WO2019193756A1 - Batterie à électrolyte non aqueux et bloc-batterie - Google Patents

Batterie à électrolyte non aqueux et bloc-batterie Download PDF

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WO2019193756A1
WO2019193756A1 PCT/JP2018/014765 JP2018014765W WO2019193756A1 WO 2019193756 A1 WO2019193756 A1 WO 2019193756A1 JP 2018014765 W JP2018014765 W JP 2018014765W WO 2019193756 A1 WO2019193756 A1 WO 2019193756A1
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positive electrode
negative electrode
battery
nonaqueous electrolyte
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PCT/JP2018/014765
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English (en)
Japanese (ja)
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諒 原
圭吾 保科
大 山本
祐輝 渡邉
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株式会社 東芝
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Priority to JP2020511578A priority Critical patent/JP6874215B2/ja
Priority to PCT/JP2018/014765 priority patent/WO2019193756A1/fr
Publication of WO2019193756A1 publication Critical patent/WO2019193756A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M10/0568—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
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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

  • Embodiments of the present invention relate to a nonaqueous electrolyte battery and a battery pack.
  • the lithium ion secondary battery that is charged and discharged by moving lithium ions between the positive electrode and the negative electrode has an advantage of obtaining high energy density and high output. Utilizing this advantage, the application of lithium ion secondary batteries is being promoted widely from small applications such as portable electronic devices to large applications such as electric vehicles and power supply and demand adjustment.
  • a non-aqueous electrolyte battery using a lithium-titanium composite oxide having a lithium storage / release potential as high as about 1.55 V (vs. Li / Li + ) with respect to a lithium electrode as a negative electrode active material has been put into practical use. Yes.
  • the lithium-titanium composite oxide has excellent cycle performance because there is little volume change associated with charge / discharge.
  • a negative electrode including a lithium titanium composite oxide does not deposit lithium metal during lithium insertion / release, a secondary battery equipped with this negative electrode can be charged with a large current.
  • lithium manganate As for the positive electrode active material, lithium manganate (LiMn 2 O 4 ) has advantages that it is rich in resources, inexpensive, has little environmental impact, and has high safety in an overcharged state. Therefore, lithium manganate has been studied as an alternative material for lithium cobaltate (LiCoO 2 ). On the other hand, lithium manganate has a problem of deterioration of battery performance due to dissolution of manganese and gas generation under a high temperature environment.
  • An object of the present invention is to provide a nonaqueous electrolyte battery in which gas generation is suppressed, excellent input / output performance and excellent storage performance, and a battery pack including the nonaqueous electrolyte battery.
  • a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte.
  • the positive electrode includes a mixture of a spinel type lithium manganese composite oxide and lithium cobalt oxide.
  • the weight A of the spinel-type lithium manganese composite oxide and the weight B of the lithium cobaltate satisfy the relationship of 0.01 ⁇ B / (A + B) ⁇ 0.1.
  • the negative electrode contains spinel type lithium titanate.
  • the atomic percentage of the first P element based on C, O, Li, N, F, P and Mn contained in the positive electrode decreases in the depth direction from the surface of the positive electrode.
  • the atomic percentage of the first P element is 0.5 to at% or less.
  • the ratio of the state ratio of N element to P element in the positive electrode is 0.2 or more and 0.5 or less.
  • the atomic percentage of the second P element based on C, O, Li, N, F, P, Mn, and Ti contained in the negative electrode decreases from the negative electrode surface in the depth direction.
  • the atomic percentage of the second P element is 0.5 to at% or less.
  • a battery pack is provided.
  • the battery pack includes the nonaqueous electrolyte battery of the embodiment.
  • FIG. 1 is a graph showing an example of the positional relationship between the charge / discharge curve of the positive electrode and the charge / discharge curve of the negative electrode.
  • FIG. 2 is a graph showing another example of the positional relationship between the charge / discharge curve of the positive electrode and the charge / discharge curve of the negative electrode.
  • FIG. 3 is a cross-sectional view of the nonaqueous electrolyte battery of the first example according to the first embodiment cut in the thickness direction. 4 is an enlarged cross-sectional view of a portion A in FIG.
  • FIG. 5 is a partially cutaway perspective view of the non-aqueous electrolyte battery of the second example according to the first embodiment.
  • FIG. 6 is an exploded perspective view of an example battery pack according to the second embodiment.
  • FIG. 7 is a block diagram showing an electric circuit of the battery pack shown in FIG.
  • a battery including a positive electrode including a lithium cobalt composite oxide and a lithium manganese composite oxide and a negative electrode including a lithium titanium composite oxide operation of the positive and negative electrodes is adjusted by adjusting the open circuit voltage of the positive electrode and the charge capacity ratio of the positive and negative electrodes.
  • the state of charge (State ⁇ Of Charge; SOC) and storage temperature of the battery are adjusted.
  • a film is formed on the surface of the negative electrode active material from which lithium ions are inserted and desorbed at a potential of 1.2 V (vs. Li / Li + ) or more with respect to the lithium potential of lithium titanate, etc.
  • Attempts have been made to suppress gas generation in As attempted, gas generation during high-temperature storage can be suppressed by forming a film on the surface of the negative electrode active material.
  • the reaction between the positive electrode and the electrolyte cannot be suppressed, and the gas suppression effect is reduced.
  • a nonaqueous electrolyte battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte.
  • the positive electrode contains a mixture of spinel type lithium manganese oxide and lithium cobalt oxide.
  • the weight A of the spinel type lithium manganese composite oxide and the weight B of the lithium cobalt oxide satisfy the relationship of 0.01 ⁇ B / (A + B) ⁇ 0.1.
  • the atomic percentage of the first P element based on C, O, Li, N, F, P, and Mn contained in the positive electrode decreases in the depth direction from the surface of the positive electrode. At the first depth in the range of 3 to 10 nm from the surface of the positive electrode, the atomic percentage of the first P element is 0.5 to at% or less.
  • the ratio of the state ratio of N element to P element in the positive electrode is 0.2 or more and 0.5 or less.
  • the negative electrode contains spinel type lithium titanate.
  • the atomic percentage of the second P element based on C, O, Li, N, F, P, Mn and Ti contained in the negative electrode decreases from the surface of the negative electrode in the depth direction. At the second depth in the range of 20 to 30 nm from the surface of the negative electrode, the atomic percentage of the second P element is 0.5 to at% or less.
  • the present inventors continued research and found the following findings. That is, by satisfying all the following conditions in a non-aqueous electrolyte secondary battery including a spinel type lithium manganese complex oxide and lithium cobaltate in the positive electrode and a spinel type lithium titanate in the negative electrode, the battery can be operated in a high temperature and high charge range. Even when used, gas generation can be remarkably suppressed, and a non-aqueous electrolyte secondary battery with excellent life performance can be provided.
  • the weight ratio is 0.01 ⁇ B / (A (+ B) ⁇ 0.1.
  • the atomic percentage of the first P element based on C, O, Li, N, F, P and Mn contained in the positive electrode is determined in the depth direction from the positive electrode surface (for example, a positive electrode described later).
  • the first depth is a direction from the surface of the positive electrode into the positive electrode (for example, a direction toward the inside of a positive electrode active material-containing layer described later), that is, a depth direction.
  • the ratio of the state ratio of N element to P element in the positive electrode is set to 0.2 or more and 0.5 or less.
  • the conditions for the negative electrode are as follows.
  • the atomic percentage of the second P element based on C, O, Li, N, F, P, Mn, and Ti contained in the negative electrode is in the depth direction from the negative electrode surface (for example, a negative electrode active material-containing layer described later)
  • the second depth at which the atomic percentage of the second P element is 0.5 at% or less and the range is from 20 nm to less than 30 nm from the negative electrode surface.
  • the second depth is a direction from the negative electrode surface into the negative electrode (for example, a direction toward the inside of a negative electrode active material-containing layer described later), that is, a depth direction.
  • Such a positive electrode and a negative electrode can be, for example, a positive electrode and a negative electrode in which a film containing P and N elements is appropriately formed on the surface.
  • the nonaqueous electrolyte battery according to the embodiment including the positive electrode and the negative electrode having such a surface state is a reaction between the positive electrode and the electrolyte and the negative electrode and the electrolyte in the charged state while suppressing an increase in the resistance value of the positive electrode and the negative electrode. Can be suppressed.
  • the nonaqueous electrolyte battery according to the embodiment can remarkably suppress gas generation even when used in a high temperature and high charge region, and can exhibit excellent life performance.
  • the nonaqueous electrolyte battery according to the embodiment can suppress an increase in the resistance values of the positive electrode and the negative electrode, it can exhibit excellent input performance and output performance at low temperatures, that is, excellent low temperature performance.
  • B / (A + B) is less than 0.01, the oxidation effect of the spinel type lithium manganese composite oxide is strong, and the reaction with the electrolyte may be increased.
  • B / (A + B) is 0.1 or more, the coating on the positive electrode increases and the resistance of the positive electrode increases.
  • lithium cobaltate exhibits a catalytic action for film formation, and when B / (A + B) is 0.1 or more, the catalytic action becomes remarkable. More preferably, 0.01 ⁇ B / (A + B) ⁇ 0.04.
  • the atomic percentage of the first P element decreases from the positive electrode surface in the depth direction of the positive electrode, and the atomic percentage of the first P element at the first depth in the range of 3 to 10 nm from the positive electrode surface.
  • the positive electrode whose N is 0.5 to at% or less includes a film containing P element and N element, and the atomic percentage occupied by the P element among the elements constituting the film may be more than 0.5 to at%.
  • the atomic percentage of the first P element indicates the ratio of the P element in C, O, Li, N, F, P, and Mn contained in an arbitrary region of the positive electrode.
  • the atomic percentage of the first P element exceeds 0.5% at% at a third depth in the range of less than 3 nm from the surface of the positive electrode.
  • the third depth may be a depth in the thickness direction at a position in the coating on the positive electrode surface.
  • the atomic percentage of the first P element exceeds 0.5% at%.
  • This region may be a region occupied by the coating in the positive electrode. If it becomes deeper than this region, the atomic percentage of the first P element decreases to 0.5% at% or less. That is, at the first depth from the surface of the positive electrode, the atomic percentage of the first P element changes from a value exceeding 0.5 at% to a value of 0.5 at% or less.
  • the film containing the P element and the N element is not sufficiently formed on the positive electrode surface.
  • the reaction between the positive electrode and the non-aqueous electrolyte cannot be sufficiently suppressed, and as a result, gas generation in the high temperature and high charge region cannot be sufficiently suppressed.
  • the depth at which the atomic percentage of the first P element is 0.5 at% or less is 10 nm or more, a coating containing P and N is excessively formed on the surface of the positive electrode. In this case, the resistance value of the positive electrode is increased.
  • a non-aqueous electrolyte battery having such a surface state positive electrode is inferior in input and output performance particularly at a low temperature.
  • the ratio of the state ratio of N element to P element is less than 0.2, the effect of suppressing gas generation becomes insufficient. This is presumably because the N element has an effect of suppressing the decomposition of the coating itself.
  • the ratio of the state ratio of the N element to the P element exceeds 0.5, the resistance value of the positive electrode increases. This suggests that when N element is excessive, lithium conductivity is lowered.
  • the atomic percentage of the first P element decreases in the depth direction from the positive electrode surface, and the first depth at which the atomic percentage of the first P element becomes 0.5 or less is 3 nm from the positive electrode surface.
  • the ratio of the state ratio of the N element to the P element contained in the positive electrode is preferably 0.2 or more and 0.5 or less.
  • the atomic percentage of the second P element decreases from the negative electrode surface in the depth direction of the negative electrode, and the atomic percentage of the second P element decreases at a second depth in the range of 20 to 30 nm from the negative electrode.
  • the negative electrode having a concentration of 0.5 to at% or less includes a coating containing P element and N element, and the atomic percentage occupied by the P element among the elements constituting the coating may exceed 0.5 to at%.
  • the atomic percentage of the second P element indicates the proportion of the P element in C, O, Li, N, F, P, Mn, and Ti contained in an arbitrary region of the negative electrode.
  • the atomic percentage of the second P element exceeds 0.5% at% at the fourth depth in the range of less than 20 nm from the surface of the negative electrode.
  • the fourth depth may be a depth in the thickness direction at a position in the coating on the negative electrode surface.
  • the atomic percentage of the second P element exceeds 0.5% at%.
  • This region may be a region occupied by the coating in the negative electrode.
  • the atomic percentage of the second P element decreases to 0.5% at% or less. That is, at the second depth from the surface of the negative electrode, the atomic percentage of the second P element changes from a value exceeding 0.5 at% to a value of 0.5 at% or less.
  • the film containing the P element and the N element is not sufficiently formed on the negative electrode surface.
  • the reaction between the negative electrode and the nonaqueous electrolyte cannot be sufficiently suppressed, and as a result, gas generation in the high temperature and high charge region cannot be sufficiently suppressed.
  • the depth at which the atomic percentage of the second P element is 0.5 at% or less is 30 nm or more, the coating film containing P and N is excessively formed on the surface of the negative electrode. In this case, the resistance value of the negative electrode is increased.
  • a non-aqueous electrolyte battery having such a surface-state negative electrode is particularly inferior in input and output performance at a low temperature.
  • the atomic percentage of the second P element decreases from the negative electrode surface in the depth direction, and the second depth at which the atomic percentage of the second P element is 0.5 or less is 20 nm from the negative electrode surface. It is preferably in the range of less than 30 nm.
  • the spinel-type lithium manganese composite oxide is desirably represented by the general formula LiM x Mn 2-x O 4 .
  • M is at least one element selected from the group consisting of Mg, Ti, Cr, Fe, Co, Zn, Al, Li and Ga.
  • the subscript x in the general formula is in the range of 0.22 ⁇ x ⁇ 0.7.
  • Spinel type lithium manganese composite oxide is included in the positive electrode in the form of particles, for example.
  • the form of the particles of the spinel type lithium manganese composite oxide is not particularly limited, and may be either primary particles or secondary particles in which primary particles are aggregated. It is desirable to include secondary particles.
  • the particle size of the spinel type lithium manganese composite oxide particles is not particularly limited.
  • Lithium cobaltate is represented by, for example, the general formula Li x CoO 2 .
  • Lithium cobaltate in which the subscript x in the general formula is in the range of 0 ⁇ x ⁇ 1.1 is desirable.
  • Lithium cobaltate is contained in the positive electrode in the form of particles, for example.
  • the form of lithium cobalt oxide particles is not particularly limited, and may be either primary particles or secondary particles in which primary particles are aggregated. It is desirable to have primary particles as a main component.
  • the primary particles are, for example, a state where the number of primary particles accounts for more than half of the total number of particles of primary particles and secondary particles.
  • the particle diameter of the lithium cobalt oxide particles is not particularly limited.
  • Examples of the spinel type lithium titanate include Li 4 + x Ti 5 O 12 (x is a value that varies depending on charge and discharge, and 0 ⁇ x ⁇ 3).
  • Spinel type lithium titanate is contained in the negative electrode in the form of particles, for example.
  • the form of the spinel-type lithium titanate particles is not particularly limited, and may be either primary particles or secondary particles in which primary particles are aggregated.
  • the particle size of the spinel type lithium titanate particles is not particularly limited.
  • the open circuit voltage (OCV) of the positive electrode when the battery voltage of the nonaqueous electrolyte battery is 1.8 V is 3.9 V (vs. Li / Li + ) or more and 4.0 V (vs. Li / Li + ) or less. It is desirable to be within the range.
  • OCV open circuit voltage
  • the positive and negative electrodes It can be said that the positional relationship (charge / discharge curve balance) of the charge / discharge curve is properly adjusted.
  • the closed circuit voltage (CCV) of the positive electrode at that time can be regarded as the open circuit voltage of the positive electrode.
  • the closed circuit voltage of the positive electrode is when the battery voltage of the nonaqueous electrolyte battery is 1.8 V. It can be regarded as the open circuit voltage of the positive electrode.
  • the open circuit voltage of the positive electrode at a battery voltage of 1.8 V exceeds 4.0 V (vs. Li / Li + ).
  • the rate of progress is not appropriate between the self-discharge reaction at the positive electrode and the self-discharge reaction at the negative electrode, and the reaction at the negative electrode proceeds compared to the reaction at the positive electrode. It can be said that it is in a state of being stuck.
  • the open circuit voltage of the positive electrode exceeds 4.0 V (vs. Li / Li + )
  • the operating potential of the positive electrode is high, and the oxidative decomposition of the electrolyte becomes remarkable, which is not desirable.
  • the open circuit voltage of the positive electrode at a battery voltage of 1.8 V includes a range of less than 3.9 V (vs. Li / Li + ).
  • the rate of progress is not appropriate between the self-discharge reaction at the positive electrode and the self-discharge reaction at the negative electrode, and the reaction at the positive electrode proceeds compared to the reaction at the negative electrode. It can be said that it is in a state.
  • the negative electrode tends to be overcharged, and the negative electrode material tends to deteriorate.
  • the degree of deviation in the charge / discharge behavior of the positive electrode and the charge / discharge of the negative electrode The ratio with the degree of deviation of the discharge behavior is not appropriate.
  • the charge / discharge behavior of the positive electrode means a change in the positive electrode potential with respect to the battery capacity (charged state) represented by the charge / discharge curve of the positive electrode.
  • the charge / discharge behavior of the negative electrode means a change in the negative electrode potential with respect to the battery capacity (charged state) represented by the charge / discharge curve of the negative electrode.
  • the deviation in charge / discharge behavior of the positive electrode is too small as compared with the deviation in charge / discharge behavior of the negative electrode. Such a state will be described with reference to FIG.
  • FIG. 1 is a graph showing an example of a positional relationship between a charge / discharge curve of a positive electrode and a charge / discharge curve of a negative electrode in a nonaqueous electrolyte battery.
  • a positive electrode charge / discharge curve 70 and a negative electrode charge / discharge curve 80 indicated by broken lines represent the respective charge / discharge curves of the positive electrode and the negative electrode in which the self-discharge reaction does not proceed.
  • a positive electrode charge / discharge curve 71 and a negative electrode charge / discharge curve 81 indicated by solid lines represent the charge / discharge curves of the positive electrode and the negative electrode after the self-discharge reaction, respectively.
  • the behavior of the charge / discharge of the positive electrode shifts from the state of the positive electrode charge / discharge curve 70 indicated by the broken line to the charge side (the battery capacity is higher) with the self-discharge reaction at the positive electrode, and the positive electrode charge / discharge curve 71 indicated by the solid line.
  • the state changes.
  • the degree of this shift is shown as a shift width S1.
  • the charge / discharge behavior of the negative electrode is shifted from the state of the negative electrode charge / discharge curve 80 indicated by the broken line to the charge side (the battery capacity is higher) with the self-discharge reaction at the negative electrode, and the negative electrode charge / discharge indicated by the solid line It changes to the state of the curve 81.
  • the degree of this deviation is illustrated as a deviation width S2.
  • the deviation width S2 of the charge / discharge behavior of the negative electrode is larger than the deviation width S1 of the charge / discharge behavior of the positive electrode toward the charge side.
  • the difference between the positive electrode potential and the negative electrode potential that is, the open circuit voltage of the positive electrode at the position where the battery voltage becomes 1.8 V increases, and exceeds, for example, 4.0 V (vs. Li / Li + ).
  • the positive electrode charge / discharge curve 71 the nonaqueous electrolyte battery is charged and the positive electrode potential is increased.
  • the negative electrode charge / discharge curve 81 is greatly shifted to the charge side as compared with the positive electrode charge / discharge curve 71, in the region where the battery capacity is high, the change in the negative electrode potential due to charging is small, while the positive electrode potential is Continue to rise. Thus, the positive electrode operating potential may reach a high value, and the oxidative decomposition of the electrolyte may be promoted.
  • FIG. 2 is a graph showing another example of the positional relationship between the charge / discharge curve of the positive electrode and the charge / discharge curve of the negative electrode in the nonaqueous electrolyte battery.
  • a positive electrode charge / discharge curve 70 and a negative electrode charge / discharge curve 80 indicated by broken lines represent the charge / discharge curves of the positive electrode and the negative electrode, respectively, in which the self-discharge reaction does not proceed, as in FIG.
  • a positive electrode charge / discharge curve 72 and a negative electrode charge / discharge curve 82 indicated by solid lines represent the respective charge / discharge curves of the positive electrode and the negative electrode after the self-discharge reaction.
  • the charge / discharge behavior of the positive electrode shifts from the state of the positive electrode charge / discharge curve 70 indicated by the broken line to the charge side (the battery capacity is higher) with the self-discharge reaction at the positive electrode, and the positive electrode charge / discharge curve 72 indicated by the solid line.
  • the state changes.
  • the degree of this deviation is illustrated as a deviation width S3.
  • the charge / discharge behavior of the negative electrode is shifted from the state of the negative electrode charge / discharge curve 80 indicated by the broken line to the charge side (the battery capacity is higher) with the self-discharge reaction at the negative electrode, and the negative electrode charge / discharge indicated by the solid line It changes to the state of the curve 82.
  • the degree of this shift is illustrated as a shift width S4.
  • the deviation width S4 of the charge / discharge behavior of the negative electrode is smaller than the deviation width S3 of the charge / discharge behavior of the positive electrode toward the charge side.
  • the difference between the positive electrode potential and the negative electrode potential that is, the open circuit voltage of the positive electrode at the position where the battery voltage becomes 1.8 V is lowered, for example, lower than 3.9 V (vs. Li / Li + ).
  • the change in the negative electrode potential accompanying the change in capacity (SOC change) is small in most of the charge / discharge of the nonaqueous electrolyte battery, but the negative electrode potential rapidly decreases in the region where the charge capacity is high. .
  • the negative electrode operating potential may reach a very low value, and the deterioration of the negative electrode may be promoted.
  • the ratio Q p / Q n between the positive electrode capacity and the negative electrode capacity is preferably 0.8 or more and 1.1 or less.
  • the charge capacity per unit area of the positive electrode in the charge / discharge range of 3.0 V or more and 4.25 V or less (vs. Li / Li + ) is defined as Q p (mAh / m 2 ).
  • the capacity ratio Q p / Q n is less than 0.8, the energy density of the battery decreases.
  • lithium manganese oxides such as lithium manganate (LiMn 2 O 4 ) easily elute manganese on the low potential side, and the eluted manganese acts on the negative electrode to promote gas generation from the negative electrode. It is believed that there is.
  • the nonaqueous electrolyte battery according to the embodiment can remarkably suppress gas generation even when used in a high temperature and high charge region, and can exhibit excellent life performance. Excellent input / output performance even at low temperatures.
  • Such a nonaqueous electrolyte battery can be obtained, for example, by reacting a positive electrode and a negative electrode with a solute other than the electrolyte contained in the nonaqueous electrolyte during the initial charge and aging treatment of the nonaqueous electrolyte battery. it can.
  • the reaction between a solute (a solute other than the electrolyte) contained in the nonaqueous electrolyte and the positive electrode and the negative electrode may be accompanied by self-discharge of the positive electrode and the negative electrode. That is, by setting the surface state of the positive electrode and the negative electrode to the above state, the charged state of the positive electrode and the charged state of the negative electrode can be intentionally shifted. In this way, the positional relationship between the charge / discharge curve of the positive electrode and the charge / discharge curve of the negative electrode can be controlled.
  • the reaction on the positive electrode and the negative electrode can be controlled by adjusting the temperature and SOC during aging.
  • temperature has a large influence on the reaction on the negative electrode
  • SOC has a large influence on the reaction on the positive electrode. Therefore, by optimizing the combination of the imide salt content, temperature and SOC, a necessary and sufficient amount of imide salt can be decomposed not only on the negative electrode but also on the positive electrode. This is presumably because the lithium cobalt oxide contained in the positive electrode has a catalytic action on the decomposition reaction of the imide salt and other electrolyte components on the positive electrode.
  • the catalytic ability of lithium cobaltate can be controlled, and film formation on the positive electrode can be controlled.
  • the life performance can be improved without excessively increasing the initial resistance.
  • the reaction time varies depending on the time of aging.
  • a solute such as an imide salt contained in the non-aqueous electrolyte is contained in an amount of 0.3% by weight to 1% by weight with respect to 100% by weight of the non-aqueous electrolyte solvent.
  • the aging conditions are preferably as follows, for example. It is desirable to adjust the SOC at the time of aging to, for example, 30% or more and 80% or less. It is desirable to set the temperature during aging to, for example, 50 ° C. or more and 80 ° C. or less. The aging time is desirably set to, for example, 50 hours or more and 100 hours or less.
  • a non-aqueous electrolyte battery to be measured is prepared.
  • the target non-aqueous electrolyte battery is a battery having a capacity of 80% or more of the rated capacity.
  • the capacity maintenance rate of the battery is determined by the following method.
  • the battery is charged to the operating upper limit voltage.
  • the current value at this time is a current value corresponding to the 1C rate obtained from the rated capacity.
  • the voltage is held for 3 hours.
  • the battery is discharged to the lower limit of the operating voltage at a rate of 1C.
  • the above charging / discharging is performed for a total of 3 cycles, and the discharge capacity obtained in the third additional cycle is recorded.
  • the ratio of the obtained discharge capacity to the rated capacity is defined as the capacity maintenance rate.
  • composition of the active material contained in the positive electrode and the negative electrode can be measured by powder X-ray diffraction (XRD) measurement as follows.
  • the nonaqueous electrolyte battery is discharged in order to make the nonaqueous electrolyte battery safe to dismantle.
  • the nonaqueous electrolyte battery is discharged at 1 C until the battery voltage reaches 1.0V.
  • lithium ions remaining in the negative electrode active material may exist even when the battery is discharged. Therefore, care should be taken when analyzing the X-ray diffraction pattern.
  • the battery in such a state is disassembled in a glove box filled with argon.
  • An electrode (positive electrode or negative electrode) containing the active material to be measured is taken out from the decomposed battery.
  • the electrode is washed with a suitable solvent.
  • a suitable solvent for example, ethyl methyl carbonate may be used. If the cleaning is insufficient, an impurity phase such as lithium carbonate or lithium fluoride may be mixed under the influence of lithium ions remaining in the electrode. In that case, for example, an airtight container that can perform measurement in an inert gas may be used as the measurement atmosphere.
  • vacuum drying is performed. After drying, the active material-containing layer (positive electrode active material-containing layer or negative electrode active material-containing layer) is separated from the current collector using a spatula or the like to obtain a powdery sample containing the active material.
  • the crystal structure of the active material is identified by powder X-ray analysis measurement on the powder sample.
  • the measurement is performed in a measurement range where 2 ⁇ is 10 ° to 90 ° using CuK ⁇ rays as a radiation source. By this measurement, an X-ray diffraction pattern of the compound contained in the selected particle can be obtained.
  • X-ray source Cu target Output: 45 kV, 200 mA
  • Solar slit 5 ° for both incident and reception Step width: 0.02 deg
  • Scan speed 20 deg / min
  • Semiconductor detector D / teX Ultra 250
  • Sample plate holder Flat glass sample plate holder (thickness 0.5 mm) Measurement range: 10 ° ⁇ 2 ⁇ ⁇ 90 °.
  • the sample containing the active material is observed with a scanning electron microscope (SEM).
  • SEM scanning electron microscope
  • the particle size distribution of the selected particles is selected to be as wide as possible.
  • the type and composition of the constituent elements of the active material are specified by energy dispersive X-ray spectroscopy (EDX). Thereby, the kind and quantity of elements other than Li among the elements contained in each selected particle
  • EDX energy dispersive X-ray spectroscopy
  • the powdery sample collected from the active material-containing layer as described above is washed with acetone and dried.
  • the obtained powder is dissolved with hydrochloric acid, and the conductive agent is removed by filtration, and then diluted with ion-exchanged water to prepare a measurement sample.
  • the ratio of metals contained in the measurement sample is calculated by inductively coupled plasma emission spectroscopy (Inductively-Coupled-Plasma-Atomic-Emission-Spectroscopy; ICP-AES).
  • the mass ratio is estimated from the content ratio of elements unique to each active material.
  • the ratio between the inherent element and the mass of the active material is determined from the composition of the constituent elements determined by energy dispersive X-ray spectroscopy.
  • the measurement sample obtained from the positive electrode active material-containing layer can contain spinel type lithium manganese composite oxide and lithium cobalt oxide.
  • the chemical formula and formula amount of the spinel type lithium manganese composite oxide and lithium cobaltate are calculated from the obtained metal ratio, and the spinel type lithium manganese composite oxide and cobalt acid contained in the positive electrode material layer of a predetermined weight collected. Find the weight ratio of lithium.
  • the coating on the positive electrode surface and the coating on the negative electrode surface can be measured by surface elemental analysis by X-ray photoelectron spectroscopy (XPS).
  • the nonaqueous electrolyte battery is discharged, disassembled in a glove box in an inert atmosphere, and the positive electrode and the negative electrode are taken out. Each electrode is washed with dimethyl carbonate and then vacuum-dried.
  • the electrode is introduced into the XPS apparatus while maintaining an inert atmosphere, and the spectrum is measured while etching the electrode surface with argon gas.
  • the atomic percentage (atom%) calculated by the relative sensitivity coefficient attached to the apparatus is obtained for each element to be measured with respect to the etching depth (nm) obtained as the SiO 2 thermal oxide film conversion value.
  • a measuring device for example, VG Theta Probe manufactured by Thermo Fisher Scientific can be used. It is desirable to obtain an atomic percentage every 1 nm of etching depth.
  • the atomic percentage for each element of C, O, Li, N, F, P and Mn with respect to the etching depth is obtained. From the measurement result, the atomic percentage of the P element based on C, O, Li, N, F, P and Mn at an arbitrary depth from the positive electrode surface, that is, the atomic percentage of the first P element can be calculated. it can.
  • the etching amount E in terms of SiO 2 corresponds to the depth from the surface of the positive electrode.
  • the atomic percentage about each element of C, O, Li, N, F, P, Mn, and Ti with respect to the etching depth is obtained. From the measurement result, the atomic percentage of P element based on C, O, Li, N, F, P, Mn and Ti at an arbitrary depth from the negative electrode surface, that is, the atomic percentage of the second P element is calculated. be able to.
  • the etching amount E in terms of SiO 2 corresponds to the depth from the negative electrode surface.
  • C, O, Li, N, F, P, Mn contained in the negative electrode corresponding to the etching amount E (nm) in terms of SiO 2 and Ti content can be measured.
  • the atomic percentage of P element decreases from the value exceeding 0.5 at% in the depth direction from the negative electrode surface, and the atomic percentage of P element is at a depth in the range of 20 nm to less than 30 nm from the negative electrode surface.
  • it is 0.5 at% or less, it can be determined that a surface state in which a film containing P element and N element is formed on the negative electrode surface is obtained.
  • the depth from the negative electrode surface where the atomic percentage of the P element has turned to a value of 0.5 at% or less corresponds to the second depth described above.
  • a non-aqueous electrolyte battery to be measured is prepared.
  • the prepared nonaqueous electrolyte battery is discharged at a constant current of 0.2 C until the battery voltage reaches 1.8V.
  • the discharged nonaqueous electrolyte battery is disassembled in an inert atmosphere such as argon.
  • the positive electrode and the negative electrode are taken out from the disassembled nonaqueous electrolyte battery. At this time, care should be taken so that the positive electrode and the negative electrode do not come into electrical contact.
  • the extracted positive electrode is immersed in an organic solvent such as ethyl methyl carbonate and washed. After washing, the positive electrode is dried.
  • the positive electrode and the negative electrode can be accommodated in the battery in a state of an electrode group in which a separator is disposed, for example.
  • the electrode group is taken out in a state in which a repeating structure of -positive electrode-separator-negative electrode-separator-positive electrode is held.
  • the taken-out electrode group is separated into a separator, a positive electrode, and a negative electrode using, for example, tweezers.
  • the positive electrode thus obtained is washed and dried.
  • an electrode piece having a size of about 5 mm square is cut out from the dried positive electrode using a cutter. This is a sample.
  • the electrode piece prepared as a sample is placed on the measurement stage.
  • the measurement stage on which the electrode pieces are installed is introduced into a photoelectron spectrometer (for example, VG Theta Probe manufactured by Thermo Fisher Scientific), and the inside of the apparatus is evacuated.
  • a photoelectron spectrometer for example, VG Theta Probe manufactured by Thermo Fisher Scientific
  • measurement is carried out using Al K ⁇ rays as excitation X-rays and an X-ray spot diameter of 800 ⁇ 400 ⁇ m.
  • a photoelectron spectrum for the sample is obtained.
  • the state ratio of each element is calculated as follows. First, the constituent elements serving as parameters are boron (B), carbon (C), oxygen (O), lithium (Li), nitrogen (N), fluorine (F), phosphorus (P), sulfur (S), Titanium (Ti), manganese (Mn), cobalt (Co), nickel (Ni), and niobium (Nb) are used. Next, the state ratio of each element is calculated using the average matrix relative sensitivity coefficient method described in ISO 18118 (2015).
  • B is a B 1s peak appearing in a binding energy region of 185 eV to 200 eV
  • C is a C 1s peak appearing in a binding energy region of 280 eV to 295 eV
  • O is an O 1s peak appearing in a binding energy region of 520 eV to 545 eV
  • Li is a Li 1s peak appearing in a binding energy region of 50 eV to 60 eV
  • N is a N 1s peak appearing in a binding energy region of 390 eV to 410 eV
  • F is an F 1s peak appearing in a binding energy region of 675 eV to 695 eV.
  • P is a P 2p peak appearing in a binding energy region of 125 eV to 145 eV
  • S is an S 2p peak appearing in a binding energy region of 160 eV to 180 eV
  • Ti is Ti 2p appearing in a binding energy region of 452 eV to 462 eV.
  • Pi Mn is a Mn 2p peak appearing in the binding energy region of 630 eV to 660 eV
  • Co is a Co 2p peak appearing in the binding energy region of 780 eV to 810 eV
  • Ni is Ni appearing in the binding energy region of 64 eV to 72 eV.
  • a 3p peak is used, and Nb is a Nb 3p peak that appears in a binding energy region of 355 eV to 385 eV.
  • the battery In order to prevent the components of the nonaqueous electrolyte battery prepared for inspection from reacting with atmospheric components and moisture during disassembly, the battery is placed in an inert gas atmosphere, such as an argon gas glove box. Next, the non-aqueous electrolyte battery is opened in such a glove box. For example, in the case of a battery in which an exterior member made of a laminate film is used, the non-aqueous electrolyte battery can be opened by cutting the heat seal portions around the positive electrode current collecting tab and the negative electrode current collecting tab.
  • the positive electrode and the negative electrode are stored in the battery in the state of an electrode group in which a separator is disposed between them, the positive electrode and the negative electrode are taken out in the state of the electrode group.
  • the extracted electrode group includes a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab are cut while being careful not to short-circuit the positive and negative electrodes. Thereafter, the taken-out electrode group is disassembled and decomposed into a positive electrode, a negative electrode, and a separator.
  • the electrodes (positive electrode and negative electrode) are washed with a solvent.
  • a solvent chain carbonate (dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, etc.) or acetonitrile can be used.
  • vacuum is maintained while the inert gas atmosphere is maintained, and drying is performed. Drying can be performed, for example, under a vacuum of 50 ° C. for 10 hours. Measure the weight of the electrode.
  • the electrode is cut into, for example, a 3 cm square.
  • the state of charge of the battery may be any state.
  • the total area of both surfaces of the cut positive electrode piece is measured.
  • a bipolar electrode or a three electrode electrochemical measurement cell using a cut positive electrode piece as a working electrode and using a lithium metal foil as a counter electrode and a reference electrode is prepared.
  • the produced electrochemical measurement cell is charged to an upper limit potential of 4.25 V (vs. Li / Li + ).
  • the current value at this time is 0.1 mA / cm 2 .
  • discharging is performed until the positive electrode potential reaches 3.0 V (vs. Li / Li + ) at the same current value as that of the charge.
  • the above charging / discharging is performed for a total of 3 cycles, and the charge capacity obtained in the additional 3 cycles is recorded.
  • the recorded charge capacity by dividing by the area of the positive electrode piece (sum of both sides), and calculates the charging capacity Q p per unit area of the positive electrode.
  • the recorded charge capacity by dividing the area of Fukyokuhen to calculate the charge capacity Q n per unit area of the negative electrode.
  • a value obtained by dividing the obtained positive electrode capacity Q p by the negative electrode capacity Q n is defined as a ratio Q p / Q n of the positive electrode capacity to the negative electrode capacity.
  • the nonaqueous electrolyte battery is discharged at 1 C until the battery voltage reaches 1.0 V, and disassembled in a glove box in an inert atmosphere.
  • the nonaqueous electrolyte contained in the battery and electrode group is extracted. If the non-aqueous electrolyte can be taken out from the location where the non-aqueous electrolyte battery is opened, sampling is performed as it is.
  • the electrode group is further disassembled, and, for example, a separator containing the nonaqueous electrolyte is taken out.
  • the nonaqueous electrolyte in the separator is extracted using, for example, a centrifuge and sampling is performed.
  • the non-aqueous electrolyte can be extracted by immersing the electrode and the separator in an acetonitrile solution.
  • the weight of the acetonitrile solution is measured before and after extraction, and the extraction amount is calculated.
  • the non-aqueous electrolyte sample thus obtained is subjected to composition analysis using, for example, gas chromatography mass spectrometry (Gas-Chromatography-Mass-Spectrometry; GC-MS apparatus), nuclear magnetic resonance (Nuclear-Magnetic-Resonance; NMR) spectroscopy, etc. .
  • a calibration amount of methyl propionate or ethyl propionate is prepared, and the mixing ratio in the non-aqueous electrolyte is calculated.
  • a separator can be disposed between the positive electrode and the negative electrode in addition to the positive electrode, the negative electrode, and the nonaqueous electrolyte.
  • the nonaqueous electrolyte battery according to the embodiment may further include an exterior member for housing these.
  • nonaqueous electrolyte the positive electrode, the negative electrode, the separator, and the exterior member will be described.
  • Non-aqueous electrolyte examples include a liquid non-aqueous electrolyte prepared by dissolving an electrolyte (solute) in a non-aqueous solvent, and a gel non-aqueous electrolyte obtained by combining a liquid non-aqueous electrolyte and a polymer material. .
  • Examples of the electrolyte include lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), and lithium difluorophosphate.
  • Examples thereof include lithium salts such as (LiPO 2 F 2 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium bistrifluoromethylsulfonylimide [LiN (CF 3 SO 2 ) 2 ]. These electrolytes may be used alone or in combination of two or more.
  • the electrolyte is preferably dissolved in a range of 0.5 mol / L to 2.5 mol / L with respect to the nonaqueous solvent.
  • non-aqueous solvent examples include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC); dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and the like.
  • cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC); dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and the like.
  • Chain carbonates Cyclic ethers such as tetrahydrofuran (THF) and 2-methyltetrahydrofuran (2MeTHF); Chain ethers such as dimethoxyethane (DME); Cyclic esters such as ⁇ -butyrolactone (BL); Methyl acetate, ethyl acetate, propionic acid Examples thereof include chain esters such as methyl and ethyl propionate; organic solvents such as acetonitrile (AN) and sulfolane (SL). These organic solvents can be used alone or in the form of a mixture of two or more.
  • THF tetrahydrofuran
  • 2MeTHF 2-methyltetrahydrofuran
  • DME dimethoxyethane
  • Cyclic esters such as ⁇ -butyrolactone (BL); Methyl acetate, ethyl acetate, propionic acid Examples thereof include chain esters such as methyl and eth
  • polymer material used for the gel-like non-aqueous electrolyte examples include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).
  • PVdF polyvinylidene fluoride
  • PAN polyacrylonitrile
  • PEO polyethylene oxide
  • the non-aqueous electrolyte can further include the following compounds as other solutes.
  • compounds that can be used for other solutes include, for example, an imide salt ([R1-S ( ⁇ O) —NS ( ⁇ O) —R2] — and a counter cation containing a sulfonyl group in its molecular structure).
  • R1 and R2 are each independently a halogen group (—X), an alkoxy group (—OR), an isocyanic group (—NCO) and a hydrocarbon group. It can be selected from the group consisting of: R1 and R2 may be the same or different.
  • the halogen group here is preferably a fluoro group (—F), a chloro group (—Cl), a bromo group (—Br), or an iodo group (—I). Of these halogen groups, a fluoro group is more preferred.
  • the hydrocarbon group contained in the alkoxy group herein may be cyclic or chain-like, and may contain an unsaturated bond or a halogen substituent.
  • the hydrocarbon group as R1 and / or R2 may be cyclic or chain-like and may contain an unsaturated bond.
  • R3 is a hydrogen group or a hydrocarbon group.
  • the hydrocarbon group herein may be cyclic or chain-like and may contain an unsaturated bond and / or a halogen substituent.
  • R 4, R 5, R 6, and R 8 can be independently selected from a halogen group, an alkoxy group, and a hydrocarbon group.
  • the halogen group here is preferably a fluoro group (—F), a chloro group (—Cl), a bromo group (—Br), or an iodo group (—I), and more preferably a fluoro group.
  • R4, R5, R6 and R8 may all be the same or different. Alternatively, two or three of R4, R5, R6 and R8 may be the same.
  • the hydrocarbon group contained in the alkoxy group here may be cyclic, chain-like, or may contain an unsaturated bond.
  • R7 is a hydrogen group or a hydrocarbon group.
  • the hydrocarbon group here may be cyclic, chain-like, or may contain an unsaturated bond.
  • the non-aqueous electrolyte contains an imide salt or an imide compound containing a phosphoryl group.
  • the counter cation of these imide salts is preferably at least one counter ion selected from the group consisting of lithium ions, sodium ions, potassium ions, and tetraalkylammonium ions. Among them, the counter cation is more preferably a lithium ion.
  • Examples of the imide salt containing a sulfonyl group include lithium bis (fluorosulfonyl) imide (LiFSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium bis (pentafluoroethanesulfonyl) imide (LiBETI), and the like. It is done.
  • imide salts containing a phosphoryl group and a sulfonyl group include, for example, salts of anions represented by formulas (1) and (2).
  • Examples of the imide salt containing a phosphoryl group include, for example, salts of anions represented by formulas (3) and (4).
  • Examples of compounds that can be used for other solutes include phosphazene compounds as shown in formula (5).
  • the compound that can be used for the solute of the nonaqueous electrolyte is not limited by the above examples.
  • Positive electrode includes a positive electrode current collector and a positive electrode active material-containing layer (positive electrode material layer) that is supported on one or both surfaces of the positive electrode current collector and includes a positive electrode active material, a positive electrode conductive agent, and a binder. .
  • the positive electrode active material contains spinel-type lithium manganese composite oxide and lithium cobalt oxide.
  • binder examples include, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-based rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyimide, polyamide, and the like.
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • SBR styrene butadiene rubber
  • CMC carboxymethyl cellulose
  • polyimide polyamide
  • polyamide polyamide
  • Examples of the positive electrode conductive agent include carbon black such as acetylene black and ketjen black, graphite, carbon fiber, carbon nanotube, and fullerene.
  • the type of the conductive agent can be one type or two or more types.
  • the mixing ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode active material-containing layer is 80% by weight to 95% by weight of the positive electrode active material, 3% by weight to 18% by weight of the conductive agent, and 2% by weight of the binder. It is preferable to make it 17% by weight or less.
  • the current collector is preferably an aluminum foil or an aluminum alloy foil, and the average crystal grain size is desirably 50 ⁇ m or less, more preferably 30 ⁇ m or less, and even more preferably 5 ⁇ m or less.
  • the current collector made of an aluminum foil or aluminum alloy foil having such an average crystal grain size can dramatically increase the strength, and the positive electrode can be densified with a high press pressure. The capacity can be increased.
  • Aluminum foil or aluminum alloy foil with an average crystal grain size of 50 ⁇ m or less is affected by many factors such as material composition, impurities, processing conditions, heat treatment history and annealing conditions, and the above (diameter) is the manufacturing process. The above factors are adjusted in combination.
  • the thickness of the current collector is 20 ⁇ m or less, more preferably 15 ⁇ m or less.
  • the purity of the aluminum foil is preferably 99% or more.
  • As the aluminum alloy an alloy containing elements such as magnesium, zinc, and silicon is preferable.
  • the content of transition metals such as iron, copper, nickel and chromium is preferably 1% or less.
  • the positive electrode is prepared by suspending a positive electrode active material, a positive electrode conductive agent, and a binder in a suitable solvent, and applying the resulting slurry to a positive electrode current collector and drying to prepare a positive electrode active material-containing layer. It is produced by applying a press.
  • the positive electrode active material, the positive electrode conductive agent, and the binder may be formed in a pellet shape and used as the positive electrode active material-containing layer.
  • the positive electrode material layer preferably has a porosity of 20% to 50%.
  • the positive electrode provided with the positive electrode material layer having such a porosity has a high density and is excellent in affinity with the nonaqueous electrolyte. More preferable porosity is 25% or more and 40% or less.
  • the density of the positive electrode material layer is preferably 2.5 g / cm 3 or more.
  • Negative electrode has a negative electrode current collector and a negative electrode active material-containing layer (negative electrode material layer) that is supported on one or both sides of the negative electrode current collector and includes a negative electrode active material, a negative electrode conductive agent, and a binder. .
  • the negative electrode active material contains spinel type lithium titanate (for example, Li 4 + x Ti 5 O 12 (0 ⁇ x ⁇ 3)) as described above.
  • the negative electrode active material is a metal containing lithium titanium composite oxide other than spinel type lithium titanate and at least one element selected from the group consisting of Ti and P, V, Sn, Cu, Ni, Nb and Fe
  • One or more other titanium-containing oxides such as composite oxides may be further included.
  • spinel type lithium titanate accounts for 70% or more of the weight ratio of the negative electrode active material.
  • lithium-titanium composite oxides include lithium-titanium oxide and lithium-titanium composite oxides in which some of the constituent elements of lithium-titanium oxide are replaced with different elements.
  • the lithium titanium oxide include ramsdellite-type lithium titanate (for example, Li 2 + y Ti 3 O 7 (y is a value that varies depending on charge / discharge, 0 ⁇ y ⁇ 3)) and the like.
  • the molar ratio of oxygen in the lithium-titanium composite oxide is formally shown as 12 for spinel type Li 4 + x Ti 5 O 12 and 7 for ramsdellite type Li 2 + y Ti 3 O 7 , for example. These values can change due to influences such as oxygen non-stoichiometry.
  • Examples of the metal composite oxide containing Ti and at least one element selected from the group consisting of P, V, Sn, Cu, Ni, Nb, and Fe include TiO 2 —P 2 O 5 , TiO 2. —V 2 O 5 , TiO 2 —P 2 O 5 —SnO 2 , TiO 2 —P 2 O 5 —MeO (Me is at least one element selected from the group consisting of Cu, Ni and Fe) And so on.
  • This metal composite oxide has a low crystallinity and preferably has a microstructure in which a crystal phase and an amorphous phase coexist or exist as an amorphous phase alone. With such a microstructure, cycle performance can be greatly improved.
  • the negative electrode active material contains a compound other than spinel type lithium titanate
  • the other compound preferably contains a lithium titanium composite oxide.
  • the negative electrode containing a titanium-containing oxide such as a lithium-titanium composite oxide has a Li storage potential of 0.4 V (vs. Li / Li + ) or higher, the negative electrode surface when input / output with a large current is repeated. The deposition of metallic lithium on the top can be prevented.
  • the negative electrode active material may contain an active material other than the lithium-titanium composite oxide. In that case, an active material having a Li occlusion potential of 0.4 V (vs. Li / Li + ) or more should be used. Is desirable.
  • binder examples include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-based rubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyimide, and polyamide.
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • SBR styrene butadiene rubber
  • CMC carboxymethyl cellulose
  • polyimide polyimide
  • polyamide polyamide
  • Examples of the negative electrode conductive agent include carbon black such as acetylene black and ketjen black, graphite, carbon fiber, carbon nanotube, and fullerene.
  • the type of the conductive agent can be one type or two or more types.
  • the mixing ratio of the negative electrode active material, the conductive agent, and the binder in the negative electrode active material-containing layer is 70% by weight to 96% by weight of the negative electrode active material, 2% by weight to 28% by weight of the conductive agent, and 2% by weight of the binder.
  • the content is preferably 28% by weight or less.
  • the current collector is preferably an aluminum foil or an aluminum alloy foil that is electrochemically stable in a potential range nobler than 1.0 V.
  • the negative electrode is prepared by suspending, for example, a negative electrode active material, a negative electrode conductive agent, and a binder in a suitable solvent, applying the obtained slurry to a negative electrode current collector, and drying to prepare a negative electrode active material-containing layer. It is produced by applying a press.
  • the negative electrode active material, the negative electrode conductive agent, and the binder may be formed in a pellet shape and used as the negative electrode active material-containing layer.
  • the negative electrode material layer preferably has a porosity of 20% to 50%.
  • the negative electrode material layer having such a porosity is excellent in affinity with the non-aqueous electrolyte and can be increased in density. More preferable porosity is 25% or more and 40% or less.
  • the density of the negative electrode material layer is preferably 2.0 g / cm 3 or more.
  • Separators include a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), and a synthetic resin nonwoven fabric.
  • PVdF polyvinylidene fluoride
  • Exterior member may be formed of a laminate film or a metal container. When a metal container is used, the lid can be integrated with or separate from the container.
  • the wall thickness of the metal container is more preferably 0.5 mm or less and 0.2 mm or less.
  • Examples of the shape of the exterior member include a flat type, a square type, a cylindrical type, a coin type, a button type, a sheet type, and a laminated type.
  • a large battery mounted on a two-wheeled or four-wheeled vehicle may be used.
  • the thickness of the laminate film exterior member is 0.2 mm or less.
  • the laminate film include a multilayer film including a resin film and a metal layer disposed between the resin films.
  • the metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction.
  • the resin film for example, a polymer material such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) can be used.
  • the laminate film can be formed into the shape of an exterior member by sealing by heat sealing.
  • the metal container is made of aluminum or aluminum alloy.
  • the aluminum alloy an alloy containing elements such as magnesium, zinc, and silicon is preferable.
  • the content of transition metals such as iron, copper, nickel, and chromium is preferably set to 100 ppm or less in order to drastically improve long-term reliability and heat dissipation in a high temperature environment.
  • the metal container made of aluminum or aluminum alloy has an average crystal grain size of 50 ⁇ m or less, more preferably 30 ⁇ m or less, and even more preferably 5 ⁇ m or less.
  • the average crystal grain size By setting the average crystal grain size to 50 ⁇ m or less, the strength of a metal container made of aluminum or an aluminum alloy can be dramatically increased, and the container can be made thinner. As a result, it is possible to realize a nonaqueous electrolyte battery that is lightweight, has high output, and is excellent in long-term reliability.
  • the battery of the embodiment is particularly suitable for a vehicle battery because it has a long life and is excellent in safety.
  • the flat type nonaqueous electrolyte secondary battery includes a flat wound electrode group 1, an exterior member 2, a positive electrode terminal 7, a negative electrode terminal 6, and a nonaqueous electrolyte.
  • the exterior member 2 is a bag-shaped exterior member made of a laminate film.
  • the wound electrode group 1 is housed in the exterior member 2.
  • the wound electrode group 1 includes a positive electrode 3, a negative electrode 4, and a separator 5, and a laminate in which the negative electrode 4, the separator 5, the positive electrode 3, and the separator 5 are stacked in this order from the outside in a spiral shape. It is formed by winding and press molding.
  • the positive electrode 3 includes a positive electrode current collector 3a and a positive electrode active material-containing layer 3b.
  • the positive electrode active material-containing layer 3b contains a positive electrode active material.
  • the positive electrode active material-containing layer 3b is formed on both surfaces of the positive electrode current collector 3a.
  • the negative electrode 4 includes a negative electrode current collector 4a and a negative electrode active material-containing layer 4b.
  • the negative electrode active material-containing layer 4b contains a negative electrode active material. In the outermost layer of the negative electrode 4, the negative electrode active material-containing layer 4b is formed only on one surface on the inner surface side of the negative electrode current collector 4a, and in the other portions, the negative electrode active material-containing layer 4b is formed on both surfaces of the negative electrode current collector 4a. Is formed.
  • a strip-like positive electrode terminal 7 is connected to the positive electrode current collector 3 a of the positive electrode 3.
  • a strip-like negative electrode terminal 6 is connected to the negative electrode current collector 4 a of the outermost negative electrode 4.
  • the positive electrode terminal 7 and the negative electrode terminal 6 are extended to the outside through the opening of the exterior member 2.
  • a nonaqueous electrolyte solution is further injected into the exterior member 2 as a nonaqueous electrolyte.
  • the battery according to the embodiment is not limited to the configuration shown in FIG. 3 and FIG. 4 described above, and may be configured as shown in FIG.
  • the wound electrode group 11 is housed in a metal bottomed rectangular cylindrical container (exterior member) 12.
  • the non-aqueous electrolyte liquid non-aqueous electrolyte
  • the flat wound electrode group 11 is formed by winding a laminate in which the negative electrode, the separator, the positive electrode, and the separator are laminated in this order from the outside in a spiral shape and press-molding.
  • the negative electrode tab 14 has one end electrically connected to the negative electrode current collector and the other end electrically connected to the negative electrode terminal 15.
  • the negative electrode terminal 15 is fixed to the rectangular lid 13 with a hermetic seal with a glass material 16 interposed.
  • One end of the positive electrode tab 17 is electrically connected to the positive electrode current collector, and the other end is electrically connected to the positive electrode terminal 18 fixed to the rectangular lid 13.
  • the negative electrode tab 14 is made of, for example, a material such as aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si.
  • the negative electrode tab 14 is preferably made of the same material as that of the negative electrode current collector in order to reduce contact resistance with the negative electrode current collector.
  • the positive electrode tab 17 is made of, for example, aluminum or a material such as an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si.
  • the positive electrode tab 17 is preferably made of the same material as the positive electrode current collector in order to reduce contact resistance with the positive electrode current collector.
  • the illustrated non-aqueous electrolyte battery uses a wound electrode group in which a separator is wound together with a positive electrode and a negative electrode. However, the separator is folded into ninety nines, and the positive electrode and the negative electrode are alternately arranged at the folded portion.
  • a type of electrode group may be used.
  • the non-aqueous electrolyte battery includes a positive electrode including a mixture of a spinel-type lithium manganese composite oxide and lithium cobalt oxide, a negative electrode including a spinel-type lithium titanate, and a non-aqueous electrolyte. It comprises.
  • the weight A of the spinel type lithium manganese composite oxide and the weight B of the lithium cobaltate satisfy the relationship of 0.01 ⁇ B / (A + B) ⁇ 0.1.
  • the positive electrode has a first depth in which the atomic percentage of the first P element described above decreases from the surface of the positive electrode in the depth direction and becomes 0.5% at% or less.
  • the ratio of the state ratio of N element to P element in the positive electrode is 0.2 or more and 0.5 or less.
  • the negative electrode has a second depth at which the atomic percentage of the second P element described above decreases from the surface of the negative electrode in the depth direction and becomes 0.5 at% or less.
  • nonaqueous electrolyte battery since it has the above-described configuration, it is possible to reduce the amount of gas generated even in a high temperature environment, and it is excellent in input / output performance and storage performance.
  • An electrolyte battery can be provided.
  • a battery pack is provided.
  • This battery pack includes the nonaqueous electrolyte battery according to the first embodiment.
  • the battery pack according to the second embodiment can also include a plurality of nonaqueous electrolyte batteries.
  • the plurality of nonaqueous electrolyte batteries can be electrically connected in series, or can be electrically connected in parallel.
  • a plurality of nonaqueous electrolyte batteries can be connected in a combination of series and parallel.
  • the battery pack according to the second embodiment can include five first nonaqueous electrolyte batteries. These non-aqueous electrolyte batteries can be connected in series. Moreover, the non-aqueous electrolyte battery connected in series can comprise an assembled battery. That is, the battery pack according to the second embodiment can include an assembled battery.
  • the battery pack according to the second embodiment can include a plurality of assembled batteries.
  • the plurality of assembled batteries can be connected in series, parallel, or a combination of series and parallel.
  • FIG. 6 is an exploded perspective view of an example battery pack according to the second embodiment.
  • FIG. 7 is a block diagram showing an electric circuit of the battery pack of FIG.
  • the battery pack 20 shown in FIGS. 6 and 7 includes a plurality of unit cells 21.
  • the unit cell 21 may be an example of a flat type nonaqueous electrolyte battery according to the first embodiment described with reference to FIG.
  • the plurality of single cells 21 are laminated so that the negative electrode terminal 51 and the positive electrode terminal 61 extending to the outside are aligned in the same direction, and are fastened with the adhesive tape 22 to constitute the assembled battery 23. These unit cells 21 are electrically connected to each other in series as shown in FIG.
  • the printed wiring board 24 is arranged to face the side surface from which the negative electrode terminal 51 and the positive electrode terminal 61 of the unit cell 21 extend. On the printed wiring board 24, as shown in FIG. 7, a thermistor 25, a protection circuit 26, and a terminal 27 for energizing external devices are mounted.
  • the printed wiring board 24 is provided with an insulating plate (not shown) on the surface facing the assembled battery 23 in order to avoid unnecessary wiring and wiring of the assembled battery 23.
  • the positive electrode side lead 28 is connected to the positive electrode terminal 61 located in the lowermost layer of the assembled battery 23, and the tip thereof is inserted into the positive electrode side connector 29 of the printed wiring board 24 and electrically connected thereto.
  • the negative electrode side lead 30 is connected to a negative electrode terminal 51 located on the uppermost layer of the assembled battery 23, and the tip thereof is inserted into and electrically connected to the negative electrode side connector 31 of the printed wiring board 24.
  • These connectors 29 and 31 are connected to the protection circuit 26 through wirings 32 and 33 formed on the printed wiring board 24.
  • the thermistor 25 detects the temperature of the unit cell 21, and the detection signal is transmitted to the protection circuit 26.
  • the protection circuit 26 can cut off the plus side wiring 34a and the minus side wiring 34b between the protection circuit 26 and the energization terminal 27 to the external device under a predetermined condition.
  • An example of the predetermined condition is, for example, when the temperature detected by the thermistor 25 is equal to or higher than a predetermined temperature.
  • Another example of the predetermined condition is when, for example, overcharge, overdischarge, overcurrent, or the like of the cell 21 is detected. This detection of overcharge or the like is performed for each individual cell 21 or the entire assembled battery 23. When detecting each single cell 21, the battery voltage may be detected, or the positive electrode potential or the negative electrode potential may be detected.
  • a lithium electrode used as a reference electrode is inserted into each unit cell 21.
  • a wiring 35 for voltage detection is connected to each single cell 21. A detection signal is transmitted to the protection circuit 26 through these wirings 35.
  • Protective sheets 36 made of rubber or resin are disposed on the three side surfaces of the assembled battery 23 excluding the side surfaces from which the positive electrode terminal 61 and the negative electrode terminal 51 protrude.
  • the assembled battery 23 is stored in a storage container 37 together with each protective sheet 36 and the printed wiring board 24. That is, the protective sheet 36 is disposed on each of the inner side surface in the long side direction and the inner side surface in the short side direction of the storage container 37, and the printed wiring board 24 is disposed on the inner side surface on the opposite side in the short side direction.
  • the assembled battery 23 is located in a space surrounded by the protective sheet 36 and the printed wiring board 24.
  • the lid 38 is attached to the upper surface of the storage container 37.
  • a heat shrink tape may be used for fixing the assembled battery 23.
  • protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the assembled battery.
  • 6 and 7 show the configuration in which the unit cells 21 are connected in series, but in order to increase the battery capacity, they may be connected in parallel. Further, the assembled battery packs can be connected in series and / or in parallel.
  • the aspect of the battery pack according to the second embodiment is appropriately changed depending on the application.
  • a battery pack in which cycle performance with high current performance is desired is preferable.
  • Specific applications include power supplies for digital cameras, and in-vehicle applications such as two-wheel to four-wheel hybrid electric vehicles, two-wheel to four-wheel electric vehicles, and assist bicycles.
  • the battery pack according to the second embodiment is particularly suitable for in-vehicle use.
  • the battery pack according to the second embodiment includes the nonaqueous electrolyte battery according to the first embodiment. Therefore, according to the second embodiment, it is possible to reduce the amount of gas generated even in a high temperature environment, and it is possible to provide a battery pack having excellent input / output performance and excellent storage performance.
  • Example Hereinafter, based on an Example, the said embodiment is described in detail. Although an Example is described, unless it exceeds the main point of this invention, it is not limited to the Example described below.
  • Example 1 Preparation of positive electrode>
  • a spinel type lithium manganese oxide represented by the general formula LiAl 0.3 Mn 1.7 O 4 represented by the general formula LiM x Mn 2-x O 4 , where M is Al and x is 0.3 96% by weight of spinel-type lithium manganate whose 2-x is 1.7
  • lithium cobaltate (LiCoO 2 ) powder were prepared. Since the weight ratio A of the spinel-type lithium manganese composite oxide in the positive electrode active material is 96 (wt%) and the weight ratio B of lithium cobaltate in the positive electrode active material is 4 (wt%), B / (A + B) Is 0.04.
  • acetylene black and graphite were prepared as a conductive agent, and polyvinylidene fluoride (PVdF) was prepared as a binder.
  • PVdF polyvinylidene fluoride
  • acetylene black 6 parts by weight of acetylene black was added to 90 parts by weight of a positive electrode active material (a mixture of spinel type lithium manganate and cobalt oxide) and mixed with a Henschel mixer.
  • a positive electrode active material a mixture of spinel type lithium manganate and cobalt oxide
  • 4 parts by weight of PVdF and N-methylpyrrolidone (NMP) were added to this mixture at a constant ratio, and kneaded with a planetary mixer to form a slurry.
  • This slurry was applied to both surfaces of a current collector made of an aluminum foil having a thickness of 20 ⁇ m, and then the coating film was dried. Furthermore, the dried coating film was press-molded to produce a positive electrode in which a positive electrode material layer was formed on both sides of the current collector.
  • Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a weight ratio of 1: 2 to prepare a mixed solvent.
  • the mixed solvent was 100% by weight, and 0.5% by weight of LiFSI as an imide salt was added. Further, by mixing of LiPF 6 1.0M lithium salt other than the imide salt in a mixed solvent. In this way, a liquid nonaqueous electrolyte was prepared.
  • Electrode group A plurality of negative electrodes and positive electrodes were alternately laminated via a separator made of a cellulose porous film having a thickness of 20 ⁇ m between them to produce an electrode group.
  • the obtained electrode group was stored in a pack (exterior member) made of a laminate film having a thickness of 0.1 mm.
  • the produced battery was subjected to initial charging in the following procedure. First, the battery was charged with a constant current of 1 A (1 C) under a temperature environment of 25 ° C. until the voltage reached 2.8 V.
  • the initially charged battery was discharged to 1.8 V, and the discharge capacity obtained at that time was measured. Using this discharge capacity as a reference of 100%, constant current charging was performed at 1 A until the state of charge (SOC) reached 30%.
  • SOC state of charge
  • the battery adjusted to SOC 30% was transferred to an aging tank, and in that state, an aging treatment was performed for 50 hours under a constant temperature environment of 65 ° C. After the aging treatment, the battery was removed from the aging tank and allowed to cool to room temperature. Thus, the nonaqueous electrolyte battery of Example 1 was obtained.
  • ⁇ Adjustment to the shipment status> The obtained battery was discharged to 1.8 V at 1 A in a constant temperature bath at 25 ° C. and then rested for 10 minutes. Next, the battery was charged at 2.8 V until the current value reached 50 mA, and then rested for 10 minutes. Then, it discharged to 1.8V. The discharge capacity obtained at this time is set as the inspection capacity. The battery was charged at a constant current of 1 A until it reached 80% of the inspection capacity, and the product was shipped.
  • Example 2 During the aging treatment, the SOC of the battery was adjusted to 80%. Except for this change, the nonaqueous electrolyte battery of Example 2 was obtained by the same procedure as that of Example 1.
  • Example 3 The amount of imide salt (LiFSI) added to the non-aqueous electrolyte was changed to 0.3% by weight. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, the nonaqueous electrolyte battery of Example 3 was obtained by the same procedure as that of Example 1.
  • Example 4 The amount of imide salt (LiFSI) added to the non-aqueous electrolyte was changed to 1% by weight. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, the nonaqueous electrolyte battery of Example 4 was obtained by the same procedure as that of Example 1.
  • Example 5 During the aging treatment, the SOC of the battery was adjusted to 50%. The temperature of the aging tank was set to 50 ° C. Except for these changes, a nonaqueous electrolyte battery of Example 5 was obtained by the same procedure as in Example 1.
  • Example 6 During the aging treatment, the SOC of the battery was adjusted to 50%. Moreover, the temperature of the aging tank was set to 80 degreeC. Except for these changes, the nonaqueous electrolyte battery of Example 6 was obtained by the same procedure as that of Example 1.
  • Example 7 During the aging treatment, the SOC of the battery was adjusted to 50%. Except for this change, the nonaqueous electrolyte battery of Example 7 was obtained by the same procedure as that of Example 1.
  • Example 8 During the aging treatment, the SOC of the battery was adjusted to 50%. Moreover, the aging process was implemented over 100 hours. Except for these changes, the nonaqueous electrolyte battery of Example 8 was obtained by the same procedure as that of Example 1.
  • Example 9 As an imide salt added to a non-aqueous electrolyte, an lithium salt of an anion represented by the above chemical formula (1) which is an imide salt containing a phosphoryl group and a sulfonyl group instead of LiFSI (Li (F 2 PO) (FSO 2 ) N ) was used. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. A nonaqueous electrolyte battery of Example 9 was obtained by the same procedure as Example 1 except for these changes.
  • LiFSI Li (F 2 PO) (FSO 2 ) N
  • Example 10 As an imide salt added to the nonaqueous electrolyte, an anion lithium salt (Li (F 2 PO) 2 N) represented by the above chemical formula (3), which is an imide salt containing a phosphoryl group, was used instead of LiFSI. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, a nonaqueous electrolyte battery of Example 10 was obtained in the same procedure as in Example 1.
  • Li (F 2 PO) 2 N anion lithium salt represented by the above chemical formula (3), which is an imide salt containing a phosphoryl group
  • Example 11 The weight ratio A of the spinel-type lithium manganese composite oxide in the positive electrode active material was changed to 99 (wt%), and the weight ratio B of the lithium cobaltate in the positive electrode active material was changed to 1 (wt%). In this case, B / (A + B) is 0.01. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, the nonaqueous electrolyte battery of Example 11 was obtained by the same procedure as in Example 1.
  • Example 12 The weight ratio A of the spinel-type lithium manganese composite oxide in the positive electrode active material was changed to 95 (wt%), and the weight ratio B of the lithium cobaltate in the positive electrode active material was changed to 5 (wt%). In this case, B / (A + B) is 0.05. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, a nonaqueous electrolyte battery of Example 12 was obtained by the same procedure as that of Example 1.
  • Example 13 The weight ratio A of the spinel-type lithium manganese composite oxide in the positive electrode active material was changed to 91 (wt%), and the weight ratio B of the lithium cobaltate in the positive electrode active material was changed to 9 (wt%). In this case, B / (A + B) is 0.09. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. A nonaqueous electrolyte battery of Example 13 was obtained by the same procedure as Example 1 except for these changes.
  • Comparative Example 2 The weight ratio A of the spinel-type lithium manganese composite oxide in the positive electrode active material was changed to 90 (wt%), and the weight ratio B of the lithium cobaltate in the positive electrode active material was changed to 10 (wt%). In this case, B / (A + B) is 0.1. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. Except for these changes, a nonaqueous electrolyte battery of Comparative Example 2 was obtained by the same procedure as in Example 1.
  • Comparative Example 3 During the aging treatment, the SOC of the battery was adjusted to 20%. A nonaqueous electrolyte battery of Comparative Example 3 was obtained by the same procedure as in Example 1 except for this change.
  • Comparative Example 4 During the aging treatment, the SOC of the battery was adjusted to 90%. A non-aqueous electrolyte battery of Comparative Example 4 was obtained by the same procedure as in Example 1 except for this change.
  • Comparative Example 5 The amount of imide salt (LiFSI) added to the non-aqueous electrolyte was changed to 0.1% by weight. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. A nonaqueous electrolyte battery of Comparative Example 5 was obtained by the same procedure as in Example 1 except for these changes.
  • Comparative Example 6 The amount of imide salt (LiFSI) added to the non-aqueous electrolyte was changed to 1.5% by weight. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. A nonaqueous electrolyte battery of Comparative Example 6 was obtained by the same procedure as in Example 1 except for these changes.
  • Comparative Example 7 During the aging treatment, the SOC of the battery was adjusted to 50%. The temperature of the aging tank was set to 40 ° C. A nonaqueous electrolyte battery of Comparative Example 7 was obtained by the same procedure as in Example 1 except for these changes.
  • Comparative Example 8 During the aging treatment, the SOC of the battery was adjusted to 50%. The temperature of the aging tank was set to 90 ° C. A nonaqueous electrolyte battery of Comparative Example 8 was obtained by the same procedure as in Example 1 except for these changes.
  • Comparative Example 9 Addition of the imide salt to the non-aqueous electrolyte was omitted. Also, during the aging treatment, the SOC of the battery was adjusted to 50%. A nonaqueous electrolyte battery of Comparative Example 9 was obtained by the same procedure as in Example 1 except for these changes.
  • Table 1 summarizes the components of the nonaqueous electrolyte used in the nonaqueous electrolyte battery and the aging conditions. Specifically, as the component of the nonaqueous electrolyte, the type and content of the imide salt used for the solute, the composition of the nonaqueous solvent, and a lithium salt other than the imide salt are shown. As the aging conditions, the temperature during aging, the SOC of the battery during aging, and the aging time are shown.
  • Table 1 shows the first depth from the positive electrode surface where the atomic percentage of P element is 0.5 at% or less and the second depth from the negative electrode surface where the atomic percentage of P element is 0.5 at% or less.
  • Table 2 shows A N / A P in the positive electrode.
  • ⁇ Measurement of open circuit voltage of positive electrode> The battery voltage of the nonaqueous electrolyte battery was adjusted to 2.8V. Specifically, each nonaqueous electrolyte battery was charged in a thermostat maintained at 25 ° C. until the voltage became 2.8 V with a constant current of 1 A (1 C). Next, each battery was charged in the same thermostat until the current value reached 50 mA at a constant voltage of 2.8 V. Thereafter, each non-aqueous electrolyte battery was left in an open circuit state for 30 minutes.
  • the battery was discharged at a constant current of 0.2 C until the battery voltage reached 1.8V.
  • the positive electrode potential when discharged to 1.8 V was measured. Since a low discharge rate of 0.2 C was adopted, the positive electrode potential thus obtained was regarded as the open circuit voltage of the positive electrode. Table 2 shows the obtained open circuit voltages.
  • Table 2 below shows the relationship B / A + B between the weight ratio A of the spinel-type lithium manganese composite oxide and the weight ratio of lithium cobaltate in the positive electrode active material included in the produced nonaqueous electrolyte battery, and the nonaqueous electrolyte.
  • the weight ratio A of the spinel type lithium manganese composite oxide and the weight ratio B of the lithium cobaltate in the positive electrode active material are 0.01 ⁇ B
  • the relationship of /A+B ⁇ 0.1 was satisfied.
  • the ratio A N / A P state ratio of N elements for P element was in the range of 0.2 to 0.5.
  • the second depth from the negative electrode surface at which the atomic percentage of the P element is greater than 0.5 at% to less than 0.5 at% It was within the range of 20 nm or more and less than 30 nm.
  • Example 1-13 the surface state of the positive electrode and the surface state of the negative electrode similar to those of the nonaqueous electrolyte battery according to the embodiment described above were obtained. That is, in any of Examples 1-13, it can be determined that the film was formed on the surface of the positive electrode without excess or deficiency, and the film was formed on the surface of the negative electrode without excess or deficiency.
  • the positive open circuit voltage when the battery voltage was 1.8 V was 3.9 V (vs. Li / Li + ) or more and 4.0 V (vs. Li / Li + ) or less.
  • the ratio Q p / Q n between the positive electrode charge capacity Q p and the negative electrode charge capacity Q n per unit area was 0.8 or more and 1.1 or less.
  • the atomic percentage of P element was 0.5 at% or less at a shallow depth of 2 nm from the surface of the positive electrode.
  • the ratio A N / A P of the N element state ratio A N to the P element state ratio A P in the positive electrode was a low value of 0.05. From these, it can be seen that in Comparative Example 1, a sufficient film could not be formed on the surface of the positive electrode. Further, since the positive electrode open circuit voltage when the battery voltage was 1.8 V exceeded 4.0 V (vs. Li / Li + ), it was found that the self-discharge of the positive electrode did not proceed sufficiently. In Comparative Example 1, since lithium cobaltate was not included in the positive electrode active material, it was considered that a sufficient film could not be obtained as a result of not being able to utilize the catalytic action for the self-discharge reaction on the positive electrode surface.
  • Comparative Example 2 it can be seen that the atomic percentage of the P element did not fall below 0.5 at% until reaching a deep depth of 15 nm from the surface of the positive electrode, and an excessive film was formed on the surface of the positive electrode. Since SeikyokuHiraki circuit voltage when the battery voltage 1.8 V was below 3.9 V (vs. Li / Li +), it can be seen that self-discharge of the positive electrode had progressed excessively. This is considered to be because the catalytic action for the self-discharge reaction at the positive electrode was too strong as a result of the large amount of lithium cobaltate in the positive electrode active material.
  • Comparative Example 4 it can be seen that the atomic percentage of the P element did not become 0.5 at% or less until the depth of 10 nm was reached from the positive electrode surface, and an excessive film was formed on the positive electrode surface. . This is probably because the SOC during the aging treatment was high and the self-discharge reaction proceeded too much at the positive electrode.
  • the ratio A N / A P of the N element state ratio A N to the P element state ratio A P is less than 0.2, which is sufficient for the positive electrode surface. It can be seen that no film was formed. This is considered due to the fact that the content of the imide salt in the non-aqueous electrolyte is small.
  • Comparative Example 8 it can be seen that the atomic percentage of the P element did not fall below 0.5 at% until reaching a deep depth of 30 nm from the surface of the negative electrode, and an excessive film was formed on the negative electrode surface. This is considered to be a result of the self-discharge reaction at the negative electrode proceeding too much because the temperature during the aging treatment was high.
  • the battery resistance, storage performance, and gas generation suppression performance were evaluated for each nonaqueous electrolyte battery. Specifically, battery resistance was determined by pulse discharge resistance measurement, a high-temperature storage test was performed, and a recovery capacity retention rate and gas generation amount were determined. Details of the evaluation method will be described below.
  • the battery was waited for 1 hour at an ambient temperature of 25 ° C. Then, 10 A (10 C) constant current discharge was performed for 10 seconds. The voltage drop during the constant current discharge was determined. The value obtained by dividing the voltage drop by the current value (10 A) when the constant current was discharged was taken as the resistance value.
  • the battery taken out from the 60 ° C. thermostat was allowed to cool to room temperature, discharged to 1.8 V at 1 A in a 25 ° C. thermostat, and then rested for 10 minutes. Next, the battery was charged at 2.8 V until the current value reached 50 mA, and then rested for 10 minutes. Thereafter, the discharge capacity obtained when discharging to 1.8 V at 1 A was taken as the recovery capacity. The ratio of the recovery capacity to the discharge capacity measured in the same manner before the test was taken as the recovery capacity retention rate.
  • the battery before the test was submerged in a rectangular parallelepiped scale container containing water, and the volume was read from the change in the position of the water surface.
  • the battery after the test was submerged, the volume was read, and the change from before the test was taken as the amount of gas generated.
  • Table 3 summarizes the evaluation results of the obtained nonaqueous electrolyte battery. Specifically, the resistance value obtained by the pulse discharge resistance measurement, the recovery capacity retention rate and the gas generation amount obtained as a result of the storage test at a high temperature (60 ° C.) are shown. Each of the pulse discharge resistance value, the high-temperature storage recovery capacity maintenance rate, and the gas generation amount is based on the evaluation result of the nonaqueous electrolyte battery of Example 7 as the reference value 100, and the evaluation results of other nonaqueous electrolyte batteries are compared with this reference. Shown as a relative value.
  • Comparative Examples 1, 3, 5, 7, and 9 the recovery capacity maintenance rate of the nonaqueous electrolyte battery was inferior.
  • Comparative Examples 1, 3, 5, and 9 it is considered that a sufficient film was not formed on the surface of the positive electrode, and as a result, the reaction between the positive electrode and the nonaqueous electrolyte could not be suppressed during high temperature storage.
  • Comparative Example 7 it is considered that the reaction between the negative electrode and the non-aqueous electrolyte could not be suppressed during high-temperature storage as a result of not forming a sufficient film on the surface of the negative electrode.
  • the non-aqueous electrolyte battery includes a positive electrode including a mixture of a spinel-type lithium manganese composite oxide and lithium cobalt oxide, and a negative electrode including a spinel-type lithium titanate.
  • the weight A of the spinel type lithium manganese composite oxide and the weight B of the lithium cobaltate satisfy the relationship of 0.01 ⁇ B / (A + B) ⁇ 0.1, and the range from 3 to 10 nm from the positive electrode surface.
  • the atomic percentage of the first P element explained earlier at a certain first depth is 0.5% at% or less
  • the ratio of the state ratio of N element to P element in the positive electrode is 0.2 or more and 0.5 or less
  • Since the atomic percentage of the second P element described above at the second depth in the range of 20 mm to less than 30 mm from the surface is 0.5 mm at% or less, it has excellent input / output performance and excellent high temperature Can get storage performance .

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Abstract

La présente invention porte sur une batterie à électrolyte non aqueux qui comprend une électrode positive, une électrode négative et un électrolyte non aqueux. L'électrode positive contient un mélange d'un oxyde composite de lithium-manganèse de type spinelle et d'un cobaltate de lithium, et satisfait la relation 0,01 ≤ B/ (A +B) < 0,1 où A est le poids de l'oxyde composite de lithium-manganèse et B est le poids du cobaltate de lithium. L'électrode négative contient un titanate de lithium de type spinelle. Un premier pourcentage atomique d'élément P, pris en référence aux atomes C, O, Li, N, F, P et Mn contenus dans l'électrode positive, diminue dans le sens de l'épaisseur à partir de la surface de l'électrode positive, et le premier pourcentage atomique d'élément P à une première profondeur dans la plage de 3 nm à moins de 10 nm à partir de la surface d'électrode positive n'est pas supérieur à 0,5 % atomique. Le rapport du rapport d'état de l'élément N à l'élément P dans l'électrode positive est de 0,2 à 0,5. Un second pourcentage atomique d'élément P, pris en référence aux atomes C, O, Li, N, F, P, Mn, et Ti contenus dans l'électrode négative, diminue dans le sens de l'épaisseur à partir de la surface de l'électrode négative, et le second pourcentage atomique d'élément P à une seconde épaisseur dans la plage de 20 nm à moins de 30 nm à partir de la surface d'électrode négative n'est pas supérieur à 0,5 % atomique.
PCT/JP2018/014765 2018-04-06 2018-04-06 Batterie à électrolyte non aqueux et bloc-batterie WO2019193756A1 (fr)

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JP2000173619A (ja) * 1998-09-29 2000-06-23 Sanyo Electric Co Ltd リチウムイオン電池
JP2006066341A (ja) * 2004-08-30 2006-03-09 Toshiba Corp 非水電解質二次電池
JP2009129797A (ja) * 2007-11-27 2009-06-11 Gs Yuasa Corporation:Kk 非水電解質電池
WO2015107832A1 (fr) * 2014-01-16 2015-07-23 株式会社カネカ Batterie secondaire à électrolyte non aqueux et bloc-batterie utilisant celle-ci
JP2016015214A (ja) * 2014-07-01 2016-01-28 セントラル硝子株式会社 非水電解液電池用電解液、及びこれを用いた非水電解液電池
JP2016207313A (ja) * 2015-04-16 2016-12-08 株式会社カネカ 非水電解液二次電池及びその組電池

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000173619A (ja) * 1998-09-29 2000-06-23 Sanyo Electric Co Ltd リチウムイオン電池
JP2006066341A (ja) * 2004-08-30 2006-03-09 Toshiba Corp 非水電解質二次電池
JP2009129797A (ja) * 2007-11-27 2009-06-11 Gs Yuasa Corporation:Kk 非水電解質電池
WO2015107832A1 (fr) * 2014-01-16 2015-07-23 株式会社カネカ Batterie secondaire à électrolyte non aqueux et bloc-batterie utilisant celle-ci
JP2016015214A (ja) * 2014-07-01 2016-01-28 セントラル硝子株式会社 非水電解液電池用電解液、及びこれを用いた非水電解液電池
JP2016207313A (ja) * 2015-04-16 2016-12-08 株式会社カネカ 非水電解液二次電池及びその組電池

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