WO2013058263A1 - Lithium ion secondary battery and secondary battery system - Google Patents

Lithium ion secondary battery and secondary battery system Download PDF

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Publication number
WO2013058263A1
WO2013058263A1 PCT/JP2012/076782 JP2012076782W WO2013058263A1 WO 2013058263 A1 WO2013058263 A1 WO 2013058263A1 JP 2012076782 W JP2012076782 W JP 2012076782W WO 2013058263 A1 WO2013058263 A1 WO 2013058263A1
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Prior art keywords
secondary battery
mass
manganese
lithium ion
ion secondary
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PCT/JP2012/076782
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French (fr)
Japanese (ja)
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玲緒 小林
宏文 ▲高▼橋
心 ▲高▼橋
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株式会社日立製作所
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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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • 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 a lithium ion secondary battery and a secondary battery system.
  • a lithium ion secondary battery As a power source for electronic equipment, a lithium ion secondary battery is expected as a secondary battery expected to be reduced in size and weight.
  • a positive electrode active material of these lithium ion secondary batteries metal oxides containing lithium such as lithium cobaltate (LiCoO 2 ) and lithium manganate (LiMn 2 O 4 ) have been studied and put into practical use.
  • lithium manganate (LiMn 2 O) has the characteristics that it is abundant in resources, is inexpensive, and is thermally stable even during abuse such as overcharge. 4 ) is attracting attention.
  • lithium manganate has a problem in that manganese (Mn) is eluted by hydrogen fluoride (HF) or the like present in the electrolyte, and therefore when the battery is held at 50 ° C. or higher or when a charge / discharge cycle is performed. As a result, the capacity decreased and the resistance increased.
  • HF hydrogen fluoride
  • Patent Documents 1 and 2 propose a method of mixing a layered lithium manganese oxide with lithium manganate.
  • the lithium manganese complex oxide includes two or more kinds of lithium manganese complex oxides having different crystal structures.
  • the lithium ion secondary battery whose reversible capacity
  • Patent Document 2 discloses an electrode group in which a positive electrode sheet and a negative electrode sheet are formed via a separator and a non-aqueous electrolyte, a laminate-like outer case that houses the electrode group, the positive electrode sheet, and the negative electrode
  • the positive electrode active material used for the positive electrode formed on the positive electrode sheet is spinel lithium manganese oxide and layered lithium
  • the non-aqueous secondary battery containing manganese oxide and having the lithium compound (except LiBF 4 ) containing boron in a non-aqueous solution in which a lithium salt is dissolved in a carbonate-based non-aqueous solvent It is disclosed. It is described that this non-aqueous secondary battery can increase the output maintenance rate in pulse charge / discharge by adding a lithium compound containing boron.
  • Patent Document 3 proposes a method for defining the amount of electrolyte per discharge capacity for a battery using lithium manganate. That is, a non-aqueous secondary battery using a lithium manganese composite oxide having a spinel structure as a positive electrode active material and a carbon material as a negative electrode active material and having an electrolyte of 6 to 8 g per 1 Ah of discharge capacity is disclosed. This non-aqueous secondary battery is described as being capable of producing a battery having a life capacity of 1000 cycles or more at room temperature even in a battery having a battery capacity of 10 Ah or more and usable in 10 C discharge.
  • Patent Document 4 proposes a technique for regulating the weight of the positive electrode active material and the volume of the void in the battery can for a battery using lithium manganate. That is, in a lithium ion secondary battery using lithium oxide containing manganese for the positive electrode and a carbon material for the negative electrode, the volume of the void in the battery can per gram of the positive electrode active material is 0.10 ml or more and 0.20. A lithium ion secondary battery having milliliters or less is disclosed. This lithium ion secondary battery suppresses the phenomenon that a battery can swells during storage in a charge / discharge process or in a high temperature state.
  • JP 2003-36846 A JP 2007-165111 A JP 2003-346906 A JP-A-11-265731
  • the present invention suppresses elution of manganese from the positive electrode active material when stored at a high temperature for a lithium ion secondary battery using manganese oxide as the positive electrode active material, and reduces the capacity of the lithium ion secondary battery.
  • the purpose is to suppress resistance rise and life reduction.
  • the lithium ion secondary battery of the present invention that solves the above problems includes a positive electrode having at least a manganese oxide as a positive electrode active material, a negative electrode capable of occluding and releasing lithium, and an electrolyte solution comprising a non-aqueous solvent containing a lithium salt.
  • a positive electrode having at least a manganese oxide as a positive electrode active material
  • a negative electrode capable of occluding and releasing lithium
  • an electrolyte solution comprising a non-aqueous solvent containing a lithium salt.
  • the present invention relates to the ratio of the active material mass and the electrolyte solution mass of a lithium ion secondary battery having excellent life characteristics.
  • the present invention defines the amount of electrolyte used in order to apply inexpensive and highly heat-stable manganese oxide as the positive electrode active material of a lithium ion secondary battery. Thereby, the quantity of manganese eluting at the time of high temperature storage is suppressed, and the lifetime improvement as a lithium ion secondary battery is realizable.
  • FIG. 2 is a schematic diagram schematically showing a partial cross section of a lithium ion secondary battery as an example of an embodiment of the present invention.
  • the lithium ion secondary battery 10 has a configuration in which a separator 3 is interposed between a positive electrode plate 1 and a negative electrode plate 2. These positive electrode plate 1, negative electrode plate 2 and separator 3 are wound and sealed in a battery can 4 made of stainless steel or aluminum together with a non-aqueous electrolyte.
  • a positive electrode lead piece 7 is connected to the positive electrode plate 1 and a negative electrode lead piece 5 is connected to the negative electrode plate 2 so that current can be taken out.
  • Insulating plates 9 are provided between the positive electrode plate 1 and the negative electrode lead piece 5 and between the negative electrode plate 2 and the positive electrode lead piece 7, respectively. Further, between the battery can 4 that is in contact with the negative electrode lead piece 5 and the sealing lid portion 6 that is in contact with the positive electrode lead piece 7, leakage of the electrolyte is prevented, and a positive electrode and a negative electrode are provided.
  • a packing 8 is provided.
  • the positive electrode plate 1 is obtained by applying a positive electrode mixture to a current collector formed of aluminum or the like.
  • the positive electrode mixture includes a positive electrode active material, a conductive material, a binder, and the like that contribute to occlusion and release of lithium.
  • a manganese oxide capable of inserting lithium or forming a lithium compound can be used as the positive electrode active material.
  • lithium manganate having a spinel structure (a typical chemical formula is LiMn 2 O 4, hereinafter sometimes abbreviated as “spinel manganese”)
  • lithium manganate having a rock salt structure typically
  • LiMO 2 and M may contain transition metals such as Ni and Co in addition to Mn, or Li 2 MO 3 and M may contain transition metals such as Ni and Co in addition to Mn.
  • Olivine Lithium manganese phosphate having a structure (LiMPO 4 as a typical chemical formula, M may contain a transition metal such as Fe in addition to Mn), lithium silicate substituted with manganese (Li 2 MSiO as a typical chemical formula) 4 , M may contain transition metals such as Fe in addition to Mn), manganese dioxide having a spinel structure (representative chemical formula ⁇ -MnO 2 )), manganese dioxide having a rutile structure (a typical chemical formula is ⁇ -MnO 2 ), and the like.
  • lithium manganate spinel manganese having a spinel structure
  • M is And at least one selected from the group consisting of Al, Co, Cr, Ni, Fe, Zn, Mg, and Cu.
  • the spinel manganese has LiMn 2 O 4 as a base material and is intended to suppress deterioration due to M substitution.
  • a + b + c ⁇ 3 the spinel structure is disturbed.
  • the Li content a is 1.0 ⁇ a ⁇ 1.1.
  • a ⁇ 1.0 the Li site is occupied by other elements, so that the diffusion of Li ions is inhibited.
  • 1.1 ⁇ a the content of transition metal such as manganese in the positive electrode active material is relatively decreased with respect to the content of Li, and the capacity of the lithium ion secondary battery is decreased. End up.
  • a more preferable range is 1.06 ⁇ a ⁇ 1.1.
  • the negative electrode plate 2 is obtained by applying a negative electrode mixture to a current collector formed of copper or the like.
  • the negative electrode mixture includes a negative electrode active material, a conductive material, a binder, and the like that contribute to occlusion and release of lithium.
  • the negative electrode active material metallic lithium, a carbon material, or a material capable of inserting lithium or capable of forming a lithium compound can be used, and a carbon material is particularly suitable.
  • the carbon material examples include graphite such as natural graphite and artificial graphite, and amorphous carbon such as coal-based coke, coal-based pitch carbide, petroleum-based coke, petroleum-based pitch carbide, and pitch-coke carbide.
  • graphite such as natural graphite and artificial graphite
  • amorphous carbon such as coal-based coke, coal-based pitch carbide, petroleum-based coke, petroleum-based pitch carbide, and pitch-coke carbide.
  • the above carbon material is subjected to various surface treatments.
  • These carbon materials can be used not only by one type but also by combining two or more types.
  • Examples of the material capable of inserting lithium or forming a compound include metals such as aluminum, tin, silicon, indium, gallium and magnesium, alloys containing these elements, and metal oxides containing tin and silicon. .
  • the composite material of the above-mentioned metal, an alloy, a metal oxide, and the carbon material of a graphite type or an amorphous carbon is mentioned.
  • An example of a method for manufacturing a lithium ion secondary battery is as follows.
  • a slurry is prepared by mixing the positive electrode active material with a conductive material of carbon material powder and a binder such as polyvinylidene fluoride.
  • the value obtained by dividing the mass (g) of the conductive material by the mass (g) of the positive electrode active material is preferably 0.03 to 0.10.
  • the value obtained by dividing the mass (g) of the binder by the mass (g) of the positive electrode active material is preferably 0.02 to 0.10.
  • the obtained slurry is coated on both sides of an aluminum foil having a thickness of 15 ⁇ m to 25 ⁇ m by, for example, a roll transfer machine. After coating on both sides, the electrode plate of the positive electrode plate 1 is formed by press drying.
  • the thickness of the mixture portion where the positive electrode active material, the conductive material and the binder are mixed is desirably 200 ⁇ m to 250 ⁇ m.
  • the negative electrode is mixed with a binder and applied in the same manner as the positive electrode, and press dried to form an electrode.
  • the thickness of the negative electrode mixture is preferably 100 ⁇ m to 150 ⁇ m.
  • a copper foil having a thickness of 7 ⁇ m to 20 ⁇ m is used as a current collector.
  • the material to be applied preferably has a ratio of the mass (g) of the negative electrode active material to the mass (g) of the binder of, for example, about 90:10 to 98: 2.
  • the obtained electrode plate is cut into a predetermined length, an electrode is formed, and the tab portion of the current drawing portion is formed by spot welding or ultrasonic welding.
  • the tab portion is made of a metal foil made of the same material as the rectangular current collector, and is installed to take out current from the electrode.
  • the tab portion becomes the positive electrode lead piece 7 and the negative electrode lead piece 5.
  • a microporous film for example, a separator 3 formed of polyethylene (PE), polypropylene (PP) or the like is sandwiched between the tabbed positive electrode plate 1 and the negative electrode plate 2, and this is rolled into a cylindrical shape to form an electrode.
  • a group is housed in a battery can 4 which is a cylindrical container.
  • a bag-shaped separator may be used to store the electrodes therein, which are sequentially stacked and stored in the square container.
  • the material of the container is preferably stainless steel or aluminum.
  • a non-aqueous electrolyte solution is injected and sealed using the lid 6 and the packing 8.
  • Non-aqueous electrolytes include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl acetate (MA), methyl propyl carbonate (MPC) Lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium bis-oxalatoborate (LiBOB), etc., in a solvent such as vinylene carbonate (VC) It is desirable to use a solution in which the lithium salt is dissolved.
  • the concentration of the lithium salt is preferably 0.7 mol / l to 1.5 mol / l.
  • the fabricated lithium ion secondary battery has a configuration in which a pair of positive and negative electrodes face each other with a separator and a non-aqueous electrolyte, and has a high energy density and excellent high rate characteristics.
  • a secondary battery can be provided.
  • Example 1 In the present invention, examples in which a positive electrode active material and an electrolytic solution are combined will be introduced.
  • lithium manganate spinel manganese represented by the chemical formula Li 1.10 Mn 1.86 Mg 0.04 O 4 was used.
  • lithium hexafluorophosphate LiPF
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • concentration in the electrolyte solution measured by the titration method was 6 wtppm.
  • the positive electrode active material and 4.8 g of the electrolytic solution were put in a fluororesin container and sealed.
  • the positive electrode active material and the fluororesin container were previously vacuum dried at 120 ° C. for 1 hour. Further, the fluororesin container was put in an aluminum laminate bag and sealed, and then sealed in an airtight container made of SUS. The above operation was performed in a glove box in an Ar atmosphere. This prevented moisture from the outside from being mixed into the electrolyte during high-temperature storage described below.
  • the airtight container made of SUS was stored at a high temperature in a constant temperature bath at 80 ° C. After storing for 7 days, the airtight container was taken out of the thermostatic bath and cooled to room temperature. The electrolytic solution was taken out from the container, concentrated by heating to white sulfuric acid smoke, heated and dissolved with dilute nitric acid, and manganese was quantified with a high frequency inductively coupled plasma emission spectrometer. The mass of manganese eluted in the electrolyte (hereinafter referred to as eluted manganese mass) was 1860 ⁇ g.
  • Example 2 Evaluation was made in the same configuration as in Example 1 except that the mass of the positive electrode active material was changed to 1.5 g.
  • Example 3 Evaluation was made in the same configuration as Example 1 except that the mass of the positive electrode active material was 1.0 g and the electrolytic solution was 7.2 g.
  • Comparative Example 2 Evaluation was made with the same configuration as in Example 1 except that the mass of the positive electrode active material was changed to 0.5 g.
  • Table 1 The results in Table 1 are graphed in FIG. 1 with the horizontal axis representing the electrolyte mass (g) / manganese oxide mass (g) and the vertical axis representing the eluted manganese mass ( ⁇ g) / manganese oxide mass (g). .
  • the eluted manganese mass per manganese oxide mass initially decreases. This is because the reaction rate at which the moisture changes to hydrogen fluoride is proportional to the square of the moisture concentration, whereas the rate of the reaction increases as the moisture adhering to the positive electrode active material is diluted with the electrolyte and the concentration decreases. That is, when the production rate of hydrogen fluoride decreases, the amount of eluting manganese decreases. In addition, since water is produced in the reaction of spinel manganese and hydrogen fluoride, the amount of water is constant throughout the reaction. That is, the elution reaction of manganese continues to occur at a reaction rate according to the concentration of moisture, and as a result, the mass of eluted manganese in a certain period has a positive correlation with the concentration of moisture.
  • the mass of eluted manganese per mass of manganese oxide increases. This is because the amount of water contained in an electrolyte present in a certain concentration increases as the amount of electrolyte increases, the amount of hydrogen fluoride changed from moisture increases, and the mass of eluted manganese increases. Because. Although the elution rate does not change because the concentration of water contained in the electrolyte is constant, the amount of water increases as the amount of electrolyte increases, so the mass of eluted manganese also increases.
  • the number of positive electrode active materials may be two or more. Moreover, you may include positive electrode active materials other than manganese oxide. Also in this case, not the electrolyte mass per mass of the positive electrode active material but the electrolyte mass per mass of the manganese oxide is within the above range. This is because manganese elution does not occur in positive electrode active materials other than manganese oxide, so that only manganese oxide needs to be considered.
  • the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g)
  • FIG. 2 shows a 18650 (diameter 18 mm ⁇ height 650 mm) type battery to which the regulation of manganese oxide mass and electrolyte mass shown in this embodiment is applied.
  • the manufacturing method of 18650 battery is shown below.
  • the mass (g) of the positive electrode active material, the mass (g) of the conductive material of the carbon material powder, and the mass (g) of PVdF used as the binder are 90: 4.5: 5.5.
  • an appropriate amount of NMP is added to prepare a slurry.
  • manganese oxide is used as the positive electrode active material.
  • the prepared slurry is stirred for 3 hours with a planetary mixer and kneaded.
  • the kneaded slurry is applied to both sides of an aluminum foil having a thickness of 20 ⁇ m using an applicator of a roll transfer machine. This is pressed by a roll press machine so that the mixture density becomes 2.70 g / cm 3 to obtain a positive electrode.
  • the mass (g) of graphite as the negative electrode active material, the mass (g) of carbon black as the conductive material, and the mass (g) of PVdF used as the binder were 92.2: 1.6: 6.2. Knead by stirring for 30 minutes with a slurry mixer. The kneaded slurry is applied to both sides of a 10 ⁇ m thick copper foil using an applicator, dried, and then pressed with a roll press to obtain a negative electrode. The positive electrode and the negative electrode are each cut into a predetermined size, and a current collecting tab is installed by ultrasonic welding on a portion of these electrodes where the slurry is not applied (uncoated portion). A porous polyethylene film is sandwiched between these positive and negative electrodes, wound into a cylindrical shape, and then inserted into a 18650 type battery can.
  • the lid of the battery can and the battery can are welded by laser welding to seal the battery.
  • a 18650 type battery is obtained by injecting a non-aqueous electrolyte from a liquid injection port provided in the battery can.
  • LiPF 6 lithium hexafluorophosphate
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • the battery to which the provisions of the manganese oxide mass and the electrolyte mass shown in the present embodiment are applied is not limited to the above configuration.
  • the shape of the outer container may be changed from a cylindrical shape to a rectangular shape, that is, a rectangular parallelepiped shape.
  • the material of the outer container may be aluminum laminate.
  • a separator is interposed between the positive electrode and the negative electrode.
  • the positive electrode active material and the negative electrode active material are not coated on the tab portions of the positive electrode current collector and the negative electrode current collector.
  • the tab portions are respectively connected to external current collecting terminals to form battery elements.
  • An aluminum laminate sheet is welded to the outer periphery of the battery element by heat welding, thereby sealing the battery element. You may arrange
  • FIG. 3 shows a secondary battery system equipped with a lithium ion secondary battery to which the rules for manganese oxide mass and electrolyte mass shown in the present embodiment are applied.
  • a plurality of lithium ion secondary batteries 10, for example, 4 to 8, are connected in series to form an assembled battery of lithium ion secondary batteries. Further, a plurality of assembled batteries of the lithium ion secondary batteries are connected to constitute a lithium ion secondary battery group.
  • the cell controller 11 is formed corresponding to such a group of lithium ion secondary batteries and controls the lithium ion secondary battery 10.
  • the cell controller 11 monitors overcharge and overdischarge of the lithium ion secondary battery 10 and monitors the remaining capacity of the lithium ion secondary battery 10.
  • the battery controller 12 gives a signal to the cell controller 11 using, for example, communication means, and acquires a signal from the cell controller 11 using, for example, communication means.
  • the battery controller 12 performs power input / output management for the cell controller 11.
  • the battery controller 12 gives a signal to the input unit 111 of the first cell controller 11, for example. Such a signal is transmitted from the output unit 112 of the cell controller 11 to the input unit 111 of another cell controller 11 to the series. This signal is given to the battery controller 12 from the output unit 112 of the last cell controller 11. In this way, the battery controller 12 can monitor the cell controller 11.
  • FIG. 4 shows a secondary battery system equipped with a lithium ion secondary battery for a low temperature part and a high temperature part to which the regulation of the manganese oxide mass and the electrolyte mass shown in the present embodiment is applied. .
  • the secondary battery system has a high temperature portion 14 that is relatively high temperature and a low temperature portion 15 that is relatively low temperature. And in the high temperature part 14 of a secondary battery system, the lithium ion battery (lithium ion secondary battery 110 for high temperature parts) with relatively much electrolyte solution quantity with respect to the mass of manganese oxide is arrange
  • the lithium ion secondary battery and the secondary battery system having the above-described configuration, elution of manganese during high temperature storage is suppressed. Therefore, when the battery is held at 50 ° C. or higher or when a charge / discharge cycle is performed, it is possible to suppress a decrease in capacity, an increase in resistance, and the like, and a longer life can be achieved than in the past.
  • the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.
  • the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described.
  • a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment.
  • the lithium ion secondary battery and secondary battery system of the present invention can be expected to have a longer life than the conventional configuration, and is particularly useful as a large stationary power source.

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Abstract

The objectives of the present invention are to suppress the elution of manganese from a cathode active material during storage at high temperature of a lithium ion secondary battery using a manganese oxide as the cathode active material and to suppress the drop in capacity, the increase in resistance, and the shortening of the service life of the lithium ion secondary battery. The lithium ion secondary battery of the present invention has a cathode having at least manganese oxide as the cathode active material, an anode capable of storing and discharging lithium, and an electrolytic solution composed of a nonaqueous solvent containing lithium salt. If the weight of the electrolytic solution is A (g), and the weight of the manganese oxide is B (g), then the value of C = A/B is from 0.96 to 8.50.

Description

リチウムイオン二次電池および二次電池システムLithium ion secondary battery and secondary battery system
　本発明は、リチウムイオン二次電池および二次電池システムに関する。 The present invention relates to a lithium ion secondary battery and a secondary battery system.
　電子機器の電源として、小型化・軽量化が期待される二次電池としてリチウムイオン二次電池が期待されている。これらのリチウムイオン二次電池の正極活物質としては、コバルト酸リチウム（ＬｉＣｏＯ２）、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）等のリチウムを含有する金属酸化物が検討され、実用化されている。 As a power source for electronic equipment, a lithium ion secondary battery is expected as a secondary battery expected to be reduced in size and weight. As a positive electrode active material of these lithium ion secondary batteries, metal oxides containing lithium such as lithium cobaltate (LiCoO 2 ) and lithium manganate (LiMn 2 O 4 ) have been studied and put into practical use.
　しかしながら、近年、電池の低コスト化への要求が高まるにつれ、安価な材料を用いて長寿命化する技術開発が要求されている。 However, in recent years, as the demand for lowering the cost of batteries has increased, there has been a demand for technology development that extends the service life using inexpensive materials.
　そのために、正極材料としては、資源的に豊富であり安価であり、過充電などの濫用時においても熱的に安定であるとの特長を有していることから、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）が注目されている。 Therefore, as a positive electrode material, lithium manganate (LiMn 2 O) has the characteristics that it is abundant in resources, is inexpensive, and is thermally stable even during abuse such as overcharge. 4 ) is attracting attention.
　しかしながら、マンガン酸リチウムは、電解液中に存在するフッ化水素（ＨＦ）などによりマンガン（Ｍｎ）が溶出するなどの問題から、電池を50℃以上で保持した際や充放電サイクルを行った際に容量の低下や抵抗の上昇などが発生し、寿命特性に関して課題があった。 However, lithium manganate has a problem in that manganese (Mn) is eluted by hydrogen fluoride (HF) or the like present in the electrolyte, and therefore when the battery is held at 50 ° C. or higher or when a charge / discharge cycle is performed. As a result, the capacity decreased and the resistance increased.
　マンガン酸リチウムの充放電特性を改善させるために、これまでさまざまな検討がなされている。 Various studies have been made so far in order to improve the charge / discharge characteristics of lithium manganate.
　特許文献１及び特許文献２においては、マンガン酸リチウムに層状系リチウムマンガン酸化物を混合する手法が提案されている。 Patent Documents 1 and 2 propose a method of mixing a layered lithium manganese oxide with lithium manganate.
　すなわち、特許文献１には、リチウムマンガン複酸化物を正極活物質の主体とするリチウムイオン二次電池において、前記リチウムマンガン複酸化物は結晶構造が異なる２種以上のリチウムマンガン複酸化物を含み、かつ、前記正極の可逆容量が負極の可逆容量以下であるリチウムイオン二次電池が開示されている。このリチウムイオン二次電池によれば、充電時の負極の負担を軽減し、負極の劣化を抑制することができると記載されている。 That is, in Patent Document 1, in a lithium ion secondary battery mainly composed of a lithium manganese complex oxide as a positive electrode active material, the lithium manganese complex oxide includes two or more kinds of lithium manganese complex oxides having different crystal structures. And the lithium ion secondary battery whose reversible capacity | capacitance of the said positive electrode is below the reversible capacity | capacitance of a negative electrode is disclosed. According to this lithium ion secondary battery, it is described that the burden on the negative electrode during charging can be reduced and deterioration of the negative electrode can be suppressed.
　また、特許文献２には、正極シートと負極シートとがセパレータ及び非水系電解液を介して形成される電極群と、前記電極群を収容するラミネート状の外装ケースと、前記正極シート及び前記負極シートのそれぞれに接続される正極リード及び負極リードと、を有するリチウムイオン二次電池において、前記正極シートに形成される正極に使用される正極活物質は、スピネル系リチウムマンガン酸化物及び層状系リチウムマンガン酸化物を含有し、前記電解液は、カーボネート系の非水系溶媒にリチウム塩を溶解させた非水系溶液に、ホウ素を含有するリチウム化合物（ＬｉＢＦ４を除く）を有する非水系二次電池が開示されている。この非水系二次電池は、ホウ素を含有するリチウム化合物を添加することにより、パルス充放電における出力の維持率を高くすることができると記載されている。 Patent Document 2 discloses an electrode group in which a positive electrode sheet and a negative electrode sheet are formed via a separator and a non-aqueous electrolyte, a laminate-like outer case that houses the electrode group, the positive electrode sheet, and the negative electrode In a lithium ion secondary battery having a positive electrode lead and a negative electrode lead connected to each of the sheets, the positive electrode active material used for the positive electrode formed on the positive electrode sheet is spinel lithium manganese oxide and layered lithium The non-aqueous secondary battery containing manganese oxide and having the lithium compound (except LiBF 4 ) containing boron in a non-aqueous solution in which a lithium salt is dissolved in a carbonate-based non-aqueous solvent. It is disclosed. It is described that this non-aqueous secondary battery can increase the output maintenance rate in pulse charge / discharge by adding a lithium compound containing boron.
　一方、特許文献３には、マンガン酸リチウムを用いた電池について、放電容量あたりの電解液量を規定する手法が提案されている。すなわち、正極活物質にスピネル構造のリチウムマンガン複合酸化物、負極活物質に炭素材料を用いて、放電容量１Ａｈ当たり６ｇ～８ｇの電解液を備えた非水二次電池が開示されている。この非水二次電池は、電池容量が１０Ａｈ以上で、１０Ｃ放電で使用できる電池においても、室温で１０００サイクル以上の寿命性能を有する電池の作製が可能となると記載されている。 On the other hand, Patent Document 3 proposes a method for defining the amount of electrolyte per discharge capacity for a battery using lithium manganate. That is, a non-aqueous secondary battery using a lithium manganese composite oxide having a spinel structure as a positive electrode active material and a carbon material as a negative electrode active material and having an electrolyte of 6 to 8 g per 1 Ah of discharge capacity is disclosed. This non-aqueous secondary battery is described as being capable of producing a battery having a life capacity of 1000 cycles or more at room temperature even in a battery having a battery capacity of 10 Ah or more and usable in 10 C discharge.
　さらに、特許文献４には、マンガン酸リチウムを用いた電池について、正極活物質の重量と電池缶内の空隙部の体積を規定する手法が提案されている。すなわち、正極にマンガンを含んだリチウム酸化物、負極に炭素素材を用いたリチウムイオン二次電池において、正極活物質の質量１グラムあたり電池缶内の空隙部の体積０．１０ミリリットル以上０．２０ミリリットル以下にしたリチウムイオン二次電池が開示されている。このリチウムイオン二次電池は、充放電過程や高温状態での保存時に電池缶が膨れるという現象を抑制する。 Furthermore, Patent Document 4 proposes a technique for regulating the weight of the positive electrode active material and the volume of the void in the battery can for a battery using lithium manganate. That is, in a lithium ion secondary battery using lithium oxide containing manganese for the positive electrode and a carbon material for the negative electrode, the volume of the void in the battery can per gram of the positive electrode active material is 0.10 ml or more and 0.20. A lithium ion secondary battery having milliliters or less is disclosed. This lithium ion secondary battery suppresses the phenomenon that a battery can swells during storage in a charge / discharge process or in a high temperature state.
特開２００３－３６８４６号公報JP 2003-36846 A 特開２００７－１６５１１１号公報JP 2007-165111 A 特開２００３－３４６９０６号公報JP 2003-346906 A 特開平１１－２６５７３１号公報JP-A-11-265731
　本発明は、マンガン酸化物を正極活物質として用いたリチウムイオン二次電池に対し、高温貯蔵した際の前記正極活物質からのマンガンの溶出を抑制し、前記リチウムイオン二次電池の容量低下や抵抗上昇、寿命減少を抑制することを目的とする。 The present invention suppresses elution of manganese from the positive electrode active material when stored at a high temperature for a lithium ion secondary battery using manganese oxide as the positive electrode active material, and reduces the capacity of the lithium ion secondary battery. The purpose is to suppress resistance rise and life reduction.
　上記課題を解決する本発明のリチウムイオン二次電池は、正極活物質として少なくともマンガン酸化物を有する正極と、リチウムを吸蔵放出可能な負極と、リチウム塩を含有する非水系溶媒からなる電解液とを有し、前記電解液の質量をA（ｇ）、前記マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値が０．９６以上８．５０以下であることを特徴とする。 The lithium ion secondary battery of the present invention that solves the above problems includes a positive electrode having at least a manganese oxide as a positive electrode active material, a negative electrode capable of occluding and releasing lithium, and an electrolyte solution comprising a non-aqueous solvent containing a lithium salt. When the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g), the value of C = A / B is 0.96 or more and 8.50 or less. Features.
　本発明によれば、高温貯蔵時におけるマンガンの溶出が抑制され、長寿命であるリチウムイオン二次電池を提供することが可能となる。なお、上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。本明細書は、本願の優先権の基礎である日本国特許出願2011-229838号の明細書及び／または図面に記載されている内容を包含する。 According to the present invention, it is possible to provide a lithium ion secondary battery that has a long life because elution of manganese during high-temperature storage is suppressed. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments. This specification includes the contents described in the specification and / or drawings of Japanese Patent Application No. 2011-229838 which is the basis of the priority of the present application.
本発明による実施例および比較例におけるマンガン酸化物質量あたりの電解液質量とマンガン酸化物質量あたりの溶出マンガン質量の評価結果を示すグラフ。The graph which shows the evaluation result of the electrolyte solution mass per manganese oxide mass in the Example by this invention, and the elution manganese mass per manganese oxide mass. 本発明によるリチウムイオン二次電池を一部断面により模式的に示す概略図。Schematic which shows typically the lithium ion secondary battery by this invention by a partial cross section. 本発明によるリチウムイオン二次電池を搭載した二次電池システムを示す図。The figure which shows the secondary battery system carrying the lithium ion secondary battery by this invention. 本発明によるリチウムイオン二次電池について、低温部用と高温部用のリチウムイオン二次電池を搭載した二次電池システムを示す図。The figure which shows the secondary battery system carrying the lithium ion secondary battery for low temperature parts and high temperature parts about the lithium ion secondary battery by this invention.
　本発明は、寿命特性に優れたリチウムイオン二次電池の活物質質量と電解液質量の比に関するものである。 The present invention relates to the ratio of the active material mass and the electrolyte solution mass of a lithium ion secondary battery having excellent life characteristics.
　本発明は、安価で熱安定性の高いマンガン酸化物をリチウムイオン二次電池の正極活物質として適用するために、用いる電解液の量を規定している。これにより、高温貯蔵時に溶出するマンガンの量を抑制し、リチウムイオン二次電池としての長寿命化を実現できる。 The present invention defines the amount of electrolyte used in order to apply inexpensive and highly heat-stable manganese oxide as the positive electrode active material of a lithium ion secondary battery. Thereby, the quantity of manganese eluting at the time of high temperature storage is suppressed, and the lifetime improvement as a lithium ion secondary battery is realizable.
　図２は、本発明の実施の形態の一例である、リチウムイオン二次電池を一部断面により模式的に示す概略図である。 FIG. 2 is a schematic diagram schematically showing a partial cross section of a lithium ion secondary battery as an example of an embodiment of the present invention.
　リチウムイオン二次電池１０は、正極板１と負極板２との間にセパレータ３を介在させた構成を有する。これらの正極板１、負極板２およびセパレータ３が捲回され、非水系電解液と共にステンレス製またはアルミニウム製の電池缶４に封入される。 The lithium ion secondary battery 10 has a configuration in which a separator 3 is interposed between a positive electrode plate 1 and a negative electrode plate 2. These positive electrode plate 1, negative electrode plate 2 and separator 3 are wound and sealed in a battery can 4 made of stainless steel or aluminum together with a non-aqueous electrolyte.
　正極板１には正極リード片７が、負極板２には負極リード片５が、それぞれ接続してあり、電流が取り出されるようになっている。正極板１と負極リード片５との間、及び負極板２と正極リード片７との間には、それぞれ絶縁板９が設置してある。また、負極リード片５と接触している電池缶４と正極リード片７と接触している密閉蓋部６との間には、電解液の漏れを防止するとともに、プラス極とマイナス極とを分けるパッキン８が設置してある。 A positive electrode lead piece 7 is connected to the positive electrode plate 1 and a negative electrode lead piece 5 is connected to the negative electrode plate 2 so that current can be taken out. Insulating plates 9 are provided between the positive electrode plate 1 and the negative electrode lead piece 5 and between the negative electrode plate 2 and the positive electrode lead piece 7, respectively. Further, between the battery can 4 that is in contact with the negative electrode lead piece 5 and the sealing lid portion 6 that is in contact with the positive electrode lead piece 7, leakage of the electrolyte is prevented, and a positive electrode and a negative electrode are provided. A packing 8 is provided.
　正極板１は、アルミニウム等で形成された集電体に正極合剤を塗布したものである。正極合剤は、リチウムの吸蔵放出に寄与する正極活物質、導電材、結着剤等を含む。 The positive electrode plate 1 is obtained by applying a positive electrode mixture to a current collector formed of aluminum or the like. The positive electrode mixture includes a positive electrode active material, a conductive material, a binder, and the like that contribute to occlusion and release of lithium.
　正極活物質としては、リチウムを挿入可能又はリチウムの化合物を形成可能なマンガン酸化物を用いることができる。 As the positive electrode active material, a manganese oxide capable of inserting lithium or forming a lithium compound can be used.
　マンガン酸化物としては、スピネル構造を有するマンガン酸リチウム（代表的な化学式としてＬｉＭｎ２Ｏ４。以下、「スピネルマンガン」と略称する場合もある。）、岩塩構造を有するマンガン酸リチウム（代表的な化学式としてＬｉＭＯ２、ＭはＭｎに加え、Ｎｉ、Ｃｏ等の遷移金属を含んでも良い。またはＬｉ２ＭＯ３、ＭはＭｎに加え、Ｎｉ、Ｃｏ等の遷移金属を含んでも良い。）、オリビン構造を有するマンガンリン酸リチウム（代表的な化学式としてＬｉＭＰＯ４、ＭはＭｎに加え、Ｆｅ等の遷移金属を含んでも良い。）、マンガン置換をしたケイ酸リチウム（代表的な化学式としてＬｉ２ＭＳｉＯ４、ＭはＭｎに加え、Ｆｅ等の遷移金属を含んでも良い。）、スピネル構造を有する二酸化マンガン（代表的な化学式としてλ－ＭｎＯ２））、ルチル構造を有する二酸化マンガン（代表的な化学式としてβ－ＭｎＯ２）などが挙げられる。これらのマンガン酸化物は、１種類で用いるだけでなく、２種類以上を組み合わせて用いることもできる。 As the manganese oxide, lithium manganate having a spinel structure (a typical chemical formula is LiMn 2 O 4, hereinafter sometimes abbreviated as “spinel manganese”), lithium manganate having a rock salt structure (typical) As a chemical formula, LiMO 2 and M may contain transition metals such as Ni and Co in addition to Mn, or Li 2 MO 3 and M may contain transition metals such as Ni and Co in addition to Mn.), Olivine Lithium manganese phosphate having a structure (LiMPO 4 as a typical chemical formula, M may contain a transition metal such as Fe in addition to Mn), lithium silicate substituted with manganese (Li 2 MSiO as a typical chemical formula) 4 , M may contain transition metals such as Fe in addition to Mn), manganese dioxide having a spinel structure (representative chemical formula Λ-MnO 2 )), manganese dioxide having a rutile structure (a typical chemical formula is β-MnO 2 ), and the like. These manganese oxides can be used not only in one kind but also in combination of two or more kinds.
　正極板１の活物質（正極活物質）の一つとして、スピネル構造を有するマンガン酸リチウム（スピネルマンガン）について詳述する。 As one of the active materials (positive electrode active material) of the positive electrode plate 1, lithium manganate (spinel manganese) having a spinel structure will be described in detail.
　このスピネルマンガンとして、具体的には、一般式ＬｉａＭｎｂＭｃＯ４（但し、ａ＋ｂ＋ｃ＝３、１．０≦ａ≦１．１、０＜ｃ≦０．０７である。Ｍは、Ａｌ、Ｃｏ、Ｃｒ、Ｎｉ、Ｆｅ、Ｚｎ、Ｍｇ及びＣｕからなる群より選ばれる少なくとも一種である。）で示されるものを用いる。 As this spinel manganese, specifically, the general formula Li a Mn b M c O 4 (where a + b + c = 3, 1.0 ≦ a ≦ 1.1, 0 <c ≦ 0.07. M is And at least one selected from the group consisting of Al, Co, Cr, Ni, Fe, Zn, Mg, and Cu.
　前記スピネルマンガンは、ＬｉＭｎ２Ｏ４を母材とし、Ｍ置換による劣化抑制を図ったものである。Ｌｉ、Ｍｎ及びＭの含有量の和ａ＋ｂ＋ｃは、母材であるＬｉＭｎ２Ｏ４のスピネル構造を維持するため、ａ＋ｂ＋ｃ＝３が好ましい。ａ＋ｂ＋ｃ≠３の場合には、スピネル構造が乱れてしまう。 The spinel manganese has LiMn 2 O 4 as a base material and is intended to suppress deterioration due to M substitution. The sum a + b + c of the contents of Li, Mn and M is preferably a + b + c = 3 in order to maintain the spinel structure of LiMn 2 O 4 which is the base material. When a + b + c ≠ 3, the spinel structure is disturbed.
　Ｌｉの含有量ａは、１．０≦ａ≦１．１であるが、ａ＜１．０の場合には、Ｌｉサイトを他の元素が占有するため、Ｌｉイオンの拡散が阻害される。また、１．１＜ａの場合には、正極活物質におけるマンガン等の遷移金属の含有量がＬｉの含有量に対して相対的に減少してしまい、リチウムイオン二次電池の容量が低下してしまう。更に好ましい範囲は、１．０６≦ａ≦１．１である。 The Li content a is 1.0 ≦ a ≦ 1.1. However, when a <1.0, the Li site is occupied by other elements, so that the diffusion of Li ions is inhibited. In the case of 1.1 <a, the content of transition metal such as manganese in the positive electrode active material is relatively decreased with respect to the content of Li, and the capacity of the lithium ion secondary battery is decreased. End up. A more preferable range is 1.06 ≦ a ≦ 1.1.
　Ｍ（Ａｌ、Ｃｏ、Ｃｒ、Ｎｉ、Ｆｅ、Ｚｎ、Ｍｇ及びＣｕからなる群より選ばれる少なくとも一種）の含有量ｃは、０＜ｃ≦０．０７であるが、ｃ＝０の場合、マンガンの平均価数が３．５未満となり、結晶構造が不安定になるため、充放電によって多量のマンガンが電解液中に溶出して劣化を促進する。一方、０．０７＜ｃの場合、Ｍは２価で置換されるので、電気的中性を保つためにマンガンの価数が大幅に増加する。スピネルマンガンの充放電はマンガンの価数変化によって行われるため、マンガンの価数が増加するとリチウムイオン二次電池の容量が低下してしまう。更に好ましい範囲は、０．０１≦ｃ≦０．０３である。 The content c of M (at least one selected from the group consisting of Al, Co, Cr, Ni, Fe, Zn, Mg and Cu) is 0 <c ≦ 0.07, but when c = 0, manganese Since the average valence of becomes less than 3.5 and the crystal structure becomes unstable, a large amount of manganese is eluted in the electrolyte solution by charge and discharge, and promotes deterioration. On the other hand, in the case of 0.07 <c, since M is substituted with divalent, the valence of manganese is greatly increased to maintain electrical neutrality. Since charge / discharge of spinel manganese is performed by changing the valence of manganese, when the valence of manganese increases, the capacity of the lithium ion secondary battery decreases. A more preferable range is 0.01 ≦ c ≦ 0.03.
　負極板２は、銅等で形成された集電体に負極合剤を塗布したものである。負極合剤は、リチウムの吸蔵放出に寄与する負極活物質、導電材、結着剤等を含む。 The negative electrode plate 2 is obtained by applying a negative electrode mixture to a current collector formed of copper or the like. The negative electrode mixture includes a negative electrode active material, a conductive material, a binder, and the like that contribute to occlusion and release of lithium.
　負極活物質としては、金属リチウム、炭素材料、或いは、リチウムを挿入可能又はリチウムの化合物を形成可能な材料を用いることができ、炭素材料が特に好適である。 As the negative electrode active material, metallic lithium, a carbon material, or a material capable of inserting lithium or capable of forming a lithium compound can be used, and a carbon material is particularly suitable.
　炭素材料としては、天然黒鉛、人造黒鉛等の黒鉛類および石炭系コークス、石炭系ピッチの炭化物、石油系コークス、石油系ピッチの炭化物、ピッチコークスの炭化物等の非晶質炭素がある。好ましくは、上記の炭素材料に種々の表面処理を施したものが望ましい。 Examples of the carbon material include graphite such as natural graphite and artificial graphite, and amorphous carbon such as coal-based coke, coal-based pitch carbide, petroleum-based coke, petroleum-based pitch carbide, and pitch-coke carbide. Preferably, the above carbon material is subjected to various surface treatments.
　これらの炭素材料は、１種類で用いるだけでなく、２種類以上を組み合わせて用いることもできる。また、リチウムを挿入もしくは化合物の形成が可能な材料としては、アルミニウム、スズ、ケイ素、インジウム、ガリウム、マグネシウムなどの金属およびこれらの元素を含む合金、スズ、ケイ素などを含む金属酸化物が挙げられる。さらにまた、前述の金属や合金や金属酸化物と黒鉛系や非晶質炭素の炭素材料との複合材が挙げられる。 These carbon materials can be used not only by one type but also by combining two or more types. Examples of the material capable of inserting lithium or forming a compound include metals such as aluminum, tin, silicon, indium, gallium and magnesium, alloys containing these elements, and metal oxides containing tin and silicon. . Furthermore, the composite material of the above-mentioned metal, an alloy, a metal oxide, and the carbon material of a graphite type or an amorphous carbon is mentioned.
　リチウムイオン二次電池の作製方法の一例は、以下に示す通りである。 An example of a method for manufacturing a lithium ion secondary battery is as follows.
　正極活物質を炭素材料粉末の導電材およびポリフッ化ビニリデン等の結着剤と共に混合してスラリーを作製する。導電材の質量（ｇ）を正極活物質の質量（ｇ）で割った値は、０．０３～０．１０が望ましい。また、結着剤の質量（ｇ）を正極活物質の質量（ｇ）で割った値は、０．０２～０．１０が望ましい。そして、正極活物質をスラリー中で均一に分散させるため、混練機を用いて充分な混練を行うことが好ましい。 A slurry is prepared by mixing the positive electrode active material with a conductive material of carbon material powder and a binder such as polyvinylidene fluoride. The value obtained by dividing the mass (g) of the conductive material by the mass (g) of the positive electrode active material is preferably 0.03 to 0.10. The value obtained by dividing the mass (g) of the binder by the mass (g) of the positive electrode active material is preferably 0.02 to 0.10. And in order to disperse | distribute a positive electrode active material uniformly in a slurry, it is preferable to fully knead | mix using a kneader.
　得られたスラリーは、例えばロール転写機などによって、厚み１５μｍ～２５μｍのアルミ箔上に両面塗布する。両面塗布した後、プレス乾燥することによって正極板１の電極版を形成する。正極活物質、導電材及び結着剤を混合した合剤部分の厚さは２００μｍ～２５０μｍが望ましい。 The obtained slurry is coated on both sides of an aluminum foil having a thickness of 15 μm to 25 μm by, for example, a roll transfer machine. After coating on both sides, the electrode plate of the positive electrode plate 1 is formed by press drying. The thickness of the mixture portion where the positive electrode active material, the conductive material and the binder are mixed is desirably 200 μm to 250 μm.
　負極は、正極と同様に結着剤と混合して塗布し、プレス乾燥して電極を形成する。ここで、負極合剤の厚さは１００μｍ～１５０μｍが望ましい。負極板２には、集電体として厚さ７μｍ～２０μｍの銅箔を用いる。塗布する材料は、負極活物質の質量（ｇ）と結着剤の質量（ｇ）との比が、例えば、９０：１０～９８：２程度であることが望ましい。 The negative electrode is mixed with a binder and applied in the same manner as the positive electrode, and press dried to form an electrode. Here, the thickness of the negative electrode mixture is preferably 100 μm to 150 μm. For the negative electrode plate 2, a copper foil having a thickness of 7 μm to 20 μm is used as a current collector. The material to be applied preferably has a ratio of the mass (g) of the negative electrode active material to the mass (g) of the binder of, for example, about 90:10 to 98: 2.
　得られた電極板は所定の長さに切断し、電極を形成して、電流引き出し部のタブ部をスポット溶接または超音波溶接により形成する。タブ部は、長方形の形状をした集電体とそれぞれ同じ材質の金属箔からできており、電極から電流を取り出すために設置するものであり、正極リード片７および負極リード片５となる。 The obtained electrode plate is cut into a predetermined length, an electrode is formed, and the tab portion of the current drawing portion is formed by spot welding or ultrasonic welding. The tab portion is made of a metal foil made of the same material as the rectangular current collector, and is installed to take out current from the electrode. The tab portion becomes the positive electrode lead piece 7 and the negative electrode lead piece 5.
　タブ付けされた正極板１および負極板２の間に微多孔質膜、例えば、ポリエチレン（ＰＥ）やポリプロピレン（ＰＰ）などで形成されたセパレータ３を挟んで重ね、これを円筒状に捲いて電極群とし、円筒状容器である電池缶４に収納する。あるいは、セパレータに袋状のものを用いてこの中に電極を収納し、これらを順次重ねて角型容器に収納してもよい。容器の材質はステンレスまたはアルミニウムが望ましい。 A microporous film, for example, a separator 3 formed of polyethylene (PE), polypropylene (PP) or the like is sandwiched between the tabbed positive electrode plate 1 and the negative electrode plate 2, and this is rolled into a cylindrical shape to form an electrode. A group is housed in a battery can 4 which is a cylindrical container. Alternatively, a bag-shaped separator may be used to store the electrodes therein, which are sequentially stacked and stored in the square container. The material of the container is preferably stainless steel or aluminum.
　電池群を電池缶４に収納した後、非水系電解液を注入し、蓋部６およびパッキン８を用いて密封する。 After storing the battery group in the battery can 4, a non-aqueous electrolyte solution is injected and sealed using the lid 6 and the packing 8.
　非水系電解液としては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）、メチルアセテート（ＭＡ）、メチルプロピルカーボネート（ＭＰＣ）、ビニレンカーボネート（ＶＣ）等の溶媒に、リチウム塩としてリチウムヘキサフルオロホスフェート（ＬｉＰＦ６）、リチウムテトラフルオロボレート（ＬｉＢＦ４）、リチウムパークロレート（ＬｉＣｌＯ４）、リチウムビス－オキサラトボレート（ＬｉＢＯＢ）等のリチウム塩を溶解させたものを用いることが望ましい。リチウム塩の濃度は０．７ｍｏｌ/ｌ～１．５ｍｏｌ/ｌが望ましい。 Non-aqueous electrolytes include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl acetate (MA), methyl propyl carbonate (MPC) Lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium bis-oxalatoborate (LiBOB), etc., in a solvent such as vinylene carbonate (VC) It is desirable to use a solution in which the lithium salt is dissolved. The concentration of the lithium salt is preferably 0.7 mol / l to 1.5 mol / l.
　これにより、作製されたリチウムイオン二次電池は、一対の正極および負極が、セパレータおよび非水系電解液を介して対向した構成であって、高いエネルギー密度と優れたハイレート特性とを有するリチウムイオン二次電池を提供することができる。 Thus, the fabricated lithium ion secondary battery has a configuration in which a pair of positive and negative electrodes face each other with a separator and a non-aqueous electrolyte, and has a high energy density and excellent high rate characteristics. A secondary battery can be provided.
　以下に、本発明の実施例を示す。本発明は、これらの実施例に限定されるものではないことは言うまでもない。 Examples of the present invention are shown below. It goes without saying that the present invention is not limited to these examples.
［実施例１］
　本発明において、正極活物質と電解液を組み合わせた実施例を紹介する。 [Example 1]
In the present invention, examples in which a positive electrode active material and an electrolytic solution are combined will be introduced.
　正極活物質として、化学式がＬｉ１．１０Ｍｎ１．８６Ｍｇ０．０４Ｏ４で表されるマンガン酸リチウム（スピネルマンガン）を用いた。 As the positive electrode active material, lithium manganate (spinel manganese) represented by the chemical formula Li 1.10 Mn 1.86 Mg 0.04 O 4 was used.
　電解液として、エチレンカーボネート（ＥＣ）の体積（ｌ）と、エチルメチルカーボネート（ＥＭＣ）の体積（ｌ）との比が、１：２となるよう混合した有機溶媒に、リチウムヘキサフルオロホスフェート（ＬｉＰＦ６）を１．０ｍｏｌ/ｌの濃度となるよう溶解させたものを用いた。この電解液の密度は１．２ｇ/ｃｍ３であった。カールフィッシャー法で測定した電解液中の水分濃度は４ｗｔｐｐｍであった。また、滴定法で測定した電解液中のフッ化水素（ＨＦ）濃度は６ｗｔｐｐｍであった。 As an electrolytic solution, lithium hexafluorophosphate (LiPF) was added to an organic solvent mixed so that the ratio of the volume (l) of ethylene carbonate (EC) to the volume (l) of ethyl methyl carbonate (EMC) was 1: 2. 6 ) was used so as to have a concentration of 1.0 mol / l. The density of this electrolytic solution was 1.2 g / cm 3 . The water concentration in the electrolytic solution measured by the Karl Fischer method was 4 wtppm. Moreover, the hydrogen fluoride (HF) density | concentration in the electrolyte solution measured by the titration method was 6 wtppm.
　最初に、正極活物質５．０ｇと電解液４．８ｇをフッ素樹脂容器に入れ、密封した。正極活物質とフッ素樹脂容器は事前に１２０℃で１時間真空乾燥を行った。さらにフッ素樹脂容器をアルミラミネート袋に入れて密封した上で、ＳＵＳ製の気密容器中に封入した。以上の作業をＡｒ雰囲気のグローブボックス内で行った。これにより、後述する高温貯蔵中に外部からの水分が電解液中へ混入する事を防いだ。 First, 5.0 g of the positive electrode active material and 4.8 g of the electrolytic solution were put in a fluororesin container and sealed. The positive electrode active material and the fluororesin container were previously vacuum dried at 120 ° C. for 1 hour. Further, the fluororesin container was put in an aluminum laminate bag and sealed, and then sealed in an airtight container made of SUS. The above operation was performed in a glove box in an Ar atmosphere. This prevented moisture from the outside from being mixed into the electrolyte during high-temperature storage described below.
　次に、ＳＵＳ製の気密容器を８０℃の恒温槽の内部に高温貯蔵した。７日間貯蔵した後、気密容器を恒温槽から取出し、室温まで除冷した。容器から電解液を取出し、硫酸白煙まで加熱濃縮した後、希硝酸で加温溶解し、高周波誘導結合プラズマ発光分光分析装置でマンガンを定量した。電解液中に溶出したマンガンの質量（以下、溶出マンガン質量と称す）は１８６０μｇだった。すなわち、実施例１において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は０．９６だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は３７２だった。 Next, the airtight container made of SUS was stored at a high temperature in a constant temperature bath at 80 ° C. After storing for 7 days, the airtight container was taken out of the thermostatic bath and cooled to room temperature. The electrolytic solution was taken out from the container, concentrated by heating to white sulfuric acid smoke, heated and dissolved with dilute nitric acid, and manganese was quantified with a high frequency inductively coupled plasma emission spectrometer. The mass of manganese eluted in the electrolyte (hereinafter referred to as eluted manganese mass) was 1860 μg. That is, in Example 1, when the mass of the electrolyte was A (g) and the mass of the manganese oxide was B (g), the value of C = A / B was 0.96. Further, when the eluted manganese mass was D (μg), the value of E = D / B was 372.
［実施例２］
　正極活物質の質量を１．５ｇとした以外は、実施例１と同じ構成で評価した。溶出マンガン質量は３０５μｇだった。すなわち、実施例２において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は３．２０だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は２０３だった。 [Example 2]
Evaluation was made in the same configuration as in Example 1 except that the mass of the positive electrode active material was changed to 1.5 g. The mass of eluted manganese was 305 μg. That is, in Example 2, when the mass of the electrolyte was A (g) and the mass of the manganese oxide was B (g), the value of C = A / B was 3.20. Further, when the mass of eluted manganese was D (μg), the value of E = D / B was 203.
［実施例３］
　正極活物質の質量を１．０ｇ、電解液を７．２ｇとした以外は、実施例１と同じ構成で評価した。溶出マンガン質量は３５μｇだった。すなわち、実施例３において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は７．２０だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は３５だった。 [Example 3]
Evaluation was made in the same configuration as Example 1 except that the mass of the positive electrode active material was 1.0 g and the electrolytic solution was 7.2 g. The eluted manganese mass was 35 μg. That is, in Example 3, when the mass of the electrolyte was A (g) and the mass of the manganese oxide was B (g), the value of C = A / B was 7.20. Further, when the eluted manganese mass was D (μg), the value of E = D / B was 35.
［実施例４］
　正極活物質の質量を１．０ｇ、電解液を８．５ｇとした以外は、実施例１と同じ構成で評価した。溶出マンガン質量は１９８μｇだった。すなわち、実施例４において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は８．５０だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は１９８だった。 [Example 4]
Evaluation was made in the same configuration as in Example 1 except that the mass of the positive electrode active material was 1.0 g and the electrolytic solution was 8.5 g. The mass of eluted manganese was 198 μg. That is, in Example 4, when the mass of the electrolyte was A (g) and the mass of the manganese oxide was B (g), the value of C = A / B was 8.50. Further, when the eluted manganese mass was D (μg), the value of E = D / B was 198.
［比較例１］
　正極活物質の質量を５．０ｇ、電解液を１．０ｇとした以外は、実施例１と同じ構成で評価した。溶出マンガン質量は２４１５μｇだった。すなわち、比較例１において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は０．２０だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は４８３だった。 [Comparative Example 1]
Evaluation was made in the same configuration as in Example 1 except that the mass of the positive electrode active material was 5.0 g and the electrolytic solution was 1.0 g. The mass of eluted manganese was 2415 μg. That is, in Comparative Example 1, when the electrolyte solution mass was A (g) and the manganese oxide mass was B (g), the value of C = A / B was 0.20. Further, when the mass of eluted manganese was D (μg), the value of E = D / B was 483.
［比較例２］
　正極活物質の質量を０．５ｇとした以外は、実施例１と同じ構成で評価した。溶出マンガン質量は６２９μｇだった。すなわち、比較例２において電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は９．６０だった。また、溶出マンガン質量をD（μｇ）とするとき、E = D/Bの値は１２５８だった。 [Comparative Example 2]
Evaluation was made with the same configuration as in Example 1 except that the mass of the positive electrode active material was changed to 0.5 g. The mass of eluted manganese was 629 μg. That is, in Comparative Example 2, when the mass of the electrolytic solution was A (g) and the mass of the manganese oxide was B (g), the value of C = A / B was 9.60. Further, when the mass of eluted manganese was D (μg), the value of E = D / B was 1258.
　以上、実施例と比較例の結果をまとめて表１に示す。
Figure JPOXMLDOC01-appb-T000001
 The results of Examples and Comparative Examples are summarized in Table 1 above.
Figure JPOXMLDOC01-appb-T000001
　表１の結果を、横軸を電解液質量（ｇ）／マンガン酸化物質量（ｇ）、縦軸を溶出マンガン質量（μｇ）／マンガン酸化物質量（ｇ）として図１にグラフ化して表示する。 The results in Table 1 are graphed in FIG. 1 with the horizontal axis representing the electrolyte mass (g) / manganese oxide mass (g) and the vertical axis representing the eluted manganese mass (μg) / manganese oxide mass (g). .
　これより、マンガン酸化物質量あたりの電解液質量が増加するのに従い、マンガン酸化物質量あたりの溶出マンガン質量が当初減少する。これは、水分がフッ化水素に変化する反応の速度が水分濃度の2乗に比例するのに対し、正極活物質に付着した水分が電解液で希釈され濃度が減少するのに従い前記反応の速度、すなわちフッ化水素の生成速度が減少することにより、溶出するマンガンの量が減少するからである。なお、スピネルマンガンとフッ化水素の反応では水が生成するため、反応全体としては水分量は一定である。すなわち、マンガンの溶出反応は水分の濃度に応じた反応速度で起こり続けるため、結果として、ある期間での溶出マンガン質量は水分の濃度と正の相関を持つ。 From this, as the electrolyte solution mass per manganese oxide mass increases, the eluted manganese mass per manganese oxide mass initially decreases. This is because the reaction rate at which the moisture changes to hydrogen fluoride is proportional to the square of the moisture concentration, whereas the rate of the reaction increases as the moisture adhering to the positive electrode active material is diluted with the electrolyte and the concentration decreases. That is, when the production rate of hydrogen fluoride decreases, the amount of eluting manganese decreases. In addition, since water is produced in the reaction of spinel manganese and hydrogen fluoride, the amount of water is constant throughout the reaction. That is, the elution reaction of manganese continues to occur at a reaction rate according to the concentration of moisture, and as a result, the mass of eluted manganese in a certain period has a positive correlation with the concentration of moisture.
　一方で、マンガン酸化物質量あたりの電解液量がある値以上になると、マンガン酸化物質量あたりの溶出マンガン質量が増加する。これは、ある濃度だけ存在する電解液に含まれる水分の量が、電解液の量が増えていくのに従い増加し、水分から変化したフッ化水素の量が増加し、溶出マンガン質量が増加するためである。電解液に含まれる水分の濃度は一定のため溶出速度は変化しないが、電解液の量が増加するに従い水分の量が増加するため、溶出マンガン質量も増加する。 On the other hand, when the amount of electrolyte per mass of manganese oxide exceeds a certain value, the mass of eluted manganese per mass of manganese oxide increases. This is because the amount of water contained in an electrolyte present in a certain concentration increases as the amount of electrolyte increases, the amount of hydrogen fluoride changed from moisture increases, and the mass of eluted manganese increases. Because. Although the elution rate does not change because the concentration of water contained in the electrolyte is constant, the amount of water increases as the amount of electrolyte increases, so the mass of eluted manganese also increases.
　この観点からすると、電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は０．９６以上８．５０以下が望ましい。この範囲から値が外れるとマンガン酸化物質量あたりの溶出マンガン質量が大きいため、マンガン酸化物の劣化が著しく、これを用いたリチウムイオン二次電池の性能が悪化してしまう。 From this viewpoint, when the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g), the value of C = A / B is preferably 0.96 or more and 8.50 or less. If the value deviates from this range, the mass of eluted manganese per mass of the manganese oxide is large, so that the manganese oxide is significantly deteriorated, and the performance of the lithium ion secondary battery using the manganese oxide is deteriorated.
　さらに、前記C = A/Bの値は３．００以上８．５０以下がより好ましい。この範囲ではマンガン酸化物質量あたりの溶出マンガン質量が大きく減少するため、マンガン酸化物の劣化が小さく、これを用いたリチウムイオン二次電池の寿命をより長くすることができる。 Furthermore, the value of C = A / B is more preferably 3.00 or more and 8.50 or less. In this range, since the eluted manganese mass per manganese oxide mass is greatly reduced, the degradation of the manganese oxide is small, and the life of the lithium ion secondary battery using this can be extended.
　なお、本発明では、正極活物質の種類を２種類以上としても良い。また、マンガン酸化物以外の正極活物質を含んでも良い。この場合も、正極活物質質量あたりの電解液質量ではなく、マンガン酸化物質量あたりの電解液質量を前記の範囲とする。これは、マンガン酸化物以外の正極活物質ではマンガンの溶出が起こらないため、マンガン酸化物のみを考慮する必要があるためである。 In the present invention, the number of positive electrode active materials may be two or more. Moreover, you may include positive electrode active materials other than manganese oxide. Also in this case, not the electrolyte mass per mass of the positive electrode active material but the electrolyte mass per mass of the manganese oxide is within the above range. This is because manganese elution does not occur in positive electrode active materials other than manganese oxide, so that only manganese oxide needs to be considered.
　ここで、電解液中の水分濃度やフッ化水素濃度が本発明の条件よりも大きい場合について詳述する。電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値が６．００未満では、活物質由来の水分が反応し発生したフッ化水素によってマンガンの溶出が起こるため、電解液中の水分濃度やフッ化水素濃度は溶出マンガン質量には影響しない。前記C = A/Bの値が６．００以上では、電解液中の水分濃度やフッ化水素濃度による溶出マンガン質量への影響が支配的となるため、図１におけるカーブの傾きが本発明より大きくなり、効果が得られる前記Cの値の範囲が狭くなる。 Here, the case where the water concentration and hydrogen fluoride concentration in the electrolytic solution are larger than the conditions of the present invention will be described in detail. When the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g), if the value of C = A / B is less than 6.00, the fluorination generated by the reaction of water derived from the active material Since manganese is eluted by hydrogen, the water concentration and hydrogen fluoride concentration in the electrolyte do not affect the mass of eluted manganese. When the value of C = A / B is 6.00 or more, the influence of the moisture concentration and hydrogen fluoride concentration in the electrolytic solution on the eluted manganese mass is dominant, so the slope of the curve in FIG. The range of the C value where the effect is obtained becomes narrower.
　次に、電解液中の水分濃度やフッ化水素濃度が本発明の条件よりも小さい場合について詳述する。前記C = A/Bの値が６．００未満では、活物質由来の水分が反応し発生したフッ化水素によってマンガンの溶出が起こるため、電解液中の水分濃度やフッ化水素濃度は溶出マンガン質量には影響しない。前記C = A/Bの値が６．００以上では、電解液中の水分濃度やフッ化水素濃度による溶出マンガン質量への影響が支配的となるため、図１におけるカーブの傾きが本発明より小さくなり、効果が得られる前記Cの値の範囲が広くなる。 Next, the case where the water concentration and hydrogen fluoride concentration in the electrolytic solution are smaller than the conditions of the present invention will be described in detail. When the value of C = A / B is less than 6.00, elution of manganese is caused by hydrogen fluoride generated by reaction of water derived from the active material. Does not affect mass. When the value of C = A / B is 6.00 or more, the influence of the moisture concentration and hydrogen fluoride concentration in the electrolytic solution on the eluted manganese mass is dominant, so the slope of the curve in FIG. The range of the C value where the effect is obtained and the effect is obtained is widened.
　ただし、電解液の量を多くすると電池の質量および体積が増加するため、電解液の量は電池形状への要件に応じて制限される。したがって、電解液中の水分濃度やフッ化水素濃度によらず効果を得るためには、前記C = A/Bの値は３．００以上６．００以下であることがさらに好ましい。 However, since the mass and volume of the battery increase when the amount of the electrolyte is increased, the amount of the electrolyte is limited according to the requirements for the battery shape. Therefore, in order to obtain the effect regardless of the water concentration or hydrogen fluoride concentration in the electrolytic solution, the value of C = A / B is more preferably 3.00 or more and 6.00 or less.
　図２は、本実施の形態で示したマンガン酸化物質量と電解液質量の規定を適用した、１８６５０（直径１８ｍｍ×高さ６５０ｍｍ）型電池を示したものである。以下に１８６５０電池の製法を示す。 FIG. 2 shows a 18650 (diameter 18 mm × height 650 mm) type battery to which the regulation of manganese oxide mass and electrolyte mass shown in this embodiment is applied. The manufacturing method of 18650 battery is shown below.
　最初に、正極活物質の質量（ｇ）、炭素材料粉末の導電材の質量（ｇ）、結着剤として用いたＰＶｄＦの質量（ｇ）が、９０：４．５：５．５となるように混合し、適量のＮＭＰを加えてスラリーを作製する。この際の正極活物質としては、マンガン酸化物を用いる。作製されたスラリーをプラネタリーミキサーで３時間攪拌して、混練を行う。 
　次に、混練されたスラリーを、ロール転写機の塗布機を用いて、厚さ２０μｍのアルミニウム箔の両面に塗布する。これをロールプレス機で合剤密度が２．７０ｇ／ｃｍ３となるようにプレスし、正極を得る。 First, the mass (g) of the positive electrode active material, the mass (g) of the conductive material of the carbon material powder, and the mass (g) of PVdF used as the binder are 90: 4.5: 5.5. And an appropriate amount of NMP is added to prepare a slurry. In this case, manganese oxide is used as the positive electrode active material. The prepared slurry is stirred for 3 hours with a planetary mixer and kneaded.
Next, the kneaded slurry is applied to both sides of an aluminum foil having a thickness of 20 μm using an applicator of a roll transfer machine. This is pressed by a roll press machine so that the mixture density becomes 2.70 g / cm 3 to obtain a positive electrode.
　さらに、負極活物質として黒鉛の質量（ｇ）、導電材としてカーボンブラックの質量（ｇ）、結着剤として用いたＰＶｄＦの質量（ｇ）が、９２．２：１．６：６．２となるように混合し、スラリーミキサーで３０分攪拌して混練を行う。混練されたスラリーを、塗布機を用いて、厚さ１０μｍの銅箔の両面に塗布し、乾燥した後に、ロールプレスでプレスし、負極を得る。 
　正極および負極の電極を、それぞれ所定の大きさに裁断し、これらの電極においてスラリーを塗布していない部分（未塗布部）に超音波溶接によって集電タブを設置する。これらの正極および負極の電極の間に多孔性のポリエチレンフィルムを挟んで円筒状に捲回した後に、１８６５０型電池缶に挿入する。 Further, the mass (g) of graphite as the negative electrode active material, the mass (g) of carbon black as the conductive material, and the mass (g) of PVdF used as the binder were 92.2: 1.6: 6.2. Knead by stirring for 30 minutes with a slurry mixer. The kneaded slurry is applied to both sides of a 10 μm thick copper foil using an applicator, dried, and then pressed with a roll press to obtain a negative electrode.
The positive electrode and the negative electrode are each cut into a predetermined size, and a current collecting tab is installed by ultrasonic welding on a portion of these electrodes where the slurry is not applied (uncoated portion). A porous polyethylene film is sandwiched between these positive and negative electrodes, wound into a cylindrical shape, and then inserted into a 18650 type battery can.
　集電タブと電池缶の蓋部とを接続した後、電池缶の蓋部と電池缶とをレーザー溶接により溶接して電池を密封する。 After connecting the current collecting tab and the lid of the battery can, the lid of the battery can and the battery can are welded by laser welding to seal the battery.
　最後に、電池缶に設けた注液口から非水系電解液を注入して１８６５０型電池を得る。電解液としては、ＥＣ（エチレンカーボネート）とＥＭＣ（エチルメチルカーボネート）との混合溶媒にＬｉＰＦ６（リチウムヘキサフルオロホスフェート）を１．０ｍｏｌ／ｌの濃度となるよう溶解する。電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は０．９６以上８．５０以下となるようにする。 Finally, a 18650 type battery is obtained by injecting a non-aqueous electrolyte from a liquid injection port provided in the battery can. As an electrolytic solution, LiPF 6 (lithium hexafluorophosphate) is dissolved in a mixed solvent of EC (ethylene carbonate) and EMC (ethyl methyl carbonate) to a concentration of 1.0 mol / l. When the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g), the value of C = A / B is set to 0.96 or more and 8.50 or less.
　なお、本実施形態で示したマンガン酸化物質量と電解液質量の規定を適用した電池は上記の構成に限られないことは言うまでもない。例えば、外装容器の形状を円筒形から角形すなわち直方体形としても良い。また、外装容器の材質をアルミラミネートとしても良い。 Needless to say, the battery to which the provisions of the manganese oxide mass and the electrolyte mass shown in the present embodiment are applied is not limited to the above configuration. For example, the shape of the outer container may be changed from a cylindrical shape to a rectangular shape, that is, a rectangular parallelepiped shape. The material of the outer container may be aluminum laminate.
　外装容器にアルミラミネートを採用した場合について述べる。正極と負極との間にセパレータを介在させる。正極集電体及び負極集電体のタブ部には正極活物質及び負極活物質が未塗工である。タブ部は外部への集電端子にそれぞれ接続され、電池素子を形成する。電池素子の外周部はアルミラミネートシートが熱溶着により溶着されており、これにより電池素子が封止される。集電端子の位置は１８０度対向位置から延出させて配置してもよい。 述 べ る The case where aluminum laminate is adopted for the exterior container is described. A separator is interposed between the positive electrode and the negative electrode. The positive electrode active material and the negative electrode active material are not coated on the tab portions of the positive electrode current collector and the negative electrode current collector. The tab portions are respectively connected to external current collecting terminals to form battery elements. An aluminum laminate sheet is welded to the outer periphery of the battery element by heat welding, thereby sealing the battery element. You may arrange | position the position of a current collection terminal extended from the opposing position 180 degree | times.
　図３は、本実施形態で示したマンガン酸化物質量と電解液質量の規定を適用した、リチウムイオン二次電池を搭載した二次電池システムを示したものである。複数個のリチウムイオン二次電池１０、例えば４～８個が直列に接続され、リチウムイオン二次電池の組電池を形成する。更に、このリチウムイオン二次電池の組電池を複数接続してリチウムイオン二次電池群を構成する。 FIG. 3 shows a secondary battery system equipped with a lithium ion secondary battery to which the rules for manganese oxide mass and electrolyte mass shown in the present embodiment are applied. A plurality of lithium ion secondary batteries 10, for example, 4 to 8, are connected in series to form an assembled battery of lithium ion secondary batteries. Further, a plurality of assembled batteries of the lithium ion secondary batteries are connected to constitute a lithium ion secondary battery group.
　セルコントローラ１１は、こうしたリチウムイオン二次電池群に対応して形成され、リチウムイオン二次電池１０を制御する。セルコントローラ１１は、リチウムイオン二次電池１０の過充電や過放電のモニタリングやリチウムイオン二次電池１０の残存容量のモニタリングを行う。 The cell controller 11 is formed corresponding to such a group of lithium ion secondary batteries and controls the lithium ion secondary battery 10. The cell controller 11 monitors overcharge and overdischarge of the lithium ion secondary battery 10 and monitors the remaining capacity of the lithium ion secondary battery 10.
　バッテリーコントローラ１２は、セルコントローラ１１に信号を、例えば、通信手段を使用して与えると共に、セルコントローラ１１からの信号を、例えば、通信手段を使用して取得する。バッテリーコントローラ１２は、セルコントローラ１１に対する電力の入出力管理を行う。 The battery controller 12 gives a signal to the cell controller 11 using, for example, communication means, and acquires a signal from the cell controller 11 using, for example, communication means. The battery controller 12 performs power input / output management for the cell controller 11.
　バッテリーコントローラ１２は、例えば、最初のセルコントローラ１１の入力部１１１に信号を与える。こうした信号が、セルコントローラ１１の出力部１１２から他のセルコントローラ１１の入力部１１１にシリーズに伝えられる。この信号は、最後のセルコントローラ１１の出力部１１２からバッテリーコントローラ１２に与えられる。こうしてバッテリーコントローラ１２は、セルコントローラ１１をモニタすることが可能となる。 The battery controller 12 gives a signal to the input unit 111 of the first cell controller 11, for example. Such a signal is transmitted from the output unit 112 of the cell controller 11 to the input unit 111 of another cell controller 11 to the series. This signal is given to the battery controller 12 from the output unit 112 of the last cell controller 11. In this way, the battery controller 12 can monitor the cell controller 11.
　図４は、本実施形態で示したマンガン酸化物質量と電解液質量の規定を適用した、低温部用と高温部用のリチウムイオン二次電池を搭載した二次電池システムを示したものである。 FIG. 4 shows a secondary battery system equipped with a lithium ion secondary battery for a low temperature part and a high temperature part to which the regulation of the manganese oxide mass and the electrolyte mass shown in the present embodiment is applied. .
　二次電池システムは、比較的高温となる高温部１４と、比較的低温となる低温部１５を有している。そして、二次電池システムの高温部１４には、マンガン酸化物質量に対する電解液量が相対的に多いリチウムイオン電池（高温部用リチウムイオン二次電池１１０）が配置されている。一方、二次電池システムの低温部１５には、マンガン酸化物質量に対する電解液量が相対的に少ないリチウムイオン電池（低温部用リチウムイオン二次電池１１３）が配置されている。これにより、省スペース化と寿命維持を兼ね備えた二次電池システムを作製できる。 The secondary battery system has a high temperature portion 14 that is relatively high temperature and a low temperature portion 15 that is relatively low temperature. And in the high temperature part 14 of a secondary battery system, the lithium ion battery (lithium ion secondary battery 110 for high temperature parts) with relatively much electrolyte solution quantity with respect to the mass of manganese oxide is arrange | positioned. On the other hand, in the low temperature part 15 of the secondary battery system, a lithium ion battery (low temperature part lithium ion secondary battery 113) having a relatively small amount of electrolyte with respect to the mass of manganese oxide is disposed. Thereby, a secondary battery system having both space saving and life maintenance can be manufactured.
　高温部用リチウムイオン二次電池１１０において、電解液の質量をA（ｇ）、マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値は３．００以上８．５０以下であることが望ましい。また、低温部用リチウムイオン二次電池１１３において、前記C = A/Bの値の値は０．９６以上８．５０以下であることが望ましい。 In the high temperature portion lithium ion secondary battery 110, when the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g), the value of C = A / B is 3.00 or more and 8.50. The following is desirable. Further, in the low-temperature part lithium ion secondary battery 113, the value of C 前 記 = A / B is preferably 0.96 or more and 8.50 or less.
　上記構成を有するリチウムイオン二次電池及び二次電池システムによれば、高温貯蔵時におけるマンガンの溶出が抑制される。したがって、電池を50℃以上で保持した際や充放電サイクルを行った際に容量の低下や抵抗の上昇などが発生することを抑制でき、従来よりも長寿命化を図ることができる。 According to the lithium ion secondary battery and the secondary battery system having the above-described configuration, elution of manganese during high temperature storage is suppressed. Therefore, when the battery is held at 50 ° C. or higher or when a charge / discharge cycle is performed, it is possible to suppress a decrease in capacity, an increase in resistance, and the like, and a longer life can be achieved than in the past.
　以上、本発明の実施形態について詳述したが、本発明は、前記の実施形態に限定されるものではなく、特許請求の範囲に記載された本発明の精神を逸脱しない範囲で、種々の設計変更を行うことができるものである。例えば、前記した実施の形態は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。さらに、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
　本発明のリチウムイオン二次電池および二次電池システムは、従来の構成より長寿命化が期待でき、特に、大型定置用電源として有用である。 The lithium ion secondary battery and secondary battery system of the present invention can be expected to have a longer life than the conventional configuration, and is particularly useful as a large stationary power source.
１…正極板、２…負極板、３…セパレータ、４…電池缶、５…負極リード片、６…蓋部、７…正極リード片、８…パッキン、９…絶縁板、１０…リチウムイオン二次電池、１１…セルコントローラ、１２…バッテリーコントローラ、１３…信号線、１４…二次電池システム高温部、１５…二次電池システム低温部、１１０…高温部用リチウムイオン二次電池、１１１…入力部、１１２…出力部、１１３…低温部用リチウムイオン二次電池 DESCRIPTION OF SYMBOLS 1 ... Positive electrode plate, 2 ... Negative electrode plate, 3 ... Separator, 4 ... Battery can, 5 ... Negative electrode lead piece, 6 ... Cover part, 7 ... Positive electrode lead piece, 8 ... Packing, 9 ... Insulating plate, 10 ... Lithium ion 2 Secondary battery, 11 ... Cell controller, 12 ... Battery controller, 13 ... Signal line, 14 ... Secondary battery system high temperature part, 15 ... Secondary battery system low temperature part, 110 ... Lithium ion secondary battery for high temperature part, 111 ... Input Part, 112 ... output part, 113 ... lithium ion secondary battery for low temperature part

Claims (4)

  1. 　正極活物質として少なくともマンガン酸化物を有する正極と、リチウムを吸蔵放出可能な負極と、リチウム塩を含有する非水系溶媒からなる電解液とを有するリチウムイオン二次電池であって、
    　前記電解液の質量をA（ｇ）、前記マンガン酸化物の質量をB（ｇ）とするとき、C = A/Bの値が０．９６以上８．５０以下であることを特徴とするリチウムイオン二次電池。     A lithium ion secondary battery comprising a positive electrode having at least a manganese oxide as a positive electrode active material, a negative electrode capable of occluding and releasing lithium, and an electrolyte solution comprising a non-aqueous solvent containing a lithium salt,
    Lithium characterized in that the value of C = A / B is 0.96 or more and 8.50 or less when the mass of the electrolyte is A (g) and the mass of the manganese oxide is B (g). Ion secondary battery.
  2. 　前記リチウム塩は、ＬｉＰＦ６であることを特徴とする請求項１に記載のリチウムイオン二次電池。 The lithium ion secondary battery according to claim 1, wherein the lithium salt is LiPF 6 .
  3. 　前記正極活物質は、ＬｉａＭｎｂＭｃＯ４（但し、ａ＋ｂ＋ｃ＝３であり、Ｍは、Ａｌ、Ｃｏ、Ｃｒ、Ｎｉ、Ｆｅ、Ｚｎ、Ｍｇ及びＣｕからなる群より選ばれる少なくとも一種類の元素である。）であることを特徴とする請求項１に記載のリチウムイオン二次電池。 The positive electrode active material is Li a Mn b McO 4 (where a + b + c = 3, and M is at least one selected from the group consisting of Al, Co, Cr, Ni, Fe, Zn, Mg, and Cu) The lithium ion secondary battery according to claim 1, wherein:
  4. 　前記請求項１に記載のリチウムイオン二次電池を用いたことを特徴とする二次電池システム。 A secondary battery system using the lithium ion secondary battery according to claim 1.
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