WO2012086618A1 - Negative electrode active material, negative electrode, and nonaqueous electrolyte secondary battery - Google Patents

Negative electrode active material, negative electrode, and nonaqueous electrolyte secondary battery Download PDF

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WO2012086618A1
WO2012086618A1 PCT/JP2011/079435 JP2011079435W WO2012086618A1 WO 2012086618 A1 WO2012086618 A1 WO 2012086618A1 JP 2011079435 W JP2011079435 W JP 2011079435W WO 2012086618 A1 WO2012086618 A1 WO 2012086618A1
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negative electrode
active material
secondary battery
electrolyte secondary
electrode active
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PCT/JP2011/079435
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French (fr)
Japanese (ja)
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英高 柴田
大塚　正博
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株式会社 村田製作所
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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
    • 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 generally relates to a negative electrode active material, a negative electrode, and a non-aqueous electrolyte secondary battery, and more specifically, a negative electrode active material including a carbon material, a negative electrode including the negative electrode active material, and a non-electrode including the negative electrode
  • the present invention relates to a water electrolyte secondary battery.
  • secondary batteries with high energy density and long life are expected as cordless power sources for these electronic devices.
  • secondary batteries have been developed that use an alkali metal ion such as lithium ion as a charge carrier and use an electrochemical reaction associated with charge exchange.
  • lithium ion secondary batteries having a large energy density are widely used.
  • Patent Document 1 JP 2001-57230 A (hereinafter referred to as Patent Document 1) describes using graphite, soft carbon, or hard carbon as the negative electrode active material.
  • active research has been conducted on materials for negative electrode active materials.
  • an object of the present invention is to provide a negative electrode active material capable of improving the output characteristics of the battery, a negative electrode including the negative electrode active material, and a nonaqueous electrolyte secondary battery including the negative electrode.
  • the negative electrode active material according to the present invention includes graphite and surface-amorphized soft carbon.
  • the negative electrode active material of the present invention preferably contains graphite and surface amorphized soft carbon in a mass ratio of 95: 5 to 30:70.
  • the graphite contains surface-amorphized graphite.
  • the negative electrode according to the present invention includes a negative electrode active material having the characteristics described above.
  • the filling density of the negative electrode mixture is preferably 1.2 g / cm 3 or more and 1.5 g / cm 3 or less.
  • a non-aqueous electrolyte secondary battery according to the present invention includes the above negative electrode.
  • the output DCR of the battery can be reduced, so that the output characteristics of the battery can be improved.
  • the present inventor has repeatedly studied using various carbon materials as the negative electrode active material. As a result, it has been found that when the negative electrode active material contains graphite and surface amorphized soft carbon, the output DCR of the battery can be reduced.
  • the present invention has been made based on such knowledge of the present inventor.
  • the particles of the surface-amorphized soft carbon are an inner layer made of amorphous soft carbon and a surface formed on the surface of the inner layer and made more amorphous than the soft carbon of the inner layer. Composed of layers.
  • the surface-amorphized soft carbon particles having such a structure are formed, for example, by coating the surface of the soft carbon particles that become an amorphous inner layer with amorphous carbon from the inner layer.
  • the negative electrode active material contains graphite and surface-amorphized soft carbon, so that the non-aqueous electrolyte secondary battery including the negative electrode containing the negative electrode active material reduces the output DCR of the battery. And the output characteristics of the battery can be improved.
  • the negative electrode active material contains graphite and surface amorphized soft carbon in a mass ratio of 95: 5 to 30:70
  • the output DCR of the battery can be more effectively reduced, and the output characteristics of the battery can be reduced. Can be further improved.
  • the mass ratio of soft carbon is larger than 70%, the output DCR of the battery increases.
  • capacitance as a battery becomes small by the fall of a negative electrode capacity
  • the output DCR of the battery can be further reduced, and the output characteristics of the battery can be further improved.
  • the positive electrode and the negative electrode of the non-aqueous electrolyte secondary battery are alternately stacked via a separator.
  • the structure of the battery element may be composed of a stack of a plurality of strip-shaped positive electrodes, a plurality of strip-shaped separators and a plurality of strip-shaped negative electrodes, a stack of so-called single-wafer structures. It may be configured by folding and interposing a strip-shaped positive electrode and a strip-shaped negative electrode alternately.
  • a winding type structure in which a long positive electrode, a long separator, and a long negative electrode are wound may be employed. In the following examples, a single-wafer laminated body is adopted as the battery element structure.
  • a positive electrode mixture layer including a positive electrode active material, a conductive agent, and a binder is formed on both surfaces of the positive electrode current collector.
  • the positive electrode current collector is made of aluminum or copper.
  • the positive electrode active material is lithium cobalt oxide composite oxide, lithium manganate composite oxide, lithium nickelate composite oxide, lithium-nickel-manganese-cobalt composite oxide, lithium-manganese-nickel composite oxide, lithium-manganese- A cobalt composite oxide, a lithium-nickel-cobalt composite oxide, or the like can be used. Further, the positive electrode active material may be a mixture of the above materials.
  • the positive electrode active material may be a lithium-containing phosphate compound having an olivine type structure such as lithium iron phosphate represented by LiFePO 4 . If it has an olivine type structure, in the lithium iron phosphate represented by LiFePO 4 , a part of Fe is replaced with Al, Ti, V, Cr, Mn, Co, Ni, Zr, Nb, etc. Also good. A part of P may be replaced with B, Si, or the like. A carbon material such as acetylene black is used as the conductive agent for the positive electrode. Polyvinylidene fluoride (PVDF) or polyamideimide (PAI) is used as the binder for binding the positive electrode active material and the conductive agent.
  • PVDF polyvinylidene fluoride
  • PAI polyamideimide
  • a negative electrode mixture layer containing the negative electrode active material (graphite and surface-amorphized soft carbon) and a binder is formed on both surfaces of the negative electrode current collector.
  • the negative electrode current collector is made of copper.
  • the binder for binding the negative electrode active material polyvinylidene fluoride, polyacrylonitrile or polyamideimide is used, or a mixture of a latex binder such as styrene butadiene rubber and a thickener such as carboxymethyl cellulose is used. .
  • the filling density of the negative electrode mixture in the negative electrode is preferably 1.2 g / cm 3 or more and 1.5 g / cm 3 or less.
  • the filling density of the negative electrode mixture is within the above range, the capacity retention rate of the battery can be increased, and the AC resistance increase rate can be decreased.
  • the nonaqueous electrolytic solution is prepared by dissolving the supporting electrolyte in a nonaqueous solvent.
  • a solution obtained by dissolving LiPF 6 at a concentration of 1.0 mol / L in a non-aqueous solvent is used.
  • supporting electrolytes other than LiPF 6 include lithium salts such as LiBF 4 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiC (SO 2 CF 3 ) 3 , LiAlCl 4 , and LiSiF 6. Can be mentioned.
  • LiPF 6 and LiBF 4 are particularly preferably used as the supporting electrolyte from the viewpoint of oxidation stability.
  • a supporting electrolyte is preferably used by being dissolved in a nonaqueous solvent at a concentration of 0.1 mol / L to 3.0 mol / L, and at a concentration of 0.5 mol / L to 2.0 mol / L. More preferably, it is used after being dissolved.
  • the non-aqueous solvent include cyclic carbonates such as ethylene carbonate (EC) and propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), which are low viscosity solvents. And a lower chain carbonate of the above are used.
  • the separator is not particularly limited, and a conventionally known separator can be used.
  • the separator is not limited by its name, and a solid electrolyte or gel electrolyte having a function (role) as a separator may be used instead of the separator.
  • a separator containing an inorganic material such as alumina or zirconia may be used.
  • the separator uses a porous film containing polypropylene and / or polyethylene.
  • Example shown below is an example and this invention is not limited to the following Example.
  • the configurations of the negative electrode active materials were varied to prepare the non-aqueous electrolyte secondary batteries of Examples and Comparative Examples.
  • Example 1 (Preparation of negative electrode) A negative electrode active material comprising a mixture of surface amorphized graphite (hereinafter referred to as surface amorphized GC) and surface amorphized soft carbon (hereinafter referred to as surface amorphized SC), and a binder Polyvinylidene fluoride was blended at a mass ratio of 95: 5 and kneaded with N-methyl-2-pyrrolidone to prepare a negative electrode mixture slurry. At this time, the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 80:20 to prepare a negative electrode active material.
  • surface amorphized GC surface amorphized graphite
  • SC surface amorphized soft carbon
  • non-aqueous electrolyte As non-aqueous solvent, ethylene carbonate is a cyclic carbonate, diethyl carbonate a chain carbonate 3: with 7 mixed solvent were mixed at a volume ratio of the LiPF 6 as a supporting electrolyte 1 mol / L in the mixed solvent It was made to melt
  • lead tabs 14 and 15 were provided on the positive electrode 11 and the negative electrode 12 produced as described above.
  • the positive electrode 11 and the negative electrode 12 were laminated with a separator 13 made of a polypropylene microporous membrane permeable to lithium ions.
  • the battery element 10 was produced.
  • Sealants 16 and 17 were attached to the lead tabs 14 and 15, and as shown in FIG. 2, the laminate was housed in an outer packaging material 20 made of a laminate film containing aluminum as an intermediate layer. Then, after pouring the non-aqueous electrolyte produced above into the outer packaging material 20, the non-aqueous electrolyte secondary battery 1 was produced by sealing the opening of the outer packaging material 20.
  • the obtained nonaqueous electrolyte secondary battery 1 was charged at a constant current up to a voltage of 0.2 V at a current value of 6 mA, and then charged at a constant voltage until the current value became 0.6 mA at a voltage value of 0.2 V. .
  • the non-aqueous electrolyte secondary battery 1 charged in this way is plotted with respect to the current value after plotting the voltage value after 10 seconds of pulse discharge at each current value of 6 to 160 mA. A straight line was obtained, and the slope was calculated as the output DCR.
  • a decrease in potential due to insertion of lithium into the negative electrode active material constituting the negative electrode 12 is defined as charging, and a rise in potential due to lithium desorption from the negative electrode active material is defined as discharge.
  • Example 1 As a negative electrode active material, a mixture of a surface-amorphized GC and a soft carbon whose surface is not amorphized (hereinafter referred to as SC without surface modification) is used. A nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that SC was mixed at a mass ratio of 80:20 to produce a negative electrode active material. With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 2 (Comparative Example 2) Using a mixture of surface amorphized GC and hard carbon (hereinafter referred to as HC) as a negative electrode active material, the surface amorphized GC and HC are mixed at a mass ratio of 80:20 to obtain a negative electrode active material.
  • a nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that it was produced. With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 3 Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 100: 0, that is, the negative electrode active material was produced using only the surface amorphized GC.
  • a nonaqueous electrolyte secondary battery 1 was produced in the same manner as described above. In order to make the battery capacity the same as that of the nonaqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 2 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 98: 2 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 3 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 97: 3 to prepare a negative electrode active material. Produced.
  • the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 .
  • the output DCR was calculated in the same manner as in Example 1.
  • Example 4 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 95: 5 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 5 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 90:10 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.2 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 6 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 60:40 to produce a negative electrode active material. Produced.
  • the basis weight of the negative electrode mixture per unit area was 5.9 mg / cm 2 and the packing density was 1.30 g. / Cm 3 .
  • the output DCR was calculated in the same manner as in Example 1.
  • Example 7 The non-aqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 50:50 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 6.1 mg / cm 2 and the packing density was 1.30 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
  • Example 8 The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 30:70 to produce a negative electrode active material. Produced.
  • the basis weight of the negative electrode mixture per unit area was 6.7 mg / cm 2 and the packing density was 1.20 g. / Cm 3 .
  • the output DCR was calculated in the same manner as in Example 1.
  • Table 1 shows the output DCRs of Example 1 and Comparative Examples 1 and 2 calculated as described above, and Table 2 shows the output DCRs of Comparative Example 3 and Examples 2 to 8.
  • the filling density of the negative electrode mixture was varied to produce the non-aqueous electrolyte secondary battery of the example.
  • Example 9 (Preparation of negative electrode) A negative electrode active material composed of a mixture of surface amorphized GC and surface amorphized SC and polyvinylidene fluoride as a binder were blended at a mass ratio of 95: 5, and N-methyl- A negative electrode mixture slurry was prepared by kneading with 2-pyrrolidone. At this time, the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 85:15 to prepare a negative electrode active material. This negative electrode mixture slurry was applied onto both sides of a copper foil as a negative electrode current collector, dried, and then rolled with a rolling roller to adjust the packing density of the negative electrode mixture to produce a negative electrode. The weight per unit area of the negative electrode mixture per unit area at this time was 5.0 mg / cm 2 and the packing density was 1.0 g / cm 3 .
  • a positive electrode active material composed of lithium iron phosphate represented by LiFePO 4 , a carbon material as a conductive agent, and polyvinylidene fluoride as a binder were blended in a mass ratio of 88: 6: 6,
  • a positive electrode mixture slurry was prepared by kneading with N-methyl-2-pyrrolidone. This positive electrode mixture slurry was applied onto both surfaces of an aluminum foil as a positive electrode current collector, dried, and then rolled with a rolling roller to adjust the packing density of the positive electrode mixture to produce a positive electrode.
  • the weight per unit area of the positive electrode mixture per unit area at this time was 9.5 mg / cm 2 , and the packing density was 1.85 g / cm 3 .
  • non-aqueous electrolyte As a non-aqueous solvent, ethylene carbonate as a cyclic carbonate, ethyl methyl carbonate as a chain carbonate, and dimethyl carbonate as a chain carbonate were mixed at a volume ratio of 1: 1: 1, and vinylene carbonate was changed to 0. Using 0.5 mass% and 0.5 mass% lithium difluorobis (oxalato) phosphate added, LiPF 6 as a supporting electrolyte was dissolved in this mixed solvent to a concentration of 1 mol / L, A non-aqueous electrolyte was prepared.
  • the obtained nonaqueous electrolyte secondary battery was subjected to constant current and constant voltage charging with a current value of 60 mA and an upper limit voltage of 3.8 V and a charging time of 10 hours, and then a voltage value of 2 at a current value of 60 mA.
  • the battery was discharged at a constant current until it reached 5V. After that, from a constant current and constant voltage charge with a current value of 300 mA and an upper limit voltage of 3.8 V, a stop current value of 6.0 mA, and a constant current discharge until the voltage value becomes 2.5 V with a current value of 300 mA.
  • the stabilization cycle was repeated three times. In this way, a non-aqueous electrolyte secondary battery having a capacity of about 310 mAh was produced.
  • Example 10 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.1 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 11 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.2 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 12 A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the packing density of the negative electrode mixture was 1.3 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 13 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.4 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 14 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.5 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 15 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.6 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Example 16 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.7 g / cm 3 .
  • the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
  • Table 3 shows the capacity retention rates of Examples 9 to 16 calculated as described above and the rate of change in AC resistance value before and after storage.
  • the negative electrode containing the negative electrode active material of the present invention it is possible to provide a non-aqueous electrolyte secondary battery capable of improving the output characteristics of the battery.
  • 1 nonaqueous electrolyte secondary battery
  • 10 battery element
  • 11 positive electrode
  • 12 negative electrode
  • 13 separator
  • 20 outer packaging material

Abstract

Provided are: a negative electrode active material which is capable of improving the output characteristics of a battery; a negative electrode which contains the negative electrode active material; and a nonaqueous electrolyte secondary battery which is provided with the negative electrode. A battery element (10) of a nonaqueous electrolyte secondary battery is provided with a positive electrode (11) that contains a positive electrode active material and a negative electrode (12) that contains a negative electrode active material. The negative electrode active material contains graphite and soft carbon the surface of which is amorphized.

Description

負極活物質、負極および非水電解液二次電池Negative electrode active material, negative electrode and non-aqueous electrolyte secondary battery
　本発明は、一般的には負極活物質、負極および非水電解液二次電池に関し、特定的には、炭素材料を含む負極活物質、その負極活物質を含む負極、その負極を備えた非水電解液二次電池に関するものである。 The present invention generally relates to a negative electrode active material, a negative electrode, and a non-aqueous electrolyte secondary battery, and more specifically, a negative electrode active material including a carbon material, a negative electrode including the negative electrode active material, and a non-electrode including the negative electrode The present invention relates to a water electrolyte secondary battery.
　携帯電話、ノートパソコン、デジタルカメラ等の携帯用電子機器の市場拡大に伴い、これら電子機器のコードレス電源としてエネルギー密度が大きく長寿命の二次電池が待望されている。そして、このような要求に応えるために、リチウムイオン等のアルカリ金属イオンを荷電担体とし、その電荷授受に伴う電気化学反応を利用した二次電池が開発されている。その中でも、エネルギー密度の大きなリチウムイオン二次電池は広く普及している。 With the expansion of the market for portable electronic devices such as mobile phones, notebook computers, and digital cameras, secondary batteries with high energy density and long life are expected as cordless power sources for these electronic devices. In order to meet such demands, secondary batteries have been developed that use an alkali metal ion such as lithium ion as a charge carrier and use an electrochemical reaction associated with charge exchange. Among them, lithium ion secondary batteries having a large energy density are widely used.
　上記のリチウムイオン二次電池では、負極活物質として、従来から、リチウムイオンを吸蔵・放出可能な炭素材料が使用されている。たとえば、特開２００１‐５７２３０号公報（以下、特許文献１という）には、負極活物質としてグラファイト、ソフトカーボンまたはハードカーボンを用いることが記載されている。近年、電池性能を向上させるために負極活物質の材料について研究が盛んに行われている。 In the above lithium ion secondary battery, a carbon material that can occlude / release lithium ions has been conventionally used as the negative electrode active material. For example, JP 2001-57230 A (hereinafter referred to as Patent Document 1) describes using graphite, soft carbon, or hard carbon as the negative electrode active material. In recent years, in order to improve battery performance, active research has been conducted on materials for negative electrode active materials.
特開２００１‐５７２３０号公報JP 2001-57230 A
　特許文献１に記載されているグラファイトを負極活物質として選択して用いた場合、グラファイト粒子が非常につぶれやすいため、電解液を保持するための活物質間の空隙が小さくなるという問題がある。このため、出力時の直流抵抗（以下、出力ＤＣＲという）が高くなり、電池の出力特性が低下する。 When graphite described in Patent Document 1 is selected and used as the negative electrode active material, the graphite particles are very easily crushed, and there is a problem that the gap between the active materials for holding the electrolytic solution is reduced. For this reason, the direct current resistance at the time of output (hereinafter referred to as output DCR) increases, and the output characteristics of the battery deteriorate.
　一方、特許文献１に記載されているソフトカーボンまたはハードカーボンを負極活物質として選択して用いた場合、負極容量の低下と不可逆容量の増加により、電池として十分な容量が得られないという問題がある。この場合も、結果として電池の出力特性が低下する。 On the other hand, when soft carbon or hard carbon described in Patent Document 1 is selected and used as a negative electrode active material, there is a problem that sufficient capacity as a battery cannot be obtained due to a decrease in negative electrode capacity and an increase in irreversible capacity. is there. Also in this case, the output characteristics of the battery are deteriorated as a result.
　そこで、本発明の目的は、電池の出力特性を向上させることが可能な負極活物質、その負極活物質を含む負極、その負極を備えた非水電解液二次電池を提供することである。 Accordingly, an object of the present invention is to provide a negative electrode active material capable of improving the output characteristics of the battery, a negative electrode including the negative electrode active material, and a nonaqueous electrolyte secondary battery including the negative electrode.
　本発明に従った負極活物質は、グラファイトと、表面非晶質化ソフトカーボンとを含む。 The negative electrode active material according to the present invention includes graphite and surface-amorphized soft carbon.
　本発明の負極活物質は、グラファイトと表面非晶質化ソフトカーボンを９５：５～３０：７０の質量比で含むことが好ましい。 The negative electrode active material of the present invention preferably contains graphite and surface amorphized soft carbon in a mass ratio of 95: 5 to 30:70.
　また、本発明の負極活物質において、グラファイトが表面非晶質化グラファイトを含むことが好ましい。 Further, in the negative electrode active material of the present invention, it is preferable that the graphite contains surface-amorphized graphite.
　本発明に従った負極は、上述の特徴を有する負極活物質を含む。 The negative electrode according to the present invention includes a negative electrode active material having the characteristics described above.
　本発明の負極において、負極合材の充填密度が１．２ｇ／ｃｍ3以上１．５ｇ／ｃｍ3以下であることが好ましい。 In the negative electrode of the present invention, the filling density of the negative electrode mixture is preferably 1.2 g / cm 3 or more and 1.5 g / cm 3 or less.
　本発明に従った非水電解液二次電池は、上記の負極を備える。 A non-aqueous electrolyte secondary battery according to the present invention includes the above negative electrode.
　本発明の負極活物質を含む負極を備えた非水電解液二次電池では、電池の出力ＤＣＲを低下させることができるので、電池の出力特性を向上させることができる。 In the non-aqueous electrolyte secondary battery including the negative electrode containing the negative electrode active material of the present invention, the output DCR of the battery can be reduced, so that the output characteristics of the battery can be improved.
この発明の実施例で作製された非水電解液二次電池の内部構成を分解して概略的に示す正面図である。It is a front view which decomposes | disassembles and shows schematically the internal structure of the nonaqueous electrolyte secondary battery produced in the Example of this invention. この発明の実施例で作製された非水電解液二次電池の外観を概略的に示す正面図である。It is a front view which shows roughly the external appearance of the nonaqueous electrolyte secondary battery produced in the Example of this invention.
　本発明者は、負極活物質として種々の炭素材料を用いて検討を重ねた。その結果、負極活物質がグラファイトと表面非晶質化ソフトカーボンとを含むと、電池の出力ＤＣＲを低下させることができることを見出した。このような本発明者の知見に基づいて本発明はなされたものである。 The present inventor has repeatedly studied using various carbon materials as the negative electrode active material. As a result, it has been found that when the negative electrode active material contains graphite and surface amorphized soft carbon, the output DCR of the battery can be reduced. The present invention has been made based on such knowledge of the present inventor.
　グラファイト粒子は非常につぶれやすいため、電解液を保持するための活物質間の空隙が小さくなる。しかし、グラファイトよりも硬い材料であるソフトカーボンをグラファイトと混合すると、ソフトカーボン粒子がつぶれずにグラファイト粒子間に空隙を形成できる。このため、グラファイトとソフトカーボンの混合物を負極活物質に用いると、電解液に接する活物質の反応界面が増加する。さらに、表面非晶質化ソフトカーボンを使用することにより、ソフトカーボンの表面におけるリチウムイオンの脱離の速度を促進させることができる。なお、表面非晶質化ソフトカーボンの粒子は、非晶質のソフトカーボンからなる内部層と、その内部層の表面上に形成され、内部層のソフトカーボンよりもさらに非晶質化された表面層とから構成される。なお、このような構成の表面非晶質化ソフトカーボンの粒子は、例えば、非晶質の内部層となるソフトカーボン粒子表面に、この内部層より非晶質なソフトカーボンをコーティングして形成される。これらの作用により、負極活物質がグラファイトと表面非晶質化ソフトカーボンとを含むことによって、その負極活物質を含む負極を備えた非水電解液二次電池では、電池の出力ＤＣＲを低下させることができ、電池の出力特性を向上させることができる。 Since graphite particles are very crushed, voids between active materials for holding the electrolyte are reduced. However, when soft carbon, which is a material harder than graphite, is mixed with graphite, voids can be formed between the graphite particles without collapsing the soft carbon particles. For this reason, when a mixture of graphite and soft carbon is used for the negative electrode active material, the reaction interface of the active material in contact with the electrolyte increases. Furthermore, the use of surface-amorphized soft carbon can accelerate the rate of lithium ion desorption on the surface of the soft carbon. The particles of the surface-amorphized soft carbon are an inner layer made of amorphous soft carbon and a surface formed on the surface of the inner layer and made more amorphous than the soft carbon of the inner layer. Composed of layers. The surface-amorphized soft carbon particles having such a structure are formed, for example, by coating the surface of the soft carbon particles that become an amorphous inner layer with amorphous carbon from the inner layer. The By these actions, the negative electrode active material contains graphite and surface-amorphized soft carbon, so that the non-aqueous electrolyte secondary battery including the negative electrode containing the negative electrode active material reduces the output DCR of the battery. And the output characteristics of the battery can be improved.
　また、負極活物質がグラファイトと表面非晶質化ソフトカーボンを９５：５～３０：７０の質量比で含むことにより、電池の出力ＤＣＲをより効果的に低下させることができ、電池の出力特性をさらに向上させることができる。ソフトカーボンの質量比率を７０％より大きくすると、電池の出力ＤＣＲが増大する。また、負極容量の低下と不可逆容量の増加により電池としての容量が小さくなるので好ましくない。 In addition, when the negative electrode active material contains graphite and surface amorphized soft carbon in a mass ratio of 95: 5 to 30:70, the output DCR of the battery can be more effectively reduced, and the output characteristics of the battery can be reduced. Can be further improved. When the mass ratio of soft carbon is larger than 70%, the output DCR of the battery increases. Moreover, since the capacity | capacitance as a battery becomes small by the fall of a negative electrode capacity | capacitance and the increase of an irreversible capacity | capacitance, it is not preferable.
　上記のグラファイトが表面非晶質化グラファイトを含むことにより、電池の出力ＤＣＲをさらに低下させることができ、電池の出力特性をさらに向上させることができる。 When the above graphite contains surface-amorphized graphite, the output DCR of the battery can be further reduced, and the output characteristics of the battery can be further improved.
　本発明の一つの実施の形態では、非水電解液二次電池の正極と負極とは、セパレータを介して交互に積層されて配置されている。電池要素の構造は、複数の短冊状の正極、複数の短冊状のセパレータおよび複数の短冊状の負極の積層体、いわゆる枚葉構造の積層体から構成されてもよく、長尺状のセパレータを九十九折りして、短冊状の正極と短冊状の負極とを交互に介在させることによって構成してもよい。また、電池要素の構造として、長尺状の正極、長尺状のセパレータおよび長尺状の負極を巻回してなる巻回型構造を採用してもよい。以下の実施例では、電池要素の構造として枚葉構造の積層体、を採用している。 In one embodiment of the present invention, the positive electrode and the negative electrode of the non-aqueous electrolyte secondary battery are alternately stacked via a separator. The structure of the battery element may be composed of a stack of a plurality of strip-shaped positive electrodes, a plurality of strip-shaped separators and a plurality of strip-shaped negative electrodes, a stack of so-called single-wafer structures. It may be configured by folding and interposing a strip-shaped positive electrode and a strip-shaped negative electrode alternately. Moreover, as a structure of the battery element, a winding type structure in which a long positive electrode, a long separator, and a long negative electrode are wound may be employed. In the following examples, a single-wafer laminated body is adopted as the battery element structure.
　正極は、正極集電体の両面に正極活物質と導電剤と結着剤とを含む正極合材層が形成されている。一例として、正極集電体はアルミニウムまたは銅からなる。正極活物質は、コバルト酸リチウム複合酸化物、マンガン酸リチウム複合酸化物、ニッケル酸リチウム複合酸化物、リチウム‐ニッケル‐マンガン‐コバルト複合酸化物、リチウム‐マンガン‐ニッケル複合酸化物、リチウム‐マンガン‐コバルト複合酸化物、リチウム‐ニッケル‐コバルト複合酸化物等を用いることができる。さらに、正極活物質は、上記の材料を混合したものでもよい。正極活物質は、ＬｉＦｅＰＯ4で表わされるリン酸鉄リチウム等のオリビン型構造を有するリチウム含有リン酸化合物でもよい。オリビン型構造を有しているのであれば、ＬｉＦｅＰＯ4で表わされるリン酸鉄リチウムにおいて、Ｆｅの一部をＡｌ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｃｏ、Ｎｉ、Ｚｒ、Ｎｂ等で置換してもよい。また、Ｐの一部をＢ、Ｓｉ等で置換してもよい。正極の導電剤としては、アセチレンブラック等の炭素材料が用いられる。正極活物質と導電剤を結着させるための結着剤としては、ポリフッ化ビニリデン（ＰＶＤＦ）またはポリアミドイミド（ＰＡＩ）が用いられる。 In the positive electrode, a positive electrode mixture layer including a positive electrode active material, a conductive agent, and a binder is formed on both surfaces of the positive electrode current collector. As an example, the positive electrode current collector is made of aluminum or copper. The positive electrode active material is lithium cobalt oxide composite oxide, lithium manganate composite oxide, lithium nickelate composite oxide, lithium-nickel-manganese-cobalt composite oxide, lithium-manganese-nickel composite oxide, lithium-manganese- A cobalt composite oxide, a lithium-nickel-cobalt composite oxide, or the like can be used. Further, the positive electrode active material may be a mixture of the above materials. The positive electrode active material may be a lithium-containing phosphate compound having an olivine type structure such as lithium iron phosphate represented by LiFePO 4 . If it has an olivine type structure, in the lithium iron phosphate represented by LiFePO 4 , a part of Fe is replaced with Al, Ti, V, Cr, Mn, Co, Ni, Zr, Nb, etc. Also good. A part of P may be replaced with B, Si, or the like. A carbon material such as acetylene black is used as the conductive agent for the positive electrode. Polyvinylidene fluoride (PVDF) or polyamideimide (PAI) is used as the binder for binding the positive electrode active material and the conductive agent.
　一方、負極は、負極集電体の両面に上記の負極活物質（グラファイトおよび表面非晶質化ソフトカーボン）と結着剤とを含む負極合材層が形成されている。一例として、負極集電体は銅からなる。負極活物質を結着させるための結着剤としては、ポリフッ化ビニリデン、ポリアクリロニトリルまたはポリアミドイミドが用いられ、あるいは、スチレンブタジエンラバー等のラテックスバインダーとカルボキシメチルセルロース等の増粘剤の混合物が用いられる。 On the other hand, in the negative electrode, a negative electrode mixture layer containing the negative electrode active material (graphite and surface-amorphized soft carbon) and a binder is formed on both surfaces of the negative electrode current collector. As an example, the negative electrode current collector is made of copper. As the binder for binding the negative electrode active material, polyvinylidene fluoride, polyacrylonitrile or polyamideimide is used, or a mixture of a latex binder such as styrene butadiene rubber and a thickener such as carboxymethyl cellulose is used. .
　負極における負極合材の充填密度が１．２ｇ／ｃｍ3以上１．５ｇ／ｃｍ3以下であることが好ましい。負極合材の充填密度が上記の範囲内の場合、電池の容量維持率を高くすることができ、かつ、交流抵抗増加率を低くすることができる。 The filling density of the negative electrode mixture in the negative electrode is preferably 1.2 g / cm 3 or more and 1.5 g / cm 3 or less. When the filling density of the negative electrode mixture is within the above range, the capacity retention rate of the battery can be increased, and the AC resistance increase rate can be decreased.
　非水電解液は、支持電解質を非水溶媒に溶解して調製される。支持電解質としては、たとえば、非水溶媒中にＬｉＰＦ6を１．０ｍｏｌ／Ｌの濃度で溶解したものが使用される。ＬｉＰＦ6以外の支持電解質としては、ＬｉＢＦ4、ＬｉＡｓＦ6、ＬｉＣｌＯ4、ＬｉＣＦ3ＳＯ3、ＬｉＮ（ＳＯ2ＣＦ3）2、ＬｉＣ（ＳＯ2ＣＦ3）3、ＬｉＡｌＣｌ4、ＬｉＳｉＦ6等のリチウム塩を挙げることができる。これらの中でも、支持電解質として特にＬｉＰＦ6、ＬｉＢＦ4を用いることが酸化安定性の点から望ましい。このような支持電解質は、非水溶媒中に、０．１ｍｏｌ／Ｌ～３．０ｍｏｌ／Ｌの濃度で溶解されて用いられることが好ましく、０．５ｍｏｌ／Ｌ～２．０ｍｏｌ／Ｌの濃度で溶解されて用いられることがさらに好ましい。上記の非水溶媒としては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）等の環状炭酸エステルに、低粘性溶媒であるジメチルカーボネート（ＤＭＣ）、エチルメチルカーボネート（ＥＭＣ）、ジエチルカーボネート（ＤＥＣ）等の低級鎖状炭酸エステルを加えたものが用いられる。 The nonaqueous electrolytic solution is prepared by dissolving the supporting electrolyte in a nonaqueous solvent. As the supporting electrolyte, for example, a solution obtained by dissolving LiPF 6 at a concentration of 1.0 mol / L in a non-aqueous solvent is used. Examples of supporting electrolytes other than LiPF 6 include lithium salts such as LiBF 4 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiC (SO 2 CF 3 ) 3 , LiAlCl 4 , and LiSiF 6. Can be mentioned. Among these, LiPF 6 and LiBF 4 are particularly preferably used as the supporting electrolyte from the viewpoint of oxidation stability. Such a supporting electrolyte is preferably used by being dissolved in a nonaqueous solvent at a concentration of 0.1 mol / L to 3.0 mol / L, and at a concentration of 0.5 mol / L to 2.0 mol / L. More preferably, it is used after being dissolved. Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate (EC) and propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), which are low viscosity solvents. And a lower chain carbonate of the above are used.
　セパレータとしては、特に限定されるべきものではなく、従来から公知のものを用いることができる。なお、本発明においては、セパレータは、その名称によって限定されるべきものではなく、セパレータの代わりにセパレータとしての機能（役割）を有するような固体電解質またはゲル状電解質を用いてもよい。また、アルミナ、ジルコニア等の無機材料を含有させたセパレータを用いてもよい。たとえば、セパレータは、ポリプロピレンおよび／またはポリエチレンを含む多孔質フィルムを用いる。 The separator is not particularly limited, and a conventionally known separator can be used. In the present invention, the separator is not limited by its name, and a solid electrolyte or gel electrolyte having a function (role) as a separator may be used instead of the separator. Alternatively, a separator containing an inorganic material such as alumina or zirconia may be used. For example, the separator uses a porous film containing polypropylene and / or polyethylene.
　次に、本発明の実施例を具体的に説明する。なお、以下に示す実施例は一例であり、本発明は下記の実施例に限定されるものではない。 Next, specific examples of the present invention will be described. In addition, the Example shown below is an example and this invention is not limited to the following Example.
　以下のようにして作製した正極と負極と非水電解液とを用いて、負極活物質の構成を異ならせることにより、実施例と比較例の非水電解液二次電池を作製した。 Using the positive electrode, the negative electrode, and the non-aqueous electrolyte prepared as described below, the configurations of the negative electrode active materials were varied to prepare the non-aqueous electrolyte secondary batteries of Examples and Comparative Examples.
　（実施例１）
　（負極の作製）
　表面非晶質化グラファイト（以下、表面非晶質化ＧＣという）と表面非晶質化ソフトカーボン（以下、表面非晶質化ＳＣという）の混合物からなる負極活物質と、結着剤としてのポリフッ化ビニリデンとを質量比率で９５：５になるように配合して、Ｎ‐メチル‐２‐ピロリドンと混練することにより、負極合材スラリーを作製した。この際、表面非晶質化ＧＣと表面非晶質化ＳＣを８０：２０の質量比率で混合して負極活物質を作製した。この負極合材スラリーを、負極集電体としての銅箔の片面上に塗布し、乾燥させた後、圧延ローラーにより圧延して負極を作製した。このときの単位面積あたりの負極合材の目付け量を５．４ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。 Example 1
(Preparation of negative electrode)
A negative electrode active material comprising a mixture of surface amorphized graphite (hereinafter referred to as surface amorphized GC) and surface amorphized soft carbon (hereinafter referred to as surface amorphized SC), and a binder Polyvinylidene fluoride was blended at a mass ratio of 95: 5 and kneaded with N-methyl-2-pyrrolidone to prepare a negative electrode mixture slurry. At this time, the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 80:20 to prepare a negative electrode active material. After apply | coating this negative electrode compound-material slurry on the single side | surface of copper foil as a negative electrode electrical power collector and making it dry, it rolled with the rolling roller and produced the negative electrode. At this time, the basis weight of the negative electrode mixture per unit area was 5.4 mg / cm 2 and the packing density was 1.40 g / cm 3 .
　（正極の作製）
　金属リチウム箔を、正極集電体としての銅箔の両面上に圧着させて正極を作製した。 (Preparation of positive electrode)
A metal lithium foil was pressed on both sides of a copper foil as a positive electrode current collector to produce a positive electrode.
　（非水電解液の作製）
　非水溶媒として、環状カーボネートであるエチレンカーボネートと、鎖状カーボネートであるジエチルカーボネートを３：７の体積比率で混合した混合溶媒を用い、この混合溶媒に支持電解質としてのＬｉＰＦ6を１ｍｏｌ／Ｌの濃度になるように溶解させて、非水電解液を作製した。 (Preparation of non-aqueous electrolyte)
As non-aqueous solvent, ethylene carbonate is a cyclic carbonate, diethyl carbonate a chain carbonate 3: with 7 mixed solvent were mixed at a volume ratio of the LiPF 6 as a supporting electrolyte 1 mol / L in the mixed solvent It was made to melt | dissolve so that it might become a density | concentration, and the nonaqueous electrolyte solution was produced.
　（電池の作製）
　図１に示すように、上記で作製した正極１１と負極１２にリードタブ１４、１５を設けた。この正極１１と負極１２の間に、リチウムイオン透過性のポリプロピレン製微多孔膜からなるセパレータ１３を介在させて積層した。このようにして電池要素１０を作製した。リードタブ１４、１５にはシーラント１６、１７を取り付けて、図２に示すように、上記の積層体を、アルミニウムを中間層として含むラミネートフィルムからなる外包材２０の内部に収納した。その後、上記で作製した非水電解液を外包材２０の内部に注入した後、外包材２０の開口部を封止することにより、非水電解液二次電池１を作製した。 (Production of battery)
As shown in FIG. 1, lead tabs 14 and 15 were provided on the positive electrode 11 and the negative electrode 12 produced as described above. The positive electrode 11 and the negative electrode 12 were laminated with a separator 13 made of a polypropylene microporous membrane permeable to lithium ions. Thus, the battery element 10 was produced. Sealants 16 and 17 were attached to the lead tabs 14 and 15, and as shown in FIG. 2, the laminate was housed in an outer packaging material 20 made of a laminate film containing aluminum as an intermediate layer. Then, after pouring the non-aqueous electrolyte produced above into the outer packaging material 20, the non-aqueous electrolyte secondary battery 1 was produced by sealing the opening of the outer packaging material 20.
　（電池の評価）
　得られた非水電解液二次電池１に、６ｍＡの電流値で０．２Ｖの電圧まで定電流充電した後、０．２Ｖの電圧値で電流値が０．６ｍＡになるまで定電圧充電した。このようにして充電された非水電解液二次電池１を、６～１６０ｍＡの各電流値での１０秒間のパルス放電後の電圧値を電流値に対してプロットして、電流‐電圧の近似直線を求め、その傾きを出力ＤＣＲとして算出した。 (Battery evaluation)
The obtained nonaqueous electrolyte secondary battery 1 was charged at a constant current up to a voltage of 0.2 V at a current value of 6 mA, and then charged at a constant voltage until the current value became 0.6 mA at a voltage value of 0.2 V. . The non-aqueous electrolyte secondary battery 1 charged in this way is plotted with respect to the current value after plotting the voltage value after 10 seconds of pulse discharge at each current value of 6 to 160 mA. A straight line was obtained, and the slope was calculated as the output DCR.
　なお、上記の電池の評価では、負極１２を構成する負極活物質へのリチウム挿入によって電位が下降することを充電、負極活物質からのリチウム脱離によって電位が上昇することを放電と定義する。 In the evaluation of the battery described above, a decrease in potential due to insertion of lithium into the negative electrode active material constituting the negative electrode 12 is defined as charging, and a rise in potential due to lithium desorption from the negative electrode active material is defined as discharge.
　（比較例１）
　負極活物質として、表面非晶質化ＧＣと、表面を非晶質化していないソフトカーボン（以下、表面改質無ＳＣという）の混合物を用いて、表面非晶質化ＧＣと表面改質無ＳＣを８０：２０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Comparative Example 1)
As a negative electrode active material, a mixture of a surface-amorphized GC and a soft carbon whose surface is not amorphized (hereinafter referred to as SC without surface modification) is used. A nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that SC was mixed at a mass ratio of 80:20 to produce a negative electrode active material. With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（比較例２）
　負極活物質として、表面非晶質化ＧＣと、ハードカーボン（以下、ＨＣという）の混合物を用いて、表面非晶質化ＧＣとＨＣを８０：２０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Comparative Example 2)
Using a mixture of surface amorphized GC and hard carbon (hereinafter referred to as HC) as a negative electrode active material, the surface amorphized GC and HC are mixed at a mass ratio of 80:20 to obtain a negative electrode active material. A nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that it was produced. With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（比較例３）
　表面非晶質化ＧＣと表面非晶質化ＳＣを１００：０の質量比率で混合して、すなわち、表面非晶質化ＧＣのみを用いて負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．０ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Comparative Example 3)
Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 100: 0, that is, the negative electrode active material was produced using only the surface amorphized GC. A nonaqueous electrolyte secondary battery 1 was produced in the same manner as described above. In order to make the battery capacity the same as that of the nonaqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例２）
　表面非晶質化ＧＣと表面非晶質化ＳＣを９８：２の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．０ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 2)
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 98: 2 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例３）
　表面非晶質化ＧＣと表面非晶質化ＳＣを９７：３の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．０ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 3)
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 97: 3 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例４）
　表面非晶質化ＧＣと表面非晶質化ＳＣを９５：５の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．０ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 Example 4
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 95: 5 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.0 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例５）
　表面非晶質化ＧＣと表面非晶質化ＳＣを９０：１０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．２ｍｇ／ｃｍ2、充填密度を１．４０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 5)
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 90:10 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 5.2 mg / cm 2 and the packing density was 1.40 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例６）
　表面非晶質化ＧＣと表面非晶質化ＳＣを６０：４０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を５．９ｍｇ／ｃｍ2、充填密度を１．３０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 6)
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 60:40 to produce a negative electrode active material. Produced. In addition, in order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 manufactured in Example 1, the basis weight of the negative electrode mixture per unit area was 5.9 mg / cm 2 and the packing density was 1.30 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例７）
　表面非晶質化ＧＣと表面非晶質化ＳＣを５０：５０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を６．１ｍｇ／ｃｍ2、充填密度を１．３０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 7)
The non-aqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 50:50 to prepare a negative electrode active material. Produced. In order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 produced in Example 1, the basis weight of the negative electrode mixture per unit area was 6.1 mg / cm 2 and the packing density was 1.30 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　（実施例８）
　表面非晶質化ＧＣと表面非晶質化ＳＣを３０：７０の質量比率で混合して負極活物質を作製したこと以外は、実施例１と同様にして非水電解液二次電池１を作製した。なお、実施例１で作製された非水電解液二次電池１と電池容量を同じにするために単位面積あたりの負極合材の目付け量を６．７ｍｇ／ｃｍ2、充填密度を１．２０ｇ／ｃｍ3とした。得られた非水電解液二次電池１について、実施例１と同様にして出力ＤＣＲを算出した。 (Example 8)
The nonaqueous electrolyte secondary battery 1 was manufactured in the same manner as in Example 1 except that the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 30:70 to produce a negative electrode active material. Produced. In addition, in order to make the battery capacity the same as that of the non-aqueous electrolyte secondary battery 1 manufactured in Example 1, the basis weight of the negative electrode mixture per unit area was 6.7 mg / cm 2 and the packing density was 1.20 g. / Cm 3 . With respect to the obtained nonaqueous electrolyte secondary battery 1, the output DCR was calculated in the same manner as in Example 1.
　以上のようにして算出された実施例１と比較例１、２の出力ＤＣＲを表１に示し、比較例３と実施例２～８の出力ＤＣＲを表２に示す。 Table 1 shows the output DCRs of Example 1 and Comparative Examples 1 and 2 calculated as described above, and Table 2 shows the output DCRs of Comparative Example 3 and Examples 2 to 8.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１と表２から、表面非晶質化ＧＣに表面非晶質化ＳＣを混合した混合物の負極活物質を用いた実施例１～８では、表面非晶質化ＧＣに表面改質無ＳＣを混合した混合物の負極活物質を用いた比較例１、表面非晶質化ＧＣにＨＣを混合した混合物の負極活物質を用いた比較例２、および、表面非晶質化ＧＣのみからなる負極活物質を用いた比較例３に比べて、出力ＤＣＲが低く、電池の出力特性を向上させることができることがわかる。 From Tables 1 and 2, in Examples 1 to 8 using the negative electrode active material of the mixture of the surface amorphized GC and the surface amorphized SC, the surface amorphized GC was not subjected to surface modification. Comparative Example 1 using a negative electrode active material of a mixture in which HC was mixed, Comparative Example 2 using a negative electrode active material of a mixture of HC in a surface-amorphized GC, and a negative electrode comprising only a surface-amorphized GC It can be seen that the output DCR is lower than that of Comparative Example 3 using the active material, and the output characteristics of the battery can be improved.
　また、表１と表２から、表面非晶質化ＧＣと表面非晶質化ＳＣを９５：５～３０：７０の質量比率で混合した混合物の負極活物質を用いた実施例１、４～８では、出力ＤＣＲがさらに低く、電池の出力特性をさらに向上させることができることがわかる。 Also, from Tables 1 and 2, Examples 1, 4 to 4 using negative electrode active materials in a mixture in which surface amorphized GC and surface amorphized SC were mixed at a mass ratio of 95: 5 to 30:70. 8 shows that the output DCR is even lower, and the output characteristics of the battery can be further improved.
　次に、以下のようにして作製した正極と負極と非水電解液とを用いて、負極合材の充填密度を異ならせることにより、実施例の非水電解液二次電池を作製した。 Next, using the positive electrode, the negative electrode, and the non-aqueous electrolyte produced as follows, the filling density of the negative electrode mixture was varied to produce the non-aqueous electrolyte secondary battery of the example.
　（実施例９）
　（負極の作製）
　表面非晶質化ＧＣと表面非晶質化ＳＣの混合物からなる負極活物質と、結着剤としてのポリフッ化ビニリデンとを質量比率で９５：５になるように配合して、Ｎ‐メチル‐２‐ピロリドンと混練することにより、負極合材スラリーを作製した。この際、表面非晶質化ＧＣと表面非晶質化ＳＣを８５：１５の質量比率で混合して負極活物質を作製した。この負極合材スラリーを、負極集電体としての銅箔の両面上に塗布し、乾燥させた後、圧延ローラーにより圧延し、負極合材の充填密度を調整して負極を作製した。このときの単位面積あたりの負極合材の片面あたりの目付け量を５．０ｍｇ／ｃｍ2、充填密度を１．０ｇ／ｃｍ3とした。 Example 9
(Preparation of negative electrode)
A negative electrode active material composed of a mixture of surface amorphized GC and surface amorphized SC and polyvinylidene fluoride as a binder were blended at a mass ratio of 95: 5, and N-methyl- A negative electrode mixture slurry was prepared by kneading with 2-pyrrolidone. At this time, the surface amorphized GC and the surface amorphized SC were mixed at a mass ratio of 85:15 to prepare a negative electrode active material. This negative electrode mixture slurry was applied onto both sides of a copper foil as a negative electrode current collector, dried, and then rolled with a rolling roller to adjust the packing density of the negative electrode mixture to produce a negative electrode. The weight per unit area of the negative electrode mixture per unit area at this time was 5.0 mg / cm 2 and the packing density was 1.0 g / cm 3 .
　（正極の作製）
　ＬｉＦｅＰＯ4で表わされるリン酸鉄リチウムからなる正極活物質と、導電剤としての炭素材料と、結着剤としてのポリフッ化ビニリデンとを質量比率で８８：６：６になるように配合して、Ｎ‐メチル‐２‐ピロリドンと混練することにより、正極合材スラリーを作製した。この正極合材スラリーを、正極集電体としてのアルミニウム箔の両面上に塗布し、乾燥させた後、圧延ローラーにより圧延し、正極合材の充填密度を調整して正極を作製した。このときの単位面積あたりの正極合材の片面あたりの目付け量を９．５ｍｇ／ｃｍ2、充填密度を１．８５ｇ／ｃｍ3とした。 (Preparation of positive electrode)
A positive electrode active material composed of lithium iron phosphate represented by LiFePO 4 , a carbon material as a conductive agent, and polyvinylidene fluoride as a binder were blended in a mass ratio of 88: 6: 6, A positive electrode mixture slurry was prepared by kneading with N-methyl-2-pyrrolidone. This positive electrode mixture slurry was applied onto both surfaces of an aluminum foil as a positive electrode current collector, dried, and then rolled with a rolling roller to adjust the packing density of the positive electrode mixture to produce a positive electrode. The weight per unit area of the positive electrode mixture per unit area at this time was 9.5 mg / cm 2 , and the packing density was 1.85 g / cm 3 .
　（非水電解液の作製）
　非水溶媒として、環状カーボネートであるエチレンカーボネートと、鎖状カーボネートであるエチルメチルカーボネートと、鎖状カーボネートであるジメチルカーボネートを１：１：１の体積比率で混合した混合溶媒に、ビニレンカーボネートを０．５質量％、ジフルオロビス（オキサラト）リン酸リチウムを０．５質量％、添加したものを用い、この混合溶媒に支持電解質としてのＬｉＰＦ6を１ｍｏｌ／Ｌの濃度になるように溶解させて、非水電解液を作製した。 (Preparation of non-aqueous electrolyte)
As a non-aqueous solvent, ethylene carbonate as a cyclic carbonate, ethyl methyl carbonate as a chain carbonate, and dimethyl carbonate as a chain carbonate were mixed at a volume ratio of 1: 1: 1, and vinylene carbonate was changed to 0. Using 0.5 mass% and 0.5 mass% lithium difluorobis (oxalato) phosphate added, LiPF 6 as a supporting electrolyte was dissolved in this mixed solvent to a concentration of 1 mol / L, A non-aqueous electrolyte was prepared.
　（電池の作製）
　上記で作製した正極にアルミニウムからなる引き出し電極を、負極にニッケルからなる引き出し電極を取り付けた。正極と負極の間に、リチウムイオン透過性のポリプロピレン製微多孔膜からなるセパレータを介在させて巻回した。その際、正極と負極の対向部の面積が１５３ｃｍ2になるようにした。このようにして電池要素を作製した。上記の電池要素を、アルミニウムを中間層として含むラミネートフィルムからなる外包材の内部に収納した。その後、上記で作製した非水電解液を外包材の内部に注入した後、外包材の開口部を封止することにより、非水電解液二次電池を作製した。 (Production of battery)
An extraction electrode made of aluminum was attached to the positive electrode produced above, and an extraction electrode made of nickel was attached to the negative electrode. It wound by interposing the separator which consists of a lithium ion permeable polypropylene microporous film between the positive electrode and the negative electrode. At that time, the area of the facing portion between the positive electrode and the negative electrode was set to 153 cm 2 . In this way, a battery element was produced. Said battery element was accommodated in the outer packaging material which consists of a laminate film which contains aluminum as an intermediate | middle layer. Then, after injecting the non-aqueous electrolyte prepared above into the outer packaging material, the non-aqueous electrolyte secondary battery was fabricated by sealing the opening of the outer packaging material.
　（電池の充放電と安定化サイクル）
　得られた非水電解液二次電池に、６０ｍＡの電流値、３．８Ｖの上限電圧で、充電時間が１０時間の定電流定電圧充電を行った後、６０ｍＡの電流値で電圧値が２．５Ｖになるまで定電流放電した。その後、３００ｍＡの電流値、３．８Ｖの上限電圧で、停止電流値が６．０ｍＡの定電流定電圧充電と、３００ｍＡの電流値で電圧値が２．５Ｖになるまでの定電流放電とからなる安定化サイクルを３回繰り返した。このようにして、容量が約３１０ｍＡｈからなる非水電解液二次電池を作製した。 (Battery charge / discharge and stabilization cycle)
The obtained nonaqueous electrolyte secondary battery was subjected to constant current and constant voltage charging with a current value of 60 mA and an upper limit voltage of 3.8 V and a charging time of 10 hours, and then a voltage value of 2 at a current value of 60 mA. The battery was discharged at a constant current until it reached 5V. After that, from a constant current and constant voltage charge with a current value of 300 mA and an upper limit voltage of 3.8 V, a stop current value of 6.0 mA, and a constant current discharge until the voltage value becomes 2.5 V with a current value of 300 mA. The stabilization cycle was repeated three times. In this way, a non-aqueous electrolyte secondary battery having a capacity of about 310 mAh was produced.
　（電池の評価）
　＜サイクル試験＞
　３００ｍＡの電流値、３．８Ｖの上限電圧で、停止電流値が６．０ｍＡの定電流定電圧充電と、３００ｍＡの電流値、２．５の下限電圧での定電流放電とからなるサイクルを１００回繰り返してサイクル試験を行った。サイクル試験後、１サイクル目の放電容量に対する１００サイクル目の放電容量の割合を算出し、容量維持率として評価した。 (Battery evaluation)
<Cycle test>
A cycle consisting of a constant current and constant voltage charge with a current value of 300 mA, an upper limit voltage of 3.8 V, a stop current value of 6.0 mA, and a constant current discharge with a current value of 300 mA and a lower limit voltage of 2.5 is 100. The cycle test was performed repeatedly. After the cycle test, the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the first cycle was calculated and evaluated as a capacity retention rate.
　＜保存試験＞
　上記で得られた非水電解液二次電池について、周波数が１Ｈｚの交流抵抗値を測定した。そして、非水電解液二次電池を６０℃の温度で３０日間保存した後、周波数が１Ｈｚの交流抵抗値を測定した。保存前後の交流抵抗値の変化率を算出した。 <Storage test>
The non-aqueous electrolyte secondary battery obtained above was measured for an AC resistance value having a frequency of 1 Hz. Then, after storing the non-aqueous electrolyte secondary battery at a temperature of 60 ° C. for 30 days, an AC resistance value having a frequency of 1 Hz was measured. The change rate of the AC resistance value before and after storage was calculated.
　（実施例１０）
　負極合材の充填密度を１．１ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 10)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.1 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１１）
　負極合材の充填密度を１．２ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 11)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.2 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１２）
　負極合材の充填密度を１．３ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 12)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the packing density of the negative electrode mixture was 1.3 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１３）
　負極合材の充填密度を１．４ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 13)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.4 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１４）
　負極合材の充填密度を１．５ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 14)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.5 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１５）
　負極合材の充填密度を１．６ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。 (Example 15)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9, except that the negative electrode mixture had a packing density of 1.6 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
　（実施例１６）
　負極合材の充填密度を１．７ｇ／ｃｍ3としたこと以外は、実施例９と同様にして非水電解液二次電池を作製した。得られた非水電解液二次電池について、実施例９と同様にして容量維持率と保存前後の交流抵抗値の変化率を算出した。
　以上のようにして算出された実施例９～１６の容量維持率と保存前後の交流抵抗値の変化率を表３に示す。 (Example 16)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 9 except that the negative electrode mixture had a packing density of 1.7 g / cm 3 . For the obtained non-aqueous electrolyte secondary battery, the capacity retention rate and the rate of change in AC resistance value before and after storage were calculated in the same manner as in Example 9.
Table 3 shows the capacity retention rates of Examples 9 to 16 calculated as described above and the rate of change in AC resistance value before and after storage.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３から、負極合材の充填密度が１．２ｍｇ／ｃｍ3以上の実施例１１～１６では、容量維持率が８０％以上という高い値を示すことがわかる。負極合材の充填密度が１．５ｍｇ／ｃｍ3以下の実施例９～１４では、保存前後の交流抵抗値の変化率が２００％以下という低い値を示すことがわかる。したがって、負極合材の充填密度が１．２ｍｇ／ｃｍ3以上１．５ｍｇ／ｃｍ3以下であれば、容量維持率が高く、かつ、交流抵抗増加率が低いことがわかる。 From Table 3, it can be seen that in Examples 11 to 16 where the packing density of the negative electrode mixture was 1.2 mg / cm 3 or more, the capacity retention ratio was as high as 80% or more. In Examples 9 to 14 where the packing density of the negative electrode mixture is 1.5 mg / cm 3 or less, it can be seen that the rate of change of the AC resistance value before and after storage shows a low value of 200% or less. Therefore, the packing density of the negative-electrode mixture material is equal 1.2 mg / cm 3 or more 1.5 mg / cm 3 or less, a high capacity retention ratio, and it can be seen that the low AC resistance increase rate.
　今回開示された実施の形態と実施例はすべての点で例示であって制限的なものではないと考慮されるべきである。本発明の範囲は以上の実施の形態と実施例ではなく、請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての修正と変形を含むものであることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the claims.
　本発明の負極活物質を含む負極を備えることにより、電池の出力特性を向上させることが可能な非水電解液二次電池を提供することができる。 By providing the negative electrode containing the negative electrode active material of the present invention, it is possible to provide a non-aqueous electrolyte secondary battery capable of improving the output characteristics of the battery.
　１：非水電解液二次電池、１０：電池要素、１１：正極、１２：負極、１３：セパレータ、２０：外包材。
                                                                                 1: nonaqueous electrolyte secondary battery, 10: battery element, 11: positive electrode, 12: negative electrode, 13: separator, 20: outer packaging material.

Claims (6)

  1. 　グラファイトと、表面非晶質化ソフトカーボンとを含む、負極活物質。 Negative electrode active material containing graphite and surface-amorphized soft carbon.
  2. 　前記グラファイトと前記表面非晶質化ソフトカーボンを９５：５～３０：７０の質量比で含む、請求項１に記載の負極活物質。 The negative electrode active material according to claim 1, comprising the graphite and the surface-amorphized soft carbon in a mass ratio of 95: 5 to 30:70.
  3. 　前記グラファイトが表面非晶質化グラファイトを含む、請求項１または請求項２のいずれか１項に記載の負極活物質。 The negative electrode active material according to any one of claims 1 and 2, wherein the graphite includes surface-amorphized graphite.
  4. 　請求項１から請求項３までのいずれか１項に記載の負極活物質を含む、負極。 A negative electrode comprising the negative electrode active material according to any one of claims 1 to 3.
  5. 　負極合材の充填密度が１．２ｇ／ｃｍ3以上１．５ｇ／ｃｍ3以下である、請求項４に記載の負極。 The negative electrode according to claim 4, wherein a filling density of the negative electrode mixture is 1.2 g / cm 3 or more and 1.5 g / cm 3 or less.
  6. 　請求項４または請求項５に記載の負極を備えた、非水電解液二次電池。

                                                                                         A non-aqueous electrolyte secondary battery comprising the negative electrode according to claim 4.

PCT/JP2011/079435 2010-12-24 2011-12-20 Negative electrode active material, negative electrode, and nonaqueous electrolyte secondary battery WO2012086618A1 (en)

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JP2015064974A (en) * 2013-09-24 2015-04-09 株式会社Ｇｓユアサ Nonaqueous electrolyte secondary battery
US11024470B2 (en) 2017-03-23 2021-06-01 Gs Yuasa International Ltd. Nonaqueous electrolyte energy storage device

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JP2010218937A (en) * 2009-03-18 2010-09-30 Toyota Central R&D Labs Inc Lithium secondary battery

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JPH11310405A (en) * 1995-11-14 1999-11-09 Osaka Gas Co Ltd Negative electrode material for lithium secondary battery
JP2005004974A (en) * 2003-06-09 2005-01-06 Matsushita Electric Ind Co Ltd Lithium-ion secondary battery
JP2009070598A (en) * 2007-09-11 2009-04-02 Hitachi Vehicle Energy Ltd Lithium secondary battery
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Publication number Priority date Publication date Assignee Title
JP2015064974A (en) * 2013-09-24 2015-04-09 株式会社Ｇｓユアサ Nonaqueous electrolyte secondary battery
US11024470B2 (en) 2017-03-23 2021-06-01 Gs Yuasa International Ltd. Nonaqueous electrolyte energy storage device
US11562862B2 (en) 2017-03-23 2023-01-24 Gs Yuasa International Ltd. Nonaqueous electrolyte energy storage device

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