WO2023044752A1 - 锂离子电池、电池模块、电池包及用电装置 - Google Patents

锂离子电池、电池模块、电池包及用电装置 Download PDF

Info

Publication number
WO2023044752A1
WO2023044752A1 PCT/CN2021/120317 CN2021120317W WO2023044752A1 WO 2023044752 A1 WO2023044752 A1 WO 2023044752A1 CN 2021120317 W CN2021120317 W CN 2021120317W WO 2023044752 A1 WO2023044752 A1 WO 2023044752A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium
ion battery
electrolyte
battery
lithium ion
Prior art date
Application number
PCT/CN2021/120317
Other languages
English (en)
French (fr)
Inventor
吴则利
韩昌隆
张翠平
姜彬
艾志勇
黄磊
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to JP2022546114A priority Critical patent/JP7478827B2/ja
Priority to KR1020227027653A priority patent/KR20230044139A/ko
Priority to CN202180084957.7A priority patent/CN116670884A/zh
Priority to PCT/CN2021/120317 priority patent/WO2023044752A1/zh
Priority to EP21923586.8A priority patent/EP4178001A4/en
Publication of WO2023044752A1 publication Critical patent/WO2023044752A1/zh
Priority to US18/347,184 priority patent/US20230361352A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • 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 lithium-ion batteries, in particular to a lithium-ion battery, a battery module, a battery pack, and an electrical device with an electrolyte solution having a low lithium salt concentration.
  • lithium-ion batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields.
  • Li-ion batteries typically, electrolytes with high lithium salt concentrations are used in Li-ion batteries to obtain high kinetic performance.
  • LiPF6 which is usually used as a lithium salt in the electrolyte, has poor thermal stability and is easy to decompose at high temperature to generate HF, which damages the cathode material; while high concentration of LiPF6 leads to high viscosity of the electrolyte, which is not conducive to cycle performance.
  • Li-ion batteries with low-Li-salt-concentration electrolytes are not only less costly, but also have better thermal stability and cycle performance.
  • the lithium salt concentration is low, the conductivity of the electrolyte decreases, which affects the kinetic performance of the battery and restricts the practical application of lithium-ion batteries with low lithium salt concentration electrolytes.
  • the present application was made in view of the above-mentioned problems, and an object thereof is to provide a lithium ion battery that can have good kinetic performance even when an electrolyte solution with a low lithium salt concentration is used.
  • the first aspect of the present application provides a lithium ion battery, which has a positive pole piece, a negative pole piece, a separator and an electrolyte, the electrolyte contains a lithium salt and a solvent, wherein,
  • the mass percentage of the lithium salt in the electrolyte is a%, and the lithium ion battery satisfies 5 ⁇ a ⁇ 10;
  • the load on one side of the negative electrode sheet is W grams per 1540.25 mm 2 , and a and W satisfy 25 ⁇ a/W ⁇ 50, and the solvent contains dimethyl carbonate.
  • the present application uses a lower lithium salt concentration and dimethyl carbonate in the electrolyte, so that the battery has better safety and high-temperature cycle performance, and has good kinetic performance at the same time.
  • the electrolyte contains a positive electrode sacrificial additive with a mass percentage of b%, the mass percentage of the dimethyl carbonate in the electrolyte is c%, and the Lithium-ion batteries meet:
  • the storage performance of the battery can be improved while the dynamic performance of the battery is improved.
  • the positive sacrificial additive is a compound represented by one of the following general formulas,
  • R represents an alkylene group with 1-10 carbon atoms or represents a carbon atom, which is optionally substituted by an alkyl group with 1-9 carbon atoms,
  • the positive sacrificial additive is selected from one or more of 1,3-propane sultone, vinyl sulfate and vinyl bissulfate.
  • the power performance and high-temperature cycle performance of the battery can be further improved.
  • the mass percentage of the dimethyl carbonate in the electrolyte is c%, and the lithium-ion battery meets:
  • the lithium salt is LiPF 6 .
  • the high-temperature stability and high-temperature cycle performance of such batteries can be significantly improved.
  • a second aspect of the present application provides a battery module including the lithium-ion battery of the first aspect of the present application.
  • a third aspect of the present application provides a battery pack, including the battery module of the second aspect of the present application.
  • the fourth aspect of the present application provides an electric device, including at least one selected from the lithium ion battery of the first aspect of the present application, the battery module of the second aspect of the present application, or the battery pack of the third aspect of the present application kind.
  • FIG. 1 is a schematic diagram of a lithium-ion battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the lithium ion battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device in which a lithium-ion battery is used as a power source according to an embodiment of the present application.
  • ranges disclosed herein are defined in terms of lower and upper limits, and a given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range "a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • a certain parameter is an integer ⁇ 2
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • LiPF 6 LiPF 6 has poor thermal stability, and it is easy to decompose at high temperature to generate HF, which will damage the positive electrode material; while at low temperature, high concentration of LiPF 6 leads to high viscosity of the electrolyte, which is not conducive to cycle performance. Reducing the concentration of LiPF 6 can not only reduce the cost, but also improve the thermal stability and cycle performance of Li-ion batteries.
  • low lithium salt concentration leads to low conductivity of the electrolyte, which affects the kinetic performance of the battery. It is therefore desirable to be able to improve the kinetic performance of Li-ion batteries with electrolytes with low Li-salt concentration to make such Li-ion batteries suitable for practical applications.
  • the inventor of the present application has explored in many ways and found that for a specific lithium-ion battery with an electrolyte with a low lithium salt concentration, by adding dimethyl carbonate (DMC) in its electrolyte, the kinetics of the lithium-ion battery can be significantly improved performance.
  • DMC dimethyl carbonate
  • the thus obtained lithium-ion battery with electrolyte solution of low lithium salt concentration can be applied to various occasions, such as electric bicycles, energy storage base stations, taxis, scooters, and the like.
  • a lithium-ion battery which has a positive pole piece, a negative pole piece, a separator, and an electrolyte, and the electrolyte contains a lithium salt and a solvent, wherein,
  • the mass percentage of the lithium salt in the electrolyte is a%, and the lithium ion battery satisfies 5 ⁇ a ⁇ 10;
  • the load on one side of the negative electrode sheet is W grams per 1540.25 mm 2 , and a and W satisfy 25 ⁇ a/W ⁇ 50, and the solvent contains dimethyl carbonate.
  • the meaning of the load on one side of the negative electrode sheet is the amount of the negative film layer on one side of the negative electrode sheet.
  • the negative electrode load is high, so the energy density is high, but at this time the transmission path of lithium ions is long, there is more disordered transmission, and it is difficult to intercalate and deintercalate lithium ions, and the available lithium ions Less in quantity. That is to say, although lithium-ion batteries satisfying the above-mentioned a and a/W numerical ranges have better safety and high-temperature cycle performance, the kinetic performance is not good; and through a large number of experiments, it is found that using DMC in a solvent can improve The kinetic performance of the battery.
  • W can be selected by those skilled in the art according to actual needs, usually, W is in the range of 0.1-0.25g/1540.25mm 2 .
  • the electrolyte contains a positive electrode sacrificial additive with a mass percentage of b%, the mass percentage of the dimethyl carbonate in the electrolyte is c%, and the Lithium-ion batteries meet:
  • DMC will produce gas when it is oxidized, so the addition of DMC may cause the battery to produce gas during storage, affecting battery storage performance.
  • the positive electrode sacrificial additive can be oxidized on the surface of the positive electrode in preference to the solvent, so adding the positive electrode sacrificial additive can prevent DMC from being oxidized.
  • the amount of DMC is also related to the concentration of lithium salt: when the concentration of lithium salt is high or low, the effect of DMC on improving battery dynamics is becoming more and more limited. At this time, reducing the amount of DMC will not affect battery power too much. However, it is beneficial to alleviate the problem of DMC's oxidation and gas production.
  • the positive sacrificial additive is a compound represented by one of the following general formulas,
  • R represents an alkylene group with 1-10 carbon atoms or represents a carbon atom, which is optionally substituted by an alkyl group with 1-9 carbon atoms,
  • the positive electrode sacrificial additive is selected from one or more of 1,3-propane sultone (1,3-PS), vinyl sulfate (DTD) and diethylene sulfate (double DTD) kind.
  • the mass percentage of the dimethyl carbonate in the electrolyte is c%, and the lithium-ion battery satisfies:
  • a/W is related to the diffusion kinetics of the lithium ion anode, and the larger the value of (5-0.08 ⁇ a/W), the worse the kinetic performance of the battery.
  • the inventors found that when the concentration c% and a/W of dimethyl carbonate satisfy the above relationship, the kinetic performance of the battery can be more fully improved.
  • c% is in the range of 5-50%, optionally in the range of 9-30%.
  • the lithium salt is LiPF 6 .
  • lithium-ion batteries whose lithium salts in the electrolyte are other lithium salts
  • lithium-ion batteries whose lithium salts are all LiPF 6 are more likely to have high-temperature stability problems and high-temperature cycle performance problems. By meeting the above conditions, it can be significantly improved.
  • the high-temperature stability and high-temperature cycle performance of the lithium-ion battery ensure the kinetic performance of the battery.
  • 5 ⁇ a ⁇ 7.5 For a lithium ion battery with such a lithium salt concentration, by satisfying the above conditions, the kinetic performance of the battery can be significantly improved.
  • a lithium-ion battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, and the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material known in the art for batteries.
  • the positive active material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also abbreviated as NCM811)), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2
  • olivine-structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), phosphoric acid At least one of a composite material of lithium manganese and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also abbreviated as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate
  • phosphoric acid At least one of a composite material of lithium manganese and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • the positive electrode film layer may further optionally include a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer may also optionally include a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector can use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid Ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE) and other substrates).
  • PP polypropylene
  • PET polyethylene terephthalic acid Ethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA), acrylate and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • CMC-Na sodium carboxymethylcellulose
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the electrolyte used in this application is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent in addition to DMC, can also be selected from ethylene carbonate (EC), propylene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate, dimethyl carbonate, dicarbonate Propyl ester, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, At least one of propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • diethyl carbonate dimethyl carbonate
  • dicarbonate dicarbonate
  • the electrolyte may optionally include additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • a separator is also included in the lithium ion battery.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • a lithium ion battery can include an outer packaging.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the lithium-ion battery can 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 bag-type soft bag.
  • the material of the soft case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a lithium-ion battery 5 with a square structure as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating chamber. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the lithium-ion battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • lithium-ion batteries can be assembled into a battery module, and the number of lithium-ion batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of lithium ion batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of lithium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may also include a housing with an accommodating space, and a plurality of lithium-ion batteries 5 are accommodated in the accommodating 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 one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electric device, which includes at least one of the lithium-ion battery, battery module, or battery pack provided by the present application.
  • the lithium ion battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a lithium-ion battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module can be used.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is usually required to be light and thin, and a lithium-ion battery can be used as a power source.
  • the positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil with a thickness of 13 ⁇ m in an amount of 0.28 g (dry weight)/1540.25 mm 2 . After drying the aluminum foil at room temperature, it was transferred to an oven at 120° C. for 1 hour, and then subjected to cold pressing and slitting to obtain positive electrode sheets.
  • the artificial graphite of the negative electrode active material, the conductive agent carbon black, and the binder acrylate are mixed according to the mass ratio of 92:2:6, deionized water is added, and the negative electrode slurry is obtained under the action of a vacuum mixer.
  • the negative electrode slurry was evenly coated on the negative electrode current collector copper foil with a thickness of 8 ⁇ m in an amount of 0.2 g (dry weight)/1540.25 mm 2 . After the copper foil was dried at room temperature, it was transferred to an oven at 120° C. for 1 hour, and then subjected to cold pressing and slitting to obtain negative electrode sheets.
  • the isolation film was purchased from Cellgard, and the model was cellgard2400.
  • a bare battery cell with a capacity of 4.3Ah was placed in the outer packaging foil, and 12g of the electrolyte solution prepared above was injected into the dried battery, and the lithium-ion battery was obtained through vacuum packaging, standing, formation, shaping and other processes.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 52g EMC, 10g DMC, 8g LiPF 6 was fully stirred and dissolved to obtain the electrolyte solution for this embodiment.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 52.5g EMC, and 10g DMC to a beaker respectively , 7.5g LiPF 6 was fully stirred and dissolved to obtain the electrolyte solution for this embodiment.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 55g EMC, 10g DMC, 5g LiPF 6 was fully stirred and dissolved to obtain the electrolyte solution for this embodiment.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 16g EMC, 40g DMC, 10g LiPF 6 and 4g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 26g EMC, 30g DMC, 10g LiPF 6 and 4g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 26g EMC, 30g DMC, 10g of LiPF 6 and 4g of DTD were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 26g EMC, 30g DMC, 10g of LiPF 6 and 4g of double DTD were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 43g EMC, 15g DMC, 10g LiPF 6 and 2g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 47g EMC, 10g DMC, 10g LiPF 6 and 3g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 47g EMC, 9g DMC, 10g LiPF 6 and 4g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 25g EMC, 30g DMC, 10g LiPF 6 and 5g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 42g EMC, 15g DMC, 10g LiPF 6 and 3g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 52g EMC, 5g DMC, 10g LiPF 6 and 3g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content ⁇ 10ppm, add 30g EC, 46.5g EMC, and 12g DMC to a beaker respectively , 10g LiPF 6 , and 1.5g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 30g EC, 37g EMC, 20g DMC, 10g LiPF 6 and 3g 1,3-PS were fully stirred and dissolved to obtain the electrolyte solution for this example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that the preparation steps of the electrolyte are: in an argon atmosphere glove box with a water content of ⁇ 10ppm, add 33.75g EC, 56.25g EMC and 10g LiPF 6 was fully stirred and dissolved to obtain the electrolyte solution for this comparative example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole, the difference is that in an argon atmosphere glove box with a water content of ⁇ 10ppm, 36.38g EC, 60.62g EMC, and 3g LiPF 6 are respectively added to a beaker and fully stirred and dissolved to obtain Electrolyte was used in this comparative example.
  • the preparation process of the lithium-ion battery refers to Example 1 as a whole.
  • the difference is that, in an argon atmosphere glove box with a water content of ⁇ 10ppm, 33g EC, 55g EMC, and 12g LiPF 6 were respectively added to a beaker and fully stirred and dissolved to obtain the pair. Proportional electrolyte.
  • the DCR of Examples 1-16 is significantly lower than that of the comparative example at the same electrolyte salt concentration, that is, the improvement of the kinetic performance is obtained, and the high-temperature cycle performance is also obtained. improve.
  • Examples 5-16 positive electrode sacrificial additives were also added to the electrolyte, so that when a higher concentration of DMC was used, the expansion of the battery at high temperatures could be suppressed and the high-temperature cycle performance could be improved. It can be seen from Examples 5-10 that when the battery satisfies c ⁇ 10 ⁇ b-10 ⁇
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本申请公开了一种锂离子电池，其具有正极极片、负极极片、隔离膜及电解液，所述电解液含有锂盐和溶剂，其中，基于电解液的总重量计，所述电解液中锂盐的质量百分比为a％，所述锂离子电池满足5≤a≤10；所述负极极片单面上的负载量为W克每1540.25mm 2，且a与W满足25≤a/W≤50，并且所述溶剂中含有碳酸二甲酯。所述锂离子电池在具有较好的安全性和高温循环性能的同时，还具有良好的动力学性能。

Description

锂离子电池、电池模块、电池包及用电装置 技术领域
本申请涉及锂离子电池领域，尤其涉及一种具有低锂盐浓度电解液的锂离子电池、电池模块、电池包、以及用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。
通常，在锂离子电池中使用具有高锂盐浓度的电解液，以获得较高的动力学性能。然而，通常用作电解液中锂盐的LiPF 6的热稳定性差，在高温下容易分解产生HF，破坏正极材料；而高浓度的LiPF 6导致电解液具有高粘度，不利于循环性能。具有低锂盐浓度电解液的锂离子电池不仅成本较低，还具有更好的热稳定性和循环性能。然而，在锂盐浓度较低时，电解液的电导率降低，影响电池的动力学性能，制约了低锂盐浓度电解液的锂离子电池的实际应用。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种锂离子电池，其在使用低锂盐浓度电解液时也能具有良好的动力学性能。
为了达到上述目的，本申请的第一方面提供了一种锂离子电池，其具有正极极片、负极极片、隔离膜及电解液，所述电解液含有锂盐和溶剂，其中，
基于电解液的总重量计，所述电解液中锂盐的质量百分比为a％，所述锂离子电池满足5≤a≤10；
所述负极极片单面上的负载量为W克每1540.25mm 2，且a与W 满足25≤a/W≤50，并且所述溶剂中含有碳酸二甲酯。
由此，本申请通过在电解液中使用较低的锂盐浓度并使用碳酸二甲酯，使电池具有较好的安全性和高温循环性能，同时具有良好的动力学性能。
在任意实施方式中，基于电解液的总重量计，所述电解液中含有质量百分比为b％的正极牺牲型添加剂，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
c≤10×b-10×|0.6-a/12.5|。
由此，能够在获得电池动力学性能改善的同时，改善电池的存储性能。
在任意实施方式中，所述正极牺牲型添加剂为下述通式之一所表示的化合物，
Figure PCTCN2021120317-appb-000001
其中，R代表碳原子数为1-10的亚烷基或代表碳原子，该碳原子任选地被碳原子数为1-9的烷基取代，
可选地，所述正极牺牲型添加剂选自1，3-丙磺酸内酯、硫酸乙烯酯和双硫酸乙烯酯中的一种或多种。
由此，能够获得更好的改善电池存储性能的效果。
在任意实施方式中，2≤b≤4。
由此，能够进一步改善电池的功率性能和高温循环性能。
在任意实施方式中，基于电解液的总重量计，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
c≥10×(5-0.08×a/W)。
由此，能够更充分地改善电池的动力学性能。
在任意实施方式中，所述正极极片包含正极活性材料LiNi xCo yMn zO 2，x+y+z＝1，0＜x＜1，0＜y＜1，0＜z＜1，可选为0.1≤x≤0.8，进一步可选为0.1≤x≤0.5。
由此，兼顾电池的容量密度和存储性能、尤其是存储产气的抑制。
在任意实施方式中，所述锂盐为LiPF 6。这样的电池的高温稳定性和高温循环性能可获得显著改善。
在任意实施方式中，5≤a≤7.5。这样的电池的动力学性能可获得显著改善。
本申请的第二方面提供一种电池模块，包括本申请的第一方面的锂离子电池。
本申请的第三方面提供一种电池包，包括本申请的第二方面的电池模块。
本申请的第四方面提供一种用电装置，包括选自本申请的第一方面的锂离子电池、本申请的第二方面的电池模块或本申请的第三方面的电池包中的至少一种。
附图说明
图1是本申请一实施方式的锂离子电池的示意图。
图2是图1所示的本申请一实施方式的锂离子电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6是本申请一实施方式的锂离子电池用作电源的用电装置的示意图。
附图标记说明：
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；53顶盖组件
具体实施方式
以下，适当地参照附图详细说明了本申请的锂离子电池及其制造方法、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为 了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
在目前已有的锂离子电池中，电解液的锂盐浓度通常较高，以获 得较高的动力学性能。锂离子电池中所用的锂盐大多为LiPF 6。LiPF 6的热稳定性差，在高温下容易分解产生HF，破坏正极材料；而在低温下，高浓度的LiPF 6导致电解液具有高粘度，不利于循环性能。降低LiPF 6的浓度不仅可降低成本，还可改善锂离子电池的热稳定性和循环性能。但低锂盐浓度会导致电解液的电导率较低，从而影响电池的动力学性能。因此希望能够改善具有低锂盐浓度电解液的锂离子电池的动力学性能，以使得此类锂离子电池适于实际应用。
本申请的发明人经过多方探索，发现对于特定的具有低锂盐浓度电解液的锂离子电池，通过在其电解液中添加碳酸二甲酯(DMC)，能够显著改善该锂离子电池的动力学性能。
由此获得的低锂盐浓度电解液的锂离子电池可以应用于多种场合，例如电动自行车、储能基站、出租车、代步车等。
具体而言，本申请的一个实施方式中，提出了一种锂离子电池，其具有正极极片、负极极片、隔离膜及电解液，所述电解液含有锂盐和溶剂，其中，
基于电解液的总重量计，所述电解液中锂盐的质量百分比为a％，所述锂离子电池满足5≤a≤10；
所述负极极片单面上的负载量为W克每1540.25mm 2，且a与W满足25≤a/W≤50，并且所述溶剂中含有碳酸二甲酯。
所述负极极片单面上的负载量的含义是所述负极极片单面上的负极膜层的量。
虽然机理尚不明确，但本申请人意外地发现：本申请通过在满足上述锂盐浓度和负极极片负载量的锂离子电池中在电解液中添加碳酸二甲酯，能够显著提高该电池的动力学性能。由于该电池电解液的锂盐浓度在5重量％-10重量％之间，因此锂盐分解的情况减少，并且电解液的粘度较低，高温循环性能较好。另一方面，a/W表示相对于负极极片单位面积的负载量而言的锂盐浓度，其与锂离子负极扩散动力学相关。a/W数值较小时，负极负载量较高，因此能量密度高，但此时锂离子的传输路径长，存在更多的无序传输，锂离子的嵌入脱 出比较困难，且可提供的锂离子数量较少。也即，满足上述a和a/W数值范围的锂离子电池虽然具有较好的安全性和高温循环性能，但动力学性能不佳；而通过大量实验发现，此时在溶剂中使用DMC能够改善电池的动力学性能。
W的范围可由本领域技术人员根据实际需要选择，通常，W在0.1-0.25g/1540.25mm 2范围内。
在一些实施方式中，基于电解液的总重量计，所述电解液中含有质量百分比为b％的正极牺牲型添加剂，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
c≤10×b-10×|0.6-a/12.5|。
DMC被氧化时会产生气体，因此DMC的添加可能会导致电池在存储期间产气，影响电池存储性能。正极牺牲型添加剂可在正极表面优先于溶剂发生氧化反应，因此添加正极牺牲型添加剂可避免DMC被氧化。另一方面，DMC的用量也与锂盐浓度相关：锂盐浓度偏高或偏低时，DMC对电池动力学的改善效果越来越有限，此时减少DMC的用量不会过多影响电池动力学性能，却有利于减轻DMC的氧化产气问题。发明人发现，通过使DMC的浓度c％、正极牺牲型添加剂浓度b％和锂盐浓度a％满足上述关系式，能够在获得电池动力学性能改善的同时，改善电池的存储性能。
在一些实施方式中，所述正极牺牲型添加剂为下述通式之一所表示的化合物，
Figure PCTCN2021120317-appb-000002
其中，R代表碳原子数为1-10的亚烷基或代表碳原子，该碳原子任选地被碳原子数为1-9的烷基取代，
可选地，所述正极牺牲型添加剂选自1，3-丙磺酸内酯(1，3-PS)、硫酸乙烯酯(DTD)和双硫酸乙烯酯(双DTD)中的一种或多种。
通过具体选择上述正极牺牲型添加剂，能够获得更好的改善电池存储性能的效果。
在一些实施方式中，2≤b≤4。通过进一步限定正极牺牲型添加剂的用量，有利于在确保正极牺牲型添加剂充分发挥作用的同时，避免其在正极表面氧化程度过高而对电池的功率性能、循环性能产生影响，从而能够进一步改善电池的功率性能和高温循环性能。
在一些实施方式中，基于电解液的总重量计，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
c≥10×(5-0.08×a/W)。
如前所述，a/W与锂离子负极扩散动力学相关，(5-0.08×a/W)的值越大，电池的动力学性能越差。发明人发现当碳酸二甲酯的浓度c％与a/W满足上述关系时，能够更充分地改善电池的动力学性能。
在一些实施方式中，可选地，c％在5-50％范围内，可选地在9-30％范围内。
在一些实施方式中，所述正极极片包含正极活性材料LiNi xCo yMn zO 2，x+y+z＝1，0＜x＜1，0＜y＜1，0＜z＜1，可选为0.1≤x≤0.8，进一步可选为0.1≤x≤0.5。
通过选择x值，可以兼顾电池的容量密度和存储性能、尤其是存储产气的抑制。
在一些实施方式中，所述锂盐为LiPF 6。相对于电解液中的锂盐为其他锂盐的锂离子电池而言，锂盐全为LiPF 6的锂离子电池更容易存在高温稳定性问题和高温循环性能问题，通过满足上述条件，能够显著改善该锂离子电池的高温稳定性和高温循环性能，且确保该电池的动力学性能。
在一些实施方式中，5≤a≤7.5。对于具有该锂盐浓度的锂离子电池而言，通过满足上述条件，能够显著改善电池的动力学性能。
另外，以下适当参照附图对本申请的锂离子电池、电池模块、电池包和用电装置进行说明。
通常情况下，锂离子电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往 返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。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。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM811))、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性 化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、 聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。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。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)、丙烯酸酯及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请中电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三 氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂除了包含DMC之外，还可选自碳酸亚乙酯(EC)、碳酸亚丙酯、碳酸甲乙酯(EMC)、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1，4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
在一些实施方式中，锂离子电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，锂离子电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，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。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
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。例如，图1是作为一个示例的方形结构的锂离子电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51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51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。锂离子电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，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一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个锂离子电池5可以是沿电池模块4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。进一步可以通过紧固件将该多个锂离子电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。
在一些实施方式中，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为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提 供的锂离子电池、电池模块、或电池包中的至少一种。所述锂离子电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(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，但不限于此。
作为所述用电装置，可以根据其使用需求来选择锂离子电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对锂离子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。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用锂离子电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1
(1)电解液的制备
在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、50g EMC、10gDMC和10g LiPF 6，充分搅拌溶解后得到本实施例用电解液。
(2)正极极片的制备
将正极活性材料LiNi 0.8Co 0.1Mn 0.1O 2、粘结剂聚偏氟乙烯、导电剂乙炔黑按照质量比8∶1∶1进行混合，加入溶剂NMP，在真空搅拌 机作用下获得正极浆料。将正极浆料以0.28g(干重)/1540.25mm 2的量均匀涂敷在厚度为13μm的正极集流体铝箔上。将铝箔在室温晾干后转移至120℃烘箱干燥1h，然后经过冷压、分切得到正极极片。
(3)负极极片的制备
将负极活性材料人造石墨、导电剂碳黑、粘结剂丙烯酸酯按照质量比92∶2∶6进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料。将负极浆料以0.2g(干重)/1540.25mm 2的量均匀涂覆在厚度为8μm的负极集流体铜箔上。将铜箔在室温晾干后转移至120℃烘箱干燥1h，然后经过冷压、分切得到负极极片。
(4)隔离膜
隔离膜采购自Cellgard企业，型号为cellgard2400。
(5)锂离子电池的组装
将正极极片、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，然后卷绕得到裸电芯。将容量为4.3Ah的裸电芯置于外包装箔中，将12g上述制备的电解液注入到干燥后的电池中，经过真空封装、静置、化成、整形等工序，获得锂离子电池。
实施例2
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、52g EMC、10g DMC、8g LiPF 6充分搅拌溶解后得到本实施例用电解液。
实施例3
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、52.5g EMC、10g DMC、7.5g LiPF 6充分搅拌溶解后得到本实施例用电解液。
实施例4
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、55g EMC、10g DMC、5g LiPF 6充分搅拌溶解后得到本实施例用电解液。
实施例5
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、16g EMC、40g DMC、10g LiPF 6、4g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例6
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、26g EMC、30g DMC、10g LiPF 6、4g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例7
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、26g EMC、30g DMC、10g LiPF 6、4g DTD充分搅拌溶解后得到本实施例用电解液。
实施例8
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、26g EMC、30g DMC、10g LiPF 6、4g双DTD充分搅拌溶解后得到本实施例用电解液。
实施例9
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、43g EMC、15g DMC、10g LiPF 6、2g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例10
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、47g EMC、10g DMC、10g LiPF 6、3g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例11
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、47g EMC、9g DMC、10g LiPF 6、4g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例12
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、25g EMC、30g DMC、10g LiPF 6、5g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例13
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、42g EMC、15g DMC、10g LiPF 6、3g 1，3-PS充分搅 拌溶解后得到本实施例用电解液。
实施例14
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、52g EMC、5g DMC、10g LiPF 6、3g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例15
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、46.5g EMC、12g DMC、10g LiPF 6、1.5g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
实施例16
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入30g EC、37g EMC、20g DMC、10g LiPF 6、3g 1，3-PS充分搅拌溶解后得到本实施例用电解液。
对比例1
锂离子电池的制备过程整体上参照实施例1，区别在于，电解液的制备步骤为：在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入33.75g EC、56.25g EMC和10g LiPF 6充分搅拌溶解后得到本对比例用电解液。
对比例2
锂离子电池的制备过程整体上参照实施例1，区别在于，在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入36.38g EC、60.62g  EMC、3g LiPF 6充分搅拌溶解后得到本对比例用电解液。
对比例3
锂离子电池的制备过程整体上参照实施例1，区别在于，在含水量＜10ppm的氩气气氛手套箱中，于烧杯中分别加入33g EC、55g EMC、12g LiPF 6充分搅拌溶解后得到本对比例用电解液。
将上述实施例1～16和对比例1～3中得到的正极活性材料分别如下所示进行性能测试。测试结果如下表2所示。
锂离子电池的性能测试：
1.初始放电DCR(直流电阻，Directive Current Resistance)测试
在25℃下，将锂离子电池分别以1C的充电倍率充电到4.25V，随后恒压充电到电流小于0.05C，然后1C放电倍率下放电30min，此时电压记为V1。随后以4C的放电倍率(4C下对应的电流为I)放电30s，此时电压记为V2。则锂离子电池的初始放电DCR＝(V1-V2)/I，
2. 60℃循环性能测试
在60℃下，将锂离子电池以1C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.05C，搁置5min，再以1C恒流放电至2.5V，所得容量记为初始容量C0。对上述同一个电池重复以上步骤，并同时开始计数，记录循环第300次后电池的放电容量C300，则循环300次后电池循环容量保持率P＝C300/C0*100％。
3. 60℃存储测试
在60℃下，将锂离子电池以0.5C恒流充电至4.35V，再恒压充电至电流为0.05C，此时测试锂离子电池的厚度并记为h0。之后将锂离子电池放入60℃的恒温箱，储存30天后取出，测试此时锂离子电池的厚度并记为h1。锂离子电池存储30天后的厚度膨胀率＝[(h1-h0)/h0]×100％。
Figure PCTCN2021120317-appb-000003
Figure PCTCN2021120317-appb-000004
Figure PCTCN2021120317-appb-000005
根据上述结果可知，通过在电解液溶剂中使用DMC，在相同的电解质盐浓度下，实施例1-16的DCR明显低于对比例，即获得了动力学性能的改善，并且高温循环性能也获得改善。
实施例5-16还在电解液中加入了正极牺牲型添加剂，从而在使用较高浓度DMC时能够抑制电池在高温下的膨胀并改善高温循环性能。由实施例5-10可以看出，当电池满足c≤10×b-10×|0.6-a/12.5|时，能够进一步改善电池的高温存储性能和循环性能。由实施例11-16可以看出，当电池还满足c≥10×(5-0.08×a/W)时，DCR较低，电池的动力学性能进一步获得改善。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (11)

  1. 一种锂离子电池，其具有正极极片、负极极片、隔离膜及电解液，所述电解液含有锂盐和溶剂，其中，
    基于电解液的总重量计，所述电解液中锂盐的质量百分比为a％，所述锂离子电池满足5≤a≤10；
    所述负极极片单面上的负载量为W克每1540.25mm 2，且a与W满足25≤a/W≤50，并且所述溶剂中含有碳酸二甲酯。
  2. 如权利要求1所述的锂离子电池，其中，基于电解液的总重量计，所述电解液中含有质量百分比为b％的正极牺牲型添加剂，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
    c≤10×b-10×|0.6-a/12.5|。
  3. 如权利要求2所述的锂离子电池，其中，所述正极牺牲型添加剂为下述通式之一所表示的化合物，
    Figure PCTCN2021120317-appb-100001
    其中，R代表碳原子数为1-10的亚烷基或代表碳原子，该碳原子任选地被碳原子数为1-9的烷基取代，
    可选地，所述正极牺牲型添加剂选自1，3-丙磺酸内酯、硫酸乙烯酯和双硫酸乙烯酯中的一种或多种。
  4. 如权利要求2至3中任一项所述的锂离子电池，其中，2≤b≤4。
  5. 如权利要求1至4中任一项所述的锂离子电池，其中，基于电解液的总重量计，所述碳酸二甲酯在电解液中的质量百分比为c％，所述锂离子电池满足：
    c≥10×(5-0.08×a/W)。
  6. 如权利要求1至5中任一项所述的锂离子电池，其中，所述正极极片包含正极活性材料LiNi xCo yMn zO 2，x+y+z＝1，0＜x＜1，0＜y＜1，0＜z＜1，可选为0.1≤x≤0.8，进一步可选为0.1≤x≤0.5。
  7. 如权利要求1至6中任一项所述的锂离子电池，其中，所述锂盐为LiPF 6。
  8. 如权利要求1至7中任一项所述的锂离子电池，其中，5≤a≤7.5。
  9. 一种电池模块，其包括权利要求1-8中任一项所述的锂离子电池。
  10. 一种电池包，其包括权利要求9所述的电池模块。
  11. 一种用电装置，其包括选自权利要求1-8中任一项所述的锂离子电池、权利要求9所述的电池模块或权利要求10所述的电池包中的一种以上。
PCT/CN2021/120317 2021-09-24 2021-09-24 锂离子电池、电池模块、电池包及用电装置 WO2023044752A1 (zh)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP2022546114A JP7478827B2 (ja) 2021-09-24 2021-09-24 リチウムイオン電池、電池モジュール、電池パックおよび電気装置
KR1020227027653A KR20230044139A (ko) 2021-09-24 2021-09-24 리튬 이온 전지, 전지 모듈, 전지 팩 및 전기 장치
CN202180084957.7A CN116670884A (zh) 2021-09-24 2021-09-24 锂离子电池、电池模块、电池包及用电装置
PCT/CN2021/120317 WO2023044752A1 (zh) 2021-09-24 2021-09-24 锂离子电池、电池模块、电池包及用电装置
EP21923586.8A EP4178001A4 (en) 2021-09-24 2021-09-24 LITHIUM-ION BATTERY, BATTERY MODULE, BATTERY PACK AND ELECTRICAL DEVICE
US18/347,184 US20230361352A1 (en) 2021-09-24 2023-07-05 Lithium-ion battery, battery module, battery pack and powered device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/120317 WO2023044752A1 (zh) 2021-09-24 2021-09-24 锂离子电池、电池模块、电池包及用电装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/347,184 Continuation US20230361352A1 (en) 2021-09-24 2023-07-05 Lithium-ion battery, battery module, battery pack and powered device

Publications (1)

Publication Number Publication Date
WO2023044752A1 true WO2023044752A1 (zh) 2023-03-30

Family

ID=85719842

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/120317 WO2023044752A1 (zh) 2021-09-24 2021-09-24 锂离子电池、电池模块、电池包及用电装置

Country Status (6)

Country Link
US (1) US20230361352A1 (zh)
EP (1) EP4178001A4 (zh)
JP (1) JP7478827B2 (zh)
KR (1) KR20230044139A (zh)
CN (1) CN116670884A (zh)
WO (1) WO2023044752A1 (zh)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107210490A (zh) * 2015-02-04 2017-09-26 3M创新有限公司 包含路易斯酸：路易斯碱复合物电解质添加剂的电化学电池
US20190356013A1 (en) * 2016-04-07 2019-11-21 StoreDot Ltd. Electrolyte additives in lithium-ion batteries
CN112838270A (zh) * 2021-03-18 2021-05-25 合肥国轩高科动力能源有限公司 改善电池高温胀气的电解液添加剂、电解液及包含该电解液的锂离子电池

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105336984B (zh) * 2014-07-31 2018-05-22 东莞新能源科技有限公司 锂离子电池及其电解液
EP3195388A1 (en) * 2014-08-14 2017-07-26 Solvay Sa Nonaqueous electrolyte compositions comprising sultone and fluorinated solvent
CN110265721B (zh) * 2018-09-19 2021-03-30 宁德时代新能源科技股份有限公司 锂离子二次电池
CN111864261A (zh) * 2019-04-26 2020-10-30 宁德时代新能源科技股份有限公司 电解液及锂离子电池
CN110649317B (zh) * 2019-08-29 2021-05-25 孚能科技(赣州)股份有限公司 硅基锂离子电池电解液和锂离子二次电池
CN110767939B (zh) * 2019-10-18 2021-06-11 宁德时代新能源科技股份有限公司 用于锂离子电池的电解液、锂离子电池、电池模块、电池包及装置
EP3913721B1 (en) * 2019-12-03 2022-11-23 Contemporary Amperex Technology Co., Limited Secondary battery, electrolyte, and device containing said secondary battery
CN111342028B (zh) * 2020-03-20 2021-07-20 吉林中溢炭素科技有限公司 一种石墨基负极的锂离子电池的化成方法
CN112615056B (zh) * 2020-12-22 2023-03-31 九江天赐高新材料有限公司 一种用于制备电解液的添加剂组合物、及包含添加剂组合物的电解液、锂离子二次电池
CN113140799A (zh) * 2021-05-28 2021-07-20 陕西煤业化工技术研究院有限责任公司 一种防过充低温电解液和基于其的锂离子电池

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107210490A (zh) * 2015-02-04 2017-09-26 3M创新有限公司 包含路易斯酸：路易斯碱复合物电解质添加剂的电化学电池
US20190356013A1 (en) * 2016-04-07 2019-11-21 StoreDot Ltd. Electrolyte additives in lithium-ion batteries
CN112838270A (zh) * 2021-03-18 2021-05-25 合肥国轩高科动力能源有限公司 改善电池高温胀气的电解液添加剂、电解液及包含该电解液的锂离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4178001A4 *

Also Published As

Publication number Publication date
JP7478827B2 (ja) 2024-05-07
KR20230044139A (ko) 2023-04-03
EP4178001A8 (en) 2023-07-05
EP4178001A1 (en) 2023-05-10
JP2023545876A (ja) 2023-11-01
US20230361352A1 (en) 2023-11-09
CN116670884A (zh) 2023-08-29
EP4178001A4 (en) 2023-10-11

Similar Documents

Publication Publication Date Title
WO2023082918A1 (zh) 锂离子电池、电池模块、电池包及用电装置
WO2023070268A1 (zh) 一种电化学装置及包含该电化学装置的用电装置
WO2023029002A1 (zh) 负极集流体、含有其的二次电池、电池模块、电池包及用电装置
WO2024012166A1 (zh) 二次电池及用电装置
US20230117520A1 (en) Electrolytic solution, secondary battery, and power consumption apparatus
WO2023130888A1 (zh) 二次电池、电池模块、电池包及其用电装置
WO2023082924A1 (zh) 极片、锂离子电池、电池模块、电池包及用电装置
WO2023010927A1 (zh) 二次电池、电池模块、电池包及用电装置
WO2023225799A1 (zh) 二次电池以及包含其的电池模块、电池包及用电装置
WO2023137624A1 (zh) 二次电池、电池模块、电池包以及用电装置
WO2023142024A1 (zh) 一种长寿命二次电池及电池模块、电池包和用电装置
WO2023050406A1 (zh) 锂离子电池及包含其的电池模块、电池包和用电装置
WO2023044752A1 (zh) 锂离子电池、电池模块、电池包及用电装置
WO2023130310A1 (zh) 电解液、二次电池和用电装置
WO2023000214A1 (zh) 电解液、二次电池、电池模块、电池包和用电装置
WO2023130210A1 (zh) 二次电池的补锂方法及充放电方法
WO2023077299A1 (zh) 正极浆料、正极极片、锂离子电池、电池模块、电池包和用电装置
WO2023087168A1 (zh) 电解液、二次电池、电池模块、电池包以及用电装置
WO2024065181A1 (zh) 负极组合物及制备方法、负极浆料及制备方法、负极极片及制备方法、二次电池、用电装置以及噻蒽类化合物的应用
WO2023193230A1 (zh) 电解液、二次电池、电池模块、电池包和用电装置
WO2022188163A1 (zh) 电解液、二次电池、电池模块、电池包和装置
WO2023141954A1 (zh) 锂离子电池、电池模块、电池包和用电装置
WO2023060587A1 (zh) 负极极片、二次电池、电池模块、电池包及用电装置
WO2023130212A1 (zh) 一种锂离子二次电池、电池模块、电池包和用电装置
WO2023082866A1 (zh) 二次电池、用于制备二次电池的方法、电池模块、电池包及用电装置

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2022546114

Country of ref document: JP

ENP Entry into the national phase

Ref document number: 2021923586

Country of ref document: EP

Effective date: 20220913

WWE Wipo information: entry into national phase

Ref document number: 202180084957.7

Country of ref document: CN