WO2015132845A1 - All-solid-state battery - Google Patents

All-solid-state battery Download PDF

Info

Publication number
WO2015132845A1
WO2015132845A1 PCT/JP2014/055217 JP2014055217W WO2015132845A1 WO 2015132845 A1 WO2015132845 A1 WO 2015132845A1 JP 2014055217 W JP2014055217 W JP 2014055217W WO 2015132845 A1 WO2015132845 A1 WO 2015132845A1
Authority
WO
WIPO (PCT)
Prior art keywords
negative electrode
lithium ion
active material
conductive polymer
lithium
Prior art date
Application number
PCT/JP2014/055217
Other languages
French (fr)
Japanese (ja)
Inventor
恵理奈 横山
Original Assignee
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社日立製作所 filed Critical 株式会社日立製作所
Priority to PCT/JP2014/055217 priority Critical patent/WO2015132845A1/en
Publication of WO2015132845A1 publication Critical patent/WO2015132845A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an all solid state battery.
  • the all-solid secondary battery using the non-combustible or flame-retardant solid electrolyte can have high heat resistance and can be made safe, so that module costs can be reduced and high energy density can be achieved.
  • the solid electrolyte has a problem that the conductivity of lithium ions is lower than that of a liquid electrolyte (electrolyte solution), and it is difficult to achieve high output of the battery.
  • Patent Document 1 discloses a technique of adding an ion conductive polymer such as polyethylene oxide (PEO) and polypropylene oxide (PPO) to an active material layer.
  • PEO polyethylene oxide
  • PPO polypropylene oxide
  • Patent Document 2 discloses a negative electrode using polyethylene oxide as a binder in an active material mixture layer and using an organic electrolytic solution and a solid electrolyte as an electrolyte.
  • the porosity of the electrode containing the negative electrode material is adjusted to 10% or more and 60% or less for the purpose of improving cycle performance and discharge capacity.
  • Patent Document 1 when a solid electrolyte is used as the electrolyte, since there is no electrolytic solution in the active material mixture, even if an ion conductive polymer is added, particles such as active material particles and ion conductive polymer can be used. An air gap occurs. For this reason, it is difficult to improve the lithium ion conductivity in the active material mixture.
  • Patent Document 2 when a solid electrolyte is used as the electrolyte, many pores are present in the inside of the negative electrode layer in the range of the disclosed porosity, so the contact area between the negative electrode active material is small and lithium ions There is a disadvantage that the number of conduction paths is reduced and the internal resistance of the negative electrode mixture is large.
  • An object of the present invention is to provide a high output lithium ion battery in which the lithium ion conductivity in the negative electrode active material is improved even when a solid electrolyte is used as the electrolyte.
  • the negative electrode mixture layer includes a negative electrode active material and a lithium ion conductive polymer provided between the negative electrode active materials, and the porosity of the negative electrode mixture layer is 10% or less
  • the lithium ion secondary battery wherein the ratio of the lithium ion conductive polymer to the negative electrode mixture layer is 5 wt% or more.
  • the above polymer is added to the negative electrode active material mixture, and the battery is manufactured with a porosity of 0.01% or more and 10% or less, thereby reducing the pores in the negative electrode layer, and the lithium ion conduction path. It is possible to provide a high power battery with improved.
  • FIG. 1 is a cross-sectional view of an all-solid secondary battery according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of the main part of the all-solid-state secondary battery according to an embodiment of the present invention.
  • the all solid secondary battery 100 includes a positive electrode current collector 10, a negative electrode current collector 20, a battery case 30, a positive electrode mixture layer 40, a solid electrolyte 50, and a negative electrode mixture layer 60.
  • the positive electrode 70 in FIG. 1 has a positive electrode current collector 10 and a positive electrode mixture layer 40.
  • the negative electrode 80 in FIG. 1 has a negative electrode current collector 20 and a negative electrode mixture layer 60.
  • an aluminum foil having a thickness of 10 to 100 ⁇ m, a perforated aluminum foil having a thickness of 10 to 100 ⁇ m and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate or the like is used.
  • aluminum, materials such as stainless steel and titanium are also applicable.
  • any current collector can be used without being limited to the material, shape, manufacturing method and the like.
  • the negative electrode current collector 20 a copper foil having a thickness of 10 to 100 ⁇ m, a perforated copper foil having a thickness of 10 to 100 ⁇ m and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate or the like is used. Besides copper, materials such as stainless steel, titanium or nickel are also applicable. In the present invention, any current collector can be used without being limited to the material, shape, manufacturing method and the like.
  • the battery case 30 accommodates the positive electrode current collector 10, the negative electrode current collector 20, the positive electrode mixture layer 40, the solid electrolyte layer 50, and the negative electrode mixture layer 60.
  • the shape of the battery case 30 conforms to the shape of the electrode group configured of the positive electrode mixture layer 40, the solid electrolyte layer 50, and the negative electrode mixture layer 60, and has a cylindrical, flat oval, flat oval, square, etc. shape. May be selected.
  • the material of the battery case 30 is selected from materials having corrosion resistance to the non-aqueous electrolyte, such as aluminum, stainless steel, nickel plated steel, and the like.
  • the positive electrode mixture layer 40 has a positive electrode active material, an optional positive electrode conductive agent, and an optional positive electrode binder.
  • the above materials may be contained singly or in combination of two or more as the positive electrode active material.
  • the positive electrode active material lithium ions are desorbed in the charging process, and lithium ions desorbed from the negative electrode active material in the negative electrode mixture layer 60 are inserted in the discharging process.
  • the particle size of the positive electrode active material is usually defined to be equal to or less than the thickness of the positive electrode mixture layer 40.
  • the powder of the positive electrode active material contains coarse particles having a size equal to or larger than the mixture layer thickness, the coarse particles are removed in advance by sieve classification, air flow classification, etc. to produce particles of the mixed layer thickness or less. preferable.
  • the positive electrode active material is generally oxide-based and has high electrical resistance
  • a positive electrode conductive agent made of carbon powder is used to compensate for the electrical conductivity. Since both the positive electrode active material and the positive electrode conductive agent are usually powders, the powders can be mixed with a binder to bond the powders together and to be bonded to the positive electrode current collector 10 at the same time.
  • the positive electrode mixture layer 40 contains a positive electrode conductive agent or a positive electrode binder
  • the positive electrode conductive agent include acetylene black, carbon black, and carbon materials such as graphite or amorphous carbon.
  • positive electrode binders include styrene-butadiene rubber, carboxymethylcellulose and polyvinylidene fluoride (PVDF), and mixtures thereof.
  • FIG. 2 is a schematic cross-sectional view of the negative electrode mixture layer 60 applied to the negative electrode current collector and the solid electrolyte layer 50 provided on the negative electrode mixture layer 60.
  • the negative electrode mixture layer 60 has a negative electrode active material 62, a lithium conductive polymer 63, an optional negative electrode conductive agent 64, and an optional negative electrode binder.
  • a lithium conductive polymer 63 is filled between the negative electrode active material 62 particles. By filling the gaps between the particles, the mobility of lithium ions can be increased, and the resistance of the negative electrode mixture layer 60 can be lowered. By filling the voids inside the negative electrode layer with the lithium conductive polymer, the conduction path of lithium ions can be improved and high output can be realized.
  • a battery using a liquid for the electrolyte requires a certain amount of gaps for the electrolyte to permeate, but when using a solid electrolyte as in the present invention, the gaps are considered to be a factor in the decrease in lithium ion conductivity. Is preferably as small as possible.
  • the porosity of the inside of the negative electrode mixture layer 60 is preferably 10% or less. More preferably, it is 5% or less. When the porosity is larger than the above range, a sufficient lithium ion conduction path is not formed between the negative electrode active materials, and the output of the battery is reduced.
  • the direct current resistance value of the negative electrode mixture layer 60 is preferably 10 ⁇ or less. More preferably, it is 6 ⁇ , 5 ⁇ or less, and it is considered that this value can be obtained if the porosity in the negative electrode mixture layer 60 is 4 to 5% or less.
  • the porosity is a volume ratio of a space or void generated between particles of a negative electrode active material or the like with respect to the volume of the negative electrode mixture, and can be determined, for example, by mercury porosimetry.
  • the lithium conductive polymer 63 one having high lithium ion conductivity and being stable in each process of electrode preparation, such as a process of preparing a negative electrode mixture with a binder and a solvent, and a subsequent kneading process of the negative electrode mixture Those which are stable with respect to the solvent and do not cause elution or peeling can be used. In addition, it is desirable to use one that is chemically and electrochemically stable even during operation of the secondary battery.
  • fluorine-based resins such as polyvinylidene fluoride and polytetrafluoroethylene
  • polymer compounds used for solid electrolytes such as polyethylene oxide, polypropylene oxide and polyacrylonitrile
  • polyvinyl alcohol polyethylene glycol, polypropylene glycol
  • polyvinyl pyrrolidone Water-soluble polymer compounds such as styrene-maleic anhydride copolymer, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, crosslinkable polymer compounds such as styrene-butadiene rubber, olefin polymers such as polyethylene and polypropylene Compounds, polymeric amine compounds and the like can be used.
  • it may be a hydrolyzate of these polymers, a cross-linked product, a variety of reactants such as an acid-modified product, or a modified product, or a salt such as a neutralized salt of an acid or a base or a metal salt.
  • R 1 is hydrogen, an alkyl group or an alkyl group having oxygen.
  • n is the number of repeating units. It is believed that lithium ion transfer takes place via oxygen in the structure.
  • the branched polyethylene oxide is a structure in which polyethylene oxide of Formula 1 is further branched from R 1 in Formula 1, which is higher in hardness and higher in mechanical strength than linear polyethylene oxide.
  • R 2 is a functional group having at least one of elements C, N, S, O, and H. It is believed that lithium ion transfer takes place via oxygen in the structure.
  • R 2 preferably has a structure such as —COOR—, —CO—, NH, and a sulfo group having a high degree of lithium ion conductivity.
  • x and y are composition ratios of copolymerization, and can appropriately take a value of 0 ⁇ y / (x + y) ⁇ 1.
  • R 3 and R 4 are functional groups having at least one of elements C, N, S, O, and H. R 3 and R 4 may be the same or different. n is the number of repeating units.
  • the lithium conductive polymer 6 is lower in hardness and softer than the negative electrode active material and the conductive material particles, so that a slurry containing the negative electrode active material, the lithium conductive polymer 6 and the conductive material is applied to the current collector and pressure is applied.
  • the lithium conductive polymer 6 can be deformed and filled so as to enter between the negative electrode active material and the conductive material. Since the contact area between the negative electrode active material and the lithium conductive polymer 6 is increased by being deformed and filled, high lithium ion conductivity can be realized even with a negative electrode active material mixture that does not use a liquid electrolyte. Can.
  • the average molecular weight of the lithium conductive polymer 6 is preferably 1,000 to 400,000. More preferably, it is 5,000 to 100,000, and particularly preferably 10,000 to 50,000.
  • the average molecular weight is smaller than the lower limit value of the above range, the polymers are aggregated at the time of preparation of the electrode, and a good electron conduction path is not formed, and the output of the battery is reduced.
  • the value is larger than the upper limit value, it is considered that since the polymer becomes hard, it gets into the voids of the negative electrode active material and it becomes difficult to fill the voids.
  • the negative electrode active material can be flexibly deformed even with respect to the expansion and contraction of the negative electrode active material, and a gap can be hardly generated between the negative electrode active material and the polymer.
  • a carbon material capable of reversibly inserting and desorbing lithium ions such as artificial graphite, natural graphite, and coke can be used.
  • an oxide that intercalates and releases lithium such as an oxide containing Si, Sn, and Ti can be used.
  • a silicon-based material Si, SiO, a tin-based material, lithium titanate with or without a substitution element, lithium vanadium complex oxide can be used.
  • various alloys for example, an alloy of lithium and tin, aluminum, antimony or the like can be used.
  • the carbon material natural graphite, composite carbonaceous material obtained by forming a film on natural graphite by dry CVD method or wet spray method, resin material such as epoxy and phenol, or pitch material obtained from petroleum or coal As artificial graphite manufactured by baking, a non-graphitizable carbon material, etc. are mentioned.
  • the above materials may be contained singly or in combination as the negative electrode active material 62. In the negative electrode active material 62, insertion and desorption reactions or conversion reactions of lithium ions proceed in the charge and discharge process.
  • the particle size of the negative electrode active material 62 is usually defined to be equal to or less than the thickness of the negative electrode mixture layer 60. If the powder of the negative electrode active material 62 has coarse particles having a size equal to or larger than the mixture layer thickness, the coarse particles are removed in advance by sieve classification, air flow classification or the like, and particles of a thickness of the negative electrode mixture layer 60 or less It is preferable to make it.
  • a negative electrode conductive agent 64 and a negative electrode binder can be added to the negative electrode mixture layer 60.
  • acetylene black, carbon black, and carbon materials such as graphite or amorphous carbon can be used.
  • the negative electrode binder styrene-butadiene rubber, carboxymethyl cellulose and polyvinylidene fluoride (PVDF), or a mixture of two or more of them can be used.
  • the negative electrode mixture layer 60 is formed of a negative electrode active material 62, a lithium conductive polymer 63, a negative electrode conductive agent, a negative electrode binder, and an organic solvent mixed negative electrode slurry by a doctor blade method, a dipping method, a spray method or the like. After adhering to the current collector 20, the organic solvent can be dried and pressure-formed by a roll press.
  • the negative electrode active material 62 and the particles of the lithium conductive polymer 63 make it possible to obtain a negative electrode mixture having a higher density and a lower porosity than when the voids are filled.
  • a large press pressure is required.
  • the ratio of the lithium conductive polymer 63 in the negative electrode slurry without changing the amount of the negative electrode active material 62 as in (2).
  • the void between the negative electrode active material 63 can be filled with the lithium conductive polymer 63, and the porosity can be lowered.
  • the lithium conductive polymer 63 can be inserted between the negative electrode active materials by pressing, and thus does not require a pressing pressure as large as (1).
  • the porosity can be lowered by increasing the proportion of the negative electrode active material 63 or the conductive material, but it is preferable to increase the proportion of the lithium conductive polymer 63. Since the negative electrode active material 63 and the conductive material are hard materials as compared with the lithium conductive polymer 63, a large pressing pressure is required to fill the voids. Also, from the viewpoint of lithium ion conductivity, it is preferable to fill the voids with the lithium conductive polymer 63 rather than the conductive material.
  • lithium ion conduction to the negative electrode mixture is performed.
  • the proportion of the polymer is preferably 1 to 20 wt%.
  • the porosity is 5% or less, it is preferably 10 to 20 wt%.
  • the electrode is pressed at a predetermined pressure in order to set the porosity to a preferable range and to form a conductive path of ions or electrons.
  • a known method capable of uniformly pressing the electrode mixture layer can be selected according to the electrode area.
  • an apparatus capable of pressing a large area such as a uniaxial press when the electrode area is small, or a roll press when the electrode area is large can be suitably used.
  • the pressing pressure can be set arbitrarily, but the pressure or pressure at which the lithium conductive polymer forms a sufficient contact surface with the negative electrode active material, and the negative electrode active material loses the lithium ion storage capacity, and so on.
  • the pressure be less than or equal to the pressure that causes structural change such as shaking.
  • the pressing pressure depends on the amount of lithium conductive polymer added and the composition of the electrode. In order to reduce the porosity in the negative electrode mixture, a larger press pressure is required than when the amount of lithium conductive polymer added is increased. The relationship between the pressing pressure and the porosity can be confirmed by observing the cross section of the negative electrode mixture by SEM after pressing.
  • the negative electrode mixture of the present invention in which the porosity is kept low is higher in density than the conventional negative electrode mixture.
  • the electrode density after pressing solid content The density
  • the density is in the range of 1.0 to 2.5 g / cm.sup.- 3 .
  • the density is more preferably in the range of 1.2 to 2.3 g / cm.sup.- 3 , further preferably 1.5 to 2.0 g / cm.sup.- 3 .
  • the solid electrolyte layer 50 has solid electrolyte particles 52 and an optional binder.
  • the solid electrolyte particle is not particularly limited as long as it is a solid material which conducts lithium ions, but from the viewpoint of safety, it is desirable to contain a nonflammable inorganic solid electrolyte.
  • an oxide glass represented by Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , LiAlGe (PO 4 ) 3 , Li 3.4 V 0.6 Si 0.4 O 4 , Li 2 P 2 O 6 or the like, Li 0.34 Perovskite-type oxides represented by La 0.51 TiO 2.94 etc., garnet-type oxides represented by LiLaZrO 2, etc. can be used.
  • the oxide conductor may contain a lithium halide such as LiCl or LiI.
  • a lithium halide such as LiCl or LiI.
  • sulfide-based inorganic solid electrolytes and polymer electrolytes can also be suitably used.
  • the above solid electrolytes can be used alone or in combination of two or more.
  • the binder is not particularly limited, and examples thereof include lithium ion conductive crystals such as Li 3 BO 3 .
  • the coating amount of the negative electrode active material on the electrode foil is adjusted to be substantially constant at 8 mg / m 2 ⁇ 0.5 mg, and the ratio of lithium conductive polymer type and lithium conductive polymer, and the press pressure are changed.
  • the porosity was adjusted by
  • the application amount of the negative electrode active material to the electrode foil is not limited to this value.
  • the amount can be appropriately adjusted in the range of about 1 to 20 mg / m 2 .
  • the lithium conductive polymer represented by the following formula (4) was dissolved in NMP, and allowed to stand at 70 ° C. for 3 hours to prepare a 10 wt% uniform polymer solution.
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the positive electrode active material LiCoO 2 is 90 wt%
  • a conductive auxiliary agent of acetylene black (AB) is 5 wt%
  • PVDF is 5% by weight solids ratio
  • LiCoO 2 AB powder having an average particle diameter of 10 [mu] m, in NMP
  • the dissolved PVDF and lithium conductive polymer solution were mixed in an agate mortar to make a slurry.
  • the slurry was applied on a 20 ⁇ m thick aluminum foil.
  • the coated electrode was allowed to stand still in a dryer maintained at 80 ° C. to distill off NMP, punched into a circle with a diameter of 15 mm, and uniaxially pressed from above and below to obtain a positive electrode.
  • ⁇ Production of resistance evaluation cell> The cell for resistance measurement was measured in a glove box purged with argon gas with a dew point of ⁇ 80 ° C. or less.
  • the negative electrode layer of the prepared electrode was made to face the polymer sheet, and the positive electrode was further laminated in the form of a polymer sheet. The laminate was inserted into the aluminate pack.
  • the polymer sheet was prepared by dissolving branched PEO and lithium salt LiFSI in acetonitrile and drying at 80 ° C. ⁇ Evaluation of resistance> Charge / discharge was performed at 0.01 C at a voltage range of 4.2 to 2.5 V, and direct current resistance was measured when discharged at SOC 50% for 10 seconds.
  • an all solid secondary battery was manufactured using a lithium conductive polymer represented by the following formula (5).
  • the average molecular weight of the lithium conductive polymer is 15,000.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was manufactured using a lithium conductive polymer represented by the following formula (6).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was manufactured using the lithium conductive polymer represented by the formula (5).
  • the average molecular weight of the lithium conductive polymer is 15,000.
  • the other preparation conditions are the same as in Example 2.
  • an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was produced without using a lithium conductive polymer.
  • the other preparation conditions are the same as in Example 1.
  • an all solid secondary battery was manufactured using the lithium conductive polymer represented by the formula (6).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • the porosity was confirmed by SEM, it was 10.7%. Due to the high porosity, the DC resistance value showed a high value of 12.1 ⁇ .
  • an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4).
  • the average molecular weight of the lithium conductive polymer is 10000.
  • the other preparation conditions are the same as in Example 1.
  • the porosity was confirmed by SEM, it was 10.1%. Due to the high porosity, the DC resistance value showed a high value of 11.4 ⁇ .
  • Table 1 shows the porosity and the output characteristics of the all-solid secondary batteries produced in Examples 1 to 5 and Comparative Examples 1 to 5.
  • Positive electrode current collector 10 Negative electrode current collector 20 Battery case 30 Positive electrode mixture layer 40 Solid electrolyte layer 50 Solid electrolyte particles 52 Negative electrode mixture layer 60 Negative electrode active material 62 Lithium conductive polymer 63 Negative electrode conductive agent 64 Positive electrode 70 Negative electrode 80 All solid secondary battery 100

Abstract

The purpose of the present invention is to provide a high-output lithium ion battery which has improved lithium ion conductivity in a negative electrode active material even in cases where a solid electrolyte is used as the electrolyte. A lithium ion secondary battery which comprises: a positive electrode wherein a positive electrode mixture layer is provided on the surface of a positive electrode collector; a negative electrode wherein a negative electrode mixture layer is provided on the surface of a negative electrode collector; and a solid electrolyte that is provided between the positive electrode and the negative electrode. The negative electrode mixture layer contains a negative electrode active material and a lithium ion conductive polymer that is provided among the negative electrode active material. The negative electrode mixture layer has a void fraction of 10% or less. The ratio of the lithium ion conductive polymer relative to the negative electrode mixture layer is 5 wt% or more.

Description

全固体電池All solid battery
　本発明は、全固体電池に関する。 The present invention relates to an all solid state battery.
　不燃性又は難燃性の固体電解質を用いた全固体二次電池は高耐熱化が可能であり、安全化を図ることができるため、モジュールコストを低減できるとともに、高エネルギー密度化が可能である。しかし、固体電解質は、液体系の電解質（電解液）と比較してリチウムイオンの伝導度が低く、電池の高出力化が難しいという課題がある。 The all-solid secondary battery using the non-combustible or flame-retardant solid electrolyte can have high heat resistance and can be made safe, so that module costs can be reduced and high energy density can be achieved. . However, the solid electrolyte has a problem that the conductivity of lithium ions is lower than that of a liquid electrolyte (electrolyte solution), and it is difficult to achieve high output of the battery.
　特許文献１には、活物質層にポリエチレンオキシド（ＰＥＯ）およびポリプロピレンオキシド（ＰＰＯ）等のイオン伝導性ポリマーを添加する技術が開示されている。 Patent Document 1 discloses a technique of adding an ion conductive polymer such as polyethylene oxide (PEO) and polypropylene oxide (PPO) to an active material layer.
　また、特許文献２には、活物質合剤層に結着剤としてポリエチレンオキシドを用い、電解質として有機電解液ならびに固体電解質を用いた負極が開示されている。また、サイクル性、放電容量の向上を目的とし負極材料を含む電極の空隙率を１０％以上６０％以下に調節している。 Further, Patent Document 2 discloses a negative electrode using polyethylene oxide as a binder in an active material mixture layer and using an organic electrolytic solution and a solid electrolyte as an electrolyte. In addition, the porosity of the electrode containing the negative electrode material is adjusted to 10% or more and 60% or less for the purpose of improving cycle performance and discharge capacity.
特開２０１０－９２６２２号公報JP, 2010-92622, A 特開平７－３１２２１９号公報Japanese Patent Application Laid-Open No. 7-312219
　しかし、特許文献１において、電解質として固体電解質を用いた場合、活物質合剤中に電解液がないため、イオン伝導性ポリマーを添加したとしても活物質粒子、イオン伝導性ポリマー等の粒子間に空隙が生じる。このため、活物質合剤中におけるリチウムイオン伝導度を向上させることは難しい。 However, in Patent Document 1, when a solid electrolyte is used as the electrolyte, since there is no electrolytic solution in the active material mixture, even if an ion conductive polymer is added, particles such as active material particles and ion conductive polymer can be used. An air gap occurs. For this reason, it is difficult to improve the lithium ion conductivity in the active material mixture.
　また、特許文献２においても、電解質として固体電解質を用いた場合、開示された空隙率の範囲では負極層内部に空孔が多く存在するため、負極活物質間の接触面積が小さく、リチウムイオンの伝導パスが少なくなり、負極合材内部の抵抗が大きいというデメリットがある。 Further, also in Patent Document 2, when a solid electrolyte is used as the electrolyte, many pores are present in the inside of the negative electrode layer in the range of the disclosed porosity, so the contact area between the negative electrode active material is small and lithium ions There is a disadvantage that the number of conduction paths is reduced and the internal resistance of the negative electrode mixture is large.
　本発明は、電解質として固体電解質を用いた場合であっても負極活物質中のリチウムイオン伝導度を改善した高出力なリチウムイオン電池を提供することを目的とした。 An object of the present invention is to provide a high output lithium ion battery in which the lithium ion conductivity in the negative electrode active material is improved even when a solid electrolyte is used as the electrolyte.
　上記課題を解決するための本発明の特徴は、例えば以下の通りである。正極集電体の表面に正極合剤層が設けられた正極と、負極集電体の表面に負極合剤層が設けられた負極と、正極と負極との間に設けられた固体電解質とを有するリチウムイオン二次電池において、負極合剤層は、負極活物質と、負極活物質の間に設けられたリチウムイオン導電性高分子とを有し、負極合剤層の空隙率は１０％以下であり、負極合剤層に対するリチウムイオン導電性高分子の割合は５wt％以上であるリチウムイオン二次電池。 The features of the present invention for solving the above problems are, for example, as follows. A positive electrode provided with a positive electrode mixture layer on the surface of the positive electrode current collector, a negative electrode provided with a negative electrode mixture layer on the surface of the negative electrode current collector, and a solid electrolyte provided between the positive electrode and the negative electrode In the lithium ion secondary battery, the negative electrode mixture layer includes a negative electrode active material and a lithium ion conductive polymer provided between the negative electrode active materials, and the porosity of the negative electrode mixture layer is 10% or less The lithium ion secondary battery, wherein the ratio of the lithium ion conductive polymer to the negative electrode mixture layer is 5 wt% or more.
　本発明では、上記ポリマーを負極活物質合剤中に添加し、空隙率を０．０１％以上１０％以下として電池を作製することで負極層内部の空孔を低減し、リチウムイオンの伝導パスを向上させた高出力の電池を提供することができる。 In the present invention, the above polymer is added to the negative electrode active material mixture, and the battery is manufactured with a porosity of 0.01% or more and 10% or less, thereby reducing the pores in the negative electrode layer, and the lithium ion conduction path. It is possible to provide a high power battery with improved.
　本発明により、電解質として固体電解質を用いた場合であっても負極活物質中のリチウムイオン伝導度を改善した高出力なリチウムイオン電池を提供することができる。上記した以外の課題、構成及び効果は以下の実施形態の説明により明らかにされる。 According to the present invention, even when a solid electrolyte is used as the electrolyte, it is possible to provide a high-power lithium ion battery in which the lithium ion conductivity in the negative electrode active material is improved. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.
本発明の一実施形態に係る全固体二次電池の断面概念図である。It is a cross-sectional conceptual diagram of the all-solid-state secondary battery which concerns on one Embodiment of this invention. 本発明の一実施形態に係る全固体二次電池の要部の断面概念図である。It is a cross-sectional conceptual diagram of the principal part of the all-solid-state secondary battery which concerns on one Embodiment of this invention.
　以下、図面等を用いて、本発明の実施形態について説明する。以下の説明は本発明の内容の具体例を示すものであり、本発明がこれらの説明に限定されるものではなく、本明細書に開示される技術的思想の範囲内において当業者による様々な変更および修正が可能である。また、本発明を説明するための全図において、同一の機能を有するものは、同一の符号を付け、その繰り返しの説明は省略する場合がある。 Hereinafter, embodiments of the present invention will be described using the drawings and the like. The following description shows specific examples of the content of the present invention, and the present invention is not limited to these descriptions, and various modifications by those skilled in the art can be made within the scope of the technical idea disclosed herein. Changes and modifications are possible. Moreover, in all the drawings for explaining the present invention, what has the same function may attach the same numerals, and may omit explanation of the repetition.
　図１は、本発明の一実施形態に係る全固体二次電池の断面図である。図２は、本発明の一実施形態に係る全固体二次電池の要部の断面図である。全固体二次電池１００は、正極集電体１０、負極集電体２０、電池ケース３０、正極合剤層４０、固体電解質５０、負極合剤層６０を有する。図１中の正極７０は、正極集電体１０および正極合剤層４０を有する。図１中の負極８０は、負極集電体２０および負極合剤層６０を有する。
＜正極集電体１０＞
　正極集電体１０は、正極４０に電気的に接続されている。正極集電体１０には、厚さが１０～１００μｍのアルミニウム箔、厚さが１０～１００μｍで孔径が０．１～１０ｍｍのアルミニウム製穿孔箔、エキスパンドメタル、又は発泡金属板等が用いられる。アルミニウムの他に、ステンレスやチタン等の材質も適用可能である。本発明では、材質、形状、製造方法等に制限されることなく、任意の集電体を使用することができる。
＜負極集電体２０＞
　負極集電体２０は、負極６０に電気的に接続されている。負極集電体２０には、厚さが１０～１００μｍの銅箔、厚さが１０～１００μｍで孔径０．１～１０ｍｍの銅製穿孔箔、エキスパンドメタル、又は発泡金属板等が用いられる。銅の他に、ステンレス、チタン、又はニッケル等の材質も適用可能である。本発明では、材質、形状、製造方法等に制限されることなく、任意の集電体を使用することができる。
＜電池ケース３０＞
　電池ケース３０は、正極集電体１０、負極集電体２０、正極合剤層４０、固体電解質層５０、および負極合剤層６０を収容する。電池ケース３０の形状は、正極合剤層４０、固体電解質層５０、負極合剤層６０で構成される電極群の形状に合わせ、円筒形、偏平長円形状、扁平楕円形状、角形等の形状を選択してもよい。電池ケース３０の材料として、アルミニウム、ステンレス鋼、ニッケルメッキ鋼製等、非水電解質に対し耐食性のある材料から選択される。
＜正極合剤層４０＞
　正極合剤層４０は、正極活物質、任意の正極導電剤、任意の正極バインダを有する。 FIG. 1 is a cross-sectional view of an all-solid secondary battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the main part of the all-solid-state secondary battery according to an embodiment of the present invention. The all solid secondary battery 100 includes a positive electrode current collector 10, a negative electrode current collector 20, a battery case 30, a positive electrode mixture layer 40, a solid electrolyte 50, and a negative electrode mixture layer 60. The positive electrode 70 in FIG. 1 has a positive electrode current collector 10 and a positive electrode mixture layer 40. The negative electrode 80 in FIG. 1 has a negative electrode current collector 20 and a negative electrode mixture layer 60.
<Positive Electrode Current Collector 10>
The positive electrode current collector 10 is electrically connected to the positive electrode 40. For the positive electrode current collector 10, an aluminum foil having a thickness of 10 to 100 μm, a perforated aluminum foil having a thickness of 10 to 100 μm and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate or the like is used. Besides aluminum, materials such as stainless steel and titanium are also applicable. In the present invention, any current collector can be used without being limited to the material, shape, manufacturing method and the like.
<Anode Current Collector 20>
The negative electrode current collector 20 is electrically connected to the negative electrode 60. As the negative electrode current collector 20, a copper foil having a thickness of 10 to 100 μm, a perforated copper foil having a thickness of 10 to 100 μm and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam metal plate or the like is used. Besides copper, materials such as stainless steel, titanium or nickel are also applicable. In the present invention, any current collector can be used without being limited to the material, shape, manufacturing method and the like.
<Battery case 30>
The battery case 30 accommodates the positive electrode current collector 10, the negative electrode current collector 20, the positive electrode mixture layer 40, the solid electrolyte layer 50, and the negative electrode mixture layer 60. The shape of the battery case 30 conforms to the shape of the electrode group configured of the positive electrode mixture layer 40, the solid electrolyte layer 50, and the negative electrode mixture layer 60, and has a cylindrical, flat oval, flat oval, square, etc. shape. May be selected. The material of the battery case 30 is selected from materials having corrosion resistance to the non-aqueous electrolyte, such as aluminum, stainless steel, nickel plated steel, and the like.
<Positive electrode mixture layer 40>
The positive electrode mixture layer 40 has a positive electrode active material, an optional positive electrode conductive agent, and an optional positive electrode binder.
　正極活物質として、ＬｉＣｏＯ2、ＬｉＮｉＯ2、ＬｉＭｎ2Ｏ4、ＬｉＭｎＯ3、ＬｉＭｎ2Ｏ3、ＬｉＭｎＯ2、Ｌｉ4Ｍｎ5Ｏ12、ＬｉＭｎ2-xＭｘＯ2（ただし、Ｍ＝Ｃｏ、Ｎｉ、Ｆｅ、Ｃｒ、Ｚｎ、Ｔｉからなる群から選ばれる少なくとも１種、ｘ＝０．０１～０．２）、Ｌｉ2Ｍｎ3ＭＯ8（ただし、Ｍ＝Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎからなる群から選ばれる少なくとも１種）、Ｌｉ1-xＡxＭｎ2Ｏ4（ただし、Ａ＝Ｍｇ、Ｂ、Ａｌ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｒ、Ｚｎ、Ｃａからなる群から選ばれる少なくとも１種、ｘ＝０．０１～０．１）、ＬｉＮｉ1-xＭxＯ2（ただし、Ｍ＝Ｃｏ、Ｆｅ、Ｇａからなる群から選ばれる少なくとも１種、ｘ＝０．０１～０．２）、ＬｉＦｅＯ2、Ｆｅ2（ＳＯ4）3、ＬｉＣｏ1-xＭxＯ2（ただし、Ｍ＝Ｎｉ、Ｆｅ、Ｍｎからなる群から選ばれる少なくとも１種、ｘ＝０．０１～０．２）、ＬｉＮｉ1-xＭxＯ2（ただし、Ｍ＝Ｍｎ、Ｆｅ、Ｃｏ、Ａｌ、Ｇａ、Ｃａ、Ｍｇからなる群から選ばれる少なくとも１種、ｘ＝０．０１～０．２）、Ｆｅ（ＭｏＯ4）3、ＦｅＦ3、ＬｉＦｅＰＯ4、及びＬｉＭｎＰＯ4等が挙げられる。正極活物質として上記の材料が一種単独または二種以上含まれていてもよい。正極活物質は、充電過程においてリチウムイオンが脱離し、放電過程において、負極合剤層６０中の負極活物質から脱離したリチウムイオンが挿入される。 As a positive electrode active material, LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 3 , LiMn 2 O 3 , LiMn 2 O 3 , LiMnO 2 , Li 4 Mn 5 O 12 , LiMn 2-x MxO 2 (where M = Co, Ni, Fe) , At least one selected from the group consisting of Cr, Zn and Ti, x = 0.01 to 0.2), Li 2 Mn 3 MO 8 (where M = Fe, Co, Ni, Cu, Zn) At least one selected from the group consisting of Li 1 -x A x Mn 2 O 4 (wherein A = Mg, B, Al, Fe, Co, Ni, Cr, Zn, Ca); x = 0.01 to 0.1), LiNi 1-x M x O 2 (wherein M = at least one selected from the group consisting of Co, Fe and Ga, x = 0.01 to 0.2), LiFeO 2, Fe 2 (SO 4 ) 3, LiCo 1-x M x O 2 However, M = Ni, Fe, at least one selected from the group consisting of Mn, x = 0.01 ~ 0.2) , LiNi 1-x M x O 2 ( however, M = Mn, Fe, Co , Al And at least one selected from the group consisting of Ga, Ca and Mg, x = 0.01 to 0.2), Fe (MoO 4 ) 3 , FeF 3 , LiFePO 4 , LiMnPO 4 and the like. The above materials may be contained singly or in combination of two or more as the positive electrode active material. In the positive electrode active material, lithium ions are desorbed in the charging process, and lithium ions desorbed from the negative electrode active material in the negative electrode mixture layer 60 are inserted in the discharging process.
　正極活物質の粒径は、正極合剤層４０の厚さ以下になるように通常は規定される。正極活物質の粉末中に合剤層厚さ以上のサイズを有する粗粒がある場合、予めふるい分級や風流分級等により粗粒を除去し、合剤層厚さ以下の粒子を作製することが好ましい。 The particle size of the positive electrode active material is usually defined to be equal to or less than the thickness of the positive electrode mixture layer 40. When the powder of the positive electrode active material contains coarse particles having a size equal to or larger than the mixture layer thickness, the coarse particles are removed in advance by sieve classification, air flow classification, etc. to produce particles of the mixed layer thickness or less. preferable.
　また、正極活物質は、一般に酸化物系であるために電気抵抗が高いので、電気伝導性を補うための炭素粉末からなる正極導電剤を利用する。正極活物質及び正極導電剤はともに通常は粉末であるので、粉末にバインダを混合して、粉末同士を結合させると同時に正極集電体１０へ接着させることができる。 In addition, since the positive electrode active material is generally oxide-based and has high electrical resistance, a positive electrode conductive agent made of carbon powder is used to compensate for the electrical conductivity. Since both the positive electrode active material and the positive electrode conductive agent are usually powders, the powders can be mixed with a binder to bond the powders together and to be bonded to the positive electrode current collector 10 at the same time.
　正極合剤層４０に正極導電剤や正極バインダが含まれる場合、正極導電剤として、アセチレンブラック、カーボンブラック、及び黒鉛又は非晶質炭素等の炭素材料等が挙げられる。正極バインダとして、スチレン－ブタジエンゴム、カルボキシメチルセルロース及びポリフッ化ビニリデン（ＰＶＤＦ）、これらの混合物等が挙げられる。 When the positive electrode mixture layer 40 contains a positive electrode conductive agent or a positive electrode binder, examples of the positive electrode conductive agent include acetylene black, carbon black, and carbon materials such as graphite or amorphous carbon. Examples of positive electrode binders include styrene-butadiene rubber, carboxymethylcellulose and polyvinylidene fluoride (PVDF), and mixtures thereof.
　正極活物質、正極導電剤、正極バインダ、及び有機溶媒を混合した正極スラリーを、ドクターブレード法、ディッピング法、又はスプレー法等によって正極集電体１０へ付着させた後、有機溶媒を乾燥させ、ロールプレスによって加圧成形することにより、正極７０を作製することができる。また、塗布から乾燥までを複数回行うことにより、複数の正極合剤層４０を正極集電体１０に積層化させることも可能である。
＜負極合剤層６０＞
図２は、負極集電体に塗布された負極合剤層６０および、負極合剤層６０上に設けられた固体電解質層５０の断面概念図である。負極合剤層６０は、負極活物質６２、リチウム伝導性高分子６３、任意の負極導電剤６４、任意の負極バインダを有する。負極活物質６２粒子間にはリチウム伝導性高分子６３が充填されている。粒子間の空隙を埋めることによってリチウムイオンの移動度が増し、負極合剤層６０の抵抗を低くすることができる。負極層内部の空隙をリチウム伝導性高分子が充填することで、リチウムイオンの伝導パスが向上し高出力化を実現できる。 After a positive electrode slurry obtained by mixing a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and an organic solvent is attached to the positive electrode current collector 10 by a doctor blade method, dipping method, spray method or the like, the organic solvent is dried, The positive electrode 70 can be manufactured by pressure forming using a roll press. In addition, it is also possible to laminate a plurality of positive electrode mixture layers 40 on the positive electrode current collector 10 by performing application to drying a plurality of times.
<Negative electrode mixture layer 60>
FIG. 2 is a schematic cross-sectional view of the negative electrode mixture layer 60 applied to the negative electrode current collector and the solid electrolyte layer 50 provided on the negative electrode mixture layer 60. The negative electrode mixture layer 60 has a negative electrode active material 62, a lithium conductive polymer 63, an optional negative electrode conductive agent 64, and an optional negative electrode binder. A lithium conductive polymer 63 is filled between the negative electrode active material 62 particles. By filling the gaps between the particles, the mobility of lithium ions can be increased, and the resistance of the negative electrode mixture layer 60 can be lowered. By filling the voids inside the negative electrode layer with the lithium conductive polymer, the conduction path of lithium ions can be improved and high output can be realized.
　電解質に液体を用いる電池では電解液を浸透させるためのある程度の空隙が必要であるが、本発明のように固体電解質を用いる場合は空隙がリチウムイオン伝導度低下の一要因になると考えられるため空隙はなるべく少ないことが好ましい。 A battery using a liquid for the electrolyte requires a certain amount of gaps for the electrolyte to permeate, but when using a solid electrolyte as in the present invention, the gaps are considered to be a factor in the decrease in lithium ion conductivity. Is preferably as small as possible.
　負極合材層６０内部の空隙率は、１０％以下であることが好ましい。より好ましくは５％以下である。上記範囲よりも空隙率が大きいと、負極活物質間に十分なリチウムイオン伝導パスが形成されず、電池の出力が低下する。リチウムイオン二次電池の実用化を考えると、負極合剤層６０の直流抵抗値１０Ω以下であることが好ましい。さらに好ましくは６Ω、５Ω以下であり、負極合材層６０内部の空隙率が４～５％以下であればこの値が得られると考えられる。ここで、空隙率とは、負極合剤の体積に対する、負極活物質等の粒子間に生じる空間、空隙の体積割合であり、例えば水銀圧入法により求めることができる。 The porosity of the inside of the negative electrode mixture layer 60 is preferably 10% or less. More preferably, it is 5% or less. When the porosity is larger than the above range, a sufficient lithium ion conduction path is not formed between the negative electrode active materials, and the output of the battery is reduced. In consideration of practical use of the lithium ion secondary battery, the direct current resistance value of the negative electrode mixture layer 60 is preferably 10 Ω or less. More preferably, it is 6 Ω, 5 Ω or less, and it is considered that this value can be obtained if the porosity in the negative electrode mixture layer 60 is 4 to 5% or less. Here, the porosity is a volume ratio of a space or void generated between particles of a negative electrode active material or the like with respect to the volume of the negative electrode mixture, and can be determined, for example, by mercury porosimetry.
　リチウム伝導性高分子６３としては、リチウムイオン伝導度が高く電極作製の各工程において安定なもの、例えば結合剤や溶媒とともに負極合剤を調製する工程、その後の負極合剤の混練工程において、該溶剤に対して安定であり、溶出あるいは剥離等を生じないものを用いることができる。また、二次電池の作動時においても化学的、電気化学的に安定なものを用いることが望ましい。 As the lithium conductive polymer 63, one having high lithium ion conductivity and being stable in each process of electrode preparation, such as a process of preparing a negative electrode mixture with a binder and a solvent, and a subsequent kneading process of the negative electrode mixture Those which are stable with respect to the solvent and do not cause elution or peeling can be used. In addition, it is desirable to use one that is chemically and electrochemically stable even during operation of the secondary battery.
　具体的には、ポリフッ化ビニリデン、ポリテトラフルオルエチレンなどのフッ素系樹脂、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリアクリロニトリルなどの固体電解質に用いられる高分子化合物、ポリビニルアルコール、ポリエチレングリコール、ポリプロピレングリコール、ポリビニルピロリドン、スチレン－無水マレイン酸共重合体、メチルセルロース、カルボキシメチルセルロース、ヒドロキシエチルセルロース、ポリアクリル酸などの水溶性高分子化合物、スチレン－ブタジエンラバーなどの架橋性高分子化合物、ポリエチレン、ポリプロピレンなどのオレフィン系高分子化合物、高分子アミン化合物などが使用可能である。さらにこれらの高分子の加水分解物、架橋反応物、酸変性物など各種の反応物、変性物であってもよく、酸または塩基の中和塩、金属塩などの塩であってもよい。 Specifically, fluorine-based resins such as polyvinylidene fluoride and polytetrafluoroethylene, polymer compounds used for solid electrolytes such as polyethylene oxide, polypropylene oxide and polyacrylonitrile, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyvinyl pyrrolidone Water-soluble polymer compounds such as styrene-maleic anhydride copolymer, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, crosslinkable polymer compounds such as styrene-butadiene rubber, olefin polymers such as polyethylene and polypropylene Compounds, polymeric amine compounds and the like can be used. Furthermore, it may be a hydrolyzate of these polymers, a cross-linked product, a variety of reactants such as an acid-modified product, or a modified product, or a salt such as a neutralized salt of an acid or a base or a metal salt.
　特に、リチウムイオン伝導度の観点からは下記（式１）のような直鎖状のポリエチレンオキサイドまたは、分岐したポリエチレンオキサイド、下記（式２）のようにＣＮ基を有するモノマーと－ＣＯＯＲ基または－ＣＯ－基のいずれかを有するモノマーとを重合させたポリマー、－Ｐ＝Ｎ－基を有するポリマーが好ましい。 In particular, from the viewpoint of lithium ion conductivity, linear polyethylene oxide as shown in the following (formula 1) or branched polyethylene oxide, a monomer having a CN group as shown in the following (formula 2) and -COOR group or- A polymer obtained by polymerizing a monomer having any of CO-groups and a polymer having -P = N- group are preferable.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　式１においてＲ1は、水素、アルキル基または酸素を有するアルキル基である。ｎは繰り返し単位数である。構造中の酸素を介してリチウムイオンの伝達が行われると考えられる。分岐したポリエチレンオキサイドとは、式１においてＲ1からさらに式１のポリエチレンオキシドが分岐する構造であり、直鎖状のポリエチレンオキシドよりも硬度が高く、機械的強度が高い。 In Formula 1, R 1 is hydrogen, an alkyl group or an alkyl group having oxygen. n is the number of repeating units. It is believed that lithium ion transfer takes place via oxygen in the structure. The branched polyethylene oxide is a structure in which polyethylene oxide of Formula 1 is further branched from R 1 in Formula 1, which is higher in hardness and higher in mechanical strength than linear polyethylene oxide.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　式２において、Ｒ2は、元素Ｃ、N、S、O、Hのいずれか少なくとも一種を有する官能基である。構造中の酸素を介してリチウムイオンの伝達が行われると考えられる。Ｒ2は、－ＣＯＯＲ－、－ＣＯ－、NH、スルホ基のようなリチウムイオンの伝達度が高い構造を有していることが好ましい。x、yは、共重合の組成比であり、0＜ｙ/(ｘ+ｙ)≦1の値を適宜取り得る。 In Formula 2, R 2 is a functional group having at least one of elements C, N, S, O, and H. It is believed that lithium ion transfer takes place via oxygen in the structure. R 2 preferably has a structure such as —COOR—, —CO—, NH, and a sulfo group having a high degree of lithium ion conductivity. x and y are composition ratios of copolymerization, and can appropriately take a value of 0 <y / (x + y) ≦ 1.
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　式３において、Ｒ3、Ｒ4は、元素Ｃ、N、S、O、Hのいずれか少なくとも一種を有する官能基である。Ｒ3、Ｒ4は同一であってもよく異なっていても構わない。ｎは繰り返し単位数である。 In Formula 3, R 3 and R 4 are functional groups having at least one of elements C, N, S, O, and H. R 3 and R 4 may be the same or different. n is the number of repeating units.
　リチウム伝導性高分子６は負極活物質や導電材粒子よりも硬度が低く、柔らかいため、負極活物質、リチウム伝導性高分子６、導電材を有するスラリーを集電体に塗布し、圧力をかけることで、リチウム伝導性高分子６が変形し、負極活物質、導電材の間に入り込むように充填されることができる。変形して充填されることで、負極活物質とリチウム伝導性高分子６との接触面積が増すため、液体電解質を用いない負極活物質合剤であっても高いリチウムイオン導電性を実現することができる。 The lithium conductive polymer 6 is lower in hardness and softer than the negative electrode active material and the conductive material particles, so that a slurry containing the negative electrode active material, the lithium conductive polymer 6 and the conductive material is applied to the current collector and pressure is applied. Thus, the lithium conductive polymer 6 can be deformed and filled so as to enter between the negative electrode active material and the conductive material. Since the contact area between the negative electrode active material and the lithium conductive polymer 6 is increased by being deformed and filled, high lithium ion conductivity can be realized even with a negative electrode active material mixture that does not use a liquid electrolyte. Can.
　リチウム伝導性高分子６の平均分子量は１０００～４０００００であることが好ましい。さらに好ましくは、５０００～１０００００であり、特に好ましくは１００００～５００００である。上記範囲の下限値より平均分子量が小さい場合は電極作製時にポリマー同士が凝集するため良好な電子伝導パスが形成されなくなり電池の出力が低下する。一方，上限値より大きい場合はポリマーが固くなるため負極活物質の空隙に入り込み、空隙を充填しにくくなると考えられる。ある程度の柔らかさを持つことで、負極活物質の膨張収縮に対しても柔軟に変形し、負極活物質とポリマーとの間に隙間を生じさせにくくすることができる。 The average molecular weight of the lithium conductive polymer 6 is preferably 1,000 to 400,000. More preferably, it is 5,000 to 100,000, and particularly preferably 10,000 to 50,000. When the average molecular weight is smaller than the lower limit value of the above range, the polymers are aggregated at the time of preparation of the electrode, and a good electron conduction path is not formed, and the output of the battery is reduced. On the other hand, when the value is larger than the upper limit value, it is considered that since the polymer becomes hard, it gets into the voids of the negative electrode active material and it becomes difficult to fill the voids. By having a certain degree of softness, the negative electrode active material can be flexibly deformed even with respect to the expansion and contraction of the negative electrode active material, and a gap can be hardly generated between the negative electrode active material and the polymer.
　負極活物質６２としては、リチウムイオンを可逆的に挿入脱離可能な炭素材料、例えば人造黒鉛，天然黒鉛，コークスを用いることができる。また、リチウムを挿入放出する酸化物例えばＳｉ，Ｓｎ，Ｔｉを含む酸化物を用いることができる。シリコン系材料Ｓｉ、ＳｉＯ、スズ系材料、置換元素ありまたは置換元素無しのチタン酸リチウム、リチウムバナジウム複合酸化物を用いることができる。また、種々の合金、例えばリチウムとスズ、アルミニウム、アンチモン等との合金を用いることができる。 As the negative electrode active material 62, a carbon material capable of reversibly inserting and desorbing lithium ions, such as artificial graphite, natural graphite, and coke can be used. Alternatively, an oxide that intercalates and releases lithium, such as an oxide containing Si, Sn, and Ti can be used. A silicon-based material Si, SiO, a tin-based material, lithium titanate with or without a substitution element, lithium vanadium complex oxide can be used. Further, various alloys, for example, an alloy of lithium and tin, aluminum, antimony or the like can be used.
　炭素材料としては、天然黒鉛や、天然黒鉛に乾式のＣＶＤ法もしくは湿式のスプレー法によって被膜を形成した複合炭素質材料、エポキシやフェノール等の樹脂材料もしくは石油や石炭から得られるピッチ系材料を原料として焼成により製造される人造黒鉛、難黒鉛化炭素材などが挙げられる。負極活物質６２として上記の材料が一種単独または二種以上含まれていてもよい。負極活物質６２は、充放電過程において、リチウムイオンが挿入脱離反応、もしくは、コンバージョン反応が進行する。 As the carbon material, natural graphite, composite carbonaceous material obtained by forming a film on natural graphite by dry CVD method or wet spray method, resin material such as epoxy and phenol, or pitch material obtained from petroleum or coal As artificial graphite manufactured by baking, a non-graphitizable carbon material, etc. are mentioned. The above materials may be contained singly or in combination as the negative electrode active material 62. In the negative electrode active material 62, insertion and desorption reactions or conversion reactions of lithium ions proceed in the charge and discharge process.
　負極活物質６２の粒径は、負極合剤層６０の厚さ以下になるように通常は規定される。負極活物質６２の粉末中に合剤層厚さ以上のサイズを有する粗粒がある場合、予めふるい分級や風流分級等により粗粒を除去し、負極合剤層６０の厚さ以下の粒子を作製することが好ましい。 The particle size of the negative electrode active material 62 is usually defined to be equal to or less than the thickness of the negative electrode mixture layer 60. If the powder of the negative electrode active material 62 has coarse particles having a size equal to or larger than the mixture layer thickness, the coarse particles are removed in advance by sieve classification, air flow classification or the like, and particles of a thickness of the negative electrode mixture layer 60 or less It is preferable to make it.
　負極合剤層６０には、負極導電剤６４や負極バインダを添加することができる。負極導電剤としては、アセチレンブラック、カーボンブラック、及び黒鉛又は非晶質炭素等の炭素材料等を用いることができる。負極バインダとしては、スチレン－ブタジエンゴム、カルボキシメチルセルロース及びポリフッ化ビニリデン（ＰＶＤＦ）、または、これら二種以上の混合物を用いることができる。

＜負極合剤層の製造方法＞～
　負極合剤層６０は、負極活物質６２、リチウム伝導性高分子６３、負極導電剤、負極バインダ、及び有機溶媒を混合した負極スラリーを、ドクターブレード法、ディッピング法、又はスプレー法等によって負極集電体２０へ付着させた後、有機溶媒を乾燥させ、ロールプレスによって加圧成形することにより作製することができる。 A negative electrode conductive agent 64 and a negative electrode binder can be added to the negative electrode mixture layer 60. As the negative electrode conductive agent, acetylene black, carbon black, and carbon materials such as graphite or amorphous carbon can be used. As the negative electrode binder, styrene-butadiene rubber, carboxymethyl cellulose and polyvinylidene fluoride (PVDF), or a mixture of two or more of them can be used.

<Method of producing negative electrode mixture layer>
The negative electrode mixture layer 60 is formed of a negative electrode active material 62, a lithium conductive polymer 63, a negative electrode conductive agent, a negative electrode binder, and an organic solvent mixed negative electrode slurry by a doctor blade method, a dipping method, a spray method or the like. After adhering to the current collector 20, the organic solvent can be dried and pressure-formed by a roll press.
　負極合剤層６０の空隙率を低くする方法としては、例えば（１）加圧成形時のプレス圧を上げる、（２）負極スラリー中のリチウム伝導性高分子６３の比率を上げる方法がある。加圧成形時のプレス圧を上げることで、負極活物質６２やリチウム伝導性高分子６３の粒子により、空隙が埋まりより高密度、低空隙率な負極合剤を得ることができる。負極合剤層中の負極活物質６２やリチウム伝導性高分子６３の粒子の比率を変えることなくプレス圧のみで空隙率を下げる場合、大きなプレス圧を必要とする。これに対して、（２）のように負極活物質６２の量を変えずに負極スラリー中のリチウム伝導性高分子６３の比率を上げる方法がある。リチウム伝導性高分子６３の比率を上げることで負極活物質６３間の空隙をリチウム伝導性高分子６３で充填し、空隙率を下げることができる。リチウム伝導性高分子６３は、プレスにより負極活物質間に入り込むことができるので、（１）程の大きなプレス圧を必要としない。 As a method of decreasing the porosity of the negative electrode mixture layer 60, for example, (1) there is a method of increasing the pressing pressure at the time of pressure molding, and (2) increasing the ratio of the lithium conductive polymer 63 in the negative electrode slurry. By raising the pressing pressure at the time of pressure molding, the negative electrode active material 62 and the particles of the lithium conductive polymer 63 make it possible to obtain a negative electrode mixture having a higher density and a lower porosity than when the voids are filled. When the porosity is reduced only by the press pressure without changing the ratio of the particles of the negative electrode active material 62 and the lithium conductive polymer 63 in the negative electrode mixture layer, a large press pressure is required. On the other hand, there is a method of raising the ratio of the lithium conductive polymer 63 in the negative electrode slurry without changing the amount of the negative electrode active material 62 as in (2). By increasing the ratio of the lithium conductive polymer 63, the void between the negative electrode active material 63 can be filled with the lithium conductive polymer 63, and the porosity can be lowered. The lithium conductive polymer 63 can be inserted between the negative electrode active materials by pressing, and thus does not require a pressing pressure as large as (1).
　空隙率は、負極活物質６３や導電材の割合増加により下げることもできるが、リチウム伝導性高分子６３の割合を増加させることが好ましい。負極活物質６３や導電材は、リチウム伝導性高分子６３と比較して固い素材であるため、空隙を埋めるには、大きなプレス圧が必要となる。また、リチウムイオン導電性の観点からも導電材よりリチウム伝導性高分子６３で空隙を充填することが好ましい。 The porosity can be lowered by increasing the proportion of the negative electrode active material 63 or the conductive material, but it is preferable to increase the proportion of the lithium conductive polymer 63. Since the negative electrode active material 63 and the conductive material are hard materials as compared with the lithium conductive polymer 63, a large pressing pressure is required to fill the voids. Also, from the viewpoint of lithium ion conductivity, it is preferable to fill the voids with the lithium conductive polymer 63 rather than the conductive material.
　後述するように、リチウムイオン導電性高分子の割合を増加させることで負極合剤中の負極合材層６０内部の空隙率を、１０％以下とするためには、負極合剤に対するリチウムイオン導電性高分子の比率は、１～２０wt％であることが好ましい。さらに空隙率を、５％以下とする場合は１０～２０wt％、であることが好ましい。負極合剤に対するリチウムイオン導電性高分子の比率と空隙率との関係は、プレスをかけた後に負極合剤の断面をＳＥＭにより観察することにより確認することができる。 As described later, in order to make the porosity in the negative electrode mixture layer 60 in the negative electrode mixture 60% or less by increasing the proportion of the lithium ion conductive polymer, lithium ion conduction to the negative electrode mixture is performed. The proportion of the polymer is preferably 1 to 20 wt%. Furthermore, in the case where the porosity is 5% or less, it is preferably 10 to 20 wt%. The relationship between the ratio of the lithium ion conductive polymer to the negative electrode mixture and the porosity can be confirmed by observing the cross section of the negative electrode mixture with SEM after pressing.
　本発明では空隙率を好ましい範囲にし、イオンや電子の導電パスを形成するために、電極を所定の圧力でプレスする。プレスの方法としては、電極面積に応じて、電極合剤層を均一にプレス可能な公知の方法を選択できる。例えば、電極面積が小さい場合は１軸プレス機、大きな場合はロールプレス機などの大面積をプレス可能な装置を好適に用いることができる。プレス圧力は任意に設定できるが、リチウム伝導性高分子が負極活物質と十分な接触面を形成する以上の圧力で、かつ負極活物質がリチウムイオンの吸蔵能力を喪失するような圧壊や極度のつぶれなどの構造変化をおこす圧力以下であることがのぞましい。プレス圧力はリチウム伝導性高分子の添加量や電極組成に依存する。負極合剤中の空隙率を下げるためにリチウム伝導性高分子の添加量を上げた場合より大きなプレス圧が必要となる。プレス圧と空隙率との関係は、プレスをかけた後に負極合剤の断面をＳＥＭにより観察することにより確認することができる。 In the present invention, the electrode is pressed at a predetermined pressure in order to set the porosity to a preferable range and to form a conductive path of ions or electrons. As a method of pressing, a known method capable of uniformly pressing the electrode mixture layer can be selected according to the electrode area. For example, an apparatus capable of pressing a large area such as a uniaxial press when the electrode area is small, or a roll press when the electrode area is large can be suitably used. The pressing pressure can be set arbitrarily, but the pressure or pressure at which the lithium conductive polymer forms a sufficient contact surface with the negative electrode active material, and the negative electrode active material loses the lithium ion storage capacity, and so on. It is preferable that the pressure be less than or equal to the pressure that causes structural change such as shaking. The pressing pressure depends on the amount of lithium conductive polymer added and the composition of the electrode. In order to reduce the porosity in the negative electrode mixture, a larger press pressure is required than when the amount of lithium conductive polymer added is increased. The relationship between the pressing pressure and the porosity can be confirmed by observing the cross section of the negative electrode mixture by SEM after pressing.
　空隙率を低く抑えた本発明の負極合剤は従来の負極合剤よりも密度が高い。例えば、負極合剤中の炭素系、チタン酸リチウム等負極活物質比率を８０％以上とし、リチウム伝導性高分子により空隙率を本発明の範囲に調節した場合、プレス後の電極密度（固形分密度）は1.0～2.5 g/cm-3の範囲となる。密度をあげれば空隙率が下がり、よりリチウムイオン伝導度が高い負極合剤となる。密度は、1.2～2.3g/cm-3、さらに1.5～2.0g/cm-3の範囲がより好ましい。
＜固体電解質層５０＞
　固体電解質層５０は、固体電解質粒子５２および任意のバインダを有する。固体電解質粒子は，リチウムイオンを伝導する固体材料であれば特に限定はないが、安全性の観点から不燃性の無機固体電解質を含むことが望ましい。具体的には、Ｌｉ1.4Ａｌ0.4Ｔｉ1.6（ＰＯ4）3、ＬｉＡｌＧｅ（ＰＯ4）3、Ｌｉ3.4Ｖ0.6Ｓｉ0.4Ｏ4、Ｌｉ2Ｐ2Ｏ6などで代表される酸化物ガラス、Ｌｉ0.34Ｌａ0.51ＴｉＯ2.94などで代表されるペロブスカイト型酸化物、ＬｉＬａＺｒＯ２に代表されるガーネット型酸化物などが使用できる。酸化物伝導体の中に、ＬｉＣｌ、ＬｉＩなどのハロゲン化リチウムが含まれていてもよい。また，硫化物系の無機固体電解質ならびにポリマー電解質も好適に用いることができる。以上の固体電解質を単独あるいは２つ以上を組み合わせて使用することができる。 The negative electrode mixture of the present invention in which the porosity is kept low is higher in density than the conventional negative electrode mixture. For example, when the ratio of the negative electrode active material such as carbon and lithium titanate in the negative electrode mixture is 80% or more and the porosity is adjusted to the range of the present invention by a lithium conductive polymer, the electrode density after pressing (solid content The density) is in the range of 1.0 to 2.5 g / cm.sup.- 3 . When the density is increased, the porosity is lowered, and the negative electrode mixture having higher lithium ion conductivity is obtained. The density is more preferably in the range of 1.2 to 2.3 g / cm.sup.- 3 , further preferably 1.5 to 2.0 g / cm.sup.- 3 .
<Solid Electrolyte Layer 50>
The solid electrolyte layer 50 has solid electrolyte particles 52 and an optional binder. The solid electrolyte particle is not particularly limited as long as it is a solid material which conducts lithium ions, but from the viewpoint of safety, it is desirable to contain a nonflammable inorganic solid electrolyte. Specifically, an oxide glass represented by Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , LiAlGe (PO 4 ) 3 , Li 3.4 V 0.6 Si 0.4 O 4 , Li 2 P 2 O 6 or the like, Li 0.34 Perovskite-type oxides represented by La 0.51 TiO 2.94 etc., garnet-type oxides represented by LiLaZrO 2, etc. can be used. The oxide conductor may contain a lithium halide such as LiCl or LiI. Further, sulfide-based inorganic solid electrolytes and polymer electrolytes can also be suitably used. The above solid electrolytes can be used alone or in combination of two or more.
　固体電解質層５０にバインダが含まれる場合，バインダは特に限定されないが，Ｌｉ3ＢＯ3などのリチウムイオン伝導性結晶が挙げられる。 When the solid electrolyte layer 50 contains a binder, the binder is not particularly limited, and examples thereof include lithium ion conductive crystals such as Li 3 BO 3 .
　以下、本発明を実施するための形態を具体的な実施例によって説明する。本実施例では、電極箔への負極活物質の塗布量を８mg/m2±０．５mgとほぼ一定に調節し、リチウム伝導性高分子種、リチウム伝導性高分子の比率、プレス圧を変化させることで空隙率を調節した。なお、電極箔への負極活物質の塗布量はこの値に限られるものではなく、例えばLTO、炭素系負極の場合の場合、約１～２０mg/m2の範囲で適宜調節可能である。 Hereinafter, modes for carrying out the present invention will be described by way of specific examples. In this example, the coating amount of the negative electrode active material on the electrode foil is adjusted to be substantially constant at 8 mg / m 2 ± 0.5 mg, and the ratio of lithium conductive polymer type and lithium conductive polymer, and the press pressure are changed. The porosity was adjusted by The application amount of the negative electrode active material to the electrode foil is not limited to this value. For example, in the case of LTO and a carbon-based negative electrode, the amount can be appropriately adjusted in the range of about 1 to 20 mg / m 2 .
　＜リチウム伝導性高分子溶液の作製＞
下記式（４）に示すリチウム伝導性高分子をＮＭＰに溶解させ、７０℃で３時間静置して、１０重量％の均一なポリマー溶液を作製した。リチウム伝導性高分子の平均分子量は１００００である。 <Preparation of lithium conductive polymer solution>
The lithium conductive polymer represented by the following formula (4) was dissolved in NMP, and allowed to stand at 70 ° C. for 3 hours to prepare a 10 wt% uniform polymer solution. The average molecular weight of the lithium conductive polymer is 10000.
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
＜負極層の作製＞
　負極活物質ＬｉＴｉ4Ｏ12が８０．６重量％、導電助剤アセチレンブラック（ＡＢ）が４．７重量％、ＰＶＤＦが４．７重量％、リチウム伝導性高分子が１０重量％の固形分比になるように，平均粒子径２０μｍのＬＴＯ，ＡＢ粉末，ＮＭＰに溶解させたＰＶＤＦ，リチウム伝導性高分子溶液をメノウ乳鉢内で混合して，スラリーを作製した。その後，厚み２０μｍのアルミニウム箔上にスラリーを塗工した。塗工後の電極を，温度を８０℃に保った乾燥機内に静置してＮＭＰを留去したのちに，直径１５ｍｍの円形に打ち抜き，上下から12Mpaの圧力にて１軸プレスして負極を得た。空隙率は水銀圧入法により算出した。
＜正極の作製＞
　正極活物質ＬｉＣｏＯ2が９０重量％，導電助剤アセチレンブラック（ＡＢ）が５重量％，ＰＶＤＦが５重量％の固形分比になるように、平均粒子径１０μｍのＬｉＣｏＯ2、ＡＢ粉末、ＮＭＰに溶解させたＰＶＤＦ、リチウム伝導性高分子溶液をメノウ乳鉢内で混合して、スラリーを作製した。その後、厚み２０μｍのアルミニウム箔上にスラリーを塗工した。塗工後の電極を温度を８０℃に保った乾燥機内に静置してＮＭＰを留去したのちに直径１５ｍｍの円形に打ち抜き、上下から１軸プレスして正極を得た。
＜抵抗評価セルの作製＞
　露点－８０℃以下のアルゴンガスで置換したグローブボックス内で抵抗測定用セルを測定した。まず作製した電極の負極層とポリマーシートを対向させ，さらに正極をポリマーシート状に積層した．積層体をアルミネートパック中に挿入した．その後，パックから端子が露出するようにアルミパックを真空シールして，抵抗評価用セルを作製した。ポリマーシートは分岐鎖を有するＰＥＯとリチウム塩ＬｉＦＳＩをアセトニトリルに溶解させ，８０℃で乾燥させて作製した。
＜抵抗評価＞
０．０１Ｃで４．２～２．５Ｖの電圧範囲で充放電をおこない，ＳＯＣ５０％で１０秒間放電したときの直流抵抗を測定した。 <Fabrication of negative electrode layer>
Solid content ratio of negative electrode active material LiTi 4 O 12 80.6% by weight, conductive agent acetylene black (AB) 4.7% by weight, PVDF 4.7% by weight, and lithium conductive polymer 10% by weight As a result, LTO and AB powders having an average particle diameter of 20 μm, PVDF dissolved in NMP, and a lithium conductive polymer solution were mixed in an agate mortar to prepare a slurry. Then, the slurry was applied on a 20 μm thick aluminum foil. The coated electrode is allowed to stand still in a dryer maintained at 80 ° C. to distill off NMP, then punched into a circle with a diameter of 15 mm and uniaxially pressed from above and below at a pressure of 12 Mpa to make the negative electrode Obtained. The porosity was calculated by the mercury intrusion method.
<Fabrication of positive electrode>
The positive electrode active material LiCoO 2 is 90 wt%, a conductive auxiliary agent of acetylene black (AB) is 5 wt%, so that PVDF is 5% by weight solids ratio, LiCoO 2, AB powder having an average particle diameter of 10 [mu] m, in NMP The dissolved PVDF and lithium conductive polymer solution were mixed in an agate mortar to make a slurry. Then, the slurry was applied on a 20 μm thick aluminum foil. The coated electrode was allowed to stand still in a dryer maintained at 80 ° C. to distill off NMP, punched into a circle with a diameter of 15 mm, and uniaxially pressed from above and below to obtain a positive electrode.
<Production of resistance evaluation cell>
The cell for resistance measurement was measured in a glove box purged with argon gas with a dew point of −80 ° C. or less. First, the negative electrode layer of the prepared electrode was made to face the polymer sheet, and the positive electrode was further laminated in the form of a polymer sheet. The laminate was inserted into the aluminate pack. After that, the aluminum pack was vacuum sealed so that the terminals were exposed from the pack, and a cell for resistance evaluation was fabricated. The polymer sheet was prepared by dissolving branched PEO and lithium salt LiFSI in acetonitrile and drying at 80 ° C.
<Evaluation of resistance>
Charge / discharge was performed at 0.01 C at a voltage range of 4.2 to 2.5 V, and direct current resistance was measured when discharged at SOC 50% for 10 seconds.
　本実施例において、下記式（５）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１５０００である。その他の作製条件は実施例１と同じである。 In the present example, an all solid secondary battery was manufactured using a lithium conductive polymer represented by the following formula (5). The average molecular weight of the lithium conductive polymer is 15,000. The other preparation conditions are the same as in Example 1.
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
　本実施例において、下記式（６）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。その他の作製条件は実施例１と同じである。 In the present example, an all solid secondary battery was manufactured using a lithium conductive polymer represented by the following formula (6). The average molecular weight of the lithium conductive polymer is 10000. The other preparation conditions are the same as in Example 1.
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
　本実施例において、式（５）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１５０００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝８５：５：５：５重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例２と同じである。 In the present example, an all solid secondary battery was manufactured using the lithium conductive polymer represented by the formula (5). The average molecular weight of the lithium conductive polymer is 15,000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 85: 5: 5: 5 wt%. The other preparation conditions are the same as in Example 2.
　本比較例において、式（４）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝７１．６：４．２：４．２：２０重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。 In the present comparative example, an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4). The average molecular weight of the lithium conductive polymer is 10000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 71.6: 4.2: 4.2: 20% by weight. The other preparation conditions are the same as in Example 1.
比較例１Comparative Example 1
　本比較例において、式（４）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝８７．１：５．２：５．２：２．５重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。 In the present comparative example, an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4). The average molecular weight of the lithium conductive polymer is 10000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 87.1: 5.2: 5.2: 2.5 wt%. The other preparation conditions are the same as in Example 1.
比較例２Comparative example 2
　本比較例において、式（４）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝８８．６：５．２：５．２：１重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。 In the present comparative example, an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4). The average molecular weight of the lithium conductive polymer is 10000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 88.6: 5.2: 5.2: 1 wt%. The other preparation conditions are the same as in Example 1.
比較例３Comparative example 3
　本比較例において、リチウム伝導性高分子を用いずに全固体二次電池を作製した。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ＝９０：５：５重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。 In the present comparative example, an all solid secondary battery was produced without using a lithium conductive polymer. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF = 90: 5: 5 wt%. The other preparation conditions are the same as in Example 1.
比較例４Comparative example 4
　本実施例において、式（６）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝８５：５：５：５重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。空隙率をＳＥＭにより確認したところ、１０．７％であった。空隙率が高いため、直流抵抗値は１２．１Ωと高い値を示した。 In the present example, an all solid secondary battery was manufactured using the lithium conductive polymer represented by the formula (6). The average molecular weight of the lithium conductive polymer is 10000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 85: 5: 5: 5 wt%. The other preparation conditions are the same as in Example 1. When the porosity was confirmed by SEM, it was 10.7%. Due to the high porosity, the DC resistance value showed a high value of 12.1 Ω.
比較例５Comparative example 5
　本比較例において、式（４）に示すリチウム伝導性高分子を用いて全固体二次電池を作製した。リチウム伝導性高分子の平均分子量は１００００である。固形分比がＬＴＯ：ＡＢ：ＰＶＤＦ：リチウム伝導性高分子＝８５：５：５：５重量％になるように材料を混合しスラリーを調整した。その他の作製条件は実施例１と同じである。空隙率をＳＥＭにより確認したところ、１０．１％であった。空隙率が高いため、直流抵抗値は１１．４Ωと高い値を示した。 In the present comparative example, an all solid secondary battery was produced using the lithium conductive polymer represented by the formula (4). The average molecular weight of the lithium conductive polymer is 10000. The slurry was prepared by mixing the materials such that the solid content ratio was LTO: AB: PVDF: lithium conductive polymer = 85: 5: 5: 5 wt%. The other preparation conditions are the same as in Example 1. When the porosity was confirmed by SEM, it was 10.1%. Due to the high porosity, the DC resistance value showed a high value of 11.4 Ω.
　表１に、実施例１～５、比較例１～５で作製した全固体二次電池の空隙率と出力特性を示す。 Table 1 shows the porosity and the output characteristics of the all-solid secondary batteries produced in Examples 1 to 5 and Comparative Examples 1 to 5.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　正極集電体１０
　負極集電体２０
　電池ケース３０
　正極合剤層４０
　固体電解質層５０
　固体電解質粒子５２
　負極合剤層６０
　負極活物質６２
　リチウム伝導性高分子６３
　負極導電剤６４
　正極７０
　負極８０
　全固体二次電池１００ Positive electrode current collector 10
Negative electrode current collector 20
Battery case 30
Positive electrode mixture layer 40
Solid electrolyte layer 50
Solid electrolyte particles 52
Negative electrode mixture layer 60
Negative electrode active material 62
Lithium conductive polymer 63
Negative electrode conductive agent 64
Positive electrode 70
Negative electrode 80
All solid secondary battery 100

Claims (9)

  1. 　正極集電体の表面に正極合剤層が設けられた正極と、
    　負極集電体の表面に負極合剤層が設けられた負極と、
    　前記正極と前記負極との間に設けられた固体電解質とを有するリチウムイオン二次電池において、
    　前記負極合剤層は、負極活物質と、前記負極活物質の間に設けられたリチウムイオン導電性高分子とを有し、
    　前記負極合剤層の空隙率は１０％以下であり、
    　前記負極合剤層に対する前記リチウムイオン導電性高分子の割合は５wt％以上であるリチウムイオン二次電池。     A positive electrode provided with a positive electrode mixture layer on the surface of the positive electrode current collector;
    A negative electrode provided with a negative electrode mixture layer on the surface of a negative electrode current collector;
    In a lithium ion secondary battery having a solid electrolyte provided between the positive electrode and the negative electrode,
    The negative electrode mixture layer includes a negative electrode active material and a lithium ion conductive polymer provided between the negative electrode active material,
    The porosity of the negative electrode mixture layer is 10% or less,
    The lithium ion secondary battery whose ratio of the said lithium ion conductive polymer with respect to the said negative mix layer is 5 wt% or more.
  2. 　請求項１において、
    　前記負極活物質合剤の固形分密度は、１．０～２．５ mg/cm3の範囲であるリチウムイオン二次電池。     In claim 1,
    The solid content density of the negative electrode active material mixture is in the range of 1.0 to 2.5 mg / cm 3 .
  3. 　請求項１または請求項２において、
    　前記リチウムイオン導電性高分子は、（式１）で表わされる高分子化合物、（式２）で表わされる高分子化合物、（式３）で表わされる高分子化合物のいずれか少なくとも一種を含むリチウムイオン二次電池。
    Figure JPOXMLDOC01-appb-C000001
     （式１においてＲ1は、水素、アルキル基または酸素を有するアルキル基である。ｎは繰り返し単位数である。）
    Figure JPOXMLDOC01-appb-C000002
     （式２において、Ｒ2は、元素Ｃ、N、S、O、Hのいずれか少なくとも一種を有する官能基である。x、yは、共重合の組成比であり、0＜ｙ/(ｘ+ｙ)≦1を満たす。）
    Figure JPOXMLDOC01-appb-C000003
     （式３において、Ｒ3、Ｒ4は、元素Ｃ、N、S、O、Hのいずれか少なくとも一種を有する官能基である。Ｒ3、Ｒ4は同一であってもよく、異なっていてもよい。ｎは繰り返し単位数である。）     In claim 1 or claim 2,
    The lithium ion conductive polymer is a lithium ion including at least one of a polymer compound represented by (Formula 1), a polymer compound represented by (Formula 2), and a polymer compound represented by (Formula 3) Secondary battery.
    Figure JPOXMLDOC01-appb-C000001
     (In formula 1, R 1 is hydrogen, an alkyl group or an alkyl group having oxygen. N is the number of repeating units.)
    Figure JPOXMLDOC01-appb-C000002
     (In Formula 2, R 2 is a functional group having at least one of elements C, N, S, O, and H. x and y are copolymerization composition ratios, and 0 <y / (x + y) ≦ 1))
    Figure JPOXMLDOC01-appb-C000003
     (In Formula 3, R 3 and R 4 are functional groups having at least one of elements C, N, S, O, and H. R 3 and R 4 may be the same or different. N is the number of repeating units.)
  4. 　請求項３において、
    前記負極集電体表面における前記負極活物質の塗布量は、６～１３ｍｇ/ｃｍ2の範囲である。     In claim 3,
    The coating amount of the negative electrode active material on the surface of the negative electrode current collector is in the range of 6 to 13 mg / cm 2 .
  5. 　請求項４において、
    　前記負極活物質合剤は導電材とバインダを有することを特徴とするリチウムイオン二次電池。     In claim 4,
    The said negative electrode active material mixture has a conductive material and a binder, The lithium ion secondary battery characterized by the above-mentioned.
  6. 　請求項５において、
    　前記リチウム伝導性高分子の平均分子量が１０００～４０００００であるリチウムイオン二次電池。     In claim 5,
    A lithium ion secondary battery in which the average molecular weight of the lithium conductive polymer is 1000 to 400000.
  7. 　請求項３において、
    　前記リチウム伝導性高分子は、（式１）で表わされる高分子化合物であり、前記負極合剤層に対する前記リチウムイオン導電性高分子の割合は１０～２０wt％の範囲であるリチウムイオン二次電池。     In claim 3,
    The lithium conductive polymer is a polymer compound represented by (Formula 1), and the ratio of the lithium ion conductive polymer to the negative electrode mixture layer is in the range of 10 to 20 wt%. .
  8. 　請求項６または請求項７において、
    　前記負極活物質は、人造黒鉛，天然黒鉛，コークス，リチウムを挿入放出する酸化物のいずれか少なくとも一種を含み、
    　前記酸化物はＳｉ，Ｓｎ，Ｔｉのいずれか少なくとも一種を含む酸化物であることを特徴とするリチウムイオン二次電池。     In claim 6 or claim 7,
    The negative electrode active material includes at least one of artificial graphite, natural graphite, coke, and an oxide that intercalates and releases lithium,
    The said oxide is an oxide containing any one or more of Si, Sn, and Ti, The lithium ion secondary battery characterized by the above-mentioned.
  9. 　請求項８において、
    　前記固体電解質は、Ｌｉ1.4Ａｌ0.4Ｔｉ1.6（ＰＯ4）3、ＬｉＡｌＧｅ（ＰＯ4）3、Ｌｉ3.4Ｖ0.6Ｓｉ0.4Ｏ4、Ｌｉ2Ｐ2Ｏ6、Ｌｉ0.34Ｌａ0.51ＴｉＯ2.94、ＬｉＬａＺｒＯ２のいずれか少なくとも一種を含むリチウムイオン二次電池。     In claim 8,
    The solid electrolyte may be any one of Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , LiAlGe (PO 4 ) 3 , Li 3.4 V 0.6 Si 0.4 O 4 , Li 2 P 2 O 6 , Li 0.34 La 0.51 TiO 2.94 and LiLaZrO 2 Or lithium ion secondary battery containing at least one type.
PCT/JP2014/055217 2014-03-03 2014-03-03 All-solid-state battery WO2015132845A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2014/055217 WO2015132845A1 (en) 2014-03-03 2014-03-03 All-solid-state battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2014/055217 WO2015132845A1 (en) 2014-03-03 2014-03-03 All-solid-state battery

Publications (1)

Publication Number Publication Date
WO2015132845A1 true WO2015132845A1 (en) 2015-09-11

Family

ID=54054690

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2014/055217 WO2015132845A1 (en) 2014-03-03 2014-03-03 All-solid-state battery

Country Status (1)

Country Link
WO (1) WO2015132845A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108987687A (en) * 2018-06-22 2018-12-11 中南大学 A kind of low-temperature lithium ion battery graphite cathode material and preparation method thereof
CN110212157A (en) * 2019-07-11 2019-09-06 天津市捷威动力工业有限公司 A kind of electrodes of lithium-ion batteries and preparation method thereof and lithium ion battery
CN111864211A (en) * 2019-04-25 2020-10-30 本田技研工业株式会社 Electrode for secondary battery, method for manufacturing same, and secondary battery
WO2023042579A1 (en) * 2021-09-14 2023-03-23 マクセル株式会社 Battery

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07312219A (en) * 1994-03-24 1995-11-28 Fuji Photo Film Co Ltd Nonaqueous secondary battery and charging method
JPH117942A (en) * 1997-06-19 1999-01-12 Matsushita Electric Ind Co Ltd Total solid lithium battery
JPH11273735A (en) * 1998-03-19 1999-10-08 Yuasa Corp Lithium-ion polymer secondary battery
JP2008140633A (en) * 2006-11-30 2008-06-19 Nissan Motor Co Ltd Module structure of bipolar secondary battery
JP2009176484A (en) * 2008-01-22 2009-08-06 Idemitsu Kosan Co Ltd Positive electrode and negative electrode for all-solid lithium secondary battery, and all-solid lithium secondary battery
JP2010009951A (en) * 2008-06-27 2010-01-14 Mitsubishi Chemicals Corp Composite graphite particle for nonaqueous secondary battery, negative electrode material containing it, anode, and nonaqueous secondary battery
JP2012234665A (en) * 2011-04-28 2012-11-29 Nippon Zeon Co Ltd Anode slurry composition for lithium secondary battery, method of manufacturing anode for lithium secondary battery, anode for lithium secondary battery, and lithium secondary battery
JP2013109881A (en) * 2011-11-18 2013-06-06 Sumitomo Electric Ind Ltd Electrode for nonaqueous electrolyte battery, nonaqueous electrolyte battery, and electric vehicle
WO2014020654A1 (en) * 2012-07-30 2014-02-06 株式会社 日立製作所 All-solid ion secondary cell

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07312219A (en) * 1994-03-24 1995-11-28 Fuji Photo Film Co Ltd Nonaqueous secondary battery and charging method
JPH117942A (en) * 1997-06-19 1999-01-12 Matsushita Electric Ind Co Ltd Total solid lithium battery
JPH11273735A (en) * 1998-03-19 1999-10-08 Yuasa Corp Lithium-ion polymer secondary battery
JP2008140633A (en) * 2006-11-30 2008-06-19 Nissan Motor Co Ltd Module structure of bipolar secondary battery
JP2009176484A (en) * 2008-01-22 2009-08-06 Idemitsu Kosan Co Ltd Positive electrode and negative electrode for all-solid lithium secondary battery, and all-solid lithium secondary battery
JP2010009951A (en) * 2008-06-27 2010-01-14 Mitsubishi Chemicals Corp Composite graphite particle for nonaqueous secondary battery, negative electrode material containing it, anode, and nonaqueous secondary battery
JP2012234665A (en) * 2011-04-28 2012-11-29 Nippon Zeon Co Ltd Anode slurry composition for lithium secondary battery, method of manufacturing anode for lithium secondary battery, anode for lithium secondary battery, and lithium secondary battery
JP2013109881A (en) * 2011-11-18 2013-06-06 Sumitomo Electric Ind Ltd Electrode for nonaqueous electrolyte battery, nonaqueous electrolyte battery, and electric vehicle
WO2014020654A1 (en) * 2012-07-30 2014-02-06 株式会社 日立製作所 All-solid ion secondary cell

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108987687A (en) * 2018-06-22 2018-12-11 中南大学 A kind of low-temperature lithium ion battery graphite cathode material and preparation method thereof
CN108987687B (en) * 2018-06-22 2021-04-27 中南大学 Low-temperature lithium ion battery graphite negative electrode material and preparation method thereof
CN111864211A (en) * 2019-04-25 2020-10-30 本田技研工业株式会社 Electrode for secondary battery, method for manufacturing same, and secondary battery
CN111864211B (en) * 2019-04-25 2024-02-27 本田技研工业株式会社 Electrode for secondary battery, method for manufacturing same, and secondary battery
CN110212157A (en) * 2019-07-11 2019-09-06 天津市捷威动力工业有限公司 A kind of electrodes of lithium-ion batteries and preparation method thereof and lithium ion battery
WO2023042579A1 (en) * 2021-09-14 2023-03-23 マクセル株式会社 Battery

Similar Documents

Publication Publication Date Title
CN107925058B (en) Negative electrode for secondary battery, method for producing same, and secondary battery comprising same
EP2863457B1 (en) Lithium secondary battery comprising multilayered active material layer
CN106797022B (en) Potassium ion secondary battery or potassium ion capacitor
JP4884774B2 (en) Method for producing electrode for electrochemical cell
JP4061586B2 (en) Positive electrode active material for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using the same
US20160013480A1 (en) Multi-layer battery electrode design for enabling thicker electrode fabrication
CN105576279B (en) Lithium secondary battery
JP2012164624A (en) Negative electrode active material for lithium ion secondary battery, and lithium ion secondary battery comprising the negative electrode active material
CN111095626B (en) Negative active material for lithium secondary battery and method for preparing same
CN114556611A (en) Negative electrode and secondary battery comprising same
CN107660316B (en) Positive electrode of lithium electrochemical power generation device
JP2007287570A (en) Lithium ion secondary battery
KR20130069432A (en) Coating of disordered carbon active material using water-based binder slurry
KR20190060719A (en) Anode Having Double Active Material Layers, Method of Preparing the Same, and Secondary Battery Comprising the Same
JP2016076342A (en) Electrode for nonaqueous secondary battery, and nonaqueous secondary battery
JP2011192561A (en) Manufacturing method for nonaqueous electrolyte secondary battery
WO2012147647A1 (en) Lithium ion secondary cell
JP2019175657A (en) Lithium ion secondary battery
WO2015132845A1 (en) All-solid-state battery
JP2017111894A (en) Lithium ion secondary battery
CN113994512A (en) Lithium secondary battery and method for manufacturing the same
KR100441525B1 (en) Electrode material, preparation method of the electrode material, electrode and battery comprising the electrode
JP3981866B2 (en) Method for producing positive electrode for lithium battery and positive electrode for lithium battery
JP2007242348A (en) Lithium-ion secondary battery
WO2021241001A1 (en) Battery

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14884560

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14884560

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP