WO2007060906A1 - Positive electrode active material particle for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using same - Google Patents

Positive electrode active material particle for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using same Download PDF

Info

Publication number
WO2007060906A1
WO2007060906A1 PCT/JP2006/323075 JP2006323075W WO2007060906A1 WO 2007060906 A1 WO2007060906 A1 WO 2007060906A1 JP 2006323075 W JP2006323075 W JP 2006323075W WO 2007060906 A1 WO2007060906 A1 WO 2007060906A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
active material
electrode active
secondary battery
electrolyte secondary
Prior art date
Application number
PCT/JP2006/323075
Other languages
French (fr)
Japanese (ja)
Inventor
Mori Nagayama
Yasuhiko Ohsawa
Mikio Kawai
Original Assignee
Nissan Motor Co., Ltd.
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 Nissan Motor Co., Ltd. filed Critical Nissan Motor Co., Ltd.
Publication of WO2007060906A1 publication Critical patent/WO2007060906A1/en

Links

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
    • 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
    • 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
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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 positive electrode active material particles, and more particularly to positive electrode active material particles that can provide a nonaqueous electrolyte secondary battery excellent in output characteristics.
  • a lithium ion secondary battery basically has a configuration in which a positive electrode and a negative electrode capable of occluding and releasing Li ions are arranged via a separator and filled with an electrolyte.
  • the separator is made of porous and electrically insulating material, and is used for the purpose of preventing an internal short circuit generated when the positive electrode and the negative electrode are in contact with each other.
  • a secondary battery used for a power source for an automobile such as a hybrid has a large output, that is, a large current discharge characteristic, for a certain period of time in order to assist power during starting, starting and acceleration. Sex is required. Therefore, in order to increase the output of the secondary battery, as disclosed in Japanese Unexamined Patent Publication No. 2000-260423, the average particle diameter of the electrode active material can be reduced or the electrode active material can be reduced. Means for reducing the thickness of the material layer, increasing the electrode reaction area, and improving the electron conductivity and lithium ion diffusibility in the electrode active material layer are used.
  • a high voltage In order to improve the adhesion of electrode components such as electrode active materials and conductive aids.
  • the filling ratio of the electrode active material in the electrode active material layer is increased and the gaps between the electrode active materials are crushed, so that the electrolyte solution is sufficiently contained in the electrode active material layer. It is difficult to impregnate.
  • the electron conductivity in the electrode is improved, the contact area between the electrolyte and the electrode active material is remarkably reduced, and the diffusion resistance of Li ions is increased, making it difficult to obtain a high-power secondary battery. There was a problem.
  • an object of the present invention is to provide a positive electrode active material for a non-aqueous electrolyte secondary battery that can improve the output characteristics of the non-aqueous electrolyte secondary battery.
  • the present inventors can sufficiently ensure voids in the positive electrode by using positive electrode active material particles for a nonaqueous electrolyte secondary battery in which the aspect ratio of the short axis to the long axis has a specific value. I found that the problem could be solved.
  • the present invention solves the above-mentioned problems with the positive electrode active material particles for nonaqueous electrolyte secondary batteries in which the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to LOOO.
  • FIG. 1 shows a schematic diagram of positive electrode active material particles according to the present invention
  • FIG. 1 (A) is a graph in the longitudinal direction.
  • FIG. 1 is a schematic diagram of positive electrode active material particles (I) having a spheroid shape
  • FIG. 1 (B) is a schematic diagram of positive electrode active material particles (I) having a spheroid shape with respect to the minor axis direction. ).
  • FIG. 2 shows measurement results of resistance values and discharge capacities when secondary batteries of Examples and Comparative Examples are discharged.
  • the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to: LOOO positive electrode active material particles for secondary battery (simply described as “positive electrode active material”) Yes).
  • the positive electrode active material having a large ratio of the longest shaft diameter to the shortest shaft diameter includes many shapes such as a plate shape and a needle shape.
  • the positive electrode active material having a shape that expands one-dimensionally only in the vertical direction or the horizontal direction can ensure the porosity in the positive electrode active material layer by being arranged in various directions.
  • the contact resistance between electrode constituent materials such as a positive electrode active material and a conductive additive can be reduced. Is possible. Therefore, according to the strong positive electrode active material, the porosity in the positive electrode active material layer can be ensured, and sufficient electron conductivity can be ensured without lowering the diffusion resistance of lithium ions.
  • the output of the battery can be increased.
  • the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to 1000, preferably 2 to: LOO.
  • the ratio of the average longest shaft diameter to the average shortest shaft diameter exceeds 1000, as shown by comparison with the following examples, particularly Example 3 and Comparative Example 3, such a positive electrode active material is used. Even if a thin film is formed, it is very difficult or impossible to remove the thin film with the strength of the substrate. Further, if the ratio of the average longest axis diameter to the average shortest axis diameter is less than 1.5, it is difficult to secure the porosity in the positive electrode active material layer due to an increase in the degree of filling, which is also not preferable.
  • the aspect ratio of the positive electrode active material may be measured using an electron microscope, with the longest axial diameter (maximum diameter) of the positive electrode active material and the diameter perpendicular thereto as the shortest axial diameter (minimum diameter). it can.
  • the aspect ratio is measured by taking an electron micrograph of the positive electrode active material, extracting 10 or more positive electrode active materials, preferably 100 or more, randomly from the photo, and measuring the longest axis diameter (maximum diameter) of each positive electrode active material. And measure the shortest shaft diameter (minimum diameter) with image processing software. This is done by calculating the average of.
  • the average shortest axis diameter of the positive electrode active material is preferably 10 m or less, more preferably 8-0.
  • a force of 02 ⁇ m, even more preferably 5 to 0.05 ⁇ m, particularly preferably 3 to 0.1 ⁇ m is good.
  • the reaction surface area can be increased while ensuring the electron conductivity, and the output of the secondary battery can be further increased.
  • the average shortest axis diameter of the positive electrode active material is less than 0.02 m, such a positive electrode active material is used as shown in the following examples, particularly as compared with Example 3 and Comparative Example 3. Even if it is used to form a thin film, it may be very difficult or impossible to peel the thin film.
  • the positive electrode active material in which the ratio of the longest axis diameter to the shortest axis diameter is 1.5-1000, more preferably 2.0 to L00, is used as the positive electrode active material. It is preferable to include 50 to: LOO number% with respect to the total amount.
  • the electron conductivity in the positive electrode active material can be improved and the diffusion resistance of lithium ions can be reduced, and the output of the secondary battery can be further increased.
  • the number of positive electrode active materials can be easily measured by extracting a part of the used electrode and observing it with an electron microscope or the like.
  • the positive electrode active material (I) preferably contains 50 to: LOO number%, more preferably 70 to 99 number%, particularly preferably 80 to 95 number, based on the total amount of the positive electrode active material. % Is good.
  • the shape of the positive electrode active material (I) is not particularly limited, but at least one selected from a group force consisting of a plate shape, a disc shape, a spheroid shape, a column shape, and a needle shape is preferable. With these shapes, sufficient voids can be secured in the positive electrode active material layer.
  • FIG. 1A is a schematic view of a positive electrode active material (I) having a spheroid shape with respect to the major axis direction, and the positive electrode active material (I) has a rugby ball shape.
  • FIG. 1B is a schematic diagram of the positive electrode active material (I) having a spheroid shape with respect to the minor axis direction.
  • the shape of the positive electrode active material (I) is particularly preferably at least one selected from the group consisting of a columnar shape, a needle shape, and a spheroid shape with respect to the major axis direction of the positive electrode active material (I). is there. If the shape has such a one-dimensional extension, the positive electrode active material (I) can be prevented from being laminated in the horizontal direction by a press or the like, and the positive electrode active material layer can be sufficiently formed. In addition to ensuring sufficient voids, the diffusion path of lithium ions can be shortened, and the output of the secondary battery can be further increased.
  • the positive electrode active material according to the present invention is not particularly limited in composition or the like other than having a predetermined shape.
  • the positive electrode active material preferably has a composition for inserting and extracting lithium ions.
  • a preferable example is a lithium-transition metal composite oxide that is a composite oxide of a transition metal and lithium.
  • Li'Co-based complex oxides such as LiCoO,
  • Li'Ni complex oxides such as LiNiO
  • Li 'Mn complex oxides such as spinel LiMn O
  • Li'Fe complex oxides such as LiFeO and some of these transition metals as other elements
  • lithium transition metal composite oxides are excellent in reactivity and cycle characteristics, and are low-cost materials. Therefore, it is possible to form a battery with excellent output characteristics by using these materials for the electrodes.
  • a transition metal such as LiFePO and a lithium phosphate compound or sulfate compound can be used as the positive electrode active material.
  • Transition metal oxides and sulfides such as V O, MnO, TiS, MoS, MoO; PbO, A
  • the use of the positive electrode active material according to the present invention is not particularly limited, but it is preferably used for a positive electrode for a nonaqueous electrolyte secondary battery. Specifically, it is preferably used for a positive electrode active material layer in a positive electrode for a non-aqueous electrolyte secondary battery. As a result, a non-aqueous electrolyte secondary battery having excellent output characteristics can be provided.
  • a second aspect of the present invention is a positive electrode for a non-aqueous electrolyte secondary battery having a positive electrode active material layer containing a positive electrode active material, wherein the positive electrode active material is the first positive electrode active material of the present invention described above. It is a positive electrode for a non-aqueous electrolyte secondary battery (also simply referred to as “positive electrode”). According to the positive electrode, it is possible to provide a nonaqueous electrolyte secondary battery having excellent output characteristics.
  • the porosity of the positive electrode active material layer is preferably 30 to 60%, more preferably 35 to 55%, and particularly preferably 40 to 50%. If the porosity power of the positive electrode active material layer is 30% or more, sufficient voids can be secured and the diffusion resistance of lithium ions can be reduced, and if it is 60% or less, the positive electrode active material, the conductive auxiliary, etc. Contact resistance Resistance can be reduced.
  • the porosity of the positive electrode active material layer can be calculated by calculating the thickness when the positive electrode is completely filled with the theoretical density and comparing it with the actual film thickness.
  • the thickness of the positive electrode active material layer is preferably 5 to 200 m, particularly 10 to LOO m.
  • the thickness of the positive electrode active material layer is 5 ⁇ m or more, sufficient discharge capacity can be obtained, and if the thickness is 200 ⁇ m or less, the diffusion distance of electrons and lithium ions in the positive electrode active material layer is significantly shortened. The diffusion resistance can be reduced.
  • the positive electrode of the present invention is characterized by containing a positive electrode active material having the specific aspect ratio described above.
  • the positive electrode active material layer is not particularly limited in addition to the positive electrode active material.
  • an electrolyte salt for increasing ion conductivity a conductive additive for increasing electron conductivity, a binder, an electrolyte, and the like may be included.
  • the electrolyte salt is not particularly limited, but includes BETI (lithium bis (perfluoroethylenesulfurimide); also referred to as Li (C F SO) N), LiBF, LiPF, LiN (SO CF),
  • LiN SO C F
  • LiBOB lithium bisoxide borate
  • Examples of the conductive assistant include acetylene black, carbon black, and graphite.
  • As the binder polyvinylidene fluoride (PVDF), SBR, polyimide and the like can be used.
  • PVDF polyvinylidene fluoride
  • SBR polyvinylidene fluoride
  • polyimide polyimide
  • the conductive assistant and the binder are not limited to these.
  • Preferred examples of the electrolyte include non-aqueous electrolytes using an organic solvent. Thereby, the ionic conduction in the positive electrode active material layer becomes smooth, and the output of the entire battery can be improved.
  • the non-aqueous electrolyte may be any of a liquid electrolyte (electrolytic solution), a solid electrolyte, and a polymer gel electrolyte.
  • the nonaqueous electrolyte is not particularly limited as long as it can be used in a normal secondary battery with the following preferable examples.
  • electrolyte examples include LiBOB (lithium bisoxide borate), LiPF, LiBF, LiCIO
  • LiAsF, LiTaF, LiAlCl, Li B CI and other inorganic acid anion salts LiCF SO, Li (
  • CF SO CF SO N, Li (CF SO) N, etc.
  • electrolyte salt cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyl Ethers such as tetrahydric oral furan, 1,4 dioxane, 1,2 dimethoxyethane, 1,2 dibutoxetane; ⁇ — latatones such as butaguchi ratataton; -tolyls such as acetonitrile; methyl propionate Esters of amides such as dimethylformamide; those using an organic solvent (plasticizer) such as an aprotic solvent in which at least one selected from methyl acetate and methyl formate is mixed Can be used.
  • organic solvent plasticizer
  • aprotic solvent in which at least one selected from methyl acetate and methyl formate is
  • the solid electrolyte is not particularly limited as long as it is composed of a polymer having ion conductivity. Examples thereof include polyethylene oxide (PEO), polypropylene oxide (PP 2 O), and copolymers thereof.
  • a strong polyalkylene oxide polymer can dissolve the above-mentioned electrolyte salt well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.
  • the polymer gel electrolyte is not particularly limited, but the electrolyte gel containing an electrolyte in an electrolyte polymer having ion conductivity, or the same in the skeleton of an electrolyte polymer having no ion conductivity. The thing etc. which hold
  • the electrolytic solution contained in the polymer gel electrolyte is the same as described above. Further, as the electrolyte polymer having ion conductivity, the above-described solid electrolyte or the like is used. Examples of electrolyte polymers that do not have ionic conductivity include gelled polymers such as poly (vinylidene fluoride) (PVDF), poly (bulvyl chloride) (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). Monomers or polymers can be used. However, it is not necessarily limited to these.
  • PVDF poly (vinylidene fluoride)
  • PVC poly (bulvyl chloride)
  • PAN polyacrylonitrile
  • PMMA polymethyl methacrylate
  • Monomers or polymers can be used. However, it is not necessarily limited to these.
  • PAN, PMMA, etc. which have almost no ionic conductivity, fall into a category, and therefore can be used as electrolyte polymers having the above ionic conductivity. It is exemplified as a polymer for electrolytes having no ionic conductivity used in the above.
  • the ratio (mass ratio) of the electrolyte polymer (host polymer) to the electrolyte solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10. It is. This prevents the electrolyte from seeping out from the outer periphery of the positive electrode active material layer. By providing the edge processing portion, it is possible to effectively seal. For this reason, the battery characteristics can be prioritized relatively with respect to the ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte.
  • the structure of the positive electrode of the present invention is not particularly limited, but the positive electrode active material layer is formed on one surface of the current collector.
  • the current collector is not particularly limited as long as it is used in a conventional secondary battery, and is composed of a conductive material cover such as aluminum, copper, stainless steel (SUS), titanium, or nickel. Anything is acceptable.
  • the thickness of the current collector may be about 10 to 50 / ⁇ ⁇ .
  • a positive electrode active material layer containing the first positive electrode active material of the present invention is formed on one surface of the current collector, and the other surface Accordingly, it is desirable to determine the structure in accordance with the use of the positive electrode, which may be a bipolar electrode using the positive electrode of the present invention, in which a negative electrode active material layer containing a general negative electrode active material is formed. Yes.
  • a third aspect of the present invention is a nonaqueous electrolyte secondary battery using the above-described second positive electrode for a nonaqueous electrolyte secondary battery of the present invention.
  • the second positive electrode for a non-aqueous electrolyte secondary battery of the present invention it is possible to provide a non-aqueous electrolyte secondary battery excellent in output characteristics when charged and discharged with a large current.
  • the second positive electrode is used.
  • a secondary battery using the second positive electrode of the present invention can be used as the positive electrode.
  • the negative electrode used in the secondary battery of the present invention is not particularly limited as long as it is a negative electrode generally used conventionally. Specifically, it is a negative electrode having a conventional structure in which a negative electrode active material layer containing at least a negative electrode active material such as carbon is coated on a current collector that has strength such as copper, nickel, titanium, and SUS.
  • the secondary battery of the present invention can be obtained by stacking a positive electrode and a negative electrode with a separator interposed therebetween, and impregnating this with an electrolyte.
  • the separator used in the secondary battery of the present invention can be used without particular limitation as long as it is generally used.
  • microporous polyethylene fill Polyolefin-based porous membranes or nonwoven fabrics such as microporous, microporous polypropylene film, microporous ethylene propylene copolymer film, and laminates thereof. These have an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low.
  • a composite resin film in which a polyolefin resin-based non-woven fabric or a polyolefin resin-based porous resin film is used as a reinforcing material layer, and the reinforcing material layer is filled with a vinylidene fluoride resin compound.
  • an electrolyte layer such as a solid electrolyte or a polymer gel electrolyte may be employed.
  • the thickness of the separator may be appropriately determined according to the intended use, but may be about 15 to 50 / ⁇ ⁇ in applications such as motor drive secondary batteries for automobiles and the like. Further, the porosity and size of the separator may be appropriately determined in consideration of the characteristics of the obtained secondary battery.
  • Examples of the electrolyte impregnated in the separator include the same electrolytes used in the positive electrode active material layer, as described in the first aspect of the present invention.
  • the positive electrode, the negative electrode, and the separator are housed in a battery case or the like.
  • a battery case it is preferable to use a battery case that can prevent the impact of external force and environmental degradation when the battery is used.
  • a battery case made of a laminate material composed of a composite laminate of a polymer film and metal foil can be sealed by the force of joining its peripheral part by heat fusion or by heat-sealing its bag-like opening.
  • the positive electrode lead terminal and the negative electrode lead terminal are taken out from the heat fusion part.
  • the location where the lead terminals of the positive and negative electrodes are taken out is not particularly limited to one location.
  • the material constituting the battery case is not limited to the above, and may be plastic, metal, rubber, or a combination thereof, and the shape may be a film, plate, box or the like. It is also possible to apply a method of providing a terminal that conducts electricity between the inside and outside of the case, and connecting the current collector inside the terminal and connecting the lead terminal outside the terminal to extract the current.
  • the structure of the secondary battery of the present invention is not particularly limited, and when distinguished by the form 'structure, it is applicable to any conventionally known form or structure such as a stacked battery or a wound battery. It is possible.
  • the internal parallel connection type battery and the bipolar internal series connection type battery are not bipolar. Any of these can be applied.
  • the secondary battery of the present invention is preferably a bipolar battery. Compared to normal batteries, it is possible to construct a battery with a higher capacity and output characteristics than that of a single battery.
  • the secondary battery according to the present invention described above is preferably used as a lithium ion secondary battery from the viewpoint of practicality.
  • a nickel hydride secondary battery, a nickel-powered Dominum secondary battery, a sodium ion secondary battery are used. It can also be applied to secondary batteries such as secondary batteries, potassium ion secondary batteries, magnesium ion secondary batteries, and calcium ion secondary batteries.
  • the secondary battery of the present invention can be an assembled battery formed by connecting a plurality of the batteries.
  • a battery module with a high capacity and a high output can be formed by connecting at least two secondary batteries of the present invention in series and Z or in parallel to form an assembled battery.
  • N secondary batteries as described above are connected in parallel, and M secondary batteries connected in parallel with each other are made of metal, and a resin battery case And use it as an assembled battery.
  • the number of series-parallel connection of secondary batteries is determined according to the purpose of use. For example, they may be combined so that they can be applied to a power source for driving a vehicle that requires high energy density and high output density as a large capacity power source such as an electric vehicle (EV) or a hybrid electric vehicle (HEV).
  • EV electric vehicle
  • HEV hybrid electric vehicle
  • the battery assembly of the present invention is not limited to the battery described here, and any conventionally known battery can be used as appropriate.
  • the assembled battery may be provided with various measuring devices and control devices depending on the use application.For example, a voltage measuring connector may be provided for monitoring the battery voltage. There are no particular restrictions.
  • the secondary battery and the assembled battery of the present invention have excellent output characteristics as described above. Therefore, vehicles with particularly stringent requirements regarding energy density and output characteristics, for example, batteries for electric vehicles, fuel cell vehicles, hybrid electric vehicles, etc. It is suitable as a power source for driving and can provide a vehicle having excellent running performance.
  • the secondary battery or the assembled battery of the present invention which should not be limited to these, can be installed under the floor of a vehicle, in a trunk room, an engine room, a roof, a hood, or the like.
  • a fourth aspect of the present invention is the first method for producing a positive electrode active material of the present invention.
  • the first method for producing a positive electrode active material of the present invention there is a method having a step of sieving the positive electrode active material precursor with a sieve having sieves having different vertical and horizontal lengths. Used.
  • a conventional method for producing a positive electrode active material for example, in the case of a lithium transition metal composite oxide, a lithium compound and a transition metal compound are mixed, and the resulting mixture is fired to obtain a lithium-transition metal composite acid.
  • the method of making items is widely used.
  • the positive electrode active material obtained by the conventional method includes many spherical materials, and various other shapes. Therefore, in the present invention, the positive electrode active material having various shapes obtained by the conventional method is used as the positive electrode active material precursor, and this is sieved with a sieve having a sieve having a predetermined shape.
  • a method for producing the first positive electrode active material is provided.
  • the positive electrode active material precursor is a conventional method having various shapes such as a spherical shape, a rod shape, a scale shape, a plate shape, a disc shape, a spheroid shape, a column shape, and a needle shape as described above.
  • the obtained positive electrode active material is used.
  • a conventionally known method may be used so as to obtain a positive electrode active material having a desired composition.
  • JP-A-2002-279986 And the methods described in Japanese Patent Application Laid-Open No. 2003-217584 are used.
  • the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5: LOOO, Sift with different sieves.
  • the longitudinal direction of the mesh is defined as horizontal. Since the positive electrode active material of the present invention has a one-dimensionally expanded shape, it is possible to prevent the shortest shaft diameter with the sieve.
  • the first positive electrode active material of the present invention can be obtained by removing most of the positive electrode active material precursor having a longest shaft diameter ratio of less than 1.5 on the sieve.
  • the ratio of the vertical and horizontal lengths of the sieve mesh is preferably 1.5 to L000 times, more preferably 2 to L00 times.
  • the positive electrode active material can be sieved from the positive electrode active material precursor with sufficient accuracy.
  • the length of the horizontal mesh is preferably less than about 1000 times due to the strength of the sieve.
  • the vertical length of the mesh of the sieve is preferably 0.1 to: LOO / zm, more preferably 0.5 to 10111.
  • the lateral length of the mesh is preferably from 0.15 to L00,000 m, more preferably from 0.75 to L0,000 / z m.
  • the shape of the sieve mesh is not particularly limited as long as the maximum portions of the vertical and horizontal lengths of the sieve mesh are the above-mentioned conditions.
  • Examples of the shape of the sieve mesh include a rectangle, a trapezoid, a deformed triangle, a deformed hexagon, and a rhombus, and a rectangle is particularly preferable.
  • a punched plate with no restrictions on the material, line shape and weaving method of the sieve may be used.
  • a weaving method of the sieve a ton'cap weave and a tie rod weave are preferably mentioned because a sieve having the above conditions can be easily obtained.
  • the punching board which does not restrict
  • the positive electrode active material of the present invention preferably contains a large amount of the positive electrode active material (I) having a ratio of the longest shaft diameter to the shortest shaft diameter of 1.5 to L000. Therefore, from the viewpoint of increasing the content of the positive electrode active material (I), in the method of the present invention, as described above, the positive electrode active material precursor is a sieve having sieves having different vertical and horizontal lengths. After sieving, it is desirable to have a step of further sieving with a sieve having sieves having the same vertical and horizontal lengths.
  • the positive electrode active material (I) having a ratio of the longest shaft diameter to the shortest shaft diameter of 1.5 to L000 remains on the sieve, and the length of the longest shaft diameter with respect to the shortest shaft diameter that has been completely removed in the above process. Only positive electrode active material precursors with a ratio of less than 1.5 can be passed through the sieve.
  • the difference between the vertical and horizontal lengths of the sieves is preferably 10% or less, more preferably 5% or less.
  • the positive electrode active material precursor power positive electrode active material (I) can be sieved with higher accuracy.
  • the mesh of the sieve is preferably 0.1-lOO ⁇ m, more preferably 0.5 to LO / zm.
  • the shape of the sieve mesh is not particularly limited as long as the maximum portions of the longitudinal length and the lateral length of the sieve mesh are the above-mentioned conditions.
  • Examples of the shape of the sieve mesh include a square, an ellipse, a fan, and a rhombus. A square is particularly preferable. A punched plate with no restrictions on the material, alignment, and weaving of the sieve may be used.
  • the following method may be used in addition to the method described above.
  • a raw material compound of a positive electrode active material is mixed, and the resulting mixture is formed into a spheroidal shape or a needle shape. Is used.
  • the raw material mixture may be appropriately selected and used so as to obtain a positive electrode active material having a desired composition.
  • examples of the raw material compound include a lithium compound and a transition metal compound.
  • lithium compound examples include hydroxides, oxides, organic acid salts, carbonates, and oxalates containing lithium element. Specifically, LiOH-H 2 O, Li CO 2, CH C
  • OOLi OOLi
  • any transition metal generally used as a positive electrode active material may be used.
  • Mn, Ti, Li, Fe, Ni, Mg, Zn, Co, Cr, Al examples thereof include one or more elements selected from the group consisting of B, Si, Sn, P, V, Sb, Nb, Ta, Mo, and W.
  • the transition metal compound include hydroxides, oxides, organic acid salts, carbonates, oxalates, nitrates, hydrochlorides, and sulfates containing a transition metal element. Specifically, cobalt oxide, acid manganese, acid nickel, etc. are mentioned.
  • the raw material compounds described above are mixed in a predetermined ratio so that a positive electrode active material having a desired composition is obtained, and the resulting mixture is formed into a spheroidal shape, a columnar shape, or a needle shape. To do.
  • the mixture preferably further contains a binder in addition to the raw material compound. This improves the moldability of the mixture and makes it easier to adjust the shape of the resulting positive electrode active material.
  • binder examples include carboxymethyl cellulose, polybutyl alcohol, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, polyacrylic acid Na, lignosulfonic acid Na methyl cellulose, hydroxyethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene.
  • An oxide or the like is preferably used.
  • the content of the binder in the mixture is preferably 0.1 to 20% by mass, more preferably 1 to LO mass%, based on the total weight of the solid content. Thereby, the moldability of the mixture can be improved.
  • the mixture may further contain a solvent in order to further improve the moldability.
  • a solvent include cyclic carbonates such as water, propylene carbonate (PC), and ethylene carbonate (EC); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and jet carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-di-old hexane, 1, 2-dimethoxy E Tan, 1, 2 E one ether such as Jibutokishetan; Y - Rataton such as butyl port Rataton; Asetonitoriru etc.
  • - tolyl ethers esters of methyl propionate and the like
  • examples include amides such as dimethylformamide; organic solvents such as aprotic solvents in which at least one selected from methyl acetate and methyl formate is mixed.
  • the content of the solvent in the mixture is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total weight of the solid content. Thereby, the moldability of the mixture can be improved.
  • the mixture When the mixture is sandwiched between flat plates, the mixture is preferably granulated in advance into a spherical shape. Good. Thereby, it becomes easy to manufacture a positive electrode active material having a desired shape.
  • the mixture is preferably granulated to have an average particle size of preferably 0.1 to 100 ⁇ m, more preferably about 1 to 50 ⁇ m.
  • the granulation method of the mixture is not particularly limited, and spray granulation method, stirring granulation method, compression granulation method, fluidized granulation method and the like are used, and in accordance with conventionally known granulation methods. If you go.
  • the surface can be used without particular limitation as long as the mixture can be slid.
  • Specific examples of the material of the flat plate include aluminum, copper, stainless steel (SUS), titanium, nickel, and silica glass.
  • the rolls may be brought into contact with each other, or a slight gap may be provided for dropping particles having a predetermined width or less.
  • the width of the gap is determined by the short axis length of the target active material, preferably 10 ⁇ m or less, more preferably 8 to 0.02 ⁇ m, even more preferably 5 to 0.05 / zm, particularly preferably 3 ⁇ 1.
  • the mixture obtained as described above is extruded with a hole force having a predetermined hole diameter using a spinning die or the like, and formed into a fiber shape.
  • a method of grinding is used.
  • the hole diameter of the hole through which the mixture is extruded may be appropriately determined so as to obtain a positive electrode active material having a desired aspect ratio, but is preferably 10 m or less, more preferably 8 to 0.02 m. More preferably, it is 5 to 0.05 m, more preferably 3 to 0.1 m.
  • a known pulverization method such as a ball mill, a jet mill, a stamp mill, or a roller mill may be used.
  • the first positive electrode active material of the present invention is obtained by forming the mixture into a predetermined shape as described above and then firing the mixture.
  • the firing temperature of the mixture formed into a predetermined shape is not particularly limited, but is preferably 200 to 3000 ° C, more preferably 300 to 1500 ° C.
  • the firing time is about 1 to 100 hours.
  • the following method may be used in addition to the method described above.
  • a method for producing a positive electrode active material of the present invention a method having a step of forming a raw material compound of the positive electrode active material into a thin film and then pulverizing it is used.
  • a conventional thin film forming method such as a sol-gel method, a vacuum deposition method, or a sputtering method may be used.
  • a sol-gel method because of low cost and easy production of the positive electrode active material.
  • a sol solution containing the raw material compound is applied to a flat plate and then converted into a gel that has lost fluidity due to a hydrolysis / condensation reaction. Is preferably used.
  • lithium and transition metal salts include hydroxides, nitrates, nitrites, carbonates, acetates, sulfates, oxynitrates, halides, and metal complex salts.
  • the sol solution can be prepared by adding a raw material mixture to a hydroalcoholic solution or the like.
  • the alcohol in the solution include methanol, ethanol, isopropyl alcohol, butanol and the like.
  • the ratio of alcohol to water is preferably about 0.5 to 5 times (molar ratio).
  • the raw material mixture to be added to the sol solution is added so that the weight of the metal component is 0.1 to 20 mass%, particularly 0.5 to LO mass% with respect to water. Is preferred.
  • Polybutyl alcohol, ethanolamine, or the like may be added to the sol solution as a stabilizer.
  • the stabilizer is preferably added so that the number of moles is 0.5 to 3 times the total number of moles of metal ions contained in the solution.
  • the material, shape, and the like of the flat plate on which the sol solution containing the above raw material compound is applied are particularly limited. Not limited.
  • the material of the flat plate is aluminum, copper, stainless steel! ⁇ )
  • a known coating method such as a reno-kuno roll coater, lip coater-blade coater, knife coater-gerabi coater, dip coater or the like may be used.
  • a conventionally known method can be used.
  • a method of performing a hydrolysis / polycondensation reaction in the presence of a basic catalyst or an acidic catalyst can be mentioned.
  • a method in which a basic catalyst or an acidic catalyst is further applied to a sol solution applied on a flat plate and dried is preferable.
  • Examples of the basic catalyst include ammonia aqueous solutions, amines such as ethylamine, jetylamine, and triethylamine, and those having a pH of about 9 to 14 are generally used.
  • Examples of the acidic catalyst include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and the like, and those having about ⁇ 1-5 are generally used. From the viewpoint of the reaction rate, it is preferable to use a basic catalyst, but an acid catalyst is preferable from the viewpoint of uniformly reacting the raw materials. For this reason, it is recommended to use different catalysts as needed.
  • the sol solution coated with the basic catalyst or the acidic catalyst is not particularly limited, but is preferably heated to 100 to 500 ° C, more preferably 150 to 300 ° C. .
  • the drying time may be about 1 to: LOO time.
  • the sol solution on the flat plate is gelled, it is preferably fired at 200 to 600 ° C, more preferably 200 to 400 ° C in an atmosphere such as air or an oxygen stream.
  • the firing time may be about 1 to: LOO time.
  • the thickness of the gel composed of the raw material compound formed on the flat plate is preferably 10 m or less, more preferably 5 to 0.05, from the viewpoint of obtaining the positive electrode active material (I) having a desired shape. ⁇ m, specially preferably 3 to 0.1 ⁇ m.
  • the first positive electrode active material of the present invention is obtained by pulverizing a thin film made of a raw material composite formed on a flat plate as described above.
  • Lithium cobaltate powder LiCoO, average particle size 8 m), 8 m x 20 m
  • the sieves (I) having a sieve mesh and sieves having a mesh size of 8 m ⁇ 8 m were sequentially applied.
  • the lithium cobaltate powder remaining on the sieve ( ⁇ ) was observed with a scanning electron microscope, the average value of 100 lithium cobaltate powders, the longest axis diameter 9.5 / ⁇ ⁇ , the shortest axis diameter 4.
  • the columnar shape was 2 and the aspect ratio was 2.
  • the lithium cobaltate powder remaining on the sieve ( ⁇ ) contained 35% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
  • the electrode active material, acetylene black, and polyvinylidene fluoride (PVdF) were mixed at a mass ratio of 90: 5: 5 and dissolved in N-methylpyrrolidone to prepare a slurry.
  • This slurry was applied onto an aluminum foil with a bar coater to a coating weight of 6 mgZcm 2 , dried at 130 ° C for 1 hour, and then subjected to a roll press several times to apply a positive electrode on the aluminum foil.
  • a positive electrode plate on which an active material layer (thickness 26 ⁇ m, porosity 40%) was formed was obtained.
  • foil-like lithium metal (thickness 100 m, diameter 18 ⁇ ) was fitted into a stainless steel battery lid and pressure-bonded.
  • the positive electrode obtained by punching the positive electrode plate with 16 ⁇ was placed in a stainless steel outer can, and a separator made of a polypropylene microporous film (thickness 30 m) was placed thereon.
  • 1M LiPF / EC + PC volume ratio 1: 1 electrolyte was injected, and the battery cover was mounted.
  • the secondary battery produced above was charged and discharged for 3 cycles with 0. ImAZcm 2 , then fully charged, and discharged with lOmAZcm 2 .
  • the resistance value obtained from the voltage drop immediately after the discharge at this time and the discharge capacity with respect to the capacity of 0. ImAZcm 2 were measured. The result is shown in figure 2.
  • Lithium cobaltate powder LiCoO, average particle size 8 m
  • the lithium cobaltate powder that had passed through the sieve and the lithium cobaltate powder remaining on the sieve (slag) obtained in the same manner as in Example 1 were mixed so that the mass ratio was 1: 1.
  • the average value of 100 lithium cobaltate powders was an approximate columnar shape with the longest shaft diameter of 7. O ⁇ m and the shortest shaft diameter of 4.6 m. Was 1.5.
  • the Leto lithium powder having passed through the sieve had an aspect ratio of 1.5 the following Kono Leto lithium powder contained 50 number 0/0.
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the mixture was used as an electrode active material. The result is shown in figure 2.
  • the lithium cobaltate powder remaining on the sieve (II) obtained in the same manner as in Example 1 was further passed through a sieve having a mesh size of 6 m ⁇ 20 m.
  • the average value of 100 lithium cobaltate powders was 12.3 m longest shaft diameter and 4.9 ⁇ m shortest shaft diameter.
  • the aspect ratio was 2.5.
  • the lithium cobaltate powder remaining on the sieve had an aspect ratio of lithium cobaltate powder under 5 following contains 20 number 0/0 1. was.
  • a secondary battery was produced in the same manner as in Example 1 except that the lithium cobaltate powder remaining on the sieve was used as an electrode active material, and this was evaluated. The result is shown in figure 2.
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 22 / ⁇ ⁇ , porosity 30%) was formed on the aluminum foil by changing the pressing pressure. In the same manner, a secondary battery was fabricated and evaluated. The result is shown in figure 2. [0112] (Example 1 5)
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 24 / ⁇ ⁇ , porosity 35%) was formed on the aluminum foil by changing the pressing pressure. In the same manner, a secondary battery was fabricated and evaluated. The result is shown in figure 2.
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 28 ⁇ m, porosity 45%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 31 ⁇ m, porosity 50%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 34 / ⁇ ⁇ , porosity 55%) was formed on the aluminum foil by changing the pressing pressure. A secondary battery was fabricated in the same manner as described above and evaluated. The result is shown in figure 2.
  • Example 1 In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 38 ⁇ m, porosity 60%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
  • the lithium cobaltate powder (LiCoO, average particle size 8 ⁇ m) used in Example 1 was not sieved
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that it was used as an electrode active material. The result is shown in figure 2.
  • Cobalt oxide and lithium carbonate were mixed so that the ratio of cobalt to lithium was 1: 1, and pulverized.
  • the resulting mixture was measured by laser diffraction, and the average particle size was about 1 ⁇ m. I confirmed. 1% by mass of carboxymethylcellulose was added to this mixture, and water was added, granulated with a fluidized bed granulator, and measured with a laser diffraction method to obtain spherical particles having an average particle diameter of 11 m. These spherical particles were sandwiched between SUS flat plates and slid a little at a time, then taken out and observed with a scanning electron microscope. The average value of 100 particles was the longest shaft diameter 16 m, the shortest shaft diameter 9 m, and the aspect ratio 1. rugby ball-like particles having a shape of 8 were obtained. The particles were calcined at 900 ° C. for 24 hours to obtain lithium cobaltate particles (LiCo o). Observation of the obtained lithium cobaltate particles with a scanning electron
  • the average value of 00 pieces was the longest shaft diameter 14 m, the shortest shaft diameter 8 m, and the aspect ratio 1.7.
  • the lithium cobaltate powder contained 43% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
  • Spherical particles having an average particle diameter of 11 m were obtained in the same manner as in Example 2-1, using cobalt oxide and lithium carbonate.
  • the spherical particles were calcined at 900 ° C. for 24 hours to obtain lithium cobaltate particles (LiCoO).
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
  • LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
  • the powder obtained by scraping the thin film from the substrate and pulverizing it lightly with a mortar was observed with a scanning electron microscope.
  • the average value of 100 powders had a longest shaft diameter of 7 m and a shortest shaft diameter of 3
  • a scale-like lithium conoleate powder having an aspect ratio of 2.3 was obtained.
  • the lithium cobaltate powder contained 60% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
  • LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
  • the thin film was scratched off the substrate, and the obtained powder was observed with a scanning electron microscope.
  • the average value of 100 powders had a longest shaft diameter of 120 m and a shortest shaft diameter of 1. l. ⁇ m, scale-like lithium cobaltate powder with an aspect ratio of 11 was obtained.
  • the lithium cobaltate powder contained 2% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
  • a secondary battery was produced in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material, and this was evaluated. The result is shown in figure 2.
  • the thin film was scratched off by bending the substrate, and the obtained powder was observed with a scanning electron microscope. The average value of 100 pieces was found to have a longest shaft diameter of 47 m and a shortest shaft diameter of 0.
  • a scaly lithium cobaltate powder having a 05 ⁇ m, aspect ratio of 940 was obtained.
  • the lithium cobaltate powder contained 0% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
  • a secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
  • LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
  • the thin film could not be peeled from the substrate.
  • the positive electrode active material for a non-aqueous electrolyte secondary battery of the present invention it is possible to provide a non-aqueous electrolyte secondary battery excellent in output characteristics when a large current is passed.

Landscapes

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

Abstract

The inventors of the present invention found that air gaps in a positive electrode can be sufficiently retained by using positive electrode active material particles for a nonaqueous electrolyte secondary battery which have a specific aspect ratio of the minor axis to the major axis. Specifically, the ratio of the average particle longest length to the average particle shortest breadth of the positive electrode active material particles is set between 1.5 and 1000. The output power characteristics of the nonaqueous electrolyte secondary battery can be improved by using such positive electrode active material particles.

Description

明 細 書  Specification
非水電解質二次電池用正極活物質粒子、および、これを用いた非水電 解質二次電池  Positive electrode active material particles for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using the same
技術分野  Technical field
[0001] 本発明は、正極活物質粒子に関し、特に出力特性に優れる非水電解質二次電池 を提供できる正極活物質粒子に関する。  TECHNICAL FIELD [0001] The present invention relates to positive electrode active material particles, and more particularly to positive electrode active material particles that can provide a nonaqueous electrolyte secondary battery excellent in output characteristics.
背景技術  Background art
[0002] 近年、自動車の排気ガスによる大気汚染が世界的な問題となって 、る中で、電気 を動力源とする電気自動車やエンジンとモータを組み合わせて走行するハイブリッド 車、燃料電池を動力源とする燃料電池車などが注目を集めており、これらに搭載され る高工ネルギー密度、高出力密度の電池の開発が産業上重要な位置を占めている 。さらにエンジンのみを動力とする自動車も、多種多様な電動機器の搭載を可能に する高電圧バッテリーを搭載する車両が実用化されている。リチウムイオン二次電池 などの二次電池は、そのエネルギー密度や放電電圧の高さから、このような車両に 適した電池であると考えられ、さまざまな開発が進められている。  In recent years, air pollution caused by exhaust gas from automobiles has become a global problem, and in particular, electric vehicles powered by electricity, hybrid vehicles that run in combination with an engine and motor, and fuel cells are used as power sources. Fuel cell vehicles, etc. are attracting attention, and the development of batteries with high energy density and high power density installed in them occupies an important industrial position. In addition, automobiles powered only by an engine have been put into practical use with vehicles equipped with a high-voltage battery that enables mounting of a wide variety of electric devices. Secondary batteries such as lithium ion secondary batteries are considered suitable for such vehicles because of their high energy density and high discharge voltage, and various developments are underway.
[0003] リチウムイオン二次電池は、基本的には、 Liイオンの吸蔵 ·放出が可能な正極およ び負極を、セパレータを介して配置し、これに電解質を満たした構成を有している。 前記セパレータは、ポーラスかつ電気的絶縁性を有するものからなり、正極と負極と が接触することにより発生する内部短絡の防止などを目的として用いられる。  [0003] A lithium ion secondary battery basically has a configuration in which a positive electrode and a negative electrode capable of occluding and releasing Li ions are arranged via a separator and filled with an electrolyte. . The separator is made of porous and electrically insulating material, and is used for the purpose of preventing an internal short circuit generated when the positive electrode and the negative electrode are in contact with each other.
[0004] 力 うな電池において充放電を行った場合、電池放電時には負極成分のリチウムを Liイオンとして電解質に放出し、正極では電解質から Liイオンを吸蔵することで発電 する。また、電池充電時には、正極力 電解質へ Liイオンを放出し、電解質中の Liィ オンを負極に析出させる。このように Liイオンが電解質を出入りするのと同時に、集電 体からの電子が導電助剤を通して移動することにより、電極反応が進行して充放電 が行われるのである。  [0004] When a battery is charged and discharged, when the battery is discharged, lithium as a negative electrode component is released as Li ions to the electrolyte, and at the positive electrode, power is generated by inserting Li ions from the electrolyte. During battery charging, Li ions are released to the positive electrode electrolyte, and Li ions in the electrolyte are deposited on the negative electrode. In this way, Li ions move in and out of the electrolyte, and at the same time, electrons from the current collector move through the conductive additive, so that the electrode reaction proceeds and charging / discharging is performed.
[0005] ハイブリッドなどの自動車用電源に用いられる二次電池には、始動、発進、加速時 にパワーアシストをするためにある一定時間に大きな出力、すなわち大電流放電特 性が要求されている。そこで、二次電池の高出力化を図るためには、特開 2000— 2 60423号公報に開示されて ヽるように、電極にお ヽて電極活物質の平均粒子径を 小さくしたり電極活物質層の厚さを薄くしたりして、電極反応面積を増やしつつ電極 活物質層内の電子伝導性及びリチウムイオン拡散性を向上させる手段が用いられて いる。 [0005] A secondary battery used for a power source for an automobile such as a hybrid has a large output, that is, a large current discharge characteristic, for a certain period of time in order to assist power during starting, starting and acceleration. Sex is required. Therefore, in order to increase the output of the secondary battery, as disclosed in Japanese Unexamined Patent Publication No. 2000-260423, the average particle diameter of the electrode active material can be reduced or the electrode active material can be reduced. Means for reducing the thickness of the material layer, increasing the electrode reaction area, and improving the electron conductivity and lithium ion diffusibility in the electrode active material layer are used.
[0006] 従来の二次電池では、特に平均粒子径が 10 μ m以下と微細化された電極活物質 を用いた電極活物質層にお ヽて十分な電子伝導性を確保するために、高圧でプレ スをかけて電極活物質や導電助剤などの電極構成材料の密着性を高めている。  [0006] In a conventional secondary battery, in order to ensure sufficient electron conductivity, particularly in an electrode active material layer using an electrode active material refined with an average particle diameter of 10 μm or less, a high voltage In order to improve the adhesion of electrode components such as electrode active materials and conductive aids.
[0007] し力しながら、前記電極内では、電極活物質層における電極活物質の充填率が高 くなり電極活物質間の空隙がつぶれてしまい、電極活物質層内に電解液を充分に含 浸させることが困難となる。この結果、電極における電子伝導性は向上するものの、 電解質と電極活物質との接触面積が著しく小さくなり Liイオンの拡散抵抗が大きくな るため、高出力の二次電池を得るのが困難となる問題があった。このような問題は、 水溶液を含む電解質と比較して Liイオンの伝導度が低 ヽ非水電解質を用い、負極 活物質と比較して電子伝導性が低！ヽ正極活物質を用いた非水電解質二次電池にお ける正極において特に生じ易い。したがって、非水電解質二次電池の高出力化を図 るためには、非水電解質二次電池の正極において生じる上記問題を解決するのが 有効な手段である。  [0007] However, in the electrode, the filling ratio of the electrode active material in the electrode active material layer is increased and the gaps between the electrode active materials are crushed, so that the electrolyte solution is sufficiently contained in the electrode active material layer. It is difficult to impregnate. As a result, although the electron conductivity in the electrode is improved, the contact area between the electrolyte and the electrode active material is remarkably reduced, and the diffusion resistance of Li ions is increased, making it difficult to obtain a high-power secondary battery. There was a problem. This is because the Li ion conductivity is low compared to electrolytes containing aqueous solutions, and non-aqueous electrolytes are used, and the electron conductivity is low compared to negative electrode active materials!生 じ Especially likely to occur in the positive electrode of a non-aqueous electrolyte secondary battery using a positive electrode active material. Therefore, in order to increase the output of the non-aqueous electrolyte secondary battery, it is an effective means to solve the above-mentioned problem that occurs in the positive electrode of the non-aqueous electrolyte secondary battery.
[0008] そこで、本発明では、非水電解質二次電池の出力特性を向上させることができる非 水電解質二次電池用正極活物質を提供することを目的とする。  Accordingly, an object of the present invention is to provide a positive electrode active material for a non-aqueous electrolyte secondary battery that can improve the output characteristics of the non-aqueous electrolyte secondary battery.
発明の開示  Disclosure of the invention
[0009] 本発明者らは、長軸に対する短軸のアスペクト比が特定の値を有する非水電解質 二次電池用正極活物質粒子を用いることにより、正極における空隙を十分に確保で き、上記課題を解決できることを見出した。  [0009] The present inventors can sufficiently ensure voids in the positive electrode by using positive electrode active material particles for a nonaqueous electrolyte secondary battery in which the aspect ratio of the short axis to the long axis has a specific value. I found that the problem could be solved.
[0010] すなわち、本発明は、平均最短軸径に対する平均最長軸径の比が 1. 5〜： LOOOで ある非水電解質二次電池用正極活物質粒子により上記課題を解決する。 [0010] That is, the present invention solves the above-mentioned problems with the positive electrode active material particles for nonaqueous electrolyte secondary batteries in which the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to LOOO.
図面の簡単な説明  Brief Description of Drawings
[0011] [図 1]図 1は本発明による正極活物質粒子の模式図を示す（図 1 (A)は長軸方向に対 する回転楕円体の形状を有する正極活物質粒子 (I)の模式図であり、図 1 (B)は短 軸方向に対する回転楕円体の形状を有する正極活物質粒子 (I)の模式図である)。 [0011] [Fig. 1] Fig. 1 shows a schematic diagram of positive electrode active material particles according to the present invention (Fig. 1 (A) is a graph in the longitudinal direction. FIG. 1 is a schematic diagram of positive electrode active material particles (I) having a spheroid shape, and FIG. 1 (B) is a schematic diagram of positive electrode active material particles (I) having a spheroid shape with respect to the minor axis direction. ).
[図 2]図 2は実施例及び比較例の二次電池を放電させた際の抵抗値と放電容量の測 定結果を示す。  FIG. 2 shows measurement results of resistance values and discharge capacities when secondary batteries of Examples and Comparative Examples are discharged.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0012] 本発明の第一は、平均最短軸径に対する平均最長軸径の比が 1. 5〜： LOOOである 非水電解質二次電池用正極活物質粒子 (単に「正極活物質」とも記載する)である。  In the first aspect of the present invention, the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to: LOOO positive electrode active material particles for secondary battery (simply described as “positive electrode active material”) Yes).
[0013] 最短軸径に対する最長軸径の比、すなわちアスペクト比が大きな値を有する正極 活物質は、板状、針状などの形状を多く含む。このように、縦方向または横方向のみ の一次元的に広がった形状を有する正極活物質は、種々の方向を持って配置され ることにより、正極活物質層における空隙率を確保することができる。また、このような 正極活物質は、球状の正極活物質と比較して広い表面積を有していることから、正 極活物質や導電助剤などの電極構成材料同士の接触抵抗を低減することが可能と なる。したがって、力 うな正極活物質によれば、正極活物質層内の空隙率を確保す ることができリチウムイオンの拡散抵抗を低下させることなく十分な電子伝導性を確保 することができ、二次電池の高出力化が可能となる。  The positive electrode active material having a large ratio of the longest shaft diameter to the shortest shaft diameter, that is, the aspect ratio, includes many shapes such as a plate shape and a needle shape. As described above, the positive electrode active material having a shape that expands one-dimensionally only in the vertical direction or the horizontal direction can ensure the porosity in the positive electrode active material layer by being arranged in various directions. . In addition, since such a positive electrode active material has a larger surface area than a spherical positive electrode active material, the contact resistance between electrode constituent materials such as a positive electrode active material and a conductive additive can be reduced. Is possible. Therefore, according to the strong positive electrode active material, the porosity in the positive electrode active material layer can be ensured, and sufficient electron conductivity can be ensured without lowering the diffusion resistance of lithium ions. The output of the battery can be increased.
[0014] 本発明による正極活物質は、平均最短軸径に対する平均最長軸径の比が、 1.5〜 1000であり、好ましくは 2〜： LOOである。この際、平均最短軸径に対する平均最長軸 径の比が 1000を超えると、下記実施例、特に実施例 3および比較例 3との比較から 示されるように、このような正極活物質を用いて薄膜を形成しても、薄膜を基板力ゝら剥 がすのが非常に困難であるあるいは不可能となり、好ましくない。また、平均最短軸 径に対する平均最長軸径の比が 1. 5未満であると、充填度合いが上昇して正極活 物質層内の空隙率を確保することが困難であり、やはり好ましくない。  In the positive electrode active material according to the present invention, the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5 to 1000, preferably 2 to: LOO. At this time, when the ratio of the average longest shaft diameter to the average shortest shaft diameter exceeds 1000, as shown by comparison with the following examples, particularly Example 3 and Comparative Example 3, such a positive electrode active material is used. Even if a thin film is formed, it is very difficult or impossible to remove the thin film with the strength of the substrate. Further, if the ratio of the average longest axis diameter to the average shortest axis diameter is less than 1.5, it is difficult to secure the porosity in the positive electrode active material layer due to an increase in the degree of filling, which is also not preferable.
[0015] 前記正極活物質のアスペクト比は、正極活物質の最長軸径 (最大径）と、それに直 行する径をもって最短軸径 (最小径)とし、電子顕微鏡を利用して測定することができ る。アスペクト比の測定は、正極活物質の電子顕微鏡写真を撮影し、写真から正極 活物質を 10個以上、好ましくは 100個以上無造作に抽出し、個々の正極活物質の 最長軸径 (最大径)および最短軸径 (最小径)を画像処理ソフトウェア等で測定し、そ の平均を算出することにより行われる。 [0015] The aspect ratio of the positive electrode active material may be measured using an electron microscope, with the longest axial diameter (maximum diameter) of the positive electrode active material and the diameter perpendicular thereto as the shortest axial diameter (minimum diameter). it can. The aspect ratio is measured by taking an electron micrograph of the positive electrode active material, extracting 10 or more positive electrode active materials, preferably 100 or more, randomly from the photo, and measuring the longest axis diameter (maximum diameter) of each positive electrode active material. And measure the shortest shaft diameter (minimum diameter) with image processing software. This is done by calculating the average of.
[0016] 前記正極活物質の平均最短軸径は、好ましくは 10 m以下、より好ましくは 8〜0.  [0016] The average shortest axis diameter of the positive electrode active material is preferably 10 m or less, more preferably 8-0.
02 μ m、さらにより好ましくは 5〜0. 05 μ m、特に好ましくは 3〜0. 1 μ mとするの力 ^ よい。このように正極活物質を微細化することで、電子伝導性を確保しつつ反応表面 積を増やすことができ、二次電池のさらなる高出力化が可能となる。特に、前記正極 活物質の平均最短軸径が 0. 02 mを下回る場合には、下記実施例、特に実施例 3 および比較例 3との比較力 示されるように、このような正極活物質を用いて薄膜を形 成しても、薄膜を基板力 剥がすのが非常に困難であるあるいは不可能となるおそ れがある。  A force of 02 μm, even more preferably 5 to 0.05 μm, particularly preferably 3 to 0.1 μm is good. Thus, by miniaturizing the positive electrode active material, the reaction surface area can be increased while ensuring the electron conductivity, and the output of the secondary battery can be further increased. In particular, when the average shortest axis diameter of the positive electrode active material is less than 0.02 m, such a positive electrode active material is used as shown in the following examples, particularly as compared with Example 3 and Comparative Example 3. Even if it is used to form a thin film, it may be very difficult or impossible to peel the thin film.
[0017] 前記正極活物質において、最短軸径に対する最長軸径の比が、 1. 5-1000,より 好ましくは 2. 0〜： L 00である正極活物質 (I)を、前記正極活物質の全量に対して、 50 〜： LOO個数％含むのが好ましい。これにより、正極活物質における電子伝導性の向 上およびリチウムイオンの拡散抵抗の低減ができ、二次電池のさらなる高出力化が図 れる。正極活物質の個数は、用いた電極等の一部を抜き取り、電子顕微鏡等で観察 することにより、容易に測定することが可能である。  [0017] In the positive electrode active material, the positive electrode active material (I) in which the ratio of the longest axis diameter to the shortest axis diameter is 1.5-1000, more preferably 2.0 to L00, is used as the positive electrode active material. It is preferable to include 50 to: LOO number% with respect to the total amount. As a result, the electron conductivity in the positive electrode active material can be improved and the diffusion resistance of lithium ions can be reduced, and the output of the secondary battery can be further increased. The number of positive electrode active materials can be easily measured by extracting a part of the used electrode and observing it with an electron microscope or the like.
[0018] 前記正極活物質 (I)は、前記正極活物質の全量に対して、 50〜： LOO個数％含むの が好ましいが、より好ましくは 70〜99個数％、特に好ましくは 80〜95個数％とする のがよい。  [0018] The positive electrode active material (I) preferably contains 50 to: LOO number%, more preferably 70 to 99 number%, particularly preferably 80 to 95 number, based on the total amount of the positive electrode active material. % Is good.
[0019] 前記正極活物質 (I)の形状は、特に制限されないが、板状、円盤状、回転楕円状、 柱状、および針状よりなる群力 選択される少なくとも一種が好ましく挙げられる。これ らの形状であれば、正極活物質層にお 、て十分な空隙を確保することができる。  [0019] The shape of the positive electrode active material (I) is not particularly limited, but at least one selected from a group force consisting of a plate shape, a disc shape, a spheroid shape, a column shape, and a needle shape is preferable. With these shapes, sufficient voids can be secured in the positive electrode active material layer.
[0020] 例えば、回転楕円状の形状を有する正極活物質 (I)としては、図 1に示す形状が挙 げられる。図 1 (A)は長軸方向に対する回転楕円体の形状を有する正極活物質 (I) の模式図であり、前記正極活物質 (I)はラグビーボール状の形状を有する。また、図 1 (B)は短軸方向に対する回転楕円体の形状を有する正極活物質 (I)の模式図で ある。  [0020] For example, as the positive electrode active material (I) having a spheroidal shape, the shape shown in FIG. FIG. 1A is a schematic view of a positive electrode active material (I) having a spheroid shape with respect to the major axis direction, and the positive electrode active material (I) has a rugby ball shape. FIG. 1B is a schematic diagram of the positive electrode active material (I) having a spheroid shape with respect to the minor axis direction.
[0021] 前記正極活物質 (I)の形状として、特に好ましくは、柱状、針状、および前記正極活 物質 (I)の長軸方向に対する回転楕円状よりなる群から選択される少なくとも一種で ある。これらの一次元的な広がりを有する形状であれば、プレスなどにより正極活物 質 (I)がー様に水平方向に積層されるのを抑制することができ、正極活物質層にお いて十分な空隙を確保するとともにリチウムイオンの拡散経路を短くすることができ、 二次電池のさらなる高出力化が可能となる。 [0021] The shape of the positive electrode active material (I) is particularly preferably at least one selected from the group consisting of a columnar shape, a needle shape, and a spheroid shape with respect to the major axis direction of the positive electrode active material (I). is there. If the shape has such a one-dimensional extension, the positive electrode active material (I) can be prevented from being laminated in the horizontal direction by a press or the like, and the positive electrode active material layer can be sufficiently formed. In addition to ensuring sufficient voids, the diffusion path of lithium ions can be shortened, and the output of the secondary battery can be further increased.
[0022] 本発明による正極活物質は、所定の形状を有する以外は組成などに特に制限はな い。前記正極活物質は、好ましくはリチウムイオンを吸蔵および放出する組成を有す る。好ましい一例としては、遷移金属とリチウムとの複合酸化物であるリチウム—遷移 金属複合酸化物が挙げられる。具体的には、 LiCoOなどの Li' Co系複合酸ィ匕物、  [0022] The positive electrode active material according to the present invention is not particularly limited in composition or the like other than having a predetermined shape. The positive electrode active material preferably has a composition for inserting and extracting lithium ions. A preferable example is a lithium-transition metal composite oxide that is a composite oxide of a transition metal and lithium. Specifically, Li'Co-based complex oxides such as LiCoO,
2  2
LiNiOなどの Li'Ni系複合酸化物、スピネル LiMn Oなどの Li' Mn系複合酸化物 Li'Ni complex oxides such as LiNiO, and Li 'Mn complex oxides such as spinel LiMn O
2 2 4 2 2 4
、 LiFeOなどの Li'Fe系複合酸化物およびこれらの遷移金属の一部を他の元素に  Li'Fe complex oxides such as LiFeO and some of these transition metals as other elements
2  2
より置換したものなどが使用できる。これらリチウム 遷移金属複合酸化物は、反応 性、サイクル特性に優れ、低コストな材料である。そのためこれらの材料を電極に用 いること〖こより、出力特性に優れた電池を形成することが可能である。この他、前記正 極活物質としては、 LiFePOなどの遷移金属とリチウムのリン酸化合物や硫酸化合  More substituted ones can be used. These lithium transition metal composite oxides are excellent in reactivity and cycle characteristics, and are low-cost materials. Therefore, it is possible to form a battery with excellent output characteristics by using these materials for the electrodes. In addition, as the positive electrode active material, a transition metal such as LiFePO and a lithium phosphate compound or sulfate compound can be used.
4  Four
物； V O、 MnO、 TiS、 MoS、 MoOなどの遷移金属酸化物や硫化物； PbO、 A Transition metal oxides and sulfides such as V O, MnO, TiS, MoS, MoO; PbO, A
2 5 2 2 2 3 2 gO、 NiOOHなど、を用 ヽることもできる。 2 5 2 2 2 3 2 gO, NiOOH, etc. can be used.
[0023] 本発明による正極活物質の用途としては、特に制限されないが、非水電解質二次 電池用正極に用いられるのが好ましい。具体的には、非水電解質二次電池用正極 における正極活物質層に用いられるのが好まし ヽ。これにより出力特性に優れる非 水電解質二次電池を提供することができる。  [0023] The use of the positive electrode active material according to the present invention is not particularly limited, but it is preferably used for a positive electrode for a nonaqueous electrolyte secondary battery. Specifically, it is preferably used for a positive electrode active material layer in a positive electrode for a non-aqueous electrolyte secondary battery. As a result, a non-aqueous electrolyte secondary battery having excellent output characteristics can be provided.
[0024] 本発明の第二は、正極活物質を含む正極活物質層を有する非水電解質二次電池 用正極であって、前記正極活物質が、上述した本発明の第一の正極活物質である 非水電解質二次電池用正極 (単に、「正極」とも記載する）である。前記正極によれば 、出力特性に優れる非水電解質二次電池を提供することが可能である。  [0024] A second aspect of the present invention is a positive electrode for a non-aqueous electrolyte secondary battery having a positive electrode active material layer containing a positive electrode active material, wherein the positive electrode active material is the first positive electrode active material of the present invention described above. It is a positive electrode for a non-aqueous electrolyte secondary battery (also simply referred to as “positive electrode”). According to the positive electrode, it is possible to provide a nonaqueous electrolyte secondary battery having excellent output characteristics.
[0025] 本発明の正極において、正極活物質層の空隙率は、好ましくは 30〜60%、より好 ましくは 35〜55%、特に好ましくは 40〜50%とするのがよい。正極活物質層の空隙 率力 30%以上であれば十分な空隙を確保することができリチウムイオンの拡散抵 抗を低減させることができ、 60%以下であれば正極活物質や導電助剤などの接触抵 抗を低減させることができる。 In the positive electrode of the present invention, the porosity of the positive electrode active material layer is preferably 30 to 60%, more preferably 35 to 55%, and particularly preferably 40 to 50%. If the porosity power of the positive electrode active material layer is 30% or more, sufficient voids can be secured and the diffusion resistance of lithium ions can be reduced, and if it is 60% or less, the positive electrode active material, the conductive auxiliary, etc. Contact resistance Resistance can be reduced.
[0026] なお、正極活物質層の空隙率は、正極を理論密度で完全充填した場合の厚みを 計算し、実際の膜厚と比較することにより算出できる。  [0026] The porosity of the positive electrode active material layer can be calculated by calculating the thickness when the positive electrode is completely filled with the theoretical density and comparing it with the actual film thickness.
[0027] また、正極活物質層の厚さは、 5〜200 m、特に 10〜： LOO mとするのがよい。 [0027] The thickness of the positive electrode active material layer is preferably 5 to 200 m, particularly 10 to LOO m.
正極活物質層の厚さが、 5 μ m以上であれば十分な放電容量が得られ、 200 μ m以 下であれば正極活物質層における電子およびリチウムイオンの拡散距離を大幅に短 くすることができ、拡散抵抗を小さくすることができる。  If the thickness of the positive electrode active material layer is 5 μm or more, sufficient discharge capacity can be obtained, and if the thickness is 200 μm or less, the diffusion distance of electrons and lithium ions in the positive electrode active material layer is significantly shortened. The diffusion resistance can be reduced.
[0028] 本発明の正極は、上述した特定のアスペクト比を有する正極活物質を含むことを特 徴とするものである。正極活物質層には、正極活物質の他には特に制限されないが[0028] The positive electrode of the present invention is characterized by containing a positive electrode active material having the specific aspect ratio described above. The positive electrode active material layer is not particularly limited in addition to the positive electrode active material.
、イオン伝導性を高めるための電解質塩、電子伝導性を高めるための導電助剤、バ インダー、および電解質などが含まれ得る。 In addition, an electrolyte salt for increasing ion conductivity, a conductive additive for increasing electron conductivity, a binder, an electrolyte, and the like may be included.
[0029] 電解質塩としては、特に限定されないが、 BETI (リチウムビス (パーフルォロェチレ ンスルホ-ルイミド）； Li(C F SO ) Nとも記載）、 LiBF、 LiPF、 LiN (SO CF ) 、 [0029] The electrolyte salt is not particularly limited, but includes BETI (lithium bis (perfluoroethylenesulfurimide); also referred to as Li (C F SO) N), LiBF, LiPF, LiN (SO CF),
2 5 2 2 4 6 2 3 2 2 5 2 2 4 6 2 3 2
LiN (SO C F ) 、 LiBOB (リチウムビスオキサイドボレート）またはこれらの混合物な LiN (SO C F), LiBOB (lithium bisoxide borate) or a mixture of these
2 2 5 2  2 2 5 2
どが挙げられる。  And so on.
[0030] 導電助剤としては、アセチレンブラック、カーボンブラック、グラフアイト等が挙げられ る。バインダーとしては、ポリフッ化ビ-リデン（PVDF)、 SBR、ポリイミドなどが使用 できる。しかし、導電助剤およびバインダーがこれらに限定されないことは言うまでも ない。  [0030] Examples of the conductive assistant include acetylene black, carbon black, and graphite. As the binder, polyvinylidene fluoride (PVDF), SBR, polyimide and the like can be used. However, it goes without saying that the conductive assistant and the binder are not limited to these.
[0031] 電解質としては、有機溶媒を使用した非水電解質が好ましく挙げられる。これにより 、正極活物質層におけるイオン伝導がスムーズになり、電池全体としての出力向上が 図れる。  [0031] Preferred examples of the electrolyte include non-aqueous electrolytes using an organic solvent. Thereby, the ionic conduction in the positive electrode active material layer becomes smooth, and the output of the entire battery can be improved.
[0032] 非水電解質としては、液状電解質 (電解液)、固体電解質、高分子ゲル電解質の ヽ ずれであってもよい。非水電解質は、好ましい一例を以下に示す力 通常の二次電 池で用いられるものであればよく特に限定されない。  [0032] The non-aqueous electrolyte may be any of a liquid electrolyte (electrolytic solution), a solid electrolyte, and a polymer gel electrolyte. The nonaqueous electrolyte is not particularly limited as long as it can be used in a normal secondary battery with the following preferable examples.
[0033] 電解液としては、 LiBOB (リチウムビスオキサイドボレート）、 LiPF、 LiBF、 LiCIO  [0033] Examples of the electrolyte include LiBOB (lithium bisoxide borate), LiPF, LiBF, LiCIO
6 4 6 4
、 LiAsF、 LiTaF、 LiAlCl , Li B CI 等の無機酸陰イオン塩、 LiCF SO、 Li(, LiAsF, LiTaF, LiAlCl, Li B CI and other inorganic acid anion salts, LiCF SO, Li (
4 6 6 4 2 10 10 3 34 6 6 4 2 10 10 3 3
CF SO ) N、 Li (C F SO ) N等の有機酸陰イオン塩の中力も選ばれる、少なくと も 1種類の電解質塩を含み、プロピレンカーボネート（PC)、エチレンカーボネート（E C)等の環状カーボネート類；ジメチルカーボネート、メチルェチルカーボネート、ジ ェチルカーボネート等の鎖状カーボネート類;テトラヒドロフラン、 2—メチルテトラヒド 口フラン、 1, 4 ジォキサン、 1, 2 ジメトキシェタン、 1, 2 ジブトキシェタン等のェ 一テル類； Ύ—ブチ口ラタトン等のラタトン類;ァセトニトリル等の-トリル類;プロピオ ン酸メチル等のエステル類；ジメチルホルムアミド等のアミド類；酢酸メチル、蟻酸メチ ルの中から選ばれる少なくとも 1種類または 2種以上を混合した、非プロトン性溶媒 等の有機溶媒 (可塑剤)を用いたものなどが使用できる。 CF SO) N, Li (CF SO) N, etc. Also contains one type of electrolyte salt, cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyl Ethers such as tetrahydric oral furan, 1,4 dioxane, 1,2 dimethoxyethane, 1,2 dibutoxetane; Ύ— latatones such as butaguchi ratataton; -tolyls such as acetonitrile; methyl propionate Esters of amides such as dimethylformamide; those using an organic solvent (plasticizer) such as an aprotic solvent in which at least one selected from methyl acetate and methyl formate is mixed Can be used.
[0034] 固体電解質としては、イオン伝導性を有する高分子から構成されるものであれば特 に限定されない。例えば、ポリエチレンォキシド（PEO)、ポリプロピレンォキシド（PP O)、これらの共重合体などが挙げられる。力 うなポリアルキレンォキシド系高分子は 、上述した電解質塩をよく溶解しうる。また、架橋構造を形成することによって、優れ た機械的強度が発現する。  [0034] The solid electrolyte is not particularly limited as long as it is composed of a polymer having ion conductivity. Examples thereof include polyethylene oxide (PEO), polypropylene oxide (PP 2 O), and copolymers thereof. A strong polyalkylene oxide polymer can dissolve the above-mentioned electrolyte salt well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.
[0035] 高分子ゲル電解質としては、特に限定されな ヽが、イオン伝導性を有する電解質 用高分子に電解液を含んだもの、イオン伝導性を持たない電解質用高分子の骨格 中に同様の電解液を保持させたものなどが挙げられる。  [0035] The polymer gel electrolyte is not particularly limited, but the electrolyte gel containing an electrolyte in an electrolyte polymer having ion conductivity, or the same in the skeleton of an electrolyte polymer having no ion conductivity. The thing etc. which hold | maintained electrolyte solution are mentioned.
[0036] 高分子ゲル電解質に含まれる電解液としては、上述したものと同様である。また、ィ オン伝導性を有する電解質用高分子としては、上述した固体電解質などが用いられ る。イオン伝導性を持たない電解質用高分子としては、例えば、ポリフッ化ビ-リデン (PVDF)、ポリビュルクロライド（PVC)、ポリアクリロ二トリル（PAN)、ポリメチルメタク リレート（PMMA)などのゲル化ポリマーを形成するモノマー又はポリマーが使用でき る。ただし、これらに限られるわけではない。なお、 PAN、 PMMAなどは、どちらかと 言うとイオン伝導性がほとんどな 、部類に入るものであるため、上記イオン伝導性を 有する電解質用高分子とすることもできるが、ここでは高分子ゲル電解質に用いられ るイオン伝導性を持たない電解質用高分子として例示したものである。  [0036] The electrolytic solution contained in the polymer gel electrolyte is the same as described above. Further, as the electrolyte polymer having ion conductivity, the above-described solid electrolyte or the like is used. Examples of electrolyte polymers that do not have ionic conductivity include gelled polymers such as poly (vinylidene fluoride) (PVDF), poly (bulvyl chloride) (PVC), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). Monomers or polymers can be used. However, it is not necessarily limited to these. Note that PAN, PMMA, etc., which have almost no ionic conductivity, fall into a category, and therefore can be used as electrolyte polymers having the above ionic conductivity. It is exemplified as a polymer for electrolytes having no ionic conductivity used in the above.
[0037] 高分子ゲル電解質中の電解質用高分子 (ホストポリマー）と電解液との比率 (質量 比）は、使用目的などに応じて決定すればよいが、 2 : 98〜90： 10の範囲である。こ れにより、正極活物質層の外周部からの電解質の染み出しについても、絶縁層や絶 縁処理部を設けることで効果的にシールすることができる。そのため、上記高分子ゲ ル電解質中のホストポリマーと電解液との比率 (質量比）に関しても、比較的電池特 性を優先したものとすることができる。 [0037] The ratio (mass ratio) of the electrolyte polymer (host polymer) to the electrolyte solution in the polymer gel electrolyte may be determined according to the purpose of use, but is in the range of 2:98 to 90:10. It is. This prevents the electrolyte from seeping out from the outer periphery of the positive electrode active material layer. By providing the edge processing portion, it is possible to effectively seal. For this reason, the battery characteristics can be prioritized relatively with respect to the ratio (mass ratio) between the host polymer and the electrolytic solution in the polymer gel electrolyte.
[0038] 本発明の正極の構造は、特に制限されないが、正極活物質層は集電体の片面に 形成される。前記集電体としては、従来の二次電池において用いられているものであ れば特に制限されず、アルミニウム、銅、ステンレス（SUS)、チタン、ニッケルなど、 導電性の材料カゝら構成されるものであればよい。集電体の厚さは、 10〜50 /ζ πι程度 であればよい。  [0038] The structure of the positive electrode of the present invention is not particularly limited, but the positive electrode active material layer is formed on one surface of the current collector. The current collector is not particularly limited as long as it is used in a conventional secondary battery, and is composed of a conductive material cover such as aluminum, copper, stainless steel (SUS), titanium, or nickel. Anything is acceptable. The thickness of the current collector may be about 10 to 50 / ζ πι.
[0039] また、本発明の正極がバイポーラ電池などに用いられる場合には、集電体の一方 の面に本発明の第一の正極活物質を含む正極活物質層が形成され、他方の面に従 来一般的な負極活物質を含む負極活物質層が形成された、本発明の正極を用いて なるバイポーラ電極であってもよぐ正極の用途に併せて構造を決定するのが望まし い。  [0039] When the positive electrode of the present invention is used for a bipolar battery or the like, a positive electrode active material layer containing the first positive electrode active material of the present invention is formed on one surface of the current collector, and the other surface Accordingly, it is desirable to determine the structure in accordance with the use of the positive electrode, which may be a bipolar electrode using the positive electrode of the present invention, in which a negative electrode active material layer containing a general negative electrode active material is formed. Yes.
[0040] 本発明の第三は、上述した本発明の第二の非水電解質二次電池用正極を用いた 非水電解質二次電池である。本発明の第二の非水電解質二次電池用正極によれば 、大電流で充放電した際の出力特性に優れる非水電解質二次電池を提供すること が可能となる。  [0040] A third aspect of the present invention is a nonaqueous electrolyte secondary battery using the above-described second positive electrode for a nonaqueous electrolyte secondary battery of the present invention. According to the second positive electrode for a non-aqueous electrolyte secondary battery of the present invention, it is possible to provide a non-aqueous electrolyte secondary battery excellent in output characteristics when charged and discharged with a large current.
[0041] 前記二次電池の構成は、第二の正極を用いること以外は従来公知の技術を適宜 参照できる。例えば、正極と、負極と、セパレータおよび電解質とを有する二次電池 において、前記正極に、本発明の第二の正極を用いた二次電池などが挙げられる。  [0041] For the configuration of the secondary battery, conventionally known techniques can be referred to as appropriate, except that the second positive electrode is used. For example, in a secondary battery having a positive electrode, a negative electrode, a separator, and an electrolyte, a secondary battery using the second positive electrode of the present invention can be used as the positive electrode.
[0042] 本発明の二次電池に用いられる負極としては特に制限されず、従来一般的に用い られている負極であればよい。具体的には、銅、ニッケル、チタン、 SUSなど力もなる 集電体上に、カーボンなどの負極活物質を少なくとも含む負極活物質層が塗布され てなる従来の構成を有する負極である。  [0042] The negative electrode used in the secondary battery of the present invention is not particularly limited as long as it is a negative electrode generally used conventionally. Specifically, it is a negative electrode having a conventional structure in which a negative electrode active material layer containing at least a negative electrode active material such as carbon is coated on a current collector that has strength such as copper, nickel, titanium, and SUS.
[0043] 本発明の二次電池は、正極および負極をセパレータを介して重ね合わせ、これに 電解質を含浸させるなどにより得られる。  [0043] The secondary battery of the present invention can be obtained by stacking a positive electrode and a negative electrode with a separator interposed therebetween, and impregnating this with an electrolyte.
[0044] 本発明の二次電池に用いられるセパレータとしては、従来一般的に用いられている ものであれば、特に制限なく用いることができる。例えば、微孔性ポリエチレンフィル ム、微孔性ポリプロピレンフィルム、微孔性エチレン プロピレンコポリマーフィルムな どのポリオレフイン系榭脂の多孔膜または不織布、これらの積層体などが挙げられる 。これらは、電解質 (電解液)との反応性を低く抑えることができるという優れた効果を 有する。他に、ポリオレフリン系榭脂不織布またはポリオレフイン系榭脂多孔膜を補強 材層に用い、前記補強材層中にフッ化ビニリデン榭脂化合物を充填した複合榭脂膜 なども挙げられる。また、セパレータの代わりに固体電解質または高分子ゲル電解質 などカゝらなる電解質層を採用してもよい。 [0044] The separator used in the secondary battery of the present invention can be used without particular limitation as long as it is generally used. For example, microporous polyethylene fill Polyolefin-based porous membranes or nonwoven fabrics such as microporous, microporous polypropylene film, microporous ethylene propylene copolymer film, and laminates thereof. These have an excellent effect that the reactivity with the electrolyte (electrolytic solution) can be kept low. Other examples include a composite resin film in which a polyolefin resin-based non-woven fabric or a polyolefin resin-based porous resin film is used as a reinforcing material layer, and the reinforcing material layer is filled with a vinylidene fluoride resin compound. Further, instead of the separator, an electrolyte layer such as a solid electrolyte or a polymer gel electrolyte may be employed.
[0045] セパレータの厚さは、使用用途に応じて適宜決定すればよいが、自動車等のモー タ駆動用二次電池などの用途においては、 15〜50 /ζ πι程度とすればよい。また、セ パレータの多孔度、大きさなどは、得られる二次電池の特性を考慮して、適宜決定す ればよい。  [0045] The thickness of the separator may be appropriately determined according to the intended use, but may be about 15 to 50 / ζ πι in applications such as motor drive secondary batteries for automobiles and the like. Further, the porosity and size of the separator may be appropriately determined in consideration of the characteristics of the obtained secondary battery.
[0046] セパレータに含浸させる電解質としては、正極活物質層に用いられるものと同様の ものが挙げられ、これは本発明の第一において記載した通りである。  [0046] Examples of the electrolyte impregnated in the separator include the same electrolytes used in the positive electrode active material layer, as described in the first aspect of the present invention.
[0047] 正極、負極、およびセパレータは電池ケースなどに収納される。電池ケースとしては 、電池を使用する際の外部力 の衝撃、環境劣化を防止し得るものを用いるとよい。 例えば、高分子フィルムと金属箔を複合積層したラミネート素材力 なる電池ケース をその周辺部を熱融着にて接合する力、あるいは、袋状にしたその開口部を熱融着 することにより密閉されてなり、この熱融着部から正極リード端子、負極リード端子を 取り出す構造としたものである。このとき正負極の各リード端子を取り出す個所は特に 1箇所に限定されない。また電池ケースを構成する材質は上記のものに限定されず、 プラスチック、金属、ゴム等、あるいはこれらの組み合わせによる材質が可能であり、 形状もフィルム、板、箱状等のものを使用できる。また、ケース内側と外側とを導通す るターミナルを設け、ターミナルの内側に集電体を、ターミナルの外側にリード端子を 接続して電流を取り出す方法も適用できる。  [0047] The positive electrode, the negative electrode, and the separator are housed in a battery case or the like. As the battery case, it is preferable to use a battery case that can prevent the impact of external force and environmental degradation when the battery is used. For example, a battery case made of a laminate material composed of a composite laminate of a polymer film and metal foil can be sealed by the force of joining its peripheral part by heat fusion or by heat-sealing its bag-like opening. Thus, the positive electrode lead terminal and the negative electrode lead terminal are taken out from the heat fusion part. At this time, the location where the lead terminals of the positive and negative electrodes are taken out is not particularly limited to one location. In addition, the material constituting the battery case is not limited to the above, and may be plastic, metal, rubber, or a combination thereof, and the shape may be a film, plate, box or the like. It is also possible to apply a method of providing a terminal that conducts electricity between the inside and outside of the case, and connecting the current collector inside the terminal and connecting the lead terminal outside the terminal to extract the current.
[0048] 本発明の二次電池の構造としては、特に限定されず、形態'構造で区別した場合 には、積層型電池、卷回型電池など、従来公知のいずれの形態，構造にも適用し得 るものである。また、二次電池内の電気的な接続形態で見た場合、バイポーラ型では ない内部並列接続タイプの電池およびバイポーラ型の内部直列接続タイプの電池 のいずれにも適用し得るものである。本発明の二次電池は、好ましくはバイポーラ型 の電池である。通常の電池に比べて単電池の電圧が高ぐ容量、出力特性に優れた 電池を構成できる。 [0048] The structure of the secondary battery of the present invention is not particularly limited, and when distinguished by the form 'structure, it is applicable to any conventionally known form or structure such as a stacked battery or a wound battery. It is possible. In addition, when viewed in terms of the electrical connection in the secondary battery, the internal parallel connection type battery and the bipolar internal series connection type battery are not bipolar. Any of these can be applied. The secondary battery of the present invention is preferably a bipolar battery. Compared to normal batteries, it is possible to construct a battery with a higher capacity and output characteristics than that of a single battery.
[0049] 上述した本発明による二次電池は、実用性の観点からリチウムイオン二次電池とし て用いるのが好ましいが、他に、ニッケル水素二次電池、ニッケル力ドミゥムニ次電 池、ナトリウムイオン二次電池、カリウムイオン二次電池、マグネシウムイオン二次電 池、カルシウムイオン二次電池、などの二次電池にも適用することができる。  [0049] The secondary battery according to the present invention described above is preferably used as a lithium ion secondary battery from the viewpoint of practicality. In addition, a nickel hydride secondary battery, a nickel-powered Dominum secondary battery, a sodium ion secondary battery are used. It can also be applied to secondary batteries such as secondary batteries, potassium ion secondary batteries, magnesium ion secondary batteries, and calcium ion secondary batteries.
[0050] さらに、本発明の二次電池は、複数個接続して構成した組電池とすることができる。  [0050] Furthermore, the secondary battery of the present invention can be an assembled battery formed by connecting a plurality of the batteries.
すなわち、本発明の二次電池を少なくとも 2個以上を用いて直列および Zまたは並 列に接続して組電池化することにより、高容量、高出力の電池モジュールを形成する ことが出来る。そのため、使用目的ごとの電池容量や出力に対する要求に、比較的 安価に対応することが可能になる。  That is, a battery module with a high capacity and a high output can be formed by connecting at least two secondary batteries of the present invention in series and Z or in parallel to form an assembled battery. As a result, it is possible to meet the requirements for battery capacity and output for each purpose of use at a relatively low cost.
[0051] 具体的には、例えば、上記の二次電池を N個並列に接続し、 N個並列にした二次 電池をさらに M個直列にして金属製な 、し榭脂製の組電池ケースに収納し、組電池 とする。この際、二次電池の直列 Z並列接続数は、使用目的に応じて決定する。例 えば、電気自動車 (EV)やハイブリッド電気自動車 (HEV)などの大容量電源として、 高工ネルギー密度、高出力密度が求められる車両の駆動用電源に適用し得るように 組み合わせればよい。また、組電池用の正極端子および負極端子と、各二次電池の 電極リードとは、リード線等を用いて電気的に接続すればよい。また、二次電池同士 を直列 Z並列に接続する際には、スぺーサゃバスバーのような適当な接続部材を用 いて電気的に接続すればよい。ただし、本発明の組電池は、ここで説明したものに制 限されるべきものではなぐ従来公知のものを適宜採用することができる。また、該組 電池には、使用用途に応じて、各種計測機器や制御機器類を設けてもよぐ例えば、 電池電圧を監視するために電圧計測用コネクタなどを設けてぉ 、てもよ 、など、特に 制限されるものではない。  [0051] Specifically, for example, N secondary batteries as described above are connected in parallel, and M secondary batteries connected in parallel with each other are made of metal, and a resin battery case And use it as an assembled battery. At this time, the number of series-parallel connection of secondary batteries is determined according to the purpose of use. For example, they may be combined so that they can be applied to a power source for driving a vehicle that requires high energy density and high output density as a large capacity power source such as an electric vehicle (EV) or a hybrid electric vehicle (HEV). Moreover, what is necessary is just to electrically connect the positive electrode terminal and negative electrode terminal for assembled batteries, and the electrode lead of each secondary battery using a lead wire. In addition, when connecting secondary batteries in series and Z in parallel, they may be electrically connected using an appropriate connecting member such as a spacer. However, the battery assembly of the present invention is not limited to the battery described here, and any conventionally known battery can be used as appropriate. In addition, the assembled battery may be provided with various measuring devices and control devices depending on the use application.For example, a voltage measuring connector may be provided for monitoring the battery voltage. There are no particular restrictions.
[0052] 本発明の二次電池および組電池は、上述のように優れた出力特性を有して!/ヽる。し たがって、エネルギー密度および出力特性に関して、とりわけ厳しい要求がなされる 車両、例えば、電気自動車、燃料電池自動車やハイブリッド電気自動車等のバッテリ 一や駆動用電源として好適であり、走行性能に優れた車両を提供できる。また、電気 自動車ないしハイブリッド電気自動車の車体中央部の座席下に本発明の二次電池 および Zまたは組電池を駆動用電源として搭載するのが、社内空間およびトランク ルームを広く取れるため便利である。ただし、本発明では、これらに何ら制限されるべ きものではなぐ本発明の二次電池または組電池は、車両の床下、トランクルーム、ェ ンジンルーム、屋根、ボンネットフード内などに設置することができる。 The secondary battery and the assembled battery of the present invention have excellent output characteristics as described above. Therefore, vehicles with particularly stringent requirements regarding energy density and output characteristics, for example, batteries for electric vehicles, fuel cell vehicles, hybrid electric vehicles, etc. It is suitable as a power source for driving and can provide a vehicle having excellent running performance. In addition, it is convenient to install the secondary battery and Z or the assembled battery of the present invention as a driving power source under the seat at the center of the body of an electric vehicle or a hybrid electric vehicle because a large in-house space and a trunk room can be obtained. However, in the present invention, the secondary battery or the assembled battery of the present invention, which should not be limited to these, can be installed under the floor of a vehicle, in a trunk room, an engine room, a roof, a hood, or the like.
[0053] 本発明の第四は、本発明の第一の正極活物質の製造方法である。  [0053] A fourth aspect of the present invention is the first method for producing a positive electrode active material of the present invention.
[0054] 本発明の第一の正極活物質の製造方法の一実施形態としては、正極活物質前駆 体を、縦と横の長さが異なる篩目を有する篩で篩分ける工程を有する方法が用いら れる。  [0054] As an embodiment of the first method for producing a positive electrode active material of the present invention, there is a method having a step of sieving the positive electrode active material precursor with a sieve having sieves having different vertical and horizontal lengths. Used.
[0055] 従来の正極活物質の製造方法としては、例えば、リチウム 遷移金属複合酸化物 の場合、リチウム化合物と遷移金属化合物を混合し、得られた混合物を焼成して、リ チウムー遷移金属複合酸ィ匕物とする方法が広く用いられている。し力しながら、前記 従来の方法により得られた正極活物質では球状のものが多く含まれ、その他にも種 々の形状が含まれる。そこで、本発明では、従来の方法により得られた種々の形状を 有する正極活物質を正極活物質前駆体として用い、これを所定の形状の篩目を有 する篩で篩分けることにより、本発明の第一の正極活物質を製造する方法を提供す る。  [0055] As a conventional method for producing a positive electrode active material, for example, in the case of a lithium transition metal composite oxide, a lithium compound and a transition metal compound are mixed, and the resulting mixture is fired to obtain a lithium-transition metal composite acid. The method of making items is widely used. However, the positive electrode active material obtained by the conventional method includes many spherical materials, and various other shapes. Therefore, in the present invention, the positive electrode active material having various shapes obtained by the conventional method is used as the positive electrode active material precursor, and this is sieved with a sieve having a sieve having a predetermined shape. A method for producing the first positive electrode active material is provided.
[0056] まず、正極活物質前駆体とは、上記の通り、球形、棒状、鱗片状、板状、円盤状、 回転楕円状、柱状、および針状など、種々の形状を有する従来の方法により得られ た正極活物質を用いる。このような種々の形状を有する正極活物質前駆体の製造方 法としては、所望の組成を有する正極活物質が得られるように従来公知の方法を用 いればよぐ例えば、特開 2002- 279986号公報、特開 2003— 217584号公報な どに記載の方法が用いられる。  [0056] First, the positive electrode active material precursor is a conventional method having various shapes such as a spherical shape, a rod shape, a scale shape, a plate shape, a disc shape, a spheroid shape, a column shape, and a needle shape as described above. The obtained positive electrode active material is used. As a method for producing a positive electrode active material precursor having such various shapes, a conventionally known method may be used so as to obtain a positive electrode active material having a desired composition. For example, JP-A-2002-279986 And the methods described in Japanese Patent Application Laid-Open No. 2003-217584 are used.
[0057] 次に、平均最短軸径に対する平均最長軸径の比が 1. 5〜： LOOOである本発明の正 極活物質を得るために、正極活物質前駆体を、縦と横の長さが異なる篩目を有する 篩で篩分ける。ここでは、便宜上篩目の長手方向を横、と定義する。本発明の正極 活物質は一次元的に広がった形状を有することから、前記篩により、最短軸径に対 する最長軸径の比が 1. 5未満の正極活物質前駆体の殆どを篩上に除去して本発明 の第一の正極活物質を得ることができる。 [0057] Next, in order to obtain a positive electrode active material of the present invention in which the ratio of the average longest axis diameter to the average shortest axis diameter is 1.5: LOOO, Sift with different sieves. Here, for convenience, the longitudinal direction of the mesh is defined as horizontal. Since the positive electrode active material of the present invention has a one-dimensionally expanded shape, it is possible to prevent the shortest shaft diameter with the sieve. The first positive electrode active material of the present invention can be obtained by removing most of the positive electrode active material precursor having a longest shaft diameter ratio of less than 1.5 on the sieve.
[0058] 本発明の第一の正極活物質を得るためには、前記篩が有する篩目の縦と横の長さ を調整するのがより好ましい。具体的には、前記篩の篩目の縦と横の長さの比率を、 好ましくは 1. 5〜： L000倍、より好ましくは 2〜： L00倍とするのがよい。これにより、正極 活物質前駆体から正極活物質を十分な精度で篩分けることができる。横方向の篩目 は特に長さを規定する必要は無いが、篩の強度上 1000倍程度未満であることが好 ましい。 [0058] In order to obtain the first positive electrode active material of the present invention, it is more preferable to adjust the vertical and horizontal lengths of the sieve mesh of the sieve. Specifically, the ratio of the vertical and horizontal lengths of the sieve mesh is preferably 1.5 to L000 times, more preferably 2 to L00 times. Thereby, the positive electrode active material can be sieved from the positive electrode active material precursor with sufficient accuracy. There is no need to specify the length of the horizontal mesh, but it is preferably less than about 1000 times due to the strength of the sieve.
[0059] また、前記篩の篩目の縦の長さは、好ましくは 0. 1〜： LOO /z m より好ましくは 0. 5 〜10 111とするのカ¾ぃ。前記箭目の横の長さは、好ましくは 0. 15〜： L00, 000 m、より好ましくは 0. 75〜： L0, 000 /z mとするの力よ!ヽ。  [0059] Further, the vertical length of the mesh of the sieve is preferably 0.1 to: LOO / zm, more preferably 0.5 to 10111. The lateral length of the mesh is preferably from 0.15 to L00,000 m, more preferably from 0.75 to L0,000 / z m.
[0060] ここで、前記篩目の縦の長さと横の長さの各最大部が上記条件であれば篩目の形 状は特に制限されない。篩目の形状としては、長方形、台形、変形三角形、変形六 角形、菱形などが挙げられるが、長方形であるのが特に好ましい。また篩の材質、線 形、織り方にも制限はなぐ打ち抜き板でもよい。篩の織り方としては、上記条件を有 する篩目が容易に得られることから、トン'キャップ織、タイロッド織が好ましく挙げられ る。また篩の材質、線形、織り方にも制限はなぐ打ち抜き板でもよい。  [0060] Here, the shape of the sieve mesh is not particularly limited as long as the maximum portions of the vertical and horizontal lengths of the sieve mesh are the above-mentioned conditions. Examples of the shape of the sieve mesh include a rectangle, a trapezoid, a deformed triangle, a deformed hexagon, and a rhombus, and a rectangle is particularly preferable. A punched plate with no restrictions on the material, line shape and weaving method of the sieve may be used. As a weaving method of the sieve, a ton'cap weave and a tie rod weave are preferably mentioned because a sieve having the above conditions can be easily obtained. Moreover, the punching board which does not restrict | limit the material of a sieve, a linear form, and a weave may be used.
[0061] 本発明の正極活物質では、最短軸径に対する最長軸径の比が 1. 5〜： L000である 正極活物質 (I)を多く含むのが望ましい。そこで、前記正極活物質 (I)の含有率を向 上させる観点から、本発明の方法では、上述の通り、正極活物質前駆体を、縦と横の 長さが異なる篩目を有する篩で篩分けた後、縦と横の長さが等しい篩目を有する篩 でさらに篩分ける工程を有するのが望ましい。これにより、最短軸径に対する最長軸 径の比が 1. 5〜： L000である正極活物質 (I)が篩上に残り、上記工程において除去 しきれな力つた最短軸径に対する最長軸径の比が 1. 5未満の正極活物質前駆体の みを篩に透過させることができる。  [0061] The positive electrode active material of the present invention preferably contains a large amount of the positive electrode active material (I) having a ratio of the longest shaft diameter to the shortest shaft diameter of 1.5 to L000. Therefore, from the viewpoint of increasing the content of the positive electrode active material (I), in the method of the present invention, as described above, the positive electrode active material precursor is a sieve having sieves having different vertical and horizontal lengths. After sieving, it is desirable to have a step of further sieving with a sieve having sieves having the same vertical and horizontal lengths. As a result, the positive electrode active material (I) having a ratio of the longest shaft diameter to the shortest shaft diameter of 1.5 to L000 remains on the sieve, and the length of the longest shaft diameter with respect to the shortest shaft diameter that has been completely removed in the above process. Only positive electrode active material precursors with a ratio of less than 1.5 can be passed through the sieve.
[0062] 縦と横の長さが等しい篩目を有する篩において、篩目の縦と横の長さの差を、好ま しくは 10%以下、より好ましくは 5%以下とするのがよい。これにより、正極活物質前 駆体力 正極活物質 (I)をさらに高い精度で篩分けることができる。 [0063] また、前記篩の篩目は、好ましくは 0. l-lOO ^ m,より好ましくは 0. 5〜： LO /z mと するのがよい。 [0062] In a sieve having sieves having the same vertical and horizontal lengths, the difference between the vertical and horizontal lengths of the sieves is preferably 10% or less, more preferably 5% or less. As a result, the positive electrode active material precursor power positive electrode active material (I) can be sieved with higher accuracy. [0063] The mesh of the sieve is preferably 0.1-lOO ^ m, more preferably 0.5 to LO / zm.
[0064] ここで、前記篩目の縦の長さと横の長さの各最大部が上記条件であれば篩目の形 状は特に制限されない。篩目の形状としては、正方形、楕円形、扇型、菱形等などが 挙げられるが、正方形であるのが特に好ましい。また篩の材質、線形、織り方にも制 限はなぐ打ち抜き板でもよい。  [0064] Here, the shape of the sieve mesh is not particularly limited as long as the maximum portions of the longitudinal length and the lateral length of the sieve mesh are the above-mentioned conditions. Examples of the shape of the sieve mesh include a square, an ellipse, a fan, and a rhombus. A square is particularly preferable. A punched plate with no restrictions on the material, alignment, and weaving of the sieve may be used.
[0065] また、正極活物質 (I)を多く含有し、アスペクト比が高 、正極活物質を得るために、 上述した各篩で篩 、分ける工程を繰返して行ってもょ ヽ。  [0065] In addition, in order to obtain a positive electrode active material containing a large amount of the positive electrode active material (I) and having a high aspect ratio, the above-described sieving and separating steps may be repeated.
[0066] 本発明の第一の正極活物質の製造方法としては、上述した方法の他、次の方法も 用いられる。  [0066] As a method for producing the first positive electrode active material of the present invention, the following method may be used in addition to the method described above.
[0067] 本発明の第一の正極活物質の製造方法の他の実施形態としては、正極活物質の 原料化合物を混合し、得られた混合物を、回転楕円状、または針状に成形する工程 を有する方法が用いられる。  [0067] In another embodiment of the first method for producing a positive electrode active material of the present invention, a raw material compound of a positive electrode active material is mixed, and the resulting mixture is formed into a spheroidal shape or a needle shape. Is used.
[0068] 原料ィ匕合物としては、所望する組成を有する正極活物質が得られるように適宜選択 して用いればよい。例えば、リチウム 遷移金属複合酸化物からなる正極活物質を 作製する場合には、原料化合物として、リチウム化合物、および、遷移金属化合物な どが挙げられる。  [0068] The raw material mixture may be appropriately selected and used so as to obtain a positive electrode active material having a desired composition. For example, when producing a positive electrode active material made of a lithium transition metal composite oxide, examples of the raw material compound include a lithium compound and a transition metal compound.
[0069] 前記リチウム化合物としては、リチウム元素を含む水酸化物、酸化物、有機酸塩、 炭酸塩、シユウ酸塩などが挙げられる。具体的には、 LiOH-H O, Li CO , CH C  [0069] Examples of the lithium compound include hydroxides, oxides, organic acid salts, carbonates, and oxalates containing lithium element. Specifically, LiOH-H 2 O, Li CO 2, CH C
2 2 3 3 2 2 3 3
OOLiなどが挙げられる。 For example, OOLi.
[0070] 前記遷移金属化合物において、遷移金属としては正極活物質として一般的に用い られているものであればよぐ Mn、 Ti、 Li、 Fe、 Ni、 Mg、 Zn、 Co、 Cr、 Al、 B、 Si、 S n、 P、 V、 Sb、 Nb、 Ta、 Mo、及び Wからなる群から選ばれる 1種類以上の元素など が挙げられる。前記遷移金属化合物としては、遷移金属元素を含む水酸化物、酸ィ匕 物、有機酸塩、炭酸塩、シユウ酸塩、硝酸塩、塩酸塩、硫酸塩などが挙げられる。具 体的には、酸化コバルト、酸ィ匕マンガン、酸ィ匕ニッケルなどが挙げられる。  [0070] In the transition metal compound, any transition metal generally used as a positive electrode active material may be used. Mn, Ti, Li, Fe, Ni, Mg, Zn, Co, Cr, Al, Examples thereof include one or more elements selected from the group consisting of B, Si, Sn, P, V, Sb, Nb, Ta, Mo, and W. Examples of the transition metal compound include hydroxides, oxides, organic acid salts, carbonates, oxalates, nitrates, hydrochlorides, and sulfates containing a transition metal element. Specifically, cobalt oxide, acid manganese, acid nickel, etc. are mentioned.
[0071] 本発明の方法では、所望の組成を有する正極活物質が得られるように上記した原 料化合物を所定比混合し、得られた混合物を回転楕円状、柱状、または針状に成形 する。 [0071] In the method of the present invention, the raw material compounds described above are mixed in a predetermined ratio so that a positive electrode active material having a desired composition is obtained, and the resulting mixture is formed into a spheroidal shape, a columnar shape, or a needle shape. To do.
[0072] このとき、前記混合物は、原料化合物の他に、バインダーをさらに含むのが好まし い。これにより混合物の成形性が向上し、得られる正極活物質の形状を調整しやすく なる。  [0072] At this time, the mixture preferably further contains a binder in addition to the raw material compound. This improves the moldability of the mixture and makes it easier to adjust the shape of the resulting positive electrode active material.
[0073] 前記バインダーとしては、カルボキシメチルセルロース、ポリビュルアルコール、ポリ ビニルアルコール、カルボキシメチルセルロース、メチルセルロース、ポリアクリル酸 N a、リグ-ンスルホン酸 Naメチルセルロース、ヒドロキシェチルセルロース、ポリアクリル 酸、ポリアクリルアミド、ポリエチレンォキシドなどが好ましく用いられる。混合物におけ る前記バインダーの含有量は、固形分の総重量に対して、好ましくは 0. 1〜20質量 %、より好ましくは 1〜： LO質量％とするのがよい。これにより混合物の成形性を向上さ せることができる。  [0073] Examples of the binder include carboxymethyl cellulose, polybutyl alcohol, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, polyacrylic acid Na, lignosulfonic acid Na methyl cellulose, hydroxyethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene. An oxide or the like is preferably used. The content of the binder in the mixture is preferably 0.1 to 20% by mass, more preferably 1 to LO mass%, based on the total weight of the solid content. Thereby, the moldability of the mixture can be improved.
[0074] 前記混合物には、成形性をさらに向上させるために、さらに溶媒を含んでいてもよ い。前記溶媒としては、水、プロピレンカーボネート（PC)、エチレンカーボネート（EC )等の環状カーボネート類；ジメチルカーボネート、メチルェチルカーボネート、ジェ チルカーボネート等の鎖状カーボネート類;テトラヒドロフラン、 2—メチルテトラヒドロ フラン、 1, 4 ジ才キサン、 1, 2 ジメトキシェタン、 1, 2 ジブトキシェタン等のェ 一テル類； Ύ—ブチ口ラタトン等のラタトン類;ァセトニトリル等の-トリル類;プロピオン 酸メチル等のエステル類；ジメチルホルムアミド等のアミド類；酢酸メチル、蟻酸メチル の中から選ばれる少なくともから 1種類または 2種以上を混合した、非プロトン性溶媒 等の有機溶媒などが挙げられる。混合物における前記溶媒の含有量は、固形分の 総重量に対して、好ましくは 0. 1〜20質量％、より好ましくは 1〜10質量％とするの がよい。これにより混合物の成形性を向上させることができる。 [0074] The mixture may further contain a solvent in order to further improve the moldability. Examples of the solvent include cyclic carbonates such as water, propylene carbonate (PC), and ethylene carbonate (EC); chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and jet carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-di-old hexane, 1, 2-dimethoxy E Tan, 1, 2 E one ether such as Jibutokishetan; Y - Rataton such as butyl port Rataton; Asetonitoriru etc. - tolyl ethers, esters of methyl propionate and the like; Examples include amides such as dimethylformamide; organic solvents such as aprotic solvents in which at least one selected from methyl acetate and methyl formate is mixed. The content of the solvent in the mixture is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total weight of the solid content. Thereby, the moldability of the mixture can be improved.
[0075] 前記混合物を回転楕円状に成形するには、上記の通りにして得られた混合物を、 平板で挟み、前記平板を摺動させる方法が用いられる。これにより、前記混合物を平 板間で転動させて所望の形状に成形することができる。また、 2つのローラーを接触、 もしくは一定のギャップを設けて、両ロールの対向部が上昇するように回転させ、その ローラー上に上記の混合物を置くことでも、成型することが可能である。  [0075] In order to form the mixture into a spheroid, a method is used in which the mixture obtained as described above is sandwiched between flat plates and the flat plates are slid. Thereby, the said mixture can be rolled between flat plates and shape | molded in a desired shape. It is also possible to mold by placing two rollers in contact with each other, or rotating them so that the opposing part of both rolls rises, and placing the above mixture on the rollers.
[0076] 前記混合物を平板間に挟む際に、前記混合物は、予め球状に造粒しているのが好 ましい。これにより、所望の形状を有する正極活物質を製造し易くなる。前記混合物 は、好ましくは平均粒径力 好ましくは 0. 1-100 μ m、より好ましくは 1〜50 μ m程 度に造粒されているのがよい。また、前記混合物の造粒方法としては、特に制限され ず、噴霧造粒方法、撹拌造粒方法、圧縮造粒方法または流動造粒方法などが用い られ、従来公知の造粒方法に順じて行えばょ 、。 [0076] When the mixture is sandwiched between flat plates, the mixture is preferably granulated in advance into a spherical shape. Good. Thereby, it becomes easy to manufacture a positive electrode active material having a desired shape. The mixture is preferably granulated to have an average particle size of preferably 0.1 to 100 μm, more preferably about 1 to 50 μm. In addition, the granulation method of the mixture is not particularly limited, and spray granulation method, stirring granulation method, compression granulation method, fluidized granulation method and the like are used, and in accordance with conventionally known granulation methods. If you go.
[0077] 前記平板、ロールの材質、形状などにつ!、ては、表面が平滑であり、混合物を摺動 させることが可能であれば特に制限なく用いることができる。前記平板の材質として、 具体的には、アルミニウム、銅、ステンレス（SUS)、チタン、ニッケル、シリカガラス、 などが挙げられる。 [0077] As long as the material and shape of the flat plate and roll are smooth, the surface can be used without particular limitation as long as the mixture can be slid. Specific examples of the material of the flat plate include aluminum, copper, stainless steel (SUS), titanium, nickel, and silica glass.
[0078] 前記平板を摺動させるには、前記混合物を挟んだ平板を、加圧しながら水平方向 に円運動させる方法、一方向への往復運動をする方法などを用いればよぐ特に制 限されない。前記平板を摺動させる条件は、所望するアスペクト比を有する正極活物 質を得られるように適宜決定すればょ ヽ。  [0078] In order to slide the flat plate, there is no particular limitation as long as a flat plate sandwiching the mixture is circularly moved in a horizontal direction while being pressed, or a reciprocating method in one direction is used. . The conditions for sliding the flat plate should be appropriately determined so that a positive electrode active material having a desired aspect ratio can be obtained.
[0079] 前記ロールは接触させても良いし、所定の幅以下になった粒子を落とすためにわ ずかなギャップを設けてもよい。ギャップの幅は目標とする活物質の短軸長によって 決まり、好ましくは 10 μ m以下、より好ましくは 8〜0. 02 μ m、さらにより好ましくは 5 〜0. 05 /z m、特に好ましくは 3〜0. 1 111とするのカょ1ヽ。  [0079] The rolls may be brought into contact with each other, or a slight gap may be provided for dropping particles having a predetermined width or less. The width of the gap is determined by the short axis length of the target active material, preferably 10 μm or less, more preferably 8 to 0.02 μm, even more preferably 5 to 0.05 / zm, particularly preferably 3 ~ 1.
[0080] また、前記混合物を針状に成形するには、上記の通りにして得られた混合物を、紡 糸用口金などを用い所定の孔径を有する穴力 押出し、繊維状に成形したものを粉 砕する方法などが用いられる。  [0080] In addition, in order to form the mixture into a needle shape, the mixture obtained as described above is extruded with a hole force having a predetermined hole diameter using a spinning die or the like, and formed into a fiber shape. A method of grinding is used.
[0081] 前記混合物を押出す穴の孔径としては、所望のアスペクト比を有する正極活物質 が得られるように適宜決定すればよいが、好ましくは 10 m以下、より好ましくは 8〜 0. 02 m、さら〖こより好ましくは 5〜0. 05 m、特〖こ好ましくは 3〜0. 1 mとするの がよい。  [0081] The hole diameter of the hole through which the mixture is extruded may be appropriately determined so as to obtain a positive electrode active material having a desired aspect ratio, but is preferably 10 m or less, more preferably 8 to 0.02 m. More preferably, it is 5 to 0.05 m, more preferably 3 to 0.1 m.
[0082] 繊維状に成形した混合物を粉砕するには、ボールミル，ジェットミル、スタンプミル、 ローラーミルなど、公知の粉砕方法を用いて行えばょ 、。  [0082] In order to pulverize the mixture formed into a fiber, a known pulverization method such as a ball mill, a jet mill, a stamp mill, or a roller mill may be used.
[0083] 本発明の方法では、上記の通りにして混合物を所定の形状に成形した後、焼成す ることにより本発明の第一の正極活物質が得られる。 [0084] 所定の形状に成形した混合物の焼成温度は、特に制限されないが、好ましくは 20 0〜3000°C、より好ましくは 300〜1500°Cとするのがよい。また、焼成時間としては、 1〜 100時間程度行えばよ 、。 [0083] In the method of the present invention, the first positive electrode active material of the present invention is obtained by forming the mixture into a predetermined shape as described above and then firing the mixture. [0084] The firing temperature of the mixture formed into a predetermined shape is not particularly limited, but is preferably 200 to 3000 ° C, more preferably 300 to 1500 ° C. The firing time is about 1 to 100 hours.
[0085] 本発明の第一の正極活物質の製造方法としては、上述した方法の他、次の方法も 用いられる。  [0085] As the method for producing the first positive electrode active material of the present invention, the following method may be used in addition to the method described above.
[0086] 本発明の第一の正極活物質の製造方法の他の実施形態としては、正極活物質の 原料化合物を薄膜に成形した後、粉砕する工程を有する方法が用いられる。  [0086] As another embodiment of the first method for producing a positive electrode active material of the present invention, a method having a step of forming a raw material compound of the positive electrode active material into a thin film and then pulverizing it is used.
[0087] 原料化合物を混合して薄膜に成形する方法としては、ゾルゲル法、真空蒸着法、ス パッタ法など、従来一般的な薄膜形成方法を用いて行えばよい。なかでも、低コスト であり、かつ、正極活物質の製造が容易であることから、ゾルゲル法を用いて行うの が好ましい。  [0087] As a method of mixing raw material compounds into a thin film, a conventional thin film forming method such as a sol-gel method, a vacuum deposition method, or a sputtering method may be used. Among them, it is preferable to use a sol-gel method because of low cost and easy production of the positive electrode active material.
[0088] ゾルゲル法を用いて原料化合物を薄膜に成形するには、原料化合物を含むゾル 溶液を、平板上に塗布した後に加水分解 ·縮合反応により流動性を失ったゲルとし、 このゲルを焼成する方法が好ましく用いられる。  [0088] In order to form a raw material compound into a thin film by using the sol-gel method, a sol solution containing the raw material compound is applied to a flat plate and then converted into a gel that has lost fluidity due to a hydrolysis / condensation reaction. Is preferably used.
[0089] 前記原料化合物としては、リチウム 遷移金属複合酸化物からなる正極活物質を 作製する場合には、リチウムおよび遷移金属のアルコキシドゃ塩が用いられる。リチ ゥムおよび遷移金属の塩の形態としては、水酸化物、硝酸塩、亜硝酸塩、炭酸塩、 酢酸塩、硫酸塩、ォキシ硝酸塩、ハロゲン化物、金属錯体塩などが挙げられる。  [0089] As the raw material compound, when producing a positive electrode active material composed of a lithium transition metal composite oxide, an alkoxy salt of lithium and a transition metal is used. Examples of lithium and transition metal salts include hydroxides, nitrates, nitrites, carbonates, acetates, sulfates, oxynitrates, halides, and metal complex salts.
[0090] 前記ゾル溶液は、原料ィ匕合物を水 アルコール溶液などに添加することにより調製 できる。前記溶液におけるアルコールとしては、メタノール、エタノール、イソプロピル アルコール、ブタノール等が挙げられる。アルコールと水の割合は、約 0. 5〜5倍（モ ル比）とするのが好ましい。  [0090] The sol solution can be prepared by adding a raw material mixture to a hydroalcoholic solution or the like. Examples of the alcohol in the solution include methanol, ethanol, isopropyl alcohol, butanol and the like. The ratio of alcohol to water is preferably about 0.5 to 5 times (molar ratio).
[0091] ゾル溶液に添加する前記原料ィ匕合物は、水に対して、金属成分の重量が 0. 1〜2 0質量％、特に 0. 5〜： LO質量％となるように添加するのが好ましい。  [0091] The raw material mixture to be added to the sol solution is added so that the weight of the metal component is 0.1 to 20 mass%, particularly 0.5 to LO mass% with respect to water. Is preferred.
[0092] 前記ゾル溶液には、安定化剤として、ポリビュルアルコール、エタノールァミンなど を添加してもよい。前記安定化剤は、溶液に含まれる総金属イオンモル数の 0.5〜3 倍のモル数となるように添加するのが好まし 、。  [0092] Polybutyl alcohol, ethanolamine, or the like may be added to the sol solution as a stabilizer. The stabilizer is preferably added so that the number of moles is 0.5 to 3 times the total number of moles of metal ions contained in the solution.
[0093] 上記した原料化合物を含むゾル溶液を塗布する平板の材質、形状などは、特に制 限されない。例えば、前記平板の材質としては、アルミニウム、銅、ステンレス !^)[0093] The material, shape, and the like of the flat plate on which the sol solution containing the above raw material compound is applied are particularly limited. Not limited. For example, the material of the flat plate is aluminum, copper, stainless steel! ^)
、チタン、ニッケルなどが挙げられる。 , Titanium, nickel and the like.
[0094] 前記平板上にゾル溶液を塗布する方法としては、スピンコート、スリットダイコーター[0094] As a method of applying the sol solution on the flat plate, spin coating, slit die coater
、 リノく一スローノレコーター、リップコーター- ブレードコーター、ナイフコーター- ゲラビ アコ一ター、ディップコーターなど、公知の塗布方法を用いればよい。 A known coating method such as a reno-kuno roll coater, lip coater-blade coater, knife coater-gerabi coater, dip coater or the like may be used.
[0095] 平板上に塗布したゾル溶液をゲル化させるには、従来公知の方法を用いればょ ヽ 力 例えば、塩基性触媒または酸性触媒下で加水分解 ·重縮合反応を行う方法が挙 げられる。具体的には、平板上に塗布したゾル溶液に、塩基性触媒または酸性触媒 をさらに塗布し、乾燥させる方法などが好ましく挙げられる。 [0095] In order to gel the sol solution coated on a flat plate, a conventionally known method can be used. For example, a method of performing a hydrolysis / polycondensation reaction in the presence of a basic catalyst or an acidic catalyst can be mentioned. . Specifically, a method in which a basic catalyst or an acidic catalyst is further applied to a sol solution applied on a flat plate and dried is preferable.
[0096] 塩基性触媒としては、アンモ-ゥム水溶液、ェチルァミン、ジェチルァミン、トリェチ ルァミン等のアミン類、などが挙げられ、 pH9〜14程度のものを用いるのが一般的で ある。また、酸性触媒としては、塩酸、硝酸、硫酸、リン酸などが挙げられ、 ρΗ1〜5 程度のものを用いるのが一般的である。反応速度の観点からは、塩基性触媒を用い るのが好ましいが、原料を均一に反応させる点では酸触媒が好ましい。このため、必 要に応じて触媒を使い分けると良い。 [0096] Examples of the basic catalyst include ammonia aqueous solutions, amines such as ethylamine, jetylamine, and triethylamine, and those having a pH of about 9 to 14 are generally used. Examples of the acidic catalyst include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and the like, and those having about ρΗ1-5 are generally used. From the viewpoint of the reaction rate, it is preferable to use a basic catalyst, but an acid catalyst is preferable from the viewpoint of uniformly reacting the raw materials. For this reason, it is recommended to use different catalysts as needed.
[0097] 塩基性触媒または酸性触媒を塗布したゾル溶液を乾燥させるには、特に制限され ないが、好ましくは 100〜500°C、より好ましくは 150〜300°Cに加熱するのが好まし い。また、乾燥時間は、 1〜： LOO時間程度とすればよい。 [0097] The sol solution coated with the basic catalyst or the acidic catalyst is not particularly limited, but is preferably heated to 100 to 500 ° C, more preferably 150 to 300 ° C. . The drying time may be about 1 to: LOO time.
[0098] 平板上のゾル溶液をゲル化させた後は、空気中、または酸素気流中などの雰囲気 下、好ましくは 200〜600°C、より好ましくは 200〜400°Cで焼成する。また、焼成時 間は、 1〜： LOO時間程度とすればよい。 [0098] After the sol solution on the flat plate is gelled, it is preferably fired at 200 to 600 ° C, more preferably 200 to 400 ° C in an atmosphere such as air or an oxygen stream. The firing time may be about 1 to: LOO time.
[0099] 平板上に形成された原料化合物からなるゲルの厚さは、所望の形状を有する正極 活物質 (I)を得る観点からは、好ましくは 10 m以下、より好ましくは 5〜0. 05 ^ m, 特〖こ好ましくは 3〜0. 1 μ mとするのがよい。 [0099] The thickness of the gel composed of the raw material compound formed on the flat plate is preferably 10 m or less, more preferably 5 to 0.05, from the viewpoint of obtaining the positive electrode active material (I) having a desired shape. ^ m, specially preferably 3 to 0.1 μm.
[0100] 本発明の方法では、上記の通りにして平板上に成形した原料ィ匕合物からなる薄膜 を、粉砕することにより、本発明の第一の正極活物質が得られる。 [0100] In the method of the present invention, the first positive electrode active material of the present invention is obtained by pulverizing a thin film made of a raw material composite formed on a flat plate as described above.
[0101] 原料ィ匕合物力もなる薄膜を粉砕するには、スクレイパー、基板への衝撃などを用い て前記平板上力 薄膜を搔き取った後に、ボールミル，ジェットミル、スタンプミル、口 一ラーミルなど、公知の粉砕方法を用いて行えばよ!、。 [0101] In order to pulverize a thin film that also has a raw material-combination force, after scraping the flat plate thin film using a scraper, impact on the substrate, etc., the ball mill, jet mill, stamp mill, mouth Use a known crushing method such as a single mill!
[0102] 〔実施例〕  [0102] [Example]
以下、本発明を実施例に基づいて具体的に説明する。なお、本発明は、これらの 実施例のみに限定されることはない。  Hereinafter, the present invention will be specifically described based on examples. Note that the present invention is not limited to only these examples.
[0103] (実施例 1 1) [0103] (Example 1 1)
(I)電極活物質の作製  (I) Preparation of electrode active material
コバルト酸リチウム粉末（LiCoO、 平均粒径 8 m)を、 8 m X 20 mの大きさの  Lithium cobaltate powder (LiCoO, average particle size 8 m), 8 m x 20 m
2  2
篩目を有する篩 (I)と、 8 m X 8 mの大きさの篩目を有する篩 (Π)に順次かけた。 篩 (Π)上に残ったコバルト酸リチウム粉末を走査型電子顕微鏡で観察したところ、 10 0個のコバルト酸リチウム粉末の平均値で、最長軸径 9. 5 /ζ πι、最短軸径 4. の 概略柱状で、アスペクト比が 2であった。また、篩 (Π)上に残ったコバルト酸リチウム粉 末は、アスペクト比が 1. 5以下のコバルト酸リチウム粉末を 35個数％含んでいた。篩 The sieves (I) having a sieve mesh and sieves having a mesh size of 8 m × 8 m were sequentially applied. When the lithium cobaltate powder remaining on the sieve (Π) was observed with a scanning electron microscope, the average value of 100 lithium cobaltate powders, the longest axis diameter 9.5 / ζ πι, the shortest axis diameter 4. The columnar shape was 2 and the aspect ratio was 2. Further, the lithium cobaltate powder remaining on the sieve (Π) contained 35% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less. Sieve
(II)上に残ったコバルト酸リチウム粉末を電極活物質として用いて、下記手順に従つ て二次電池を作製した。 Using the lithium cobaltate powder remaining on (II) as an electrode active material, a secondary battery was fabricated according to the following procedure.
[0104] (2)コイン型リチウム二次電池の作製  [0104] (2) Fabrication of coin-type lithium secondary battery
前記電極活物質と、アセチレンブラックと、ポリフッ化ビ-リデン (PVdF)とを質量比 で 90 : 5 : 5となるように混合し、 N—メチルピロリドンに溶解してスラリーを作成した。こ のスラリーをバーコ一ターを用いてアルミ箔上に 6mgZcm2の塗布重量となるように 塗布し、 130°Cで 1時間乾燥させた後、ロールプレスを複数回掛け、前記アルミ箔上 に正極活物質層（厚さ 26 μ m、空隙率 40%)が形成された正極板を得た。 The electrode active material, acetylene black, and polyvinylidene fluoride (PVdF) were mixed at a mass ratio of 90: 5: 5 and dissolved in N-methylpyrrolidone to prepare a slurry. This slurry was applied onto an aluminum foil with a bar coater to a coating weight of 6 mgZcm 2 , dried at 130 ° C for 1 hour, and then subjected to a roll press several times to apply a positive electrode on the aluminum foil. A positive electrode plate on which an active material layer (thickness 26 μm, porosity 40%) was formed was obtained.
[0105] 負極として、箔状のリチウム金属（厚さ 100 m、直径 18πιπιΦ)をステンレスの電 池蓋にはめ込み圧着した。  [0105] As the negative electrode, foil-like lithium metal (thickness 100 m, diameter 18πιπιΦ) was fitted into a stainless steel battery lid and pressure-bonded.
[0106] 次に、前記正極板を 16πιπιΦで打ち抜いて得られた正極を、ステンレスの外装缶 内に配し、これにポリプロピレン微多孔膜 (厚さ 30 m)のセパレータを載置した。こ れに、 1M LiPF /EC +PC (体積比 1 : 1)の電解質を注液し、前記電池蓋を載  Next, the positive electrode obtained by punching the positive electrode plate with 16πιπιΦ was placed in a stainless steel outer can, and a separator made of a polypropylene microporous film (thickness 30 m) was placed thereon. To this, 1M LiPF / EC + PC (volume ratio 1: 1) electrolyte was injected, and the battery cover was mounted.
6  6
せて、スチレンブタジエンゴムとピッチの混合物力もなるシーラントを隙間無く充填し た後に外装缶を力しめて封口して、コイン型リチウム二次電池を作製した。この電池 の寸法は、直径 20mm、高さ 3. 2mmである。 [0107] (3)評価 After that, a sealant having a mixture force of styrene butadiene rubber and pitch was filled without any gap, and then the outer can was forced and sealed to produce a coin-type lithium secondary battery. The dimensions of this battery are 20mm in diameter and 3.2mm in height. [0107] (3) Evaluation
上記で作製した二次電池を、 0. ImAZcm2で 3サイクル充放電した後、満充電状 態にし、 lOmAZcm2で放電を行なった。このときの放電直後の電圧降下から求めた 抵抗値と、 0. ImAZcm2の容量に対する放電容量を、それぞれ測定した。結果を 図 2に示す。 The secondary battery produced above was charged and discharged for 3 cycles with 0. ImAZcm 2 , then fully charged, and discharged with lOmAZcm 2 . The resistance value obtained from the voltage drop immediately after the discharge at this time and the discharge capacity with respect to the capacity of 0. ImAZcm 2 were measured. The result is shown in figure 2.
[0108] (実施例 1 2) [Example 1 2]
コバルト酸リチウム粉末（LiCoO、平均粒径 8 m)を、 8 m X 8 mの大きさの篩  Lithium cobaltate powder (LiCoO, average particle size 8 m), sieve of 8 m x 8 m
2  2
目を有する篩にかけた。前記篩を透過したコバルト酸リチウム粉末と、実施例 1と同様 にして得られた篩（Π)上に残ったコバルト酸リチウム粉末とを、質量比で 1： 1となるよ うに混合した。得られた混合物を走査型電子顕微鏡で観察したところ、 100個のコバ ルト酸リチウム粉末の平均値で、最長軸径 7. O ^ m,最短軸径 4. 6 mの概略柱状 で、アスペクト比が 1. 5であった。また、前記篩を透過したコノ レト酸リチウム粉末は、 アスペクト比が 1. 5以下のコノ レト酸リチウム粉末を 50個数0 /0含んでいた。 Screened with eyes. The lithium cobaltate powder that had passed through the sieve and the lithium cobaltate powder remaining on the sieve (slag) obtained in the same manner as in Example 1 were mixed so that the mass ratio was 1: 1. When the obtained mixture was observed with a scanning electron microscope, the average value of 100 lithium cobaltate powders was an approximate columnar shape with the longest shaft diameter of 7. O ^ m and the shortest shaft diameter of 4.6 m. Was 1.5. Further, the Leto lithium powder having passed through the sieve had an aspect ratio of 1.5 the following Kono Leto lithium powder contained 50 number 0/0.
[0109] 前記混合物を電極活物質として用いた以外は、実施例 1と同様にして二次電池を 作製し、これを評価した。結果を図 2に示す。  [0109] A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the mixture was used as an electrode active material. The result is shown in figure 2.
[0110] (実施例 1 3)  [0110] (Example 1 3)
実施例 1と同様にして得られた篩 (II)上に残ったコバルト酸リチウム粉末を、 6 m X 20 mの大きさの篩目を有する篩にさらにかけた。前記篩上に残ったコノ レト酸リ チウム粉末を走査型電子顕微鏡で観察したところ、 100個のコバルト酸リチウム粉末 の平均値で、最長軸径 12. 3 m、最短軸径 4. 9 μ mの概略柱状で、アスペクト比が 2. 5であった。また、篩上に残ったコバルト酸リチウム粉末は、アスペクト比が 1. 5以 下のコバルト酸リチウム粉末を 20個数0 /0含んで 、た。前記篩上に残ったコバルト酸リ チウム粉末を電極活物質として用 、た以外は、実施例 1と同様にして二次電池を作 製し、これを評価した。結果を図 2に示す。 The lithium cobaltate powder remaining on the sieve (II) obtained in the same manner as in Example 1 was further passed through a sieve having a mesh size of 6 m × 20 m. When the lithium cholate acid powder remaining on the sieve was observed with a scanning electron microscope, the average value of 100 lithium cobaltate powders was 12.3 m longest shaft diameter and 4.9 μm shortest shaft diameter. The aspect ratio was 2.5. Further, the lithium cobaltate powder remaining on the sieve had an aspect ratio of lithium cobaltate powder under 5 following contains 20 number 0/0 1. was. A secondary battery was produced in the same manner as in Example 1 except that the lithium cobaltate powder remaining on the sieve was used as an electrode active material, and this was evaluated. The result is shown in figure 2.
[0111] (実施例 1 4)  [0111] (Example 1 4)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 22 /ζ πι、空隙率 30%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。 [0112] (実施例 1 5) In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 22 / ζ πι, porosity 30%) was formed on the aluminum foil by changing the pressing pressure. In the same manner, a secondary battery was fabricated and evaluated. The result is shown in figure 2. [0112] (Example 1 5)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 24 /ζ πι、空隙率 35%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。  In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 24 / ζ πι, porosity 35%) was formed on the aluminum foil by changing the pressing pressure. In the same manner, a secondary battery was fabricated and evaluated. The result is shown in figure 2.
[0113] (実施例 1 6) [0113] (Example 1 6)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 28 μ m、空隙率 45%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。  In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 28 μm, porosity 45%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
[0114] (実施例 1 7) [0114] (Example 1 7)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 31 μ m、空隙率 50%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。  In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 31 μm, porosity 50%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
[0115] (実施例 1 8) [0115] (Example 1 8)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 34 /ζ πι、空隙率 55%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。  In the production of the coin-type lithium secondary battery of Example 1, Example 1 except that a positive electrode active material layer (thickness 34 / ζ πι, porosity 55%) was formed on the aluminum foil by changing the pressing pressure. A secondary battery was fabricated in the same manner as described above and evaluated. The result is shown in figure 2.
[0116] (実施例 1 9) [0116] (Example 1 9)
実施例 1のコイン型リチウム二次電池の作製において、プレス圧の変更により、前記 アルミ箔上に正極活物質層（厚さ 38 μ m、空隙率 60%)とした以外は、実施例 1と同 様にして二次電池を作製し、これを評価した。結果を図 2に示す。  In the production of the coin-type lithium secondary battery of Example 1, Example 1 and Example 1 were used except that a positive electrode active material layer (thickness 38 μm, porosity 60%) was formed on the aluminum foil by changing the press pressure. Similarly, secondary batteries were fabricated and evaluated. The result is shown in figure 2.
[0117] (比較例 1 1) [0117] (Comparative Example 1 1)
実施例 1で用いたコバルト酸リチウム粉末 (LiCoO、平均粒径 8 μ m)を篩をかけず  The lithium cobaltate powder (LiCoO, average particle size 8 μm) used in Example 1 was not sieved
2  2
にそのまま電極活物質として用いた以外は、実施例 1と同様にして二次電池を作製し 、これを評価した。結果を図 2に示す。  A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that it was used as an electrode active material. The result is shown in figure 2.
[0118] なお、前記コバルト酸リチウム粉末を、走査型電子顕微鏡で観察したところ、 100個 のコバルト酸リチウム粉末の平均値で、最長軸径 8. 2 /ζ πι、最短軸径 6. の概 略球状で、アスペクト比が 1. 2であった。また、前記コバルト酸リチウム粉末は、ァス ぺクト比が 1. 5以下のコバルト酸リチウム粉末を 88個数％含んでいた。 [0119] (実施例 2— 1) [0118] When the lithium cobaltate powder was observed with a scanning electron microscope, the average value of 100 lithium cobaltate powders was approximately the longest axis diameter 8.2 / ζπι and the shortest axis diameter 6. It was almost spherical and had an aspect ratio of 1.2. The lithium cobaltate powder contained 88% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less. [0119] (Example 2-1)
酸ィ匕コバルトと炭酸リチウムをコバルトとリチウムの比が 1： 1となるように混合した後 に粉砕し、得られた混合物をレーザ回折法で測定したところ平均粒径が約 1 μ mであ る事を確認した。この混合物に 1質量％のカルボキシメチルセルロースを添加し、若 干の水を加えて流動層造粒装置により造粒し、レーザ回折法で測定することにより 平均粒径 11 mの球状粒子を得た。この球状粒子を SUS平板間に挟み、少量ずつ 摺動させた後に取り出し、走査型電子顕微鏡で観察したところ 100個の平均値で、 最長軸径 16 m、最短軸径 9 m、アスペクト比 1. 8の形状を有するラグビーボール 状の粒子を得た。この粒子を 900°Cで 24時間焼成し、コバルト酸リチウム粒子（LiCo o )を得た。得られたコバルト酸リチウム粒子を走査型電子顕微鏡で観察したところ 1 Cobalt oxide and lithium carbonate were mixed so that the ratio of cobalt to lithium was 1: 1, and pulverized. The resulting mixture was measured by laser diffraction, and the average particle size was about 1 μm. I confirmed. 1% by mass of carboxymethylcellulose was added to this mixture, and water was added, granulated with a fluidized bed granulator, and measured with a laser diffraction method to obtain spherical particles having an average particle diameter of 11 m. These spherical particles were sandwiched between SUS flat plates and slid a little at a time, then taken out and observed with a scanning electron microscope. The average value of 100 particles was the longest shaft diameter 16 m, the shortest shaft diameter 9 m, and the aspect ratio 1. Rugby ball-like particles having a shape of 8 were obtained. The particles were calcined at 900 ° C. for 24 hours to obtain lithium cobaltate particles (LiCo o). Observation of the obtained lithium cobaltate particles with a scanning electron microscope 1
2 2
00個の平均値で、最長軸径 14 m、最短軸径 8 m、アスペクト比 1. 7であった。 また、前記コバルト酸リチウム粉末は、アスペクト比が 1. 5以下のコバルト酸リチウム 粉末を 43個数％含んで 、た。  The average value of 00 pieces was the longest shaft diameter 14 m, the shortest shaft diameter 8 m, and the aspect ratio 1.7. The lithium cobaltate powder contained 43% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
[0120] 前記コバルト酸リチウム粒子を電極活物質として用いた以外は、実施例 1と同様に して二次電池を作製し、これを評価した。結果を図 2に示す。  [0120] A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
[0121] (比較例 2— 1)  [0121] (Comparative Example 2-1)
酸ィ匕コバルトと炭酸リチウムをコバルトとを用い、実施例 2—1と同様にして、平均粒 径 11 mの球状粒子を得た。ここで、実施例 2—1の摺動工程を行なわず、この球状 粒子を、 900°Cで 24時間焼成し、コバルト酸リチウム粒子 (LiCoO )を得た。前記コ  Spherical particles having an average particle diameter of 11 m were obtained in the same manner as in Example 2-1, using cobalt oxide and lithium carbonate. Here, without performing the sliding step of Example 2-1, the spherical particles were calcined at 900 ° C. for 24 hours to obtain lithium cobaltate particles (LiCoO). The above
2  2
バルト酸リチウム粒子を走査型電子顕微鏡で観察したところ 100個の平均値で、最 長軸径 11 m、最短軸径 10 m、アスペクト比 1. 1であった。また、前記球状粒子 は、アスペクト比が 1. 5以下のコバルト酸リチウム粉末を 93個数％含んでいた。  Observation of lithium baltate particles with a scanning electron microscope revealed that the average of 100 particles had a longest shaft diameter of 11 m, a shortest shaft diameter of 10 m, and an aspect ratio of 1.1. Further, the spherical particles contained 93% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
[0122] 前記コバルト酸リチウム粒子を電極活物質として用いた以外は、実施例 1と同様に して二次電池を作製し、これを評価した。結果を図 2に示す。  [0122] A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
[0123] (実施例 3— 1)  [0123] (Example 3— 1)
LiOCH及び Co (C H O ) を、コバルトとリチウムの質量比が 1 : 1となるように混合 LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
3 2 3 2 2 3 2 3 2 2
し、これを水一エタノール（50 : 50)溶液 1Lにカ卩えて、混合した。さらに、これに安定 ィ匕剤としてポリビュルアルコール 0. 5質量0 /0をカ卩えて混合した。得られた混合物を、 平滑なアルミナ基板上にバーコ一ターによりギャップ 20 μ mで塗布し、 25%アンモ- ゥム水溶液をスプレー噴霧することにより塗布し、 50°Cで真空乾燥させた。これにより 、前記基板上に Liと Coとの複合酸化物を含むゲルを生成させ、乾燥炉中で 200°C で 24時間乾燥させ後、 700°Cで 10時間焼成し、前記基板上にコバルト酸リチウム (L iCoO )力もなる厚さ 3 μ mの薄膜を得た。 Then, this was added to 1 L of water-ethanol (50:50) solution and mixed. Furthermore, this was a poly Bulle alcohol 0.5 mass 0/0 were mixed example mosquitoes卩as stable I匕剤. The resulting mixture is A smooth alumina substrate was coated with a bar coater at a gap of 20 μm, sprayed with a 25% aqueous ammonia solution, and vacuum dried at 50 ° C. As a result, a gel containing a composite oxide of Li and Co is formed on the substrate, dried in a drying furnace at 200 ° C. for 24 hours, and then baked at 700 ° C. for 10 hours. A thin film with a thickness of 3 μm with lithium acid (L iCoO) force was obtained.
2  2
[0124] 前記薄膜を基板から搔き取り、軽く乳鉢により粉砕することで得られた粉末を、走査 型電子顕微鏡で観察したところ 100個の平均値で、最長軸径 7 m、最短軸径 3 m、アスペクト比 2. 3の鱗片状のコノ レト酸リチウム粉末を得た。また、前記コバルト 酸リチウム粉末は、アスペクト比が 1. 5以下のコバルト酸リチウム粉末を 60個数％含 んでいた。  [0124] The powder obtained by scraping the thin film from the substrate and pulverizing it lightly with a mortar was observed with a scanning electron microscope. As a result, the average value of 100 powders had a longest shaft diameter of 7 m and a shortest shaft diameter of 3 A scale-like lithium conoleate powder having an aspect ratio of 2.3 was obtained. Further, the lithium cobaltate powder contained 60% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
[0125] 前記コバルト酸リチウム粒子を電極活物質として用いた以外は、実施例 1と同様に して二次電池を作製し、これを評価した。結果を図 2に示す。  [0125] A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
[0126] (実施例 3— 2) [0126] (Example 3-2)
LiOCH及び Co (C H O ) を、コバルトとリチウムの質量比が 1 : 1となるように混合 LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
3 2 3 2 2 3 2 3 2 2
し、これを水一エタノール（50 : 50)溶液 1Lにカ卩えて、混合した。さらに、これに安定 ィ匕剤としてポリビュルアルコール 0. 5質量％をカ卩えて混合した。得られた混合物を、 平滑なアルミナ基板上にバーコ一ターによりギャップ 10 mで塗布し、 25%アンモ -ゥム水溶液をスプレー噴霧することにより塗布し、 50°Cで真空乾燥させた。これに より、前記基板上に Liと Coとの複合酸化物を含むゲルを生成させ、乾燥炉中で 200 °Cで 24時間乾燥させ後、 700°Cで 10時間焼成し、前記基板上にコバルト酸リチウム (LiCoO )からなる厚さ約 1 mの薄膜を得た。  Then, this was added to 1 L of water-ethanol (50:50) solution and mixed. Further, 0.5% by mass of polybulal alcohol was added as a stabilizer and mixed. The obtained mixture was coated on a smooth alumina substrate with a bar coater at a gap of 10 m, sprayed with a 25% aqueous ammonia solution, and vacuum-dried at 50 ° C. As a result, a gel containing a composite oxide of Li and Co is formed on the substrate, dried in a drying oven at 200 ° C for 24 hours, and then baked at 700 ° C for 10 hours. A thin film made of lithium cobaltate (LiCoO) with a thickness of about 1 m was obtained.
2  2
[0127] 前記薄膜を基板に傷をつけて搔き取り、得られた粉末を、走査型電子顕微鏡で観 察したところ 100個の平均値で、最長軸径 120 m、最短軸径 1. l ^ m,アスペクト 比 11の鱗片状のコバルト酸リチウム粉末を得た。また、前記コバルト酸リチウム粉末 は、アスペクト比が 1. 5以下のコバルト酸リチウム粉末を 2個数％含んでいた。  [0127] The thin film was scratched off the substrate, and the obtained powder was observed with a scanning electron microscope. As a result, the average value of 100 powders had a longest shaft diameter of 120 m and a shortest shaft diameter of 1. l. ^ m, scale-like lithium cobaltate powder with an aspect ratio of 11 was obtained. The lithium cobaltate powder contained 2% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
[0128] 前記コバルト酸リチウム粒子を電極活物質として用いた以外は、実施例 1と同様に して二次電池を作製し、これを評価した。結果を図 2に示す。  A secondary battery was produced in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material, and this was evaluated. The result is shown in figure 2.
[0129] (実施例 3— 3) LiOCH及び Co (C H O ) を、コバルトとリチウムの質量比が 1 : 1となるように混合[0129] (Example 3-3) LiOCH and Co (CHO) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
3 2 3 2 2 3 2 3 2 2
し、これを水一エタノール（50 : 50)溶液 2Lにカ卩えて、混合した。さらに、これに安定 ィ匕剤としてポリビュルアルコール 1. 0質量％をカ卩えて混合した。得られた混合物を、 平滑なアルミナ基板上にバーコ一ターによりギャップ 2 μ mで塗布し、 25%アンモ- ゥム水溶液をスプレー噴霧することにより塗布し、 50°Cで真空乾燥させた。これ〖こより 、前記基板上に Liと Coとの複合酸化物を含むゲルを生成させ、乾燥炉中で 200°C で 24時間乾燥させ後、 700°Cで 10時間焼成し、前記基板上にコバルト酸リチウム (L iCoO )力 なる厚さ約 0. 05 mの薄膜を得た。  Then, this was added to 2 L of water-ethanol (50:50) solution and mixed. Furthermore, 1.0% by mass of polybulal alcohol as a stabilizer was added and mixed. The obtained mixture was coated on a smooth alumina substrate with a bar coater at a gap of 2 μm, sprayed with a 25% aqueous ammonia solution, and vacuum dried at 50 ° C. From this, a gel containing a composite oxide of Li and Co is formed on the substrate, dried in a drying furnace at 200 ° C. for 24 hours, and then baked at 700 ° C. for 10 hours. Lithium cobaltate (LiCoO) force A thin film with a thickness of about 0.05 m was obtained.
2  2
[0130] 前記薄膜を基板を曲げて傷をつけて搔き取り、得られた粉末を、走査型電子顕微 鏡で観察したところ 100個の平均値で、最長軸径 47 m、最短軸径 0. 05 ^ m,ァス ぺクト比 940の鱗片状のコバルト酸リチウム粉末を得た。また、前記コバルト酸リチウ ム粉末は、アスペクト比が 1. 5以下のコバルト酸リチウム粉末を 0個数％含んでいた。  [0130] The thin film was scratched off by bending the substrate, and the obtained powder was observed with a scanning electron microscope. The average value of 100 pieces was found to have a longest shaft diameter of 47 m and a shortest shaft diameter of 0. A scaly lithium cobaltate powder having a 05 ^ m, aspect ratio of 940 was obtained. The lithium cobaltate powder contained 0% by number of lithium cobaltate powder having an aspect ratio of 1.5 or less.
[0131] 前記コバルト酸リチウム粒子を電極活物質として用いた以外は、実施例 1と同様に して二次電池を作製し、これを評価した。結果を図 2に示す。  [0131] A secondary battery was fabricated and evaluated in the same manner as in Example 1 except that the lithium cobalt oxide particles were used as an electrode active material. The result is shown in figure 2.
[0132] (比較例 3— 1)  [0132] (Comparative Example 3—1)
LiOCH及び Co (C H O ) を、コバルトとリチウムの質量比が 1 : 1となるように混合 LiOCH and Co (C H O) are mixed so that the mass ratio of cobalt to lithium is 1: 1.
3 2 3 2 2 3 2 3 2 2
し、これを水一エタノール（50 : 50)溶液 5Lにカ卩えて、混合した。さらに、これに安定 ィ匕剤としてポリビュルアルコール 3. 0質量0 /0をカ卩えて混合した。得られた混合物を、 平滑なアルミナ基板上にバーコ一ターによりギャップ 1 mで塗布し、 25%アンモ- ゥム水溶液をスプレー噴霧することにより塗布し、 50°Cで真空乾燥させた。これ〖こより 、前記基板上に Liと Coとの複合酸化物を含むゲルを生成させ、乾燥炉中で 200°C で 24時間乾燥させ後、 700°Cで 10時間焼成し、前記基板上にコバルト酸リチウム (L iCoO )力 なる厚さ約 0. 015 /z mの薄膜を得た。 Then, this was added to 5 L of water-ethanol (50:50) solution and mixed. Furthermore, this was a poly Bulle alcohol 3.0 mass 0/0 were mixed example mosquitoes卩as stable I匕剤. The obtained mixture was coated on a smooth alumina substrate with a bar coater at a gap of 1 m, sprayed with a 25% aqueous ammonia solution, and vacuum-dried at 50 ° C. From this, a gel containing a composite oxide of Li and Co is formed on the substrate, dried in a drying furnace at 200 ° C. for 24 hours, and then baked at 700 ° C. for 10 hours. A thin film having a thickness of about 0.015 / zm was obtained.
2  2
[0133] 前記薄膜は、基板からはがすことができな力つた。  [0133] The thin film could not be peeled from the substrate.
産業上の利用可能性  Industrial applicability
[0134] 本発明の非水電解質二次電池用正極活物質によれば、大電流を流した際の出力 特性に優れる非水電解質二次電池を提供することが可能となる。 [0134] According to the positive electrode active material for a non-aqueous electrolyte secondary battery of the present invention, it is possible to provide a non-aqueous electrolyte secondary battery excellent in output characteristics when a large current is passed.

Claims

請求の範囲  The scope of the claims
[I] 平均最短軸径に対する平均最長軸径の比が 1. 5〜： LOOOである、非水電解質二 次電池用正極活物質粒子。  [I] A positive electrode active material particle for a non-aqueous electrolyte secondary battery having a ratio of an average longest axis diameter to an average shortest axis diameter of 1.5 to LOOO.
[2] 前記平均最短軸径が 0. 02〜： LO mである請求項 1記載の非水電解質二次電池 用正極活物質粒子。  [2] The positive electrode active material particle for a nonaqueous electrolyte secondary battery according to [1], wherein the average shortest axis diameter is 0.02 to: LO m.
[3] 最短軸径に対する最長軸径の比が 1. 5〜： LOOOである正極活物質 (I)を、前記正 極活物質の全量に対して 50〜： LOO個数％含む請求項 1または 2に記載の非水電解 質二次電池用正極活物質粒子。  [3] The positive electrode active material (I) in which the ratio of the longest shaft diameter to the shortest shaft diameter is 1.5 to: LOOO is 50 to: LOO number% with respect to the total amount of the positive electrode active material. 2. Positive electrode active material particles for non-aqueous electrolyte secondary battery according to 2.
[4] 前記正極活物質 (I)の形状が、板状、円盤状、回転楕円状、柱状、および針状より なる群力 選択される少なくとも一種である請求項 1〜3のいずれかに記載の非水電 解質二次電池用正極活物質粒子。 [4] The shape of the positive electrode active material (I) is at least one selected from the group force consisting of a plate shape, a disc shape, a spheroid shape, a column shape, and a needle shape. Positive electrode active material particles for non-aqueous electrolyte secondary batteries.
[5] 前記正極活物質 (I)の形状が、柱状、針状、および前記正極活物質 (I)の長軸方 向に対する回転楕円状よりなる群力 選択される少なくとも一種である請求項 1〜4の いずれかに記載の非水電解質二次電池用正極活物質粒子。 [5] The shape of the positive electrode active material (I) is at least one selected from a columnar shape, a needle shape, and a group force consisting of a spheroid with respect to the major axis direction of the positive electrode active material (I). The positive electrode active material particle for nonaqueous electrolyte secondary batteries in any one of -4.
[6] 正極活物質を含む正極活物質層を有する二次電池用正極であって、 [6] A positive electrode for a secondary battery having a positive electrode active material layer containing a positive electrode active material,
前記正極活物質が、請求項 1〜5のいずれかに記載の非水電解質二次電池用正 極活物質粒子である非水電解質二次電池用電極。  The electrode for nonaqueous electrolyte secondary batteries whose said positive electrode active material is the positive electrode active material particle for nonaqueous electrolyte secondary batteries in any one of Claims 1-5.
[7] 前記正極活物質層の空隙率が、 30〜60%である請求項 6記載の非水電解質二次 電池用電極。 7. The electrode for a nonaqueous electrolyte secondary battery according to claim 6, wherein the positive electrode active material layer has a porosity of 30 to 60%.
[8] 請求項 6または 7に記載の非水電解質二次電池用正極を用いた非水電解質二次 電池。  [8] A nonaqueous electrolyte secondary battery using the positive electrode for a nonaqueous electrolyte secondary battery according to claim 6 or 7.
[9] 請求項 8記載の非水電解質二次電池を複数個接続して構成される組電池。  [9] An assembled battery constituted by connecting a plurality of the nonaqueous electrolyte secondary batteries according to claim 8.
[10] 請求項 8記載の非水電解質二次電池、または、請求項 9に記載の組電池が搭載さ れてなる車両。 [10] A vehicle on which the nonaqueous electrolyte secondary battery according to claim 8 or the assembled battery according to claim 9 is mounted.
[II] 最短軸径に対する最長軸径の比が 1. 5〜： L000である非水電解質二次電池用正 極活物質粒子の製造方法であって、  [II] A method for producing positive electrode active material particles for a nonaqueous electrolyte secondary battery having a ratio of the longest shaft diameter to the shortest shaft diameter of 1.5 to L000,
電極活物質前駆体を、縦と横の長さが異なる篩目を有する篩で篩分ける工程を有 する非水電解質二次電池用正極活物質粒子の製造方法。 A method for producing positive electrode active material particles for a non-aqueous electrolyte secondary battery, comprising a step of sieving an electrode active material precursor with a sieve having sieves having different vertical and horizontal lengths.
[12] 前記電極活物質前駆体を、前記縦と横の長さが異なる篩目を有する篩で篩分けた 後、縦と横の長さが等しい篩目を有する篩でさらに篩分ける工程を有する請求項 11 に記載の非水電解質二次電池用正極活物質粒子の製造方法。 [12] The step of sieving the electrode active material precursor with a sieve having sieves having different vertical and horizontal lengths, and further sieving with a sieve having sieves having the same vertical and horizontal lengths. The method for producing positive electrode active material particles for a non-aqueous electrolyte secondary battery according to claim 11.
[13] 最短軸径に対する最長軸径の比が 1. 5〜： LOOOである非水電解質二次電池用正 極活物質粒子の製造方法であって、  [13] A method for producing positive electrode active material particles for a non-aqueous electrolyte secondary battery, wherein the ratio of the longest shaft diameter to the shortest shaft diameter is 1.5 to: LOOO,
原料化合物を混合し、得られた混合物を、回転楕円状、または針状に成形するェ 程を有する非水電解質二次電池用正極活物質粒子の製造方法。  A method for producing positive electrode active material particles for a non-aqueous electrolyte secondary battery, comprising mixing raw material compounds and forming the resulting mixture into a spheroid or needle shape.
[14] 最短軸径に対する最長軸径の比が 1. 5〜： LOOOである非水電解質二次電池用正 極活物質粒子の製造方法であって、  [14] A method for producing positive electrode active material particles for a non-aqueous electrolyte secondary battery, wherein the ratio of the longest shaft diameter to the shortest shaft diameter is 1.5 to: LOOO,
原料化合物を薄膜状に成形した後、粉砕する工程を有する非水電解質二次電池 用正極活物質粒子の製造方法。  The manufacturing method of the positive electrode active material particle for nonaqueous electrolyte secondary batteries which has the process of grind | pulverizing after forming a raw material compound into a thin film form.
PCT/JP2006/323075 2005-11-24 2006-11-20 Positive electrode active material particle for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using same WO2007060906A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2005339521 2005-11-24
JP2005-339521 2005-11-24
JP2006-263369 2006-09-27
JP2006263369A JP5428125B2 (en) 2005-11-24 2006-09-27 Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery using the same

Publications (1)

Publication Number Publication Date
WO2007060906A1 true WO2007060906A1 (en) 2007-05-31

Family

ID=38067133

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2006/323075 WO2007060906A1 (en) 2005-11-24 2006-11-20 Positive electrode active material particle for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using same

Country Status (2)

Country Link
JP (1) JP5428125B2 (en)
WO (1) WO2007060906A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2615670A1 (en) * 2010-09-06 2013-07-17 Shin-Kobe Electric Machinery Co., Ltd. Lithium ion secondary battery

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5371032B2 (en) * 2008-07-04 2013-12-18 日産自動車株式会社 Non-aqueous electrolyte secondary battery
US9099738B2 (en) 2008-11-03 2015-08-04 Basvah Llc Lithium secondary batteries with positive electrode compositions and their methods of manufacturing
JP5149920B2 (en) * 2010-02-05 2013-02-20 トヨタ自動車株式会社 Method for producing electrode for lithium secondary battery
JP5552709B2 (en) * 2010-03-26 2014-07-16 三菱マテリアル株式会社 Cathode active material for Li-ion battery and method for producing the same
JP5457953B2 (en) * 2010-06-22 2014-04-02 日本碍子株式会社 Positive electrode of lithium secondary battery and lithium secondary battery
JP5698951B2 (en) * 2010-10-19 2015-04-08 シャープ株式会社 Positive electrode active material and method for producing the same, positive electrode and non-aqueous electrolyte secondary battery
CN103518276A (en) * 2011-05-12 2014-01-15 应用材料公司 Precursor formulation for battery active materials synthesis
JP6088923B2 (en) * 2012-09-04 2017-03-01 日本碍子株式会社 Method for producing positive electrode active material for lithium secondary battery or precursor thereof
JP6273115B2 (en) * 2013-09-13 2018-01-31 Ｊｘ金属株式会社 Positive electrode active material for lithium ion battery, positive electrode for lithium ion battery, and lithium ion battery
JP6132164B2 (en) * 2014-04-25 2017-05-24 株式会社豊田自動織機 Positive electrode for non-aqueous secondary battery and non-aqueous secondary battery
EP3208870B1 (en) * 2014-10-15 2020-01-15 Tokyo University of Science Foundation Negative electrode for potassium ion secondary batteries, negative electrode for potassium ion capacitors, potassium ion secondary battery, potassium ion capacitor, and binder for negative electrodes of potassium ion secondary batteries or negative electrodes of potassium ion capacitors
SE539560C2 (en) 2015-03-06 2017-10-10 Innventia Ab Electrode active coating for a lithium-ion battery and method of production therefore
KR102043783B1 (en) * 2017-12-22 2019-11-12 주식회사 포스코 Manufacturing method of a positive electrode active material for rechargeable battery, positive electrode active material for rechargeable battery manufacture using the same, and rechargeable battery including the same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06275277A (en) * 1992-05-18 1994-09-30 Mitsubishi Cable Ind Ltd Lithium secondary battery
JP2000223111A (en) * 1999-01-28 2000-08-11 Kyocera Corp Electrochemical element
JP2001023640A (en) * 1999-07-09 2001-01-26 Seimi Chem Co Ltd Lithium secondary battery
JP2001202948A (en) * 2000-01-19 2001-07-27 Sanyo Electronic Components Co Ltd Active material for positive electrode and method of fabrication
JP2002208399A (en) * 2000-11-09 2002-07-26 Japan Storage Battery Co Ltd Positive electrode active material for secondary battery and its manufacturing method as well as nonaqueous electrolyte secondary battery equipped with same
JP2003017050A (en) * 2001-06-27 2003-01-17 Santoku Corp Positive electrode active material for non-aqueous electrolyte secondary battery, manufacturing method thereof, non-aqueous electrolyte secondary battery and manufacturing method of positive electrode
JP2006066170A (en) * 2004-08-26 2006-03-09 Daiken Kagaku Kogyo Kk Lithium manganate powder of spinel structure, manufacturing method of the same, electrode, and lithium group secondary battery

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06275277A (en) * 1992-05-18 1994-09-30 Mitsubishi Cable Ind Ltd Lithium secondary battery
JP2000223111A (en) * 1999-01-28 2000-08-11 Kyocera Corp Electrochemical element
JP2001023640A (en) * 1999-07-09 2001-01-26 Seimi Chem Co Ltd Lithium secondary battery
JP2001202948A (en) * 2000-01-19 2001-07-27 Sanyo Electronic Components Co Ltd Active material for positive electrode and method of fabrication
JP2002208399A (en) * 2000-11-09 2002-07-26 Japan Storage Battery Co Ltd Positive electrode active material for secondary battery and its manufacturing method as well as nonaqueous electrolyte secondary battery equipped with same
JP2003017050A (en) * 2001-06-27 2003-01-17 Santoku Corp Positive electrode active material for non-aqueous electrolyte secondary battery, manufacturing method thereof, non-aqueous electrolyte secondary battery and manufacturing method of positive electrode
JP2006066170A (en) * 2004-08-26 2006-03-09 Daiken Kagaku Kogyo Kk Lithium manganate powder of spinel structure, manufacturing method of the same, electrode, and lithium group secondary battery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2615670A1 (en) * 2010-09-06 2013-07-17 Shin-Kobe Electric Machinery Co., Ltd. Lithium ion secondary battery
EP2615670A4 (en) * 2010-09-06 2015-02-25 Shin Kobe Electric Machinery Lithium ion secondary battery

Also Published As

Publication number Publication date
JP5428125B2 (en) 2014-02-26
JP2007173210A (en) 2007-07-05

Similar Documents

Publication Publication Date Title
JP5428125B2 (en) Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery using the same
JP4407211B2 (en) Nonaqueous electrolyte secondary battery
JP4061586B2 (en) Positive electrode active material for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using the same
US8187754B2 (en) Coin-type non-aqueous electrolyte battery
JP5313479B2 (en) Non-aqueous electrolyte battery
JP5625273B2 (en) Method for producing positive electrode material for lithium ion battery
EP2685533B1 (en) Positive electrode active material for lithium ion secondary batteries
JP5370937B2 (en) Positive electrode active material, positive electrode and non-aqueous secondary battery
CN109075376B (en) Nonaqueous electrolyte secondary battery
KR101671131B1 (en) Non-aqueous electrolyte solution secondary battery
JP4752508B2 (en) Secondary battery negative electrode material, secondary battery negative electrode and secondary battery using the same
KR20090049988A (en) Positive electrode for lithium-ion secondary battery, manufacturing method thereof, and lithium-ion secondary battery
KR20130031373A (en) Active material, process for production of active material, and lithium ion secondary battery
JP2007257862A (en) Electrode for secondary battery, and secondary battery
JP5734813B2 (en) Battery electrode, non-aqueous electrolyte battery, and battery pack
JP4984422B2 (en) Method for manufacturing electrode for secondary battery
JP2006059641A (en) Electrode for secondary battery and secondary battery using it
JP5527597B2 (en) Method for manufacturing lithium secondary battery
US7378189B2 (en) Electrode material for lithium secondary battery, electrode structure employing electrode material, and lithium secondary battery having electrode structure
JP5535160B2 (en) Nonaqueous electrolyte battery and battery pack
KR20090084693A (en) Non-aqueous electrolyte battery and negative electrode, and method for manufacturing the same
KR102580235B1 (en) Positive active material, lithium battery containing the material, and method of manufacturing the material
JP7038956B2 (en) Negative electrode active material with high output characteristics and lithium secondary battery containing it
JP7233013B2 (en) Non-aqueous electrolyte secondary battery
JP2010129194A (en) Anode for lithium ion secondary battery and lithium ion secondary battery

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06832936

Country of ref document: EP

Kind code of ref document: A1