WO2020063889A1 - 非水电解液、锂离子电池、电池模块、电池包及装置 - Google Patents
非水电解液、锂离子电池、电池模块、电池包及装置 Download PDFInfo
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- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
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- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
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- H01M2300/0037—Mixture of solvents
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- 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
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- 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
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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
Definitions
- the present application relates to the field of batteries, and in particular, to a non-aqueous electrolyte, a lithium ion battery, a battery module, a battery pack, and a device.
- Lithium-ion batteries are widely used in electric vehicles and consumer electronics due to their advantages such as high energy density, high output power, long cycle life, and low environmental pollution.
- the current requirements for lithium-ion batteries are: high voltage, high power, long cycle life, long storage life, and excellent safety performance.
- Non-aqueous electrolyte systems using lithium hexafluorophosphate as a conductive lithium salt and cyclic carbonate and / or chain carbonate as a solvent are widely used in lithium ion batteries.
- the above non-aqueous electrolytes still have many shortcomings.
- the above-mentioned non-aqueous electrolytes need to be improved in cycle performance, storage performance, and safety performance.
- the safety performance of the overcharge safety of the ion battery and the safety of the hot box also needs to be improved.
- the object of the present application is to provide a non-aqueous electrolyte, a lithium ion battery, a battery module, a battery pack, and a device, which can both improve the electrochemical performance and improve the lithium ion battery's electrochemical performance at high temperature and high voltage.
- Lithium-ion battery has over-charge safety, hot box safety and other safety performance, and can guarantee the lithium-ion battery has certain dynamic performance.
- the present application provides a non-aqueous electrolyte including a non-aqueous solvent, a lithium salt, and an additive, wherein the non-aqueous solvent is a high-oxidation potential type solvent, and the additive Including cyclic sulfates.
- the high oxidation potential-based solvent is selected from one or more of the compounds represented by Formula I and Formula II
- the cyclic sulfate is selected from one or more of the compounds represented by Formula III.
- R 1 and R 2 are independently selected from unsubstituted, partially halogenated or fully halogenated alkyl groups having 1 to 5 carbon atoms, and at least one of R 1 and R 2 is partially halogenated Or all halogenated alkyl groups having 1 to 5 carbon atoms; in formula II, R 3 is selected from partially halogenated or fully halogenated alkyl groups having 1 to 6 carbon atoms; in formula III, R 4 is selected from unsubstituted, partially halogenated or fully halogenated alkylene groups having 1 to 6 carbon atoms.
- the halogen atom is selected from one or more of F, Cl, Br, and I.
- the present application provides a lithium ion battery including a positive electrode sheet, a negative electrode sheet, a separator, and a non-aqueous electrolyte solution according to the first aspect of the present application.
- the present application provides a battery module including the lithium ion battery described in the second aspect of the present application.
- the present application provides a battery pack including the battery module described in the third aspect of the present application.
- the present application provides a device including the lithium ion battery according to the second aspect of the present application, and the lithium ion battery is used as a power source of the device.
- the non-aqueous electrolyte of the present application uses a high oxidation potential type solvent instead of the conventional carbonate type solvent, which can overcome the shortcomings of the conventional carbonate type solvent, such as poor oxidation resistance, easy high-pressure decomposition gas production, low flash point, and easy burning.
- the non-aqueous electrolyte of the present application can greatly improve the safety performance of lithium-ion batteries such as overcharge safety and hot box safety;
- the non-aqueous electrolyte of the present application further contains an additive cyclic sulfate, which can preferentially form a stable interface protective film on the negative electrode, and suppress the side reaction of the high oxidation potential type solvent on the negative electrode.
- the additive cyclic sulfate During the formation of the negative electrode, a lithium sulfate salt containing an alkoxy structure (-CH 2 CH 2 O-) in the structure can be formed, which can adjust the viscoelasticity of the negative electrode interface protection film and improve the lithium ion interface transfer kinetics.
- the cyclic sulfate can also form a stable interface protective film on the surface of the positive electrode, further improving the oxidation resistance of the non-aqueous electrolyte, so it is also helpful to improve the overcharge safety and hot box of the lithium ion battery to a certain extent.
- Safety performance such as safety.
- the battery module, battery pack, and device of the present application include the lithium-ion battery described above, and thus have at least the same advantages as the lithium-ion battery.
- FIG. 1 is a perspective view of an embodiment of a lithium ion battery.
- FIG. 2 is an exploded view of FIG. 1.
- FIG. 3 is a schematic diagram of an embodiment of the electrode assembly of the lithium ion battery of FIG. 2, in which a first electrode sheet, a second electrode sheet, and a separator are wound to form a wound electrode assembly.
- FIG. 4 is a schematic diagram of another embodiment of the electrode assembly of the lithium ion battery of FIG. 2, in which a first electrode sheet, a second electrode sheet, and a separator are laminated in a thickness direction to form a laminated electrode assembly.
- FIG. 5 is a perspective view of an embodiment of a battery module.
- FIG. 6 is a perspective view of an embodiment of a battery pack.
- FIG. 7 is an exploded view of FIG. 6.
- FIG. 8 is a schematic diagram of an embodiment of a device using a lithium ion battery as a power source.
- non-aqueous electrolyte, lithium ion battery, battery module, battery pack and device will be described in detail below.
- the non-aqueous electrolyte according to the first aspect of the present application which includes a non-aqueous solvent, a lithium salt, and an additive
- the non-aqueous solvent is a high oxidation potential type solvent
- the additive includes a cyclic sulfate.
- the high oxidation potential solvent is selected from one or more of the compounds represented by Formula I and Formula II.
- R 1 and R 2 are independently selected from unsubstituted, partially halogenated or fully halogenated alkyl groups having 1 to 5 carbon atoms, and at least one of R 1 and R 2 is partially halogenated Or all halogenated alkyl groups having 1 to 5 carbon atoms; in Formula II, R 3 is selected from partially or fully halogenated alkyl groups having 1 to 6 carbon atoms.
- the cyclic sulfate is selected from one or more of the compounds represented by Formula III.
- R 4 is selected from unsubstituted, partially halogenated or fully halogenated alkylene groups having 1 to 6 carbon atoms.
- the halogen atom is selected from one or more of F, Cl, Br, and I, preferably F; the alkyl group and the alkylene group may have a linear structure, and It may be a branched structure; when an alkyl group or an alkylene group is partially halogenated or fully halogenated, the specific type of the halogen atom may be one or more.
- carbonate-based solvents are often used in lithium ion battery electrolytes. These solvents have poor oxidation resistance. At room temperature (25 ° C), a slight oxidation occurs at about 4V. As the voltage and temperature increase, the oxidation of these solvents becomes more and more obvious. At the same time, these solvents have a low flash point (generally below 35 ° C), are easy to burn when exposed to open flames, and have a large amount of heat. Therefore, lithium ion batteries using conventional carbonate-based solvents have a high potential danger in terms of safety performance.
- a high oxidation potential solvent is used instead of a conventional carbonate solvent.
- the high oxidation potential solvent has the advantages of high oxidation resistance and non-flammability, and can overcome the poor oxidation resistance of conventional carbonate solvents. Disadvantages such as easy high-pressure decomposition gas production, low flash point, and easy burning, so that the non-aqueous electrolyte of the present application can greatly improve the safety performance of lithium-ion batteries such as overcharge safety and hot box safety.
- high oxidation potential solvents have the advantages of high oxidation resistance and non-combustibility, they have poor compatibility with the negative electrode, and side reactions occur at the negative electrode.
- the viscosity of the high oxidation potential solvents is greater than that of conventional carbonate solvents, and the use is high.
- the oxidation potential solvent replaces the conventional carbonate solvent, the overall viscosity of the non-aqueous electrolyte is higher, the conductivity is lowered, and the kinetic performance of the lithium ion battery is significantly deteriorated.
- the additive cyclic sulfate can preferentially form a stable interface protective film on the negative electrode, and suppress the side reaction of high oxidation potential solvents in the negative electrode.
- the additive cyclic sulfate can generate alkoxy groups in the structure during the negative electrode film formation Lithium sulfate salt based on the base structure (-CH 2 CH 2 O-), which can well adjust the viscoelasticity of the negative electrode interface protective film, improve the kinetics of lithium ion interface transfer, and finally form a thin and dense lithium ion on the negative electrode and have good kinetics of lithium ion migration Interface protective film. Therefore, the additive cyclic sulfate can well make up for the defects of high oxidation potential solvents with high viscosity and poor compatibility with the negative electrode, and help to obtain lithium ion batteries with good kinetic and electrochemical performance.
- cyclic sulfates can also form a stable interface protection film on the surface of the positive electrode, which further improves the oxidation resistance of the non-aqueous electrolyte. Therefore, it also helps to improve the safety of lithium-ion batteries such as overcharge safety and hot box safety performance.
- the high oxidation potential type solvent contains at least one F atom, and the presence of the F atom can better improve the oxidation resistance and flame retardancy of the high oxidation potential type solvent.
- R 1 and R 2 are independently selected from unsubstituted, partially fluorinated or fully fluorinated alkyl groups having 1 to 5 carbon atoms, and At least one of R 1 and R 2 is a partially fluorinated or fully fluorinated alkyl group having 1 to 5 carbon atoms; more preferably, R 1 and R 2 are independently selected from -CH 3 , -CF 3 , -CH 2 CH 3 , -CF 2 CH 3 , -CH 2 CF 3 , -CF 2 CF 3 , -CH 2 CH 2 CH 3 , -CF 2 CH 2 CH 3 , -CH 2 CH 2 CF 3 , -CH 2 CH 2 CF 3 , -CH 2 CF 2 CF 3 , -CF 2 CH 2 CF 3 , -CF 2 CF 2 CH 3 , -CF 2 CF 2 CH 3 , -CF 2 CF 2 CF 3 , and at least one of R 1 and R 2 is -CF 3 , -
- R 3 is selected from a partially fluorinated or fully fluorinated carbon atom having 1 to 6 carbon atoms; more preferably, R 3 is selected from -CHFCH 2 CH 2 CH 2 -, - CF 2 CH 2 CH 2 CH 2 -, - CF 2 CH 2 CH 2 CHF -, - CF 2 CH 2 CH 2 CF 2 -, - CH 2 CH 2 CHFCH 2 -, -CH 2 CHFCHFCH 2- , -CH 2 CH 2 CH (CF 3 ) CH 2- , -CF 2 CH 2 CH 2 CH 2- , -CF 2 CH 2 CH 2 CH 2 CF 2- , -CH 2 CH 2 CH 2 CHFCH 2 -, - CH 2 CHFCH 2 CHFCH 2 -, - CH 2 CHFCH 2 CHFCHF -, - CH 2 CH 2 CH 2 CH 2 CHF -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH
- the viscosity of the high-oxidation potential-based solvent is also generally large, and the conductivity of the non-aqueous electrolytic solution as a whole is large. The rate may decrease, which will affect the improvement of the electrochemical performance of lithium ion battery dynamic performance and cycle life.
- R 1 and R 2 are independently selected from unsubstituted, partially halogenated or all halogenated alkyl groups having 1 to 3 carbon atoms, and at least one of R 1 and R 2 is partially halogenated or all A halogenated alkyl group having 1 to 3 carbon atoms; more preferably, R 1 and R 2 are independently selected from unsubstituted, partially fluorinated or fully fluorinated alkyl groups having 1 to 3 carbon atoms, and At least one of R 1 and R 2 is a partially fluorinated or fully fluorinated alkyl group having 1 to 3 carbon atoms.
- R 3 is selected from carbon atoms, partially halogenated or fully halogenated alkylene group having 1 to 4; carbon atoms, more preferably, R 3 is selected from partially fluorinated or fully fluorinated 1 to 4 Alkylene.
- the high oxidation potential-based solvent may be specifically selected from one or more of the following compounds:
- the high oxidation potential-based solvent is selected from one or more of the compounds represented by Formula I and Formula II.
- the compound represented by formula I has a relatively low viscosity and a relatively low dielectric constant
- the compound represented by formula II has a relatively high viscosity and a relatively high dielectric constant Characteristics. Therefore, preferably, the high oxidation potential-based solvent includes both the compound represented by Formula I and the compound represented by Formula II; more preferably, the high oxidation potential-based solvent may include only the compound represented by Formula I.
- the weight of the compound represented by Formula I accounts for 30% to 100% of the total weight of the high oxidation potential-based solvent, and the weight of the compound represented by Formula II accounts for the high 0% to 70% of the total weight of the oxidation potential solvent.
- R 4 is selected from unsubstituted, partially fluorinated or fully fluorinated alkylene groups having 1 to 6 carbon atoms; more preferably, R 4 4 is selected from unsubstituted, partially fluorinated or fully fluorinated alkylene groups having 2 to 4 carbon atoms.
- the cyclic sulfate may be specifically selected from one or more of the following compounds and their fluorinated compounds:
- the cyclic sulfate is
- the weight percentage content of the cyclic sulfate is 0.1% to 10%; more preferably, the weight percentage content of the cyclic sulfate is 0.5% ⁇ 5%.
- the specific type of the lithium salt is not specifically limited, and may be any lithium salt used in existing batteries.
- the lithium salt may be specifically selected from LiPF 6 and LiN ( CF 3 SO 2 ) 2 , LiN (FSO 2 ) 2 (LiFSI), LiBF 4 , LiCF 3 SO 3 , LiClO 4 .
- the lithium salt is a mixed lithium salt composed of LiPF 6 and LiN (FSO 2 ) 2 .
- LiN (FSO 2 ) 2 has the advantages of moderate viscosity and high dissociation degree. It can promote ion conduction, improve the conductivity of non-aqueous electrolyte, and help to obtain lithium ion batteries with good dynamic performance.
- LiN (FSO 2 ) The thermal stability of 2 is high, so it can also improve the safety performance of lithium-ion batteries such as overcharge safety and hot box safety.
- the weight ratio of LiPF 6 to LiN (FSO 2 ) 2 is from 10: 1 to 1:10; more preferably, the weight ratio of LiPF 6 to LiN (FSO 2 ) 2 is from 4: 1 to 1: 4.
- the specific concentration of the lithium salt is not specifically limited, and can be adjusted according to actual needs.
- the concentration of the lithium salt may be specifically 0.7 mol / L to 2 mol / L.
- the non-aqueous electrolyte may further include other film-forming additives, and these film-forming additives help to further form an interface protective film with excellent performance on the negative electrode and the positive electrode, thereby further improving Lithium-ion battery's dynamic performance and electrochemical performance such as cycle life and storage life.
- the weight content of these film-forming additives is 0.01% to 10%; more preferably, based on the total weight of the non-aqueous electrolyte, the weight content of these film-forming additives is It is 0.1% to 5%.
- these film-forming additives may be specifically selected from a cyclic carbonate compound having an unsaturated bond, a halogen-substituted cyclic carbonate compound, a sulfite compound, a sultone compound, a disulfonate compound, and a nitrile compound ,
- a cyclic carbonate compound having an unsaturated bond a halogen-substituted cyclic carbonate compound, a sulfite compound, a sultone compound, a disulfonate compound, and a nitrile compound
- aromatic compounds isocyanate compounds, phosphazene compounds, cyclic acid anhydride compounds, phosphite compounds, phosphate compounds, borate compounds, and carboxylic acid ester compounds.
- these film-forming additives may be specifically selected from vinylene carbonate (VC), fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), 1,3-propane sultone (PS) Or several of 1,3-propene sultone (PES), adiponitrile (ADN), and succinonitrile (SN), these film-forming additives help to form a stable anode and cathode
- the interfacial protective film can effectively suppress the side reactions of high-oxidation potential solvents on the negative electrode and the positive electrode, which can better improve the dynamic performance of lithium-ion batteries, and electrochemical performance such as cycle life and storage life. More preferably, these film-forming additives include at least FEC.
- FEC can reduce the formation of a stable interface protective film on the negative electrode and reduce the reduction reaction of the cyclic sulfate on the negative electrode. This can help to improve the film formation quality of the cyclic sulfate on the surface of the positive electrode, and further improve the lithium. Cycle life of ion batteries.
- FIG. 1 is a perspective view of one embodiment of a lithium ion battery 5.
- FIG. 2 is an exploded view of FIG. 1.
- FIG. 3 is a schematic diagram of an embodiment of the electrode assembly 52 of the lithium ion battery 5 in FIG. 2, in which the first electrode piece 521, the second electrode piece 522, and the separator 523 are wound to form a wound electrode assembly.
- FIG. 4 is a schematic diagram of another embodiment of the electrode assembly 52 of the lithium-ion battery 5 in FIG. 2, in which the first electrode piece 521, the second electrode piece 522, and the separator 523 are stacked in a thickness direction to form a laminated electrode assembly.
- the lithium ion battery 5 includes a case 51, an electrode assembly 52, a top cover assembly 53, and an electrolyte (not shown).
- the electrode assembly 52 is housed in the case 51.
- the electrode assembly 52 includes a first pole piece 521, a second pole piece 522, a separation film 523, a first pole tab 524, and a second pole tab 525.
- the isolation film 523 separates the first pole piece 521 and the second pole piece 522.
- the first pole piece 521 includes a first current collector 521a and a first active material layer 521b disposed on a surface of the first current collector 521a.
- the first active material layer 521b contains a first active material.
- the first active material layer 521b may be disposed on one surface or both surfaces of the first current collector 521a according to actual needs.
- the second pole piece 522 includes a second current collector 522a and a second active material layer 522b disposed on a surface of the second current collector 522a.
- the second active material layer 522b may be disposed on one surface or both surfaces of the second current collector 522a according to actual needs.
- the second active material layer 522b contains a second active material. Deintercalation of lithium ions from the first active material and the second active material.
- the first pole piece 521 and the second pole piece 522 are electrically opposite, that is, one of the first pole piece 521 and the second pole piece 522 is a positive pole piece and the other of the first pole piece 521 and the second pole piece 522 It is the negative pole piece.
- the first tab 524 may be formed by cutting the first current collector 521a or formed separately and fixedly connected to the first current collector 521a.
- the second tab 525 may be formed by cutting the second current collector 522a or separately formed and fixedly connected to the second current collector 522a.
- the number of the electrode assemblies 52 is not limited, and may be one or more.
- the electrolyte is injected into the case 51 and impregnates the electrode assembly 51, specifically, the first electrode piece 521, the second electrode piece 522, and the separator 523.
- the lithium-ion battery 5 shown in FIG. 1 is a can-type battery, but is not limited thereto.
- the lithium-ion battery 5 may be a pouch-type battery, that is, the case 51 is replaced by a metal plastic film and the top cover component 53 is eliminated.
- the current collector of the positive pole piece is a positive electrode current collector
- the active material layer of the positive pole piece is a positive electrode active material.
- the active material of the positive electrode sheet is a positive electrode active material. Therefore, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector.
- the lithium ion battery of the third aspect of the present application includes a positive electrode sheet, a negative electrode sheet, a separator, and the non-aqueous electrolyte solution according to the first aspect of the present application as the foregoing electrolyte solution.
- the positive electrode sheet may include a positive electrode active material, a conductive agent, and a binder.
- the positive electrode active material may be selected from a layered lithium-containing oxide, a spinel-type lithium-containing oxide, and the like.
- the positive electrode active material may be selected from one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or Several.
- the present application is not limited to these materials, and other conventionally known materials that can be used as a positive electrode active material of a lithium ion battery can also be used.
- These positive electrode active materials may be used alone, or two or more of them may be used in combination, and the combination ratio may be reasonably adjusted according to actual needs.
- the types of the conductive agent and the binder are not specifically limited, and can be selected according to actual needs.
- the lithium-ion battery When the voltage of a lithium-ion battery is high, the lithium-ion battery can have a higher charge and discharge capacity and energy density, but the conventional electrolyte will be oxidized to generate gas and emit heat, and the life and high-temperature performance of the lithium-ion battery will change. Poor, especially during abuse, such as in a 150 ° C hot box, lithium-ion batteries can easily burn.
- the non-aqueous electrolyte of the present application contains a high oxidation potential type solvent, which can greatly improve the oxidation resistance of the non-aqueous electrolyte and reduce the exothermic heat, so that the high temperature performance of the lithium ion battery can be improved.
- non-aqueous electrolyte is more effective for improving the battery system with high positive electrode oxidation or high positive electrode oxidation potential, especially the improvement of electrochemical performance under high temperature and high voltage of lithium ion battery.
- the gas production can be more significantly suppressed, and the safety performance of lithium-ion batteries such as overcharge safety and hot box safety can also be more significantly improved.
- the positive electrode active material is Li 1 + x Ni a Co b M ′ (1-ab) O 2-c Y c , Li 1 + y Ni m Mn n M ′′ 2-mn O 4-p Z p One or more of them, wherein -0.1 ⁇ x ⁇ 0.2, 0.6 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1, 0 ⁇ (1-ab) ⁇ 1, 0 ⁇ c ⁇ 1, and M ′ is selected from Mn , Al, Mg, Zn, Ga, Ba, Fe, Cr, Sn, V, Sc, Ti, Zr one or more, Y is selected from one or more of F, Cl, Br; -0.1 ⁇ y ⁇ 0.2, 0.4 ⁇ m ⁇ 1.2, 0.8 ⁇ n ⁇ 1.6, 0 ⁇ (2-mn) ⁇ 0.3, 0 ⁇ p ⁇ 1, M ′′ is selected from Al, Mg, Zn, Ga, Ba, Fe, Cr Or Sn, V, Sc, Ti, or Zr, and Z is selected from one or more of F, Cl,
- the positive electrode active material may be specifically selected from one of LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.85 Co 0.15 Al 0.05 O 2 , and LiNi 0.5 Mn 1.5 O 4 Or several.
- the content of Ni in the positive electrode active material increases, but the thermal stability of the positive electrode active material decreases, and substances with strong oxidizing properties are released at high temperatures, oxidizing non-aqueous electrolytes and deteriorating High temperature performance.
- the non-aqueous electrolyte of the present application contains an oxidation-resistant high oxidation potential-based solvent, which can greatly improve the oxidation resistance of the non-aqueous electrolyte and reduce the amount of heat generation, thereby improving the high temperature performance of the lithium ion battery.
- the cut-off voltage of the lithium-ion battery is U, and 4.3V ⁇ U ⁇ 6V. That is, the non-aqueous electrolyte of the present application can increase the charge cut-off voltage of the lithium ion battery to more than 4.3V.
- the negative electrode sheet may include a negative electrode active material, a conductive agent, and a binder.
- the anode active material may be selected from a carbon-based material, a silicon-based material, a tin-based material, and the like.
- the negative electrode active material may be preferably selected from soft carbon, hard carbon, artificial graphite, natural graphite, silicon, silicon oxide compound, silicon carbon composite, silicon alloy, tin, tin oxide compound, tin alloy, lithium titanate , Metals capable of forming alloys with lithium, etc.
- the present application is not limited to these materials, and other conventionally known materials that can be used as a negative electrode active material of a lithium ion battery can also be used.
- These negative electrode active materials may be used alone or in combination of two or more. The combination ratio may be reasonably adjusted according to actual needs.
- the types of the conductive agent and the binder are not specifically limited, and can be selected according to actual needs.
- the specific type of the separator is not specifically limited, and may be any separator material used in existing batteries, such as a polyolefin separator, a ceramic separator, and the like.
- the separator may be preferably polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer composite film thereof, but the present application is not limited to these.
- FIG. 5 is a perspective view of an embodiment of the battery module 4.
- the battery module 4 provided in the third aspect of the present application includes the lithium ion battery 5 described in the second aspect of the present application.
- the battery module 4 includes a plurality of lithium-ion batteries 5.
- a plurality of lithium ion batteries 5 are arranged in the longitudinal direction.
- the battery module 4 can be used as a power source or an energy storage device.
- the number of lithium-ion batteries 5 in the battery module 4 can be adjusted according to the application and capacity of the battery module 4.
- FIG. 6 is a perspective view of an embodiment of the battery pack 1.
- FIG. 7 is an exploded view of FIG. 6.
- the battery pack 1 provided in the fourth aspect of the present application includes the battery module 4 described in the third aspect of the present application.
- the battery pack 1 includes an upper case 2, a lower case 3, and a battery module 4.
- the upper case 2 and the lower case 3 are assembled together to form a space for accommodating the battery module 4.
- the battery module 4 is placed in the space of the upper case 2 and the lower case 3 assembled together.
- the output electrode of the battery module 4 is penetrated from one or both of the upper case 2 and the lower case 3 to supply power to the outside or charge from the outside.
- the number and arrangement of the battery modules 4 used in the battery pack 1 can be determined according to actual needs.
- FIG. 8 is a schematic diagram of an embodiment of a device using a lithium ion battery as a power source.
- the device provided by the fifth aspect of the present application includes the lithium ion battery 5 described in the second aspect of the present application, and the lithium ion battery 5 can be used as a power source of the device.
- the device using the lithium ion battery 5 is an electric vehicle.
- the device using the lithium ion battery 5 may be any electric vehicle (e.g., electric bus, electric tram, electric bicycle, electric motorcycle, electric scooter, electric golf cart, electric truck) ), Electric ships, electric tools, electronic equipment and energy storage systems.
- the electric vehicle may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
- the device provided in the fifth aspect of the present application may include the battery module 4 described in the third aspect of the present application.
- the device provided in the fifth aspect of the present application may also include the device provided in the fourth aspect of the present application. Mentioned battery pack 1.
- Compound A1 was used as a non-aqueous solvent, and then 1 mol / L of LiPF 6 was dissolved as a lithium salt, and then 0.1% DTD was added to configure a non-aqueous electrolyte.
- the positive electrode active material LiNi 0.5 Mn 1.5 O 4 , the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) were thoroughly stirred and mixed in a N-methylpyrrolidone solvent system at a weight ratio of 94: 3: 3. Covered with current collector Al foil, dried and cold-pressed to obtain a positive electrode sheet.
- conductive agent acetylene black, binder styrene-butadiene rubber, thickener sodium carboxymethyl cellulose are thoroughly mixed in a deionized water solvent system at a weight ratio of 95: 2: 2: 1 and mixed well , Coated on a current collector Cu foil, dried and cold-pressed to obtain a negative electrode sheet.
- a polyethylene film is selected as the insulation film.
- the positive electrode sheet, the separator film, and the negative electrode sheet are stacked in order, so that the separator film acts as a separator between the positive and negative electrode sheets, and then wound to obtain an electrode assembly; the electrode assembly is placed in an outer casing.
- the non-aqueous electrolyte is injected, and after the steps of vacuum encapsulation, standing, forming, and shaping, a lithium ion battery is obtained.
- the lithium ion batteries of Examples 2 to 25 and Comparative Examples 1 to 7 were prepared according to a method similar to that of Example 1. The specific differences are shown in Table 1.
- the thermal shock safety performance of a lithium-ion battery is characterized by the baking time (h2-h1) of the lithium-ion battery at 150 ° C.
- lithium ion batteries prepared in the examples and comparative examples were each taken, and the lithium ion batteries were repeatedly charged and discharged through the following steps, and the discharge capacity retention rate of the lithium ion batteries was calculated.
- the cycle capacity retention rate of the lithium-ion battery (discharge capacity at the 500th cycle / discharge capacity at the first cycle) ⁇ 100%.
- the ratio of the discharge capacity of the lithium ion battery at 2C rate to the discharge capacity of 0.5C rate was used to characterize the kinetic performance of the lithium ion battery.
- Comparative Example 1 uses a conventional carbonate-based solvent in combination with the additive DTD, and the performance of the lithium ion battery is poor in all aspects, especially the hot box of the lithium ion battery.
- the safety performance is very poor.
- Lithium-ion batteries emit smoke and fire during heating (about 120 ° C); when a high oxidation potential solvent is used instead of a conventional carbonate solvent and the additive is used with a cyclic sulfate , Can significantly improve the high-temperature storage performance and hot box safety performance of lithium-ion batteries. This is because high oxidation potential solvents have the advantages of high oxidation resistance and non-combustibility.
- Comparative Example 2 only uses a high oxidation potential type solvent but does not use the additive DTD. Due to the high viscosity of the high oxidation potential type solvent, non-aqueous electrolysis is caused. The overall viscosity of the liquid is high and the conductivity is low, and the cycle performance and dynamic performance of the lithium ion battery are significantly deteriorated.
- the addition of DTD can significantly improve the cycling performance and high-temperature storage performance of lithium-ion batteries, and at the same time significantly improve the dynamic performance of lithium-ion batteries. This is because DTD can preferentially form a stable interface protective film on the negative electrode, and suppress the side reaction of high oxidation potential solvents in the negative electrode.
- DTD can generate alkoxy-containing structures (-CH 2
- the lithium sulfate salt of CH 2 O-) can well adjust the viscoelasticity of the negative electrode interface protective film, improve the lithium ion interface transfer kinetics, and finally form a thin and dense interface protective film with good lithium ion migration kinetics on the negative electrode. It can make up for the defects of high-viscosity potential solvents with high viscosity and poor compatibility with the negative electrode, so it also helps to obtain lithium-ion batteries with good high-temperature storage performance, dynamic performance and cycle performance.
- the cyclic sulfate can also form a stable interface protection film on the surface of the positive electrode, which further improves the oxidation resistance of the non-aqueous electrolyte, and therefore also helps to improve the safety performance of the hot box of the lithium ion battery to a certain extent.
- the amount of DTD added is preferably 0.1% to 10%.
- the high oxidation potential type solvents with different structures also have a certain effect on the performance of the lithium ion battery.
- the high-oxidation potential-based solvent having a ring structure has a relatively high viscosity and a relatively high dielectric constant
- the high-oxidation potential-based solvent having a chain structure has a relatively low viscosity and a relatively low dielectric constant. characteristic.
- the high oxidation potential-based solvent includes both a high-oxidation potential-based solvent having a chain structure and a high-oxidation potential-based solvent having a cyclic structure; more preferably, the high-oxidation potential-based solvent includes only a chain structure High oxidation potential solvents.
- LiFSI has the advantages of moderate viscosity and high dissociation degree, which can promote ion conduction, improve the conductivity of non-aqueous electrolyte, and help to obtain lithium ion batteries with good dynamic performance, and the thermal stability of LiFSI Higher, so it also has a certain improvement on the safety performance of the hot box of the lithium-ion battery.
- the cycle life improvement of lithium ion batteries is the most significant.
- FEC can reduce the formation of a stable interface protective film on the negative electrode, and reduce the reduction reaction of DTD on the negative electrode, which can help improve the quality of DTD film formation on the positive electrode surface, and then further add FEC to the lithium ion battery cycle.
- the improvement in life span is the most significant.
- Adding PS, VC, FEC, and ADN directly to the non-aqueous electrolyte that does not contain DTD can also improve the performance of lithium ion batteries to a certain extent, but the improvement effect of these film-forming additives is slightly worse than DTD.
- the possible reason is that the film formation resistance of PS is greater than that of DTD, it is difficult to form a thin and dense interface protection film with good lithium ion migration kinetics on the negative electrode, and the kinetic performance of lithium ion batteries is poor; VC and FEC are usually only on the negative electrode. It forms a film and oxidizes and produces gas at the positive electrode.
- the high-temperature storage performance of the lithium-ion battery and the safety performance of the hot box are poor; ADN usually only acts on the positive electrode, inhibiting the dissolution of metal ions, and side reactions occur at the negative electrode, which cannot be improved.
- ADN usually only acts on the positive electrode, inhibiting the dissolution of metal ions, and side reactions occur at the negative electrode, which cannot be improved
- the disadvantages of high-oxidation potential solvents and negative electrodes are poor, and the lithium ion battery has poor kinetic performance and cycle performance.
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Abstract
一种非水电解液、锂离子电池、电池模块、电池包及装置,所述非水电解液包括非水溶剂、锂盐以及添加剂,所述非水溶剂为高氧化电位类溶剂,所述添加剂包括环状硫酸酯。所述高氧化电位类溶剂选自式I、式II所示的化合物中的一种或几种,所述环状硫酸酯选自式III所示的化合物中的一种或几种。既能改善锂离子电池高温高电压下的电化学性能以及改善锂离子电池过充安全、热箱安全等安全性能,又能保证锂离子电池具有一定的动力学性能。
Description
本申请涉及电池领域,尤其涉及一种非水电解液、锂离子电池、电池模块、电池包及装置。
锂离子电池由于具备能量密度大、输出功率高、循环寿命长和环境污染小等优点而被广泛应用于电动汽车以及消费类电子产品中。目前对锂离子电池的需求是:高电压、高功率、长循环寿命、长存储寿命且安全性能优异。
锂离子电池目前广泛使用以六氟磷酸锂为导电锂盐以及以环状碳酸酯和/或链状碳酸酯为溶剂的非水电解液体系。然而上述非水电解液尚存在诸多不足,例如在高电压体系中,上述非水电解液的循环性能、存储性能以及安全性能有待提高,又如在钴酸锂或高镍三元体系中,锂离子电池的过充安全、热箱安全等安全性能也有待提高。
发明内容
鉴于背景技术中存在的问题,本申请的目的在于提供一种非水电解液、锂离子电池、电池模块、电池包及装置,其既能改善锂离子电池高温高电压下的电化学性能以及改善锂离子电池过充安全、热箱安全等安全性能,又能保证锂离子电池具有一定的动力学性能。
为了达到上述目的,在本申请的第一方面,本申请提供了一种非水电解液,其包括非水溶剂、锂盐以及添加剂,所述非水溶剂为高氧化电位类溶剂,所述添加剂包括环状硫酸酯。所述高氧化电位类溶剂选自式I、式II所示的化合物中的一种或几种,所述环状硫酸酯选自式III所示的化合物中的一种或几种。在式I中,R
1、R
2独立地选自未取代、部分卤代或全部卤代的碳原子数为1至5的烷基,且R
1、R
2中的至少一个为部分卤代或全部卤代的碳原子数为1至5的烷基;在式II中,R
3选自部分卤代或全部卤代的碳原子数为 1至6的亚烷基;在式III中,R
4选自未取代、部分卤代或全部卤代的碳原子数为1至6的亚烷基。其中,卤素原子选自F、Cl、Br、I中的一种或几种。
在本申请的第二方面,本申请提供了一种锂离子电池,其包括正极极片、负极极片、隔离膜以及根据本申请第一方面的非水电解液。
在本申请的第三方面,本申请提供了一种电池模块,其包括本申请的第二方面所述的锂离子电池。
在本申请的第四方面,本申请提供了一种电池包,其包括本申请的第三方面所述的电池模块。
在本申请的第五方面,本申请提供了一种装置,其包括本申请的第二方面所述的锂离子电池,所述锂离子电池用作所述装置的电源。
相对于现有技术,本申请至少包括如下所述的有益效果:
(1)本申请的非水电解液使用高氧化电位类溶剂替代常规碳酸酯类溶剂,可以克服常规碳酸酯类溶剂耐氧化性差、易高压分解产气、闪点低、易燃烧等缺点,从而本申请的非水电解液可以大大改善锂离子电池的过充安全、热箱安全等安全性能;
(2)本申请的非水电解液中还含有添加剂环状硫酸酯,其可以优先在负极形成稳定的界面保护膜,抑制高氧化电位类溶剂在负极的副反应,另外,添加剂环状硫酸酯在参与负极成膜过程中可生成结构中含烷氧基结构(-CH
2CH
2O-)的硫酸酯锂盐,很好地调节负极界面保护膜粘弹性,改善锂离子界面传递动力学,最终在负极形成薄且致密以及锂离子迁移动力学良好的界面保护膜,很好地弥补高氧化电位类溶剂粘度大以及与负极兼容性差的缺陷,有助于得到动力学性能以及电化学性能良好的锂离子电池;
(3)此外,环状硫酸酯还可以在正极表面形成稳定的界面保护膜,进一步提高非水电解液的耐氧化性,因此还在一定程度上有利于改善锂离子电池过充安全、热箱安全等安全性能。
本申请的电池模块、电池包和装置包括所述的锂离子电池,因而至少具 有与所述锂离子电池相同的优势。
图1是锂离子电池的一实施方式的立体图。
图2是图1的分解图。
图3是图2的锂离子电池的电极组件的一实施方式的示意图,其中第一极片、第二极片以及隔离膜卷绕以形成卷绕式的电极组件。
图4是图2的锂离子电池的电极组件的另一实施方式的示意图,其中第一极片、第二极片以及隔离膜沿厚度方向层叠以形成层叠式的电极组件。
图5是电池模块的一实施方式的立体图。
图6是电池包的一实施方式的立体图。
图7是图6的分解图。
图8是锂离子电池作为电源的装置的一实施方式的示意图。
其中,附图标记说明如下:
1 电池包
2 上箱体
3 下箱体
4 电池模块
5 锂离子电池
51 壳体
52 电极组件
521 第一极片
521a 第一集流体
521b 第一活性材料层
522 第二极片
522a 第二集流体
522b 第二活性材料层
523 隔离膜
524 第一极耳
525 第二极耳
53 顶盖组件
下面详细说明根据本申请的非水电解液、锂离子电池、电池模块、电池包及装置。
首先说明根据本申请第一方面的非水电解液,其包括非水溶剂、锂盐以及添加剂,所述非水溶剂为高氧化电位类溶剂,所述添加剂包括环状硫酸酯。
所述高氧化电位类溶剂选自式I、式II所示的化合物中的一种或几种。在式I中,R
1、R
2独立地选自未取代、部分卤代或全部卤代的碳原子数为1至5的烷基,且R
1、R
2中的至少一个为部分卤代或全部卤代的碳原子数为1至5的烷基;在式II中,R
3选自部分卤代或全部卤代的碳原子数为1至6的亚烷基。
所述环状硫酸酯选自式III所示的化合物中的一种或几种。在式III中,R
4选自未取代、部分卤代或全部卤代的碳原子数为1至6的亚烷基。
在R
1、R
2、R
3、R
4中:卤素原子选自F、Cl、Br、I中的一种或几种,优选为F;烷基、亚烷基可以为直链结构,也可以为支链结构;在烷基、亚烷基发生部分卤代或全部卤代时,卤素原子的具体种类可以为一种,也可以为多种。
目前,锂离子电池电解液常使用碳酸酯类溶剂。该类溶剂的耐氧化性差,常温下(25℃)在4V左右就出现轻微氧化,且随着电压和温度升高,该类溶剂氧化产气越来越明显。同时,该类溶剂的闪点低(一般在35℃以下),遇明火时很容易燃烧,且放热量大。因此使用常规碳酸酯类溶剂的锂离子电 池在安全性能上存在很高的潜在危险。
在本申请的非水电解液中,使用高氧化电位类溶剂替代常规碳酸酯类溶剂,高氧化电位类溶剂具有耐氧化性高且不可燃的优点,可以克服常规碳酸酯类溶剂耐氧化性差、易高压分解产气、闪点低、易燃烧等缺点,从而本申请的非水电解液可以大大改善锂离子电池的过充安全、热箱安全等安全性能。
但是,尽管高氧化电位类溶剂具有耐氧化性高且不可燃的优点,其与负极兼容性差,会在负极发生副反应,同时高氧化电位类溶剂的粘度较常规碳酸酯类溶剂大,使用高氧化电位类溶剂替代常规碳酸酯类溶剂后,非水电解液整体粘度较高、电导率降低,锂离子电池的动力学性能劣化明显。而添加剂环状硫酸酯可以优先在负极形成稳定的界面保护膜,抑制高氧化电位类溶剂在负极的副反应;另外,添加剂环状硫酸酯在参与负极成膜过程中可生成结构中含烷氧基结构(-CH
2CH
2O-)的硫酸酯锂盐,很好地调节负极界面保护膜粘弹性,改善锂离子界面传递动力学,最终在负极形成薄且致密以及锂离子迁移动力学良好的界面保护膜。因此添加剂环状硫酸酯可以很好地弥补高氧化电位类溶剂粘度大以及与负极兼容性差的缺陷,并有助于得到动力学性能以及电化学性能良好的锂离子电池。此外,环状硫酸酯还可以在正极表面形成稳定的界面保护膜,进一步提高非水电解液的耐氧化性,因此还在一定程度上有利于改善锂离子电池过充安全、热箱安全等安全性能。
在本申请的非水电解液中,优选地,所述高氧化电位类溶剂至少含有一个F原子,F原子的存在可以更好地提升高氧化电位类溶剂的耐氧化性以及阻燃特性。
在本申请的非水电解液中,优选地,在式I中,R
1、R
2独立地选自未取代、部分氟代或全部氟代的碳原子数为1至5的烷基,且R
1、R
2中的至少一个为部分氟代或全部氟代的碳原子数为1至5的烷基;更优选地,R
1、R
2独立地选自-CH
3、-CF
3、-CH
2CH
3、-CF
2CH
3、-CH
2CF
3、-CF
2CF
3、-CH
2CH
2CH
3、-CF
2CH
2CH
3、-CH
2CH
2CF
3、-CH
2CF
2CF
3、-CF
2CH
2CF
3、-CF
2CF
2CH
3、-CF
2CF
2CF
3,且R
1、R
2中的至少一个为-CF
3、-CF
2CH
3、-CH
2CF
3、-CF
2CF
3、-CF
2CH
2CH
3、-CH
2CH
2CF
3、-CH
2CF
2CF
3、-CF
2CH
2CF
3、-CF
2CF
2CH
3、-CF
2CF
2CF
3。
在本申请的非水电解液中,优选地,在式II中,R
3选自部分氟代或全部氟代的碳原子数为1至6的亚烷基;更优选地,R
3选自-CHFCH
2CH
2CH
2-、-CF
2CH
2CH
2CH
2-、-CF
2CH
2CH
2CHF-、-CF
2CH
2CH
2CF
2-、-CH
2CH
2CHFCH
2-、-CH
2CHFCHFCH
2-、-CH
2CH
2CH(CF
3)CH
2-、-CF
2CH
2CH
2CH
2CH
2-、-CF
2CH
2CH
2CH
2CF
2-、-CH
2CH
2CH
2CHFCH
2-、-CH
2CHFCH
2CHFCH
2-、-CH
2CHFCH
2CHFCHF-、-CH
2CH
2CH
2CH
2CHF-、-CH
2CH
2CH
2CH(CF
3)CH
2-、-CF
2CH
2CH
2CH
2CH
2CH
2-、-CH
2CH
2CH
2CH
2CHFCH
2-、-CH
2CHFCH
2CH
2CHFCH
2-、-CF
2CH
2CH
2CH
2CH
2CF
2-、-CH
2CH
2CH(CH
3)CH
2CHFCH
2-、-CH
2CH
2CH(CF
3)CH
2CHFCH
2-。
在本申请的非水电解液中,取代基R
1、R
2的碳原子数较多、分子量较大时,所述高氧化电位类溶剂的粘度通常也较大,非水电解液整体的电导率可能下降,会影响对锂离子电池动力学性能以及循环寿命等电化学性能的改善效果。优选地,R
1、R
2独立地选自未取代、部分卤代或全部卤代的碳原子数为1至3的烷基,且R
1、R
2中的至少一个为部分卤代或全部卤代的碳原子数为1至3的烷基;更优选地,R
1、R
2独立地选自未取代、部分氟代或全部氟代的碳原子数为1至3的烷基,且R
1、R
2中的至少一个为部分氟代或全部氟代的碳原子数为1至3的烷基。
在本申请的非水电解液中,取代基R
3的碳原子数较多、分子量较大时,所述高氧化电位类溶剂的粘度通常也较大,非水电解液整体的电导率可能下降,会影响对锂离子电池动力学性能以及循环寿命等电化学性能的改善效果。优选地,R
3选自部分卤代或全部卤代的碳原子数为1至4的亚烷基;更优选地,R
3选自部分氟代或全部氟代的碳原子数为1至4的亚烷基。
在本申请的非水电解液中,优选地,所述高氧化电位类溶剂可具体选自下述化合物中的一种或几种:
在本申请的非水电解液中,所述高氧化电位类溶剂选自式I、式II所示的化合物中的一种或几种。其中,二者比较而言,式I所示的化合物具有粘度相对较低、介电常数也相对较低的特性,而式II所示的化合物具有粘度相对较高、介电常数也相对较高的特性。因此,优选地,所述高氧化电位类溶剂同时包括式I所示的化合物以及式II所示的化合物;更优选地,所述高氧化电位类溶剂可仅包括式I所示的化合物。
在本申请的非水电解液中,优选地,式I所示的化合物的重量占所述高氧化电位类溶剂总重量的30%~100%,式II所示的化合物的重量占所述高氧化电位类溶剂总重量的0%~70%。
在本申请的非水电解液中,在式III中,优选地,R
4选自未取代、部分氟代或全部氟代的碳原子数为1至6的亚烷基;更优选地,R
4选自未取代、部分氟代或全部氟代的碳原子数为2至4的亚烷基。
在本申请的非水电解液中,优选地,所述环状硫酸酯可具体选自下述化合物及其氟代化合物中的一种或几种:
在本申请的非水电解液中,所述环状硫酸酯的含量较低时,可能无法完全抑制高氧化电位类溶剂在负极的副反应,会影响对锂离子电池性能的改善效果;所述环状硫酸酯的含量较多时,正负极界面成膜阻抗较大,也会影响对锂离子电池性能的改善效果。优选地,基于所述非水电解液的总重量,所述环状硫酸酯的重量百分含量为0.1%~10%;更优选地,所述环状硫酸酯的重量百分含量为0.5%~5%。
在本申请的非水电解液中,所述锂盐的具体种类并不受到具体的限制,可以是现有电池中使用的任何锂盐,例如所述锂盐可具体选自LiPF
6、LiN(CF
3SO
2)
2、LiN(FSO
2)
2(LiFSI)、LiBF
4、LiCF
3SO
3、LiClO
4中的一种或几种。
为了进一步改善锂离子电池的动力学性能,优选地,所述锂盐为LiPF
6与LiN(FSO
2)
2组成的混合锂盐。LiN(FSO
2)
2具有粘度适中、解离度高的优点,可以促进离子传导,提高非水电解液的电导率,有助于得到动力学性能良好的锂离子电池;同时LiN(FSO
2)
2的热稳定性较高,因此对锂离子电池的过充安全、热箱安全等安全性能也有一定的改善作用。
在LiPF
6与LiN(FSO
2)
2形成的混合锂盐中,LiN(FSO
2)
2的相对含量较高时,非水电解液的电导率明显提高,锂离子电池的动力学性能明显提高,但是发生集流体(例如铝箔)腐蚀的风险也变大,会对锂离子电池的循环性能不利;LiPF
6的相对含量较高时,LiN(FSO
2)
2起到的对锂离子电池动力学性能和安全性能的改善效果有限。优选地,LiPF
6与LiN(FSO
2)
2的重量比为10:1~1:10;更优选地,LiPF
6与LiN(FSO
2)
2的重量比为4:1~1:4。
在本申请的非水电解液中,所述锂盐的具体浓度也不受到具体的限制,可以根据实际需求进行调节,例如所述锂盐的浓度可具体为 0.7mol/L~2mol/L。
在本申请的非水电解液中,优选地,所述非水电解液还可包括其它成膜添加剂,这些成膜添加剂有助于进一步在负极以及正极形成性能优良的界面保护膜,从而进一步改善锂离子电池的动力学性能以及循环寿命、存储寿命等电化学性能。
优选地,基于所述非水电解液的总重量,这些成膜添加剂的重量含量为0.01%~10%;更优选地,基于所述非水电解液的总重量,这些成膜添加剂的重量含量为0.1%~5%。
优选地,这些成膜添加剂可具体选自具有不饱和键的环状碳酸酯化合物、卤素取代的环状碳酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸酯化合物、腈化合物、芳香化合物、异氰酸酯化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物、羧酸酯化合物中的一种或几种。
优选地,这些成膜添加剂可具体选自碳酸亚乙烯酯(VC)、氟代碳酸乙烯酯(FEC)、双氟代碳酸乙烯酯(DFEC)、1,3-丙磺酸内酯(PS)、1,3-丙烯磺酸内酯(PES)、己二腈(ADN)、丁二腈(SN)中的一种或几种,这几种成膜添加剂有助于在负极以及正极形成稳定的界面保护膜,有效抑制高氧化电位类溶剂在负极以及正极的副反应,从而可以更好地提高锂离子电池的动力学性能以及循环寿命、存储寿命等电化学性能。更优选地,这些成膜添加剂至少包括FEC。这是由于FEC可以在负极还原形成稳定的界面保护膜,减弱环状硫酸酯在负极的还原反应,由此可有利于提升环状硫酸酯在正极表面的成膜质量,进而更有利于改善锂离子电池的循环寿命。
其次说明根据本申请第二方面的锂离子电池。
图1是锂离子电池5的一实施方式的立体图。图2是图1的分解图。图3是图2的锂离子电池5的电极组件52的一实施方式的示意图,其中第一极片521、第二极片522以及隔离膜523卷绕以形成卷绕式的电极组件。图4是图2的锂离子电池5的电极组件52的另一实施方式的示意图,其中第一极片521、第二极片522以及隔离膜523沿厚度方向层叠以形成层叠式的电极组件。
参照图1至图4,锂离子电池5包括壳体51、电极组件52、顶盖组件53以及电解液(未示出)。
电极组件52收容于壳体51内。电极组件52包括第一极片521、第二极片522、隔离膜523、第一极耳524以及第二极耳525。隔离膜523将第一极片521和第二极片522隔开。
第一极片521包括第一集流体521a以及设置在第一集流体521a的表面上的第一活性材料层521b。第一活性材料层521b含有第一活性材料。第一活性材料层521b可以依据实际需要设置在第一集流体521a的一个表面或两个表面上。第二极片522包括第二集流体522a以及设置在第二集流体522a的表面上的第二活性材料层522b。第二活性材料层522b可以依据实际需要设置在第二集流体522a的一个表面或两个表面上。第二活性材料层522b含有第二活性材料。第一活性材料和第二活性材料实锂离子的脱嵌。第一极片521和第二极片522电性相反,即第一极片521和第二极片522中的一个为正极极片而第一极片521和第二极片522中的另一个为负极极片。其中,第一极耳524可以通过裁切第一集流体521a形成或者单独形成并固定连接于第一集流体521a。同样地,第二极耳525可以通过裁切第二集流体522a形成或者单独形成并固定连接于第二集流体522a。
电极组件52的数量不受限制,可以为一个或多个。
电解液注入在壳体51内并浸渍电极组件51,具体地浸渍第一极片521、第二极片522以及隔离膜523。
注意的是图1所示的锂离子电池5为罐型电池,但不限于此,锂离子电池5可以是袋型电池,即壳体51由金属塑膜替代且取消顶盖组件53。
在锂离子电池5中,由于第一极片521和第二极片522中的一个为正极极片,故正极极片的集流体为正极集流体、正极极片的活性材料层为正极活性材料层,正极极片的活性材料为正极活性材料。由此,所述正极极片包括正极集流体和设置于正极集流体上的正极活性材料层。
换句话说,本申请第三方面的锂离子电池包括正极极片、负极极片、隔离膜以及作为前述电解液的根据本申请第一方面的非水电解液。
在本申请的锂离子电池中,所述正极极片可包括正极活性材料、导电剂和粘结剂。其中所述正极活性材料可选自层状含锂氧化物、尖晶石型含锂氧 化物等。具体地,所述正极活性材料可选自锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物中的一种或几种。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,也可以将两种以上组合使用,组合比例还可以根据实际需求进行合理调节。所述导电剂和所述粘结剂的种类并不受到具体的限制,可根据实际需求进行选择。
当锂离子电池的电压较高时,锂离子电池可具有更高的充放电容量以及能量密度,但是常规电解液会被氧化产生气体并放出热量,锂离子电池的使用寿命以及高温性能均会变差,尤其是在滥用过程中,例如150℃热箱中,锂离子电池很容易燃烧。而本申请的非水电解液中含有高氧化电位类溶剂,其可以大幅提高非水电解液的耐氧化性并降低放热量,从而可以很好地改善锂离子电池的高温性能,因此,本申请的非水电解液对于正极氧化性高或正极氧化电位高的电池体系改进效果更加明显,尤其是对锂离子电池高温高电压下的电化学性能的改善效果更加明显,锂离子电池高温高电压下的产气可得到更明显的抑制,且锂离子电池的过充安全、热箱安全等安全性能也可以得到更明显的改进。
优选地,所述正极活性材料为Li
1+xNi
aCo
bM′
(1-a-b)O
2-cY
c、Li
1+yNi
mMn
nM″
2-m-nO
4-pZ
p中的一种或几种。其中,-0.1≤x≤0.2,0.6≤a≤1,0≤b<1,0≤(1-a-b)<1,0≤c<1,M′选自Mn、Al、Mg、Zn、Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr中的一种或几种,Y选自F、Cl、Br中的一种或几种;-0.1≤y≤0.2,0.4≤m≤1.2,0.8≤n≤1.6,0≤(2-m-n)≤0.3,0≤p≤1,M″选自Al、Mg、Zn、Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr中的一种或几种,Z选自F、Cl、Br中的一种或几种。更优选地,所述正极活性材料可具体选自LiNi
0.6Co
0.2Mn
0.2O
2、LiNi
0.8Co
0.1Mn
0.1O
2、LiNi
0.85Co
0.15Al
0.05O
2、LiNi
0.5Mn
1.5O
4中的一种或几种。随着正极活性材料Ni含量提高,正极活性材料的充放电容量提高,但正极活性材料的热稳定性降低,高温下会释放具有强氧化性的物质,氧化非水电解液并恶化锂离子电池的高温性能。而本申请的非水电解液中含有耐氧化的高氧化电位类溶剂,其可以大幅提高非水电解液的耐氧化性并降低放热量,从而能够很好地改善锂离子电池的高温性能。
在本申请的锂离子电池中,优选地,所述锂离子电池的充电截止电压为 U,且4.3V≤U≤6V。也即本申请的非水电解液可将锂离子电池的充电截止电压提高至4.3V以上。
在本申请的锂离子电池中,所述负极极片可包括负极活性材料、导电剂和粘结剂。其中所述负极活性材料可选自碳基材料、硅基材料、锡基材料等。具体地,所述负极活性材料可优选选自软碳、硬碳、人造石墨、天然石墨、硅、硅氧化合物、硅碳复合物、硅合金、锡、锡氧化合物、锡合金、钛酸锂、能与锂形成合金的金属等。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负极活性材料的传统公知材料。这些负极活性材料可以仅单独使用一种,也可以将两种以上组合使用,组合比例可以根据实际需求进行合理调节。所述导电剂和所述粘结剂的种类并不受到具体的限制,可根据实际需求进行选择。
在本申请的锂离子电池中,所述隔离膜的具体种类并不受到具体的限制,可以是现有电池中使用的任何隔离膜材料,例如聚烯烃隔离膜、陶瓷隔离膜等。具体地,所述隔离膜可优选为聚乙烯、聚丙烯、聚偏氟乙烯或它们的多层复合膜,但本申请并不仅限于这些。
接下来说明本申请第三方面的电池模块。
图5是电池模块4的一实施方式的立体图。
本申请第三方面提供的电池模块4包括本申请的第二方面所述的锂离子电池5。
参照图5,电池模块4包括多个锂离子电池5。多个锂离子电池5沿纵向排列。电池模块4可以作为电源或储能装置。电池模块4中的锂离子电池5的数量可以根据电池模块4的应用和容量进行调节。
接下来说明本申请第四方面的电池包。
图6是电池包1的一实施方式的立体图。图7是图6的分解图。
本申请第四方面提供的电池包1包括本申请的第三方面所述的电池模块4。
具体地,参照图6和图7,电池包1包括上箱体2、下箱体3以及电池模块4。上箱体2和下箱体3组装在一起并形成收容电池模块4的空间。电 池模块4置于组装在一起的上箱体2和下箱体3的空间内。电池模块4的输出极从上箱体2和下箱体3的其中之一或二者之间穿出,以向外部供电或从外部充电。电池包1采用的电池模块4的数量和排列可以依据实际需要来确定。
接下来说明本申请第五方面的装置。
图8是锂离子电池作为电源的装置的一实施方式的示意图。
本申请第五方面提供的装置包括本申请的第二方面所述的锂离子电池5,所述锂离子电池5可以用作所述装置的电源。在图8中,采用锂离子电池5的装置为电动汽车。当然不限于此,采用锂离子电池5的装置可以为除电动汽车外的任何电动车辆(例如电动大巴、电动有轨电车、电动自行车、电动摩托车、电动踏板车、电动高尔夫球车、电动卡车)、电动船舶、电动工具、电子设备及储能***。电动汽车可以为纯电动车辆、混合动力电动车、插电式混合动力电动车。当然,依据实际使用形式,本申请第五方面提供的装置可包括本申请的第三方面所述的电池模块4,当然,本申请第五方面提供的装置也可包括本申请的第四方面所述的电池包1。
为了使本申请的申请目的、技术方案和有益技术效果更加清晰,以下结合实施例,对本申请进行进一步详细说明。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,实施例的配方、比例等可因地制宜做出选择而对结果并无实质性影响。
为了便于说明,在非水电解液制备过程中所用的试剂简写如下:
实施例1
(1)非水电解液的制备
将化合物A1作为非水溶剂,然后溶解1mol/L的LiPF
6作为锂盐,之后加入0.1%的DTD,配置成非水电解液。
(2)正极极片的制备
将正极活性材料LiNi
0.5Mn
1.5O
4、导电剂乙炔黑、粘结剂聚偏氟乙烯(PVDF)按重量比94:3:3在N-甲基吡咯烷酮溶剂体系中充分搅拌混合均匀后,涂覆于集流体Al箔上烘干、冷压,得到正极极片。
(3)负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶、增稠剂羧甲基纤维素钠按重量比95:2:2:1在去离子水溶剂体系中充分搅拌混合均匀后,涂覆于集流体Cu箔上烘干、冷压,得到负极极片。
(4)隔离膜的制备
选用聚乙烯膜作为隔离膜。
(5)锂离子电池的制备
将上述正极极片、隔离膜、负极极片按顺序叠好,使隔离膜处于正、负极极片之间起到隔离的作用,然后卷绕得到电极组件;将电极组件置于外包装壳中,干燥后注入非水电解液,经过真空封装、静置、化成、整形等工序,获得锂离子电池。
实施例2~25以及对比例1~7的锂离子电池均按照与实施例1类似的方法进行制备,具体区别示出在表1中。
表1:实施例1~25以及对比例1~7的非水电解液组成
接下来说明锂离子电池的性能测试。
(1)高温存储产气测试
将实施例和对比例制备的锂离子电池各取5只,在常温下,以0.5C(即2h内完全放掉理论容量的电流值)恒流充电至4.9V,进一步在4.9V恒定电压下充电至电流低于0.05C,使其处于4.9V满充状态,存储前满充电池的体积记为D0。将满充电池置于85℃烘箱中,十天后取出,测试其存储后的体积并记为D1。
锂离子电池的体积膨胀率ε=(D1-D0)/D0×100%。
(2)热冲击安全性能(热箱)测试
将实施例和对比例制备的锂离子电池各取5只,在常温下,以0.5C恒流充电至4.9V,再在4.9V恒定电压下充电至电流低于0.05C,然后将锂离子电池放入恒温箱中,以5℃/min的升温速率将恒温箱升温至150℃,记录恒温箱由常温升温至150℃所需的时间h1。再将锂离子电池在150℃恒温箱中进行烘烤,直至锂离子电池冒烟和起火,记录恒温箱由常温升温开始至锂离子电池冒烟和起火所需的时间h2。
通过锂离子电池在150℃下承受烘烤的时间(h2-h1)表征锂离子电池热冲击安全性能。
(3)循环性能测试
将实施例和对比例制备的锂离子电池各取5只,通过以下步骤对锂离子电池重复进行充电和放电,并计算锂离子电池的放电容量保持率。
首先,在常温环境中,进行第一次充电和放电,在0.5C的充电电流下恒流充电至上限电压为4.9V,再在4.9V恒定电压下充电至电流低于0.05C,然后在0.5C的放电电流下进行恒流放电,直到最终电压为3V,记录首次循环的放电容量。按照上述操作进行500次的充电和放电循环并记录第500次循环的放电容量。
锂离子电池的循环容量保持率=(第500次循环的放电容量/首次循环的放电容量)×100%。
(4)动力学性能测试
将实施例和对比例制备的锂离子电池各取5只,然后在常温环境中进行 测试。首先,在0.5C的充电电流下恒流充电至上限电压为4.9V,再在4.9V恒定电压下充电至电流低于0.05C,然后用不同倍率(0.5C、2C)进行恒流放电,直到最终电压为3V,记录不同倍率下的放电容量。
用锂离子电池2C倍率下的放电容量与0.5C倍率下的放电容量之比表征锂离子电池的动力学性能。
表2:实施例1~25以及对比例1~7的性能测试结果
通过对比例1和实施例1~9的测试结果可以得知:对比例1使用常规碳酸酯类溶剂搭配添加剂DTD使用,锂离子电池各方面的性能均较差,尤其是锂离子电池的热箱安全性能非常差,锂离子电池在加热升温过程中(约升温至120℃)就出现冒烟和起火现象;当使用高氧化电位类溶剂替代常规碳酸酯类溶剂并搭配添加剂环状硫酸酯使用后,可以明显改善锂离子电池的高温存储性能和热箱安全性能。这是由于高氧化电位类溶剂具有耐氧化高且不可燃的优点,替代常规碳酸酯类溶剂使用后,可以克服常规碳酸酯类溶剂耐氧化性差、易高压分解产气、闪点低、易燃烧等缺点,从而大大改善锂离子电池的高温存储性能和热箱安全性能,而且对锂离子电池循环性能和动力学性能也明显的改善。
通过对比例2和实施例1~9的测试结果可以得知:对比例2仅使用高氧化电位类溶剂但未搭配添加剂DTD使用,由于高氧化电位类溶剂具有较高的粘度,导致非水电解液的整体粘度较高、电导率较低,锂离子电池的循环性能和动力学性能明显劣化。而加入DTD,可以明显改善锂离子电池的循环性能和高温存储性能,同时对锂离子电池的动力学性能也有明显的改善。这是因为DTD可以优先在负极形成稳定的界面保护膜,抑制高氧化电位类溶剂在负极的副反应;另外,DTD在参与负极成膜过程中可生成结构中含烷氧基结构(-CH
2CH
2O-)的硫酸酯锂盐,很好地调节负极界面保护膜粘弹性,改善锂离子界面传递动力学,最终可在负极形成薄且致密以及锂离子迁移动力学良好的界面保护膜,很好地弥补高氧化电位类溶剂粘度大以及与负极兼容性差的缺陷,因此还有助于得到高温存储性能、动力学性能以及循环性能良好的锂离子电池。此外,环状硫酸酯还可以在正极表面形成稳定的界面保 护膜,进一步提高非水电解液的耐氧化性,因此还在一定程度上有利于改善锂离子电池的热箱安全性能。
通过实施例1~9的测试结果还可以得知:DTD加入量较低时,可能无法完全抑制高氧化电位类溶剂在负极的副反应,会影响对锂离子电池性能的改善效果;而DTD加入量较多时,正负极界面成膜阻抗较大,也会影响对锂离子电池性能的改善效果。因此,DTD加入量优选为0.1%~10%。
通过对比例3和实施例4、实施例10~15的测试结果可以得知:未进行氟化处理的高氧化电位类溶剂耐氧化性较差且不具有阻燃特性,因此对于锂离子电池高温存储性能和热箱安全性能的改善效果不佳。
同时,通过实施例4、实施例10~17的测试结果还可以得知:不同结构的高氧化电位类溶剂对锂离子电池性能也有一定的影响。其中,环状结构的高氧化电位类溶剂具有粘度相对较高、介电常数也相对较高的特性,链状结构的高氧化电位类溶剂具有粘度相对较低、介电常数也相对较低的特性。因此,优选地,所述高氧化电位类溶剂同时包括链状结构的高氧化电位类溶剂以及环状结构的高氧化电位类溶剂;更优选地,所述高氧化电位类溶剂仅包括链状结构的高氧化电位类溶剂。
通过实施例4、实施例20~21的测试结果还可以得知:使用LiPF
6和LiFSI形成的混合锂盐后,锂离子电池的动力学性能和热箱安全性能得到进一步改善。可能的原因在于:LiFSI具有粘度适中、解离度高的优点,可以促进离子传导,提高非水电解液的电导率,有助于得到动力学性能良好的锂离子电池,同时LiFSI的热稳定性较高,因此对锂离子电池的热箱安全性能也有一定的改善作用。
通过对比例4~7和实施例4、实施例22~25的测试结果可以得知:当在含有高氧化电位类溶剂以及环状硫酸酯添加剂的非水电解液中进一步加入成膜添加剂,例如PS、VC、FEC、ADN后,锂离子电池的高温存储性能、热箱安全性能以及循环性能得到进一步提高。可能的原因在于:这些成膜添加剂在正极和负极均有一定的成膜作用,而且生成膜稳定性较好,抑制了非水电解液在循环和存储过程中的持续副反应,所以正负极界面保护膜阻抗增加较慢,锂离子电池的性能表现更好。
其中,在进一步加入FEC之后,锂离子电池的循环寿命改善最显著。可 能的原因在于:FEC可以在负极还原形成稳定的界面保护膜,减弱DTD在负极的还原反应,由此可有利于提升DTD在正极表面的成膜质量,进而进一步加入FEC后对锂离子电池循环寿命的改善最显著。
在不含有DTD的非水电解液中直接加入PS、VC、FEC、ADN也可以在一定程度上改善锂离子电池的性能,但是这些成膜添加剂的改善效果较DTD稍差。可能的原因在于:PS的成膜阻抗较DTD大,难以在负极形成薄且致密以及锂离子迁移动力学良好的界面保护膜,锂离子电池的动力学性能较差;VC、FEC通常只在负极成膜,且在正极会氧化产气,锂离子电池的高温存储性能和热箱安全性能较差;ADN通常只能作用于正极,抑制金属离子溶出,且在负极也会发生副反应,无法改善高氧化电位类溶剂与负极兼容性差的缺陷,锂离子电池的动力学性能和循环性能均较差。
根据上述说明书的揭示和教导,本申请所属领域的技术人员还可以对上述实施方式进行适当的变更和修改。因此,本申请并不局限于上面揭示和描述的具体实施方式,对本申请的一些修改和变更也应当落入本申请的权利要求的保护范围内。此外,尽管本说明书中使用了一些特定的术语,但这些术语只是为了方便说明,并不对本申请构成任何限制。
Claims (14)
- 一种非水电解液,包括非水溶剂、锂盐以及添加剂;其特征在于,所述非水溶剂为高氧化电位类溶剂,所述高氧化电位类溶剂选自式I、式II所示的化合物中的一种或几种;在式I中,R 1、R 2独立地选自未取代、部分卤代或全部卤代的碳原子数为1至5的烷基,且R 1、R 2中的至少一个为部分卤代或全部卤代的碳原子数为1至5的烷基;在式II中,R 3选自部分卤代或全部卤代的碳原子数为1至6的亚烷基;所述添加剂包括环状硫酸酯,所述环状硫酸酯选自式III所示的化合物中的一种或几种;在式III中,R 4选自未取代、部分卤代或全部卤代的碳原子数为1至6的亚烷基;其中,卤素原子选自F、Cl、Br、I中的一种或几种,优选为F。
- 根据权利要求1所述的非水电解液,其特征在于,在式I中,R 1、R 2独立地选自未取代、部分氟代或全部氟代的碳原子数为1至5的烷基,且R 1、R 2中的至少一个为部分氟代或全部氟代的碳原子数为1至5的烷基,优选地,R 1、R 2独立地选自-CH 3、-CF 3、-CH 2CH 3、-CF 2CH 3、-CH 2CF 3、-CF 2CF 3、-CH 2CH 2CH 3、-CF 2CH 2CH 3、-CH 2CH 2CF 3、-CH 2CF 2CF 3、-CF 2CH 2CF 3、-CF 2CF 2CH 3、-CF 2CF 2CF 3,且R 1、R 2中的至少一个为-CF 3、-CF 2CH 3、-CH 2CF 3、-CF 2CF 3、-CF 2CH 2CH 3、-CH 2CH 2CF 3、-CH 2CF 2CF 3、 -CF 2CH 2CF 3、-CF 2CF 2CH 3、-CF 2CF 2CF 3;在式II中,R 3选自部分氟代或全部氟代的碳原子数为1至6的亚烷基,优选地,R 3选自-CHFCH 2CH 2CH 2-、-CF 2CH 2CH 2CH 2-、-CF 2CH 2CH 2CHF-、-CF 2CH 2CH 2CF 2-、-CH 2CH 2CHFCH 2-、-CH 2CHFCHFCH 2-、-CH 2CH 2CH(CF 3)CH 2-、-CF 2CH 2CH 2CH 2CH 2-、-CF 2CH 2CH 2CH 2CF 2-、-CH 2CH 2CH 2CHFCH 2-、-CH 2CHFCH 2CHFCH 2-、-CH 2CHFCH 2CHFCHF-、-CH 2CH 2CH 2CH 2CHF-、-CH 2CH 2CH 2CH(CF 3)CH 2-、-CF 2CH 2CH 2CH 2CH 2CH 2-、-CH 2CH 2CH 2CH 2CHFCH 2-、-CH 2CHFCH 2CH 2CHFCH 2-、-CF 2CH 2CH 2CH 2CH 2CF 2-、-CH 2CH 2CH(CH 3)CH 2CHFCH 2-、-CH 2CH 2CH(CF 3)CH 2CHFCH 2-;在式III中,R 4选自未取代、部分氟代或全部氟代的碳原子数为1至6的亚烷基。
- 根据权利要求1所述的非水电解液,其特征在于,基于所述非水电解液的总重量,所述环状硫酸酯的重量百分含量为0.1%~10%,优选为0.5%~5%。
- 根据权利要求1所述的非水电解液,其特征在于,所述非水电解液还包括具有不饱和键的环状碳酸酯化合物、卤素取代的环状碳酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸酯化合物、腈化合物、芳香化合物、异氰酸酯化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物、羧酸酯化合物中的一种或几种;优选地,所述非水电解液还包括碳酸亚乙烯酯、氟代碳酸乙烯酯、双氟代碳酸乙烯酯、1,3-丙磺酸内酯、1,3-丙烯磺酸内酯、己二腈、丁二腈中的一种或几种;更优选地,所述非水电解液还包括氟代碳酸乙烯酯。
- 根据权利要求1所述的非水电解液,其特征在于,所述锂盐选自LiPF 6、LiN(CF 3SO 2) 2、LiN(FSO 2) 2、LiBF 4、LiCF 3SO 3、LiClO 4中的一种或几种;优选地,所述锂盐为LiPF 6与LiN(FSO 2) 2组成的混合锂盐;更优选地,LiPF 6与LiN(FSO 2) 2的重量比为10:1~1:10。
- 一种锂离子电池,其特征在于,包括正极极片、负极极片、隔离膜以及根据权利要求1-7中任一项所述的非水电解液。
- 根据权利要求8所述的锂离子电池,其特征在于,所述锂离子电池的充电截止电压为U,且4.3V≤U≤6V。
- 根据权利要求8所述的锂离子电池,其特征在于,所述正极极片包括Li 1+xNi aCo bM′ (1-a-b)O 2-cY c、Li 1+yNi mMn nM″ 2-m-nO 4-pZ p中的一种或几种;其中,-0.1≤x≤0.2,0.6≤a≤1,0≤b<1,0≤(1-a-b)<1,0≤c<1,M′选自Mn、Al、Mg、Zn、Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr中的一种或几种,Y选自F、Cl、Br中的一种或几种;-0.1≤y≤0.2,0.4≤m≤1.2,0.8≤n≤1.6,0≤(2-m-n)≤0.3,0≤p≤1,M″选自Al、Mg、Zn、Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr中的一种或几种,Z选自F、Cl、Br中的一种或几种。
- 一种电池模块,其特征在于,包括根据权利要求8~10中任一项所述的锂离子电池。
- 一种电池包,其特征在于,包括根据权利要求11所述的电池模块。
- 一种装置,其特征在于,包括根据权利要求8~10中任一项所述的锂离子电池,所述锂离子电池作为所述装置的电源。
- 根据权利要求13所述的装置,其特征在于,所述装置包括纯电动车辆、混合动力电动车辆、插电式混合动力电动车辆、电动自行车、电动踏板车、电动高尔夫球车、电动卡车、电动船舶及储能***。
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EP3836281A4 (en) | 2021-10-20 |
CN110970659A (zh) | 2020-04-07 |
EP3836281A1 (en) | 2021-06-16 |
US11961969B2 (en) | 2024-04-16 |
EP3836281B1 (en) | 2022-07-20 |
US20210202998A1 (en) | 2021-07-01 |
CN110970659B (zh) | 2021-03-09 |
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