1的电解液，电极组件1包括电极主体11、正极极耳12和负极极耳13，电极主体11包括围绕轴线卷绕在一起的正极极片、负极极片以及设置在正极极片和负极极片之间的隔离膜，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的正极材料层；正极极耳12连接于正极极片，负极极耳13连接于负极极片；沿轴线方向(X)，电极主体具有相对设置的两侧部14，在该锂离子电池中，电极主体11的两侧部14分别延伸出正极极耳12和负极极耳13。其中，X方向为电极主体11的正极极片、负极极片以及设置在所述正极极片和所述负极极片之间的隔离膜的卷绕的轴线方向，也是电解液在电极主体11的主要扩散方向；Y方向为电极主体11的厚度方向；Z方向为电极主体11的宽度方向。
本申请中，将正极极耳12、负极极耳13分别设置在电极主体11的两侧部14，尤其当正、负极极耳进一步向电极主体的厚度方向弯折后，电池壳体中电极主体的体积占有率增加，有利于提高电池内部空间的活性物质含量，从而有效提高锂离子电池的体积能量密度。但是，对于卷绕结构的电芯，电解液仅能从电极主体的两个侧部向电极主体中部扩散进入，尤其当极耳在电极主体的厚度方向(Y)进一步弯折后，容易导致部分电解液的扩散路径被遮挡，使得电解液对电极主体的浸润难度加大。同时，在电池的充电过程中，正、负极片活性物质层都会发生体积膨胀，极 片间的间距缩短、电芯中部的部分电解液被挤出，而在电池的放电过程中，正、负极片活性物质层又会发生体积收缩，极片间的间距增大，游离的电解液又需要重新补充到正负极极片当中。若电解液没有及时补充，在接下来的循环过程中，正、负极片间游离态的锂离子会因为电解液不足、不能及时嵌入而引发析锂问题。同时，由于正极极片表面的SEI被消耗完而不能及时形成新的SEI膜，电芯的产气性能会发生恶化，进而导致电池循环性能变差，甚至存在安全风险。
在本申请中，为了提高本申请锂离子电池的高温适用性和安全性，所述电解液中含有添加剂A。添加剂A包括含不饱和键的磷酸酯化合物、含-SO 2-键的环状化合物、含不饱和键的环状硅氧烷化合物中的至少一种，电解液在电极主体中的扩散速率v为0.01μg/s～5μg/s，优选为0.2μg/s～2μg/s。通过引入添加剂A优先在正极表面成膜，形成结构致密且稳定性较好的钝化层，阻隔正极与溶剂的直接接触，进而有效的抑制溶剂的氧化产气。本申请中，上述成膜添加剂尤其适用于产气问题较为严重的高容量电池体系。与此同时，调节电解液在电极主体中扩散速率v为0.01μg/s～5μg/s，优选为0.2μg/s～2μg/s，该电解液在电极主体中具有良好的浸润性，可以快速进入电极主体内部，并及时在正极极片表面形成新的SEI膜，进而提高锂离子电池的循环性能、安全性、改善循环过程中的产气问题。进一步地，锂离子电池还可具有较高的高温存储性能。
本申请中，电解液在电极主体的扩散速率v＝γ×H/L，其中，γ为正极极片对电解液的吸液速率(μg/s)，H为沿电极主体的宽度方向(Z)侧部的最大长度(mm)，L为沿轴线方向(X)电极主体的长度(mm)。本申请中，扩散速率v以电极主体中正极极片对电解液的吸液速率为主要影响因素进行计量，主要基于以下原因：电解液中添加剂A主要作用于正极极片的活性物质颗粒表面形成结构致密的钝化膜，从而改善锂离子电池的产气性能；同时，通常正极极片的压实密度高于负极极片，正极极片内部结构更紧密，电解液在正极极片的扩散性对电池循环性能影响更为显著。
本申请中，正极极片对电解液的吸液速率γ可通过以下方法测定：用一定内径且带有标准刻度的滴管装满电解液，滴管下口直径为0.2mm；将正极极片充分干燥(例如在70℃～90℃下干燥10h～15h)，之后裁取5cm×5cm的正方形正极极片；在湿度低于2％的干燥房内，使滴管下口与正方形正极极片接触，并保证滴管垂直于 正极极片表面，滴管内的电解液逐渐浸润至正极极片内部，记录每秒浸润到正极极片的电解液质量，即为正极极片对电解液的吸液速率。
同时，电解液在电极主体中的扩散速率v还会受电极主体结构的影响。本申请中，H为沿电极主体的宽度方向(Z)侧部的最大长度(mm)，L为沿轴线方向(X)电极主体的长度(mm)。当H越小，电解液从外进入电极主体的通道就越窄；当L越长，电解液扩散到电极主体中心区域的路径就越长。本申请中，当电极主体的长度L小于宽度H时，电极主体的体积能量密度更高、但不利于电解液快速进入电芯，电解液的扩散速率v对电极主体尺寸H、L的依赖性更强。
综合以上，本申请中，将电解液在电极主体中的扩散速率v定义为：v＝γ×H/L(μg/s)，其中，γ的单位为μg/s，H和L的单位为mm。
在本申请的一些实施方式中，电解液在电极主体中扩散速率v可以为0.25μg/s、0.37μg/s、0.58μg/s、0.68μg/s、0.75μg/s、1.08μg/s、1.55μg/s、1.97μg/s、2.5μg/s、3μg/s、4μg/s或4.97μg/s等。
在本申请的一些实施方式中，正极极片对电解液的吸液速率γ可以为0.15μg/s～7.25μg/s，进一步的为0.45μg/s～3.58μg/s。例如，正极极片对电解液的吸液速率γ为0.71μg/s、0.82μg/s、0.96μg/s、1.08μg/s、2.24μg/s、2.48μg/s、2.57μg/s、3.12μg/s、4μg/s、5μg/s、6μg/s、或6.51μg/s等。
在本申请的一些实施方式中，沿电极主体的宽度方向(Z)侧部的最大长度H(mm)以及沿轴线方向(X)电极主体的长度L(mm)满足：0.05≤H/L≤0.8。作为本申请的一些优选的实施方式，H/L为0.1～0.6。作为本申请进一步的优选的实施方式，H/L为0.15～0.5。具体地，H/L的数值可以为0.8、0.75、0.7、0.65、0.6、0.55、0.5、0.45、0.4、0.35、0.3、0.25、0.2、0.1或0.05等。H/L比值较小的电极主体结构相对于长、宽较为接近的电池来说，最大程度的降低了正极极耳和负极极耳在正极极片和负极极片中的占比，相对提高了锂离子电池的空间利用率，进而提高了锂离子电池的能量密度。同时，由于极耳分别设置在电极主体的两端，可以简化模组组装时的线路设计，在提高组装效率的同时，还能降低成本。
在本申请的一些实施方式中，沿电极主体的宽度方向(Z)侧部的最大长度H可以为10mm～280mm，进一步的为30mm～160mm，更进一步的为45mm～150mm。例如，H为90mm、91mm、100mm、120mm、150mm或160mm等。
在本申请的一些实施方式中，沿轴线方向(X)电极主体的长度L可以为50mm～500mm，进一步的为100mm～400mm，更进一步的为200mm～350mm。例如，L为200mm、300mm、301mm或350mm等。
在本申请的一些实施方式中，电极主体的轴线方向(X)为水平方向。此时，电极主体的卷绕轴方向与水平方向基本平行，电解液能够从电极主体的两端浸润、扩散进入电极主体内部，更有利于电解液的快速浸润。
作为本申请的一种具体实施方式，电极组件的卷绕轴方向为水平方向，电极组件放置于电池壳体内，并用顶盖密封，组装成锂离子电池，例如图2所示。根据不同的应用场景，该锂离子电池可以竖直放置(即Z方向与重力方向平行)，也可以平躺放置(即Y方向与重力方向平行)。
作为本申请的一种具体实施方式，电极组件的卷绕轴方向为水平方向，电极组件由铝塑膜包装，包装袋边缘通过热压、胶体固定等方式密封，组装成锂离子电池，例如图3所示。根据不同的应用场景，该锂离子电池可以竖直放置(即Z方向与重力方向平行)，也可以平躺放置(即Y方向与重力方向平行)。
在本申请的一些实施方式中，添加剂A在电解液中的质量占比w(％)与扩散速率v(μg/s)满足：0.01≤w×v≤10，优选0.1≤w×v≤10。例如，w×v为0.43、0.50、0.65、0.74、1.15、1.35、1.50、2.16、3.11、3.94、4.97、6.74或9.84等。作为本申请的一些优选实施方式中，添加剂A在电解液中的质量占比w(％)与扩散速率v(μg/s)满足：0.4≤w×v≤5。
发明人通过研究发现，电解液中添加剂A的质量百分比w与电解液在电极主体的扩散速率v的相互关系对正极极片的成膜质量及界面阻抗影响较大，从而影响了电池的产气量以及循环性能。当添加剂A在电解液中的质量占比w与所述扩散速率v满足上述关系式时，既可以保证电解液具有较高的浸润或回流速率，也能保证有足够的添加剂A形成稳定的保护膜来抑制产气，同时添加剂A的用量适中，保证锂离子电池的循环性能良好。
在一些实施方式中，添加剂A在电解液中的质量占比w可以为0.1wt％～5wt％，进一步的为0.1wt％～3wt％，更进一步的为1wt％～2wt％。
本申请中，含不饱和键的磷酸酯化合物为式1化合物中的至少一种，
Figure PCTCN2020090079-appb-000001
其中，R 1、R 2和R 3分别独立地选自碳原子数为1～6的烷基、烯基、炔基、卤代烷基、卤代烯基、卤代炔基、碳原子数为6～10的芳基或卤代芳基中的一种，并且R 1、R 2和R 3中的至少一个含有双键或三键。
在一些实施方式中，在式1中，R 1、R 2和R 3可以分别独立地为甲基、乙基、丙基、异丙基、丁基、乙烯基、烯丙基、3-丁烯基、异丁烯基、4-戊烯基、乙炔基、炔丙基、3-丁炔基、1-甲基-2-丙炔基或其卤代衍生物，且R 1、R 2和R 3中至少一个含有双键或三键。在描述式1中的R 1、R 2和R 3时，卤化衍生物包括但不限于一氟甲基、二氟甲基、三氟甲基、2,2,2-三氟乙基、2,2-二氟乙基、2,2,2-三氟乙基、3,3-二氟丙基、3,3,3-三氟丙基和六氟异丙基等。优选地，R 1、R 2和R 3可以分别独立地为乙基、丙基、异丙基、乙烯基、烯丙基、乙炔基、炔丙基和其氟代衍生物中的一种，且R 1、R 2和R 3中至少一个含有双键或三键。
优选地，含磷氧键化合物的R 1、R 2和R 3至少一个支链的末端为碳碳不饱和键。更优选地，R 1、R 2和R 3至少两个支链的末端为碳碳不饱和键。尤其优选地，含磷氧键化合物的R 1、R 2和R 3支链末端全部为碳碳不饱和键。
作为本申请的一些优选实施方式中，式1所示含有不饱和支链的磷酸酯化合物可选自下述化合物中的一种或几种：
Figure PCTCN2020090079-appb-000002
本申请中，含-SO 2-键的环状化合物包括式2～式4化合物中的至少一种，
Figure PCTCN2020090079-appb-000003
所述式2化合物中，R 4为碳原子数为1～4的亚烷基、碳原子数为1～4的氟代亚烷基、碳原子数为2～4的亚烯基、碳原子数为2～4的氟代亚烯基、碳原子数为6～14的亚芳基、碳原子数为6～10的氟代亚芳基中的一种。
所述式3化合物中，R 5、R 6、R 7和R 8分别独立地为H、碳原子数为1～6的烷基、烯基、炔基、卤代烷基、卤代烯基、卤代炔基、碳原子数为6～10的芳基或卤代芳基中的一种，n是1、2或3。
作为本申请的一些优选实施方式中，所述式2化合物中，碳原子数为1～4的亚烷基为直链或支链亚烷基。作为亚烷基的实例，具体可以举出：亚甲基、亚乙基、亚丙基、亚异丙基、亚丁基、亚异丁基、亚仲丁基、1-甲基亚丙基、2-甲基亚丙基等。
在上述式2中，碳原子数为1～4的氟代亚烷基中，氟原子的取代个数及其取代位置并没有特别的限制，可根据实际需求选择氟原子对亚烷基中的部分氢原子或者全部氢原子进行取代。例如，氟原子的个数可为1个、2个、3个、4个或多个。
作为氟代亚烷基的实例，具体可以举出：1-氟亚甲基、1-氟亚乙基、1,1,2,2-四氟亚乙基、1-氟亚丙基、2-氟亚丙基、1,1,1-三氟亚丙基、1-氟亚异丙基、1-氟亚丁基、1-氟亚异丁基、1-氟亚仲丁基等。
在上述式2中，碳原子数为2～4的亚烯基为直链或支链亚烯基，优选直链亚烯基，烯基中双键的个数可以为1个或2个。作为亚烯基的实例，具体可以举出：亚乙烯基、亚烯丙基、亚异丙烯基、亚丁烯基、亚丁二烯基、1-甲基亚乙烯基、1-甲基亚丙烯基、2-甲基亚丙烯基等。
在上述式2中，碳原子数为2～4的氟代亚烯基中，氟原子的取代个数及其取代位置并没有特别的限制，可根据实际需求选择氟原子对亚烯基中的部分氢原子或者全部氢原子进行取代。例如，氟原子的个数可为1个、2个或多个。
作为氟代亚烯基的实例，具体可以举出：1-氟亚乙烯基、1,2-二氟亚乙烯基、1- 氟亚烯丙基、1-氟亚异丙烯基、1-氟亚丁烯基、1-氟亚丁二烯基、1,2,3,4-四氟亚丁二烯基等。
在上述式2中，碳原子数为6～10的亚芳基中，芳基的具体种类并没有特别的限制，可根据实际需求进行选择，例如亚苯基、亚萘基、亚苯烷基，其中在苯基上还可以连接有其他取代基团，例如烷基。
作为亚芳基的实例，具体可以举出：亚苯基、亚苄基、1-亚萘基、2-亚萘基、邻甲基亚苯基、间甲基亚苯基、对甲基亚苯基、对乙基亚苯基、间乙基亚苯基、邻乙基亚苯基、1-四氢亚萘基、2-四氢亚萘基、4-乙烯基亚苯基、3-异丙基亚苯基、4-异丙基亚苯基、4-丁基亚苯基、4-异丁基亚苯基、4-叔丁基亚苯基、2,3-二甲基亚苯基、2,4-二甲基亚苯基、2,5-二甲基亚苯基、2,6-二甲基亚苯基、3,4-二甲基亚苯基、3,5-二甲基亚苯基、2,4,5-三甲基亚苯基、2,4,6-三甲基亚苯基等。
在上述式2中，碳原子数为6～10的氟代亚芳基中，氟原子的取代个数及其取代位置并没有特别的限制，卤原子的个数可为1个、2个、3个、4个、5个或多个。
作为氟代亚芳基的实例，具体可以举出：2-氟亚苯基、3-氟亚苯基、4-氟亚苯基、2-氟-4-甲基亚苯基、3-氟-4-甲基亚苯基、4-氟-2-甲基亚苯基、2,4-二氟亚苯基、3,4-二氟亚苯基、2,6-二氟-4-甲基亚苯基、2,6-二氟-3-甲基亚苯基、2-氟-亚萘基、4-氟-亚萘基、2,4,6-三氟亚苯基、2,3,4,6-四氟亚苯基、4-三氟甲基亚苯基、2,3,4,5-四氟亚苯基、五氟亚苯基、3,5-二(三氟甲基)亚苯基等。
作为本申请的一些优选实施方式中，式2化合物选自如下化合物中一种或多种：
Figure PCTCN2020090079-appb-000004
Figure PCTCN2020090079-appb-000005
在一些实施例中，在式3化合物中，R 5、R 6、R 7和R 8分别独立地为H、甲基、乙基、丙基、异丙基、丁基、乙烯基、烯丙基、3-丁烯基、异丁烯基、4-戊烯基、乙炔基、炔丙基、3-丁炔基、1-甲基-2-丙炔基或其卤代衍生物。在描述式3中的R 5、R 6、R 7和R 8时，卤化衍生物包括但不限于一氟甲基、二氟甲基、三氟甲基、2,2,2-三氟乙基、2,2-二氟乙基、2,2,2-三氟乙基、3,3-二氟丙基、3,3,3-三氟丙基和六氟异丙基等。更优选地，式3的化合物是1,3-丙烯磺酸内酯(PST)、1,4-丁烯磺酸内酯、1-甲基-1,3-丙烯磺酸内酯及其卤代衍生物(如氟代衍生物)中的一种或多种。
在一些优选的实施方式中，含-SO 2-键的环状化合物包含式4的化合物。式4的化合物是1,3-丙烷磺内酯(PS)。
在一些实施方式中，含-SO 2-键的环状化合物还可以选自式5化合物中的至少一种。
Figure PCTCN2020090079-appb-000006
式5中，R 17和R 18分别独立地选自碳原子数为1～4的亚烷基、碳原子数为1～4的氟代亚烷基、碳原子数为2～4的亚烯基、碳原子数为2～4的氟代亚烯基、碳原子数为6～14的亚芳基、碳原子数为6～10的氟代亚芳基中的一种。在一些实施方式中，碳原子数为1～4的亚烷基、碳原子数为1～4的氟代亚烷基、碳原子数为2～4的亚烯基、碳原子数为2～4的氟代亚烯基、碳原子数为6～14的亚芳基、碳原子数为6～10的氟代亚芳基可以分别如前文所述。在一些实施方式中R 17和R 18分别独立地选自亚甲基、亚乙基、亚丙基、亚异丙基、亚乙烯基、亚烯丙基、亚异丙烯基和其氟代衍生物中的一种。
在一些优选的实施方式中，式5化合物是甲烷二磺酸亚甲酯等。
在一些实施方式中，所述含-SO 2-键的环状化合物可包括式2～式5化合物中的至少一种。
本申请中，含不饱和键的环状硅氧烷化合物包括式6化合物中的至少一种：
Figure PCTCN2020090079-appb-000007
式6中，R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16各自独立地选自取代或未取代的碳原子数为1～4的烃基，且R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16中的至少一个含有双键或三键，取代基为卤族元素。在一些实施方式中，R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16各自独立地选自甲基、乙基、丙基、异丙基、乙烯基、烯丙基、乙炔基、炔丙基和其氟代衍生物中的一种，且R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16中至少一个含有双键或三键。
作为本申请的一些优选实施方式中，式6化合物选自如下化合物中一种或多种：
Figure PCTCN2020090079-appb-000008
作为本申请的一些优选实施方式中，添加剂A包括但不限于1,3-丙烷磺内酯、丙烯磺酸内酯、甲烷二磺酸亚甲酯、磷酸三烯丙酯、四甲基四乙烯基环四硅氧烷中的至少一种。
在进一步优选的实施方式中，添加剂A为甲烷二磺酸亚甲酯、磷酸三烯丙酯或四甲基四乙烯基环四硅氧烷中的至少一种。
在本申请的一些实施方式中，电解液在25±3℃下的粘度为0.5mPa·s～5.0mPa·s。本申请中，电解液的粘度在上述范围内时，电解液的流动速率较高，能够有效提高电解液在正极极片中的浸润速率以及电解液在电极主体的扩散速率。作为本申请一些优选的实施方式，上述电解液在0℃的粘度为1mPa·s～6.0mPa·s。这样可以保证电解液在常温以及低温条件下均具有良好的流动性，保证电池在高低温下都均有良好的动力学性能。
在本申请的一些实施方式中，所述电解液中包括低粘度溶剂，还可以选择性地添加一定量地浸润剂；其中，所述低粘度溶剂在25±3℃下的粘度≤0.65mPa·s。通过使用低粘度溶剂，或选择性地在电解液中添加浸润剂，以使电解液获得特定的流动速率，从而提高电解液在正极极片的浸润速率。
在本申请的一些实施方式中，低粘度溶剂包括但不限于碳酸二甲酯DMC、甲酸甲酯MF、甲酸乙酯EF、乙酸甲酯MA、乙酸乙酯EA、丙酸乙酯EP、丁酸乙酯EB、四氢呋喃THF、2甲基四氢呋喃、二氧戊环DOL、1,2-二甲氧基乙烷DME、乙腈AN、甲基九氟丁醚MFE和乙基九氟丁醚EFE中的至少一种。
在本申请的一些实施方式中，为了获得良好浸润性的电解液，低粘度溶剂在电解液中的质量分数占比可以为10％～80％，优选为20％～60％。该质量分数占比典型但非限制性的例如可以为10％、20％、30％、40％、50％、60％、70％或80％。
在本申请的一些实施方式中，电解液中含有浸润剂，浸润剂包括但不限于1,1,2,2-四氟乙基-2,2,3,3四氟丙基醚、1H,1H,5H-八氟戊基-1,1,2,2四氟乙基醚或 1,1,2,2-四氟乙基-2,2,2-三氟乙基醚中的至少一种。
其中，浸润剂在电解液中的质量分数占比例如为0.1％～10％。具体的，例如可以为0.1％、0.5％、1％、1.5％、2％、3％、5％、7％、9％或10％。
在根据本申请的锂离子电池中，所述电解液的溶剂还可包括其它溶剂。其它溶剂可选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸丙酯(PP)、丁酸甲酯(MB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或几种。
在根据本申请的锂离子电池中，所述电解液的电解质盐可选自LiPF 6(六氟磷酸锂)、LiBF 4(四氟硼酸锂)、LiClO 4(高氯酸锂)、LiAsF 6(六氟砷酸锂)、LiFSI(双氟磺酰亚胺锂)、LiTFSI(双三氟甲磺酰亚胺锂)、LiTFS(三氟甲磺酸锂)、LiDFOB(二氟草酸硼酸锂)、LiBOB(二草酸硼酸锂)、LiPO 2F 2(二氟磷酸锂)、LiDFOP(二氟二草酸磷酸锂)及LiTFOP(四氟草酸磷酸锂)中的一种或几种。
本申请的锂离子电池的正极材料层中的正极活性材料典型但非限制性的选自锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物或橄榄石结构的含锂磷酸盐等，但本申请并不限定于这些材料，还可以使用其他可被用作锂离子电池正极活性材料的传统公知的材料。这些正极活性材料可以仅单独使用一种，也可以将两种及以上组合使用。
在本申请的一些实施方式中，正极活性物质包含式(1)～式(3)所示的化合物中的至少一种：
Li 1+xNi aCo bM 1-a-bO 2-yA y                       式(1)
Li 1+x’Ni a’M’ 2-a’O 4-y’A’ y’                式(2)
c[Li 2MnO 3]·(1-c)[LiM” 2O 2-y”A” y”]        式(3)
其中，式(1)中，-0.1≤x≤0.2，0.5≤a<1，0.02<b<0.3，0.55<a+b<1，0≤y<0.2，M包括Mn、Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种，A包括S、N、F、Cl、Br及I中的一种或多种。式(2)中，-0.1≤x’≤0.2，0.4≤a’<0.6，0≤y’<0.2，M’包括Mn、或者Mn以及Fe、Cr、Ti、Zn、V、Al、Zr、Mg、Ce中的一种或多种，A’包括S、N、F、Cl、Br及I中的一种或多种。 式(3)中，0<c<1，0≤y’<0.2，M”为Ni、Co和Mn，或者Ni、Co和Mn以及Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种，A”包括S、N、F、Cl、Br及I中的一种或多种。
当正极活性物质选自式(1)～式(3)所示的化合物时，在充放电循环过程中，上述正极活性物质的Ni含量较高或者工作电压较高，使得正极活性物质颗粒表面与电解液发生副反应的概率增大，更容易发生产气问题。当电解液在电极主体的扩散速率在0.01μg/s～5μg/s时，可以在上述正极材料表面及时形成成膜质量良好的SEI膜，有效改善使用上述正极材料的锂离子电池的产气问题。
在本申请的一些优选实施方式中，正极活性材料可选自LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、LiNi 0.55Co 0.05Mn 0.4O 2、LiNi 0.55Co 0.1Mn 0.35O 2、LiNi 0.55Co 0.12Mn 0.33O 2、LiNi 0.55Co 0.15Mn 0.3O 2、LiNi 0.6Co 0.15Mn 0.25O 2、LiNi 0.6Co 0.18Mn 0.22O 2、LiNi 0.6Co 0.2Mn 0.2O 2(NCM622)、LiNi 0.65Co 0.05Mn 0.3O 2、LiNi 0.65Co 0.09Mn 0.26O 2、LiNi 0.65Co 0.12Mn 0.23O 2、LiNi 0.65Co 0.15Mn 0.2O 2、LiNi 0.8Co 0.1Mn 0.1O 2(NCM811)、LiNi 0.85Co 0.15Al 0.05O 2、LiNi 0.5Mn 1.5O 4、0.2[Li 2MnO 3]·0.8[LiNi 0.5Co 0.2Mn 0.3O 2]、LiNi 0.88Co 0.05Mn 0.07O 2、或0.3[Li 2MnO 3]·0.7[LiNi 0.8Co 0.1Mn 0.1O 2]中的至少一种。
在本申请的一些实施方式中，所述正极材料层还包括导电剂和粘结剂，导电剂和粘结剂的种类没有具体的限制，可根据实际需求进行选择。
本申请的发明人通过研究发现，正极材料层的孔隙率、比表面积以及OI值对电解液的扩散速率也有较大的影响。
在本申请的一些实施方式中，所述正极极片包括正极集流体和涂敷于正极集流体表面的正极材料层，所述正极材料层的孔隙率为10％～50％，优选为20％～40％。正极材料层的孔隙率越大，电解液进入正极极片内部的路径就越多越通畅，使得电解液更快速浸润正极极片。通过将正极材料层的孔隙率限定为10％～50％，既可以使电解液更快更好地浸润正极极片，又可以使电解液的填充量保持合理范围，同时，使电极主体具有较高的体积能量密度和质量能量密度。
在本申请的一些实施方式中，正极材料层的比表面积为0.5m 2/g～1.5m 2/g。正极材料层的比表面积越大，越容易吸收电解液，也能加快电解液在正极极片上的浸润。通过将正极材料层的比表面积设定为0.5m 2/g～1.5m 2/g，同样既可以使电解液迅速浸润正极极片，又能将正极材料层与电解液的接触面积控制在合理范围内，有 效防止电解液与正极极片副反应的发生。例如，正极材料层的比表面积为0.53m 2/g、0.62m 2/g、0.8m 2/g、0.92m 2/g、1m 2/g或1.2m 2/g等。
本申请中，正极材料层的晶粒取向OI值为5～120。作为优选地，正极材料层的OI值为30～70。本申请中，正极材料层的OI值为正极极片的X射线衍射图谱中(003)衍射峰与(110)衍射峰的峰面积之比。正极材料层的OI值可以反映其中层状结构的含锂化合物颗粒的堆积取向程度，正极极片中正极颗粒各晶面的表面能不同，对电解液的亲和力不同。将正极材料层的OI值调整至上述范围内，可以在一定程度上提高电解液与正极极片的浸润性，从而提升电解液在电极主体的扩散速率。例如，正极材料层的OI值为32、37、40、50、62、75、80、90或100等。
本申请中，电解液的粘度为本领域公知的含义，可采用本领域已知的方法进行测试。例如，测试参考标准为GB/T 10247-2008，采用的设备为博勒飞DV2T粘度仪。示例性测试方法如下：首先将电解液样品封口，放入恒温水浴锅中恒温，达到待测温度±0.1℃后开始测试，测试时采用18#转子。
正极材料层的孔隙率为本领域公知的含义，可采用本领域已知的方法进行测试。例如，测试参考标准为GB/T24586-2009，采用的设备为AccuPycⅡ1340，量程为0.1cm 3～3.5cm 3。测试样品制备：将正极极片冲压成直径为1.6cm的圆片，数量大于20片(如30片)，详细记录装样片数和厚度。
正极材料层的比表面积为本领域公知的含义，可采用本领域已知的方法进行测试。例如，测试参考标准为GB/T 19587-2017，采用的设备为TriStarⅡ3020，量程≥0.01m 2/g，加热范围：40℃～350℃。
正极材料层的OI值为正极极片的X射线衍射图谱中(003)衍射峰与(110)衍射峰的峰面积之比。正极极片的X射线衍射图谱可采用本领域已知的方法进行测试。例如，测试参考JIS K 0131-1996，采用的设备是BruKer D8 Discover，极片样品面积不少于30mm*30mm。
层状结构的锂过渡金属氧化物的003晶面所对应的2θ角为17°～20°；层状结构的锂过渡金属氧化物的110晶面所对应的2θ角为63°～67°。
在根据本申请的锂离子电池中，负极片可包括负极集流体以及设置于负极集流体上且含有负极活性材料的负极材料层。所述负极活性材料的种类没有具体的限制，可根据实际需求进行选择。具体地，所述负极活性材料为能够可逆地脱嵌锂的材料， 包括石墨、硅、锡、金属氧化物、硅氧化物、锡氧化物、硅合金、锡合金、硅碳复合物、锡碳复合物、钛酸锂等中的一种或几种。优选地，所述负极活性材料选自天然石墨、人造石墨或二者的混合物。所述负极材料层中还可选地包括导电剂和粘结剂，导电剂和粘结剂的种类没有具体的限制，可根据实际需求进行选择。此外，所述负极极片还可以直接选用金属锂片。
在根据本申请的锂离子电池中，所述隔离膜的材质不受限制，可以根据实际需求进行选择。
本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图2是作为示例的方形结构的锂离子电池10。
锂离子电池10还包括外包装，用于封装电极组件1和电解液(未示出)。
在一些实施例中，锂离子电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。锂离子电池的外包装也可以是软包，例如袋式软包。软包可以是铝塑膜包装或塑料膜包装，其中可包括聚丙烯PP、聚对苯二甲酸丁二醇酯PBT、聚丁二酸丁二醇酯PBS等中的一种或几种。
在一些实施例中，参照图2，外包装可包括壳体2和盖板3。其中，壳体2可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体2具有与容纳腔连通的开口，盖板3能够盖设于所述开口，以封闭所述容纳腔。电极组件1封装于所述容纳腔。
锂离子电池10所含电极组件1的数量可以为一个或几个，可根据需求来调节。
在一些实施例中，锂离子电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图4是作为一个示例的电池模块20。参照图4，在电池模块20中，多个锂离子电池10可以是沿电池模块20的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可通过紧固件将该多个锂离子电池10进行固定。
可选地，电池模块20还可以包括具有容纳空间的外壳，多个锂离子电池10容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图5和图6是作为一个示例的电池包30。参照图5和图6，在电池包30中可以 包括电池箱和设置于电池箱中的多个电池模块20。电池箱包括上箱体31和下箱体32，上箱体31能够盖设于下箱体32，并形成用于容纳电池模块20的封闭空间。多个电池模块20可以按照任意的方式排布于电池箱中。
第二方面，本申请提供了一种包含本申请的锂离子电池的用电设备。所述锂离子电池可以用作所述用电设备的电源，也可以作为所述用电设备的能量存储单元。
在本申请锂离子电池具有高能量密度和高循环性能以及高安全性的情况下，包含本申请锂离子电池的用电设备也具有上述优点，在此不再赘述。
本申请的用电设备例如可以为新能源汽车、电子装置、电动工具和电力储能设施等等。进一步地，所述用电设备可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述用电设备可根据其使用需求来选择锂离子电池、电池模块或电池包。
图7是作为一个示例的用电设备。该用电设备为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电设备对电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
实施例
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
本实施例是一种锂离子电池，其包括由正极极片、隔离膜和负极极片依次卷绕形成的电极主体，分设于所述电极主体两端的正极极耳和负极极耳，具体结构参照图1，以及浸润于所述电极主体的电解液。具体的，本实施例的锂离子电池的制备过程如下：
(1)正极极片的制备
将正极活性材料LiNi 0.8Co 0.1Mn 0.1O 2(NCM811)、导电剂Super P、粘结剂聚偏氟乙烯(PVDF)按照质量比94:3:3进行混合，加入至溶剂N-甲基吡咯烷酮(NMP)中，在真空搅拌机作用下搅拌至体系均一，获得正极浆料，其中正极浆料中的固体含量为77wt％；将正极浆料均匀涂覆于厚度为14μm的正极集流体铝箔上并在85℃下烘干，然后经过冷压、切边、裁片、分条，最后在85℃的真空条件下烘干4h，得到正极极片。
(2)负极极片的制备
将负极活性材料石墨、导电剂Super P、增稠剂羧甲基纤维素钠CMC-Na、粘结剂丁苯橡胶乳液SBR按照质量比94:2:2:2进行混合，加入至溶剂去离子水中，在真空搅拌机作用下获得负极浆料，其中负极浆料中的固体含量为54wt％；将负极浆料均匀涂覆在厚度为8μm的负极集流体铜箔上并在85℃下烘干，然后经过冷压、切边、裁片、分条，最后在120℃的真空条件下烘干12h，得到负极极片。
(3)电解液的制备
在含水量<10ppm的氩气气氛手套箱中，将EC、EMC、EA按质量比30:60:10进行混合作为有机溶剂，接着将充分干燥的锂盐LiPF 6溶解于混合后的有机溶剂中，之后加入添加剂A磷酸三烯丙酯2wt％，混合均匀后获得电解液。
该电解液中，LiPF 6的浓度为1mol/L；
(4)隔离膜的制备
以厚度为16μm的聚乙烯膜PE作为基膜，在PE多孔膜的至少一个表面涂敷含有陶瓷颗粒的涂层，形成隔离膜。
(5)锂离子电池的制备
将正极极片、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之间起到隔离的作用，然后卷绕成方形的电极主体，沿电极主体的长度方向两端焊接极耳，将电极主体装入包装铝塑膜或钢壳中，然后在80℃下烘烤除水后，注入相应的电解液并封口，之后经过静置、热冷压、化成、抽气、整形、容量测试等工序，获得成品锂离子电池。
实施例2-18和对比例1-3
实施例2-18与对比例1-3分别为一种锂离子电池，其与实施例1的不同之处均列于表1。在表1，各溶剂和添加剂A的添加量为基于电解液的总质量计算得到的 质量百分数。其他与实施例1相同。
性能测试
接下来对各实施例和对比例的锂离子电池的性能进行测试。
1)正极极片对电解液的吸液速率γ测试方法
将实施例和对比例所述的正极极片充分干燥，然后裁剪成5cm×5cm的正方形，固定在样品台上。然后挑选直径d＝0.2mm的毛细管吸取实施例和对比例中所述的电解液至一定高度h。将吸有电解液的毛细管跟正极极片垂直接触，毛细管液面下降的同时用秒表计时。当液面下降完毕后，读取吸液时间t。最后根据公式γ＝π×(d/2) 2×h×ρ/t计算得到吸液速率数值，ρ为电解液的密度。
各实施例和对比例的测试结果列于表1。
2)锂离子电池25℃循环性能测试
在25℃下，将实施例和对比例制备得到的新鲜锂离子二次电池搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后搁置5分钟，再以1C倍率恒流放电至2.8V，此为一个充放电循环，此次的放电容量记为锂离子二次电池第1次循环的放电容量。将锂离子电池按照上述方法进行800次循环充放电测试，记录每一次循环的放电容量。各实施例和对比例的测试结果列于表2。
锂离子电池25℃、1C/1C循环400次后的容量保持率(％)＝第800次循环的放电容量/第1次循环的放电容量×100％。
3)锂离子电池的高温存储体积膨胀测试
在25℃下，以1C恒流充电至电压为4.2V，然后以4.2V恒压充电至电流为0.05C，此时测试锂离子电池的体积并记为V 2；然后将满充的锂离子电池放入80℃恒温箱中，存储10天，采用排水法测试体积并记为V 3。
锂离子电池80℃存储10天后的体积膨胀率(％)＝(V 3-V 2)/V 2×100％。
各实施例和对比例的测试结果列于表2。
表1
Figure PCTCN2020090079-appb-000009
表1续
Figure PCTCN2020090079-appb-000010
表2
Figure PCTCN2020090079-appb-000011
在实施例1～18中，通过使用含有添加剂A的电解液并限定电解液在电极主体中的扩散速率在0.01μg/s～5μg/s的范围内，由于该正极钝化膜的成膜质量较高、能 够有效抑制电解液在正极活性物质表面的副反应，同时电解液具有良好浸润性能，可以有效缓解这种高能量密度设计给电解液扩散带来的阻碍，保证在循环过程中添加剂A能及时回补至电极主体内部，快速修复正极活性物质表面被消耗的SEI膜，从而可以使电芯兼顾高能量密度、高的循环容量保持率和较低的体积膨胀率。在实施例1-5中，当电解液在电极主体中的扩散速率在0.2μg/s～2μg/s时，能够进一步优化锂离子电池的能量密度、循环性能以及产气问题。
对比例1中，电解液在电极主体中的扩散速率v要明显小于本申请中限定的扩散速率。从实验数据可以看出，当电解液在电芯中的扩散速率v较小时，达不到有效的浸润速率，因此，会影响锂离子电池的循环性能。
对比例2中，电解液在电极主体中的扩散速率v要明显大于本申请中限定的扩散速率。从实验数据可以看出，当电解液在电芯中的扩散速率v较大时，会降低锂离子电池的循环性能。这是因为电解液中的溶剂(例如碳酸亚乙酯EC)和锂盐会恶化电解液在正极极片上浸润速率，而在电解液中需要一定量的碳酸亚乙酯EC用于解离锂盐，增加电导率，以及需要一定量的锂盐来提供锂离子。电解液的扩散速率太高会影响电解液对锂盐的离解和电导率。
进一步的，从实施例1～18的数据可以看出，正极成膜添加剂A在电解液中质量百分比含量与电解液在电极主体的扩散速率v的相互关系对正极极片的成膜质量及界面阻抗影响较大。当添加剂A在电解液中的质量占比w(％)与所述扩散速率v(μg/s)的乘积在0.01～10时，尤其在0.4～5的范围内时，既可以保证电解液具有较高的浸润速率，也能保证有足够的添加剂A形成稳定的保护膜来抑制产气，同时添加剂A的用量适中，保证锂离子电池的循环性能良好。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (17)

  1. 一种锂离子电池，包括：
    电极组件；以及浸润于所述电极组件的电解液；其中，
    所述电极组件包括电极主体、正极极耳和负极极耳，
    所述电极主体包括围绕轴线卷绕在一起的正极极片、负极极片以及设置在所述正极极片和所述负极极片之间的隔离膜，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的正极材料层，所述正极极耳连接于所述正极极片，所述负极极耳连接于所述负极极片；
    沿所述轴线方向(X)，所述电极主体具有相对设置的两侧部，所述正极极耳和所述负极极耳分别从所述电极主体的两侧部延伸出；
    所述电解液含有添加剂A，所述添加剂A包括含不饱和键的磷酸酯化合物、含-SO 2-键的环状化合物、含不饱和键的环状硅氧烷化合物中的至少一种，所述电解液在所述电极主体中的扩散速率v为0.01μg/s～5μg/s，
    所述v＝γ×H/L，
    所述γ为所述正极极片对所述电解液的吸液速率，单位为μg/s，
    所述H为沿所述电极主体的宽度方向(Z)所述侧部的最大长度，单位为mm，
    所述L为沿所述轴线方向(X)所述电极主体的长度，单位为mm。
  2. 根据权利要求1所述的锂离子电池，其中，所述电解液在所述电极主体中的扩散速率v为0.2μg/s～2μg/s。
  3. 根据权利要求1或2所述的锂离子电池，其中，所述H与所述L满足：0.05≤H/L≤0.8，优选地，0.1≤H/L≤0.6，更优选地，0.15≤H/L≤0.5。
  4. 根据权利要求1～3任一项所述的锂离子电池，其中，所述电极主体的轴线方向(X)为水平方向。
  5. 根据权利要求1～4任一项所述的锂离子电池，其中，所述添加剂A在所述电解液中的质量占比w(％)与所述扩散速率v(μg/s)满足：0.1≤w×v≤10，优选地，0.4≤w×v≤5。
  6. 根据权利要求1～5任一项所述的锂离子电池，其中，所述含不饱和键的磷酸酯化合物为式1化合物中的至少一种，
    Figure PCTCN2020090079-appb-100001
    其中，R 1、R 2和R 3分别独立地选自碳原子数为1～6的烷基、烯基、炔基、卤代烷基、卤代烯基、卤代炔基、碳原子数为6～10的芳基或卤代芳基中的一种，并且R 1、R 2和R 3中的至少一个含有双键或三键；
    优选地，所述含磷氧键化合物的R 1、R 2和R 3至少一个支链的末端为碳碳不饱和键；
    更优选地，所述含磷氧键化合物的R 1、R 2和R 3支链末端全部为碳碳不饱和键。
  7. 根据权利要求1～5任一项所述的锂离子电池，其中，所述含-SO 2-键的环状化合物包括式2～式5化合物中的至少一种，
    Figure PCTCN2020090079-appb-100002
    其中，R 4选自碳原子数为1～4的亚烷基、碳原子数为1～4的氟代亚烷基、碳原子数为2～4的亚烯基、碳原子数为2～4的氟代亚烯基、碳原子数为6～14的亚芳基、碳原子数为6～10的氟代亚芳基中的一种；
    R 5、R 6、R 7和R 8分别独立地为H、碳原子数为1～6的烷基、烯基、炔基、卤代烷基、卤代烯基、卤代炔基、碳原子数为6～10的芳基或卤代芳基中的一种，n是1、2或3；
    R 17和R 18分别独立地选自碳原子数为1～4的亚烷基、碳原子数为1～4的氟代亚烷基、碳原子数为2～4的亚烯基、碳原子数为2～4的氟代亚烯基、碳原子数为6～14的亚芳基、碳原子数为6～10的氟代亚芳基中的一种。
  8. 根据权利要求1～5任一项所述的锂离子电池，其中，所述含不饱和键的环 状硅氧烷化合物包括式6化合物中的至少一种，
    Figure PCTCN2020090079-appb-100003
    式6中，R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16各自独立地选自取代或未取代的碳原子数为1～4的烃基，且R 9、R 10、R 11、R 12、R 13、R 14、R 15、R 16中的至少一个含有双键或三键，所述取代的取代基团为卤族元素。
  9. 根据权利要求1～8任一项所述的锂离子电池，其中，所述添加剂A选自1,3-丙烷磺内酯、丙烯磺酸内酯、甲烷二磺酸亚甲酯、磷酸三烯丙酯、四甲基四乙烯基环四硅氧烷中的至少一种；
    优选地，所述添加剂A选自甲烷二磺酸亚甲酯、磷酸三烯丙酯和四甲基四乙烯基环四硅氧烷中的至少一种。
  10. 根据权利要求1～9任一项所述的锂离子电池，其中，所述电解液在25±3℃下的粘度为0.5mPa·s～5.0mPa·s；和/或，
    所述电解液在0℃下的粘度为1mPa·s～6.0mPa·s。
  11. 根据权利要求1～10任一项所述的锂离子电池，其中，所述电解液中包括低粘度溶剂，所述低粘度溶剂在25±3℃下的粘度不高于0.65mPa·s，
    优选地，所述低粘度溶剂选自碳酸二甲酯DMC、甲酸甲酯MF、甲酸乙酯EF、乙酸甲酯MA、乙酸乙酯EA、丙酸乙酯EP、丁酸乙酯EB、四氢呋喃THF、2甲基四氢呋喃、二氧戊环DOL、1,2-二甲氧基乙烷DME、乙腈AN、甲基九氟丁醚MFE和乙基九氟丁醚EFE中的至少一种；
    更优选地，所述低粘度溶剂在所述电解液中的质量分数为10％～80％。
  12. 根据权利要求1～11任一项所述的锂离子电池，其中，所述电解液中含有浸润剂，所述浸润剂优选包括1,1,2,2-四氟乙基-2,2,3,3四氟丙基醚、1H,1H,5H-八氟戊基-1,1,2,2四氟乙基醚和1,1,2,2-四氟乙基-2,2,2-三氟乙基醚中的至少一种；
    优选地，所述浸润剂在电解液中的质量分数为0.1％～10％。
  13. 根据权利要求1～12任一项所述的锂离子电池，其中，所述正极材料层的 孔隙率为10％～50％，优选为20％～40％。
  14. 根据权利要求1～13任一项所述的锂离子电池，其中，所述正极材料层的比表面积为0.5m 2/g～1.5m 2/g。
  15. 根据权利要求1～14任一项所述的锂离子电池，其中，所述正极材料层的晶粒取向OI值为5～120，优选地，所述OI值为30～70。
  16. 根据权利要求1～15任一项所述的锂离子电池，其中，所述正极材料层中含有正极活性物质，所述正极活性物质包含式(1)～式(3)所示的化合物中的至少一种：
    Li 1+xNi aCo bM 1-a-bO 2-yA y                    式(1)
    Li 1+x’Ni a’M’ 2-a’O 4-y’A’ y’                      式(2)
    c[Li 2MnO 3]·(1-c)[LiM” 2O 2-y”A” y”]        式(3)
    式(1)中，-0.1≤x≤0.2，0.5≤a<1，0.02<b<0.3，0.55<a+b<1，0≤y<0.2，M包括Mn、Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种，A包括S、N、F、Cl、Br及I中的一种或多种，
    式(2)中，-0.1≤x’≤0.2，0.4≤a’<0.6，0≤y’<0.2，M’包括Mn、或者Mn以及Fe、Cr、Ti、Zn、V、Al、Zr、Mg、Ce中的一种或多种，A’包括S、N、F、Cl、Br及I中的一种或多种，
    式(3)中，0<c<1，0≤y’<0.2，M”为Ni、Co和Mn，或者Ni、Co和Mn以及Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种，A”包括S、N、F、Cl、Br及I中的一种或多种。
  17. 一种用电设备，包括权利要求1～16任一项所述的锂离子电池。
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