WO2022181207A1 - 非水電解質二次電池 - Google Patents
非水電解質二次電池 Download PDFInfo
- Publication number
- WO2022181207A1 WO2022181207A1 PCT/JP2022/003367 JP2022003367W WO2022181207A1 WO 2022181207 A1 WO2022181207 A1 WO 2022181207A1 JP 2022003367 W JP2022003367 W JP 2022003367W WO 2022181207 A1 WO2022181207 A1 WO 2022181207A1
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- WIPO (PCT)
- Prior art keywords
- positive electrode
- negative electrode
- electrolyte secondary
- secondary battery
- aqueous electrolyte
- Prior art date
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- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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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
- H01M4/58—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
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
- H01M50/109—Primary casings; Jackets or wrappings characterised by their shape or physical structure of button or coin shape
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- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/147—Lids or covers
- H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
- H01M50/167—Lids or covers characterised by the methods of assembling casings with lids by crimping
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/183—Sealing members
- H01M50/184—Sealing members characterised by their shape or structure
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/183—Sealing members
- H01M50/186—Sealing members characterised by the disposition of the sealing members
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
- H01M50/437—Glass
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
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- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/14—Cells with non-aqueous electrolyte
- H01M6/16—Cells with non-aqueous electrolyte with organic electrolyte
- H01M6/162—Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte
- H01M6/164—Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte by the solvent
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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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0028—Organic electrolyte characterised by the solvent
- H01M2300/0034—Fluorinated solvents
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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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
- H01M2300/0028—Organic electrolyte characterised by the solvent
- H01M2300/0037—Mixture of solvents
- H01M2300/004—Three solvents
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- 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 non-aqueous electrolyte secondary batteries.
- This application claims priority based on Japanese Patent Application No. 2021-030396 filed in Japan on February 26, 2021, and the contents thereof are incorporated herein.
- a non-aqueous electrolyte secondary battery contains a pair of polarizable electrodes consisting of a positive electrode and a negative electrode, a separator interposed between the positive electrode and the negative electrode, and the positive electrode, the negative electrode, and the separator impregnated in a sealed container, and an electrolytic solution containing a non-aqueous solvent such as a supporting salt and an organic solvent.
- a non-aqueous electrolyte secondary battery has a high energy density and is light in weight, so that it is used as a power supply unit of electronic equipment, a power storage unit that absorbs fluctuations in the amount of power generated by a power generation device, and the like.
- a non-aqueous electrolyte secondary battery containing silicon oxide (SiO x ) as a negative electrode active material in the negative electrode can obtain a high discharge capacity. It is used as a secondary battery.
- Such coin-type non-aqueous electrolyte secondary batteries are known to have high voltage, high energy density, excellent charge-discharge characteristics, long cycle life and high reliability. Therefore, non-aqueous electrolyte batteries have been conventionally used as backup power sources for semiconductor memories and clock functions in various small electronic devices such as mobile phones, PDAs, portable game machines, and digital cameras. (See Patent Document 1, for example).
- an organic electrolyte using a cyclic carbonate, a chain carbonate, or a mixture thereof as a solvent is used as the electrolyte.
- EC ethylene carbonate
- PC propylene carbonate
- DME dimethoxyethane
- Non-aqueous electrolyte secondary battery described in Patent Document 1 it relates to a coin-type non-aqueous electrolyte secondary battery with a discharge current of about 5 to 25 ⁇ A, which is used for memory backup of mounted equipment, etc., especially in a low temperature environment. Sufficient discharge capacity is ensured in a wide temperature range including below. More specifically, in Patent Document 1, EC and PC are used as organic solvents for the purpose of maintaining discharge capacity in a high-temperature environment, and further, for the purpose of improving low-temperature characteristics, DME is used. In addition, in Patent Document 1, the concentration of the supporting salt is set to 0.6 to 1.4 mol/L, because it is usually difficult to obtain a sufficient discharge capacity if the concentration of the supporting salt is too high.
- non-aqueous electrolyte secondary batteries such as small coin-type batteries to be used not only for memory backup purposes but also as main power sources.
- the non-aqueous electrolyte secondary battery is required to have high output characteristics capable of supplying a large current in addition to being small and having a high capacity.
- high output characteristics can be obtained with the composition of the electrolyte provided in a conventional non-aqueous electrolyte secondary battery, as disclosed in Patent Document 1.
- the present invention has been made in view of the above problems, and is capable of supplying a large current over a wide temperature range, maintaining a sufficient discharge capacity even at a mA level discharge, and achieving high output and high capacity while being compact.
- An object of the present invention is to provide a non-aqueous electrolyte secondary battery in which
- the present inventors have made extensive studies to solve the above problems, and found that a small non-aqueous electrolyte secondary battery such as a coin can supply a large current over a wide temperature range and maintain a sufficient discharge capacity.
- a small non-aqueous electrolyte secondary battery such as a coin can supply a large current over a wide temperature range and maintain a sufficient discharge capacity.
- the present inventors first found that as organic solvents contained in the electrolyte, a cyclic carbonate solvent having a structure represented by the following (chemical formula 1) and a chain ether solvent having a structure represented by the following (chemical formula 2) and by adjusting the mixing ratio of each solvent, the low-temperature characteristics can be improved without impairing the capacity characteristics at room temperature and the capacity retention rate at high temperatures.
- R1, R2, R3, and R4 represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms, and a fluorinated alkyl group.
- R1, R2, R3, and R4 in the above (chemical formula 1) may be the same or different.
- R7 and R8 each represent hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms, or a fluorinated alkyl group. Also, R7 and R8 may be the same or different.
- the present inventors repeated further experiments and studies on the cyclic carbonate solvent (chemical formula 1) and chain ether solvent (chemical formula 2) that constitute the mixed solvent.
- cyclic carbonate solvent chemical formula 1
- chain ether solvent chemical formula 2
- EC ethylene carbonate
- PC propylene carbonate
- DME dimethoxyethane
- the inventors have found that by adjusting the mixing ratio of EC, PC and DME, the effect of maintaining the discharge capacity particularly in a low temperature environment can be remarkably obtained.
- the inventors of the present invention have found that a small non-aqueous electrolyte secondary battery such as a coin type can be obtained by adjusting and optimizing the composition and content of the supporting salt while making the solvent used in the electrolyte solution have the above composition.
- a large current can be supplied over a wide temperature range including low-temperature environments, and high output characteristics can be obtained.
- the inventors of the present invention have found that by combining the configuration in which the composition of the electrolytic solution is optimized and the configuration in which the arrangement structure of each battery element inside the storage container is optimized, the above-described high output can be achieved.
- the present inventors have completed the present invention based on the finding that the characteristics and high capacity characteristics can be obtained more remarkably.
- the non-aqueous electrolyte secondary battery of the present invention comprises a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, an organic solvent and a supporting salt.
- the separator is made of a glass fiber nonwoven fabric, and the electrolytic solution contains propylene carbonate (PC), ethylene carbonate (EC) and dimethoxyethane (DME) as the organic solvents.
- PC propylene carbonate
- EC ethylene carbonate
- DME dimethoxyethane
- LiFSI lithium bis(fluorosulfonyl)imide
- the viscosity of the electrolytic solution is prevented from increasing in a low temperature environment of room temperature to -30 to -40 ° C., and charge transfer is performed. can be suppressed, discharge characteristics in a low-temperature environment are improved, and sufficient discharge capacity can be maintained over a wide temperature range.
- PC and EC which have a high dielectric constant and a high solubility of the supporting salts, as the cyclic carbonate solvent.
- PC and EC have high boiling points, even if they are used or stored in a high-temperature environment, they become electrolyte solutions that are difficult to volatilize.
- PC which has a lower melting point than EC, as a cyclic carbonate solvent in combination with EC, it is possible to improve low-temperature characteristics.
- Low-temperature characteristics are improved by using DME having a low melting point as the chain ether solvent.
- DME has a low viscosity, the electrical conductivity of the electrolytic solution is improved.
- DME solvates Li ions, thereby increasing the discharge capacity of the non-aqueous electrolyte secondary battery.
- LiFSI which has excellent conductivity
- the electrolytic solution contains LiFSI at a molar ratio within the above range, the voltage drop at the initial stage of discharge can be suppressed within a certain range, so that a sufficient discharge capacity can be maintained.
- the electrolytic solution contains 4 to 7 (mol/L) of lithium bis(fluorosulfonyl)imide (LiFSI) as the supporting salt. characterized by
- a non-aqueous electrolyte secondary battery can be produced under conditions of high temperature, high humidity, and overdischarge by using LiFSI, which has excellent conductivity, at a molar ratio within the above range as the supporting salt used in the electrolyte.
- the electrical properties after storage, more specifically, the overdischarge properties are further improved. This makes it possible to more effectively prevent deterioration of the nonaqueous electrolyte secondary battery even when overdischarge occurs.
- the internal resistance of the non-aqueous electrolyte secondary battery can be effectively reduced by including LiFSI in the above range in the electrolytic solution.
- the storage container is fixed to a bottomed cylindrical positive electrode can and an opening of the positive electrode can with a gasket interposed therebetween, and the positive electrode can and and a negative electrode can forming an accommodation space between them, wherein the accommodation space is sealed by caulking the opening of the positive electrode can toward the negative electrode can.
- each battery element is arranged in the storage space of the storage container in which the positive electrode can and the negative electrode can are sealed with an optimal structure, thereby providing a structure with excellent electrical insulation and sealing performance. Volatilization of the electrolytic solution and penetration of moisture contained in the air into the battery can be prevented. As a result, even a small coin-shaped non-aqueous electrolyte secondary battery can remarkably achieve the above-described high output characteristics and high capacity characteristics.
- the storage container is insulated and sealed between the inner bottom portion and inner portion of the positive electrode can and the negative electrode can with the gasket interposed therebetween.
- the structure is characterized by
- the present invention by adopting an insulating sealing structure in which a gasket is interposed in an optimal arrangement between the positive electrode can and the negative electrode can, electrical insulation and sealing performance are further enhanced. Even with a small coin-type non-aqueous electrolyte secondary battery, excellent high-output characteristics and high-capacity characteristics can be remarkably obtained.
- the non-aqueous electrolyte secondary battery of the present invention has the above configuration, that is, a configuration that employs an insulating sealing structure in which a gasket is interposed between the inner bottom and inner part of the positive electrode can and the negative electrode can, wherein the electrolytic
- the liquid is characterized by containing 3 to 4 (mol/L) of lithium bis(fluorosulfonyl)imide (LiFSI), which is the supporting salt.
- a conductive in a non-aqueous electrolyte secondary battery employing an insulating sealing structure in which a gasket is interposed between the inner bottom and inner part of the positive electrode can and the negative electrode can, a conductive
- a battery containing LiFSI having excellent properties in the molar ratio within the above range, a large current can be obtained and a sufficient discharge capacity can be maintained.
- excellent high output characteristics and high capacity characteristics can be obtained more remarkably.
- the positive electrode is arranged so that the storage container covers the entire inner bottom portion of the positive electrode can, and the inner portion of the positive electrode can and the positive electrode
- the structure is characterized in that it is insulated and sealed with the gasket interposed between it and the negative electrode can.
- the positive electrode is arranged so as to cover the entire surface of the inner bottom of the positive electrode can, and a gasket is interposed between the inner portion of the positive electrode can and the positive electrode and the negative electrode can.
- the electrical insulation and hermeticity are further enhanced.
- excellent high-output characteristics and high-capacity characteristics can be obtained.
- the electrolytic solution contains 2 to 3 (mol/L) of lithium bis(fluorosulfonyl)imide (LiFSI) as the supporting salt. characterized by
- the positive electrode is arranged so as to cover the entire inner bottom of the positive electrode can, and a nonaqueous structure is adopted in which a gasket is interposed between the inner part of the positive electrode can and the positive electrode and the negative electrode can.
- a nonaqueous structure is adopted in which a gasket is interposed between the inner part of the positive electrode can and the positive electrode and the negative electrode can.
- the positive electrode contains at least Li 1+x Co y Mn 2-xy O 4 (0 ⁇ x ⁇ 0.33, 0 ⁇ y ⁇ 0.2).
- the positive electrode contains the compound having the above composition as the lithium manganese oxide used as the positive electrode active material, thereby obtaining the effect of further stabilizing the high output characteristics and high capacity characteristics.
- the negative electrode contains, as the negative electrode active material, SiO X (0 ⁇ X ⁇ 2) in which at least part of the surface is coated with carbon. characterized by
- the conductivity of the negative electrode is improved, and the internal resistance is increased in a low-temperature environment. is suppressed, the voltage drop at the initial stage of discharge is suppressed, the high capacity characteristics are more stabilized, a large current can be stably supplied, and the high output characteristics are also more stabilized.
- non-aqueous electrolyte secondary battery of the present invention first, by using PC and EC in an organic solvent at an optimum ratio as an electrolyte, it is possible to operate in a wide temperature range, and at the same time, DME is added at an optimum ratio. Since the low-temperature characteristics are improved by using it, the electrical conductivity of the electrolytic solution is improved. In addition to this, both high output characteristics and high capacity characteristics can be obtained by containing LiFSI as a supporting salt in the electrolyte in an optimum range.
- FIG. 1 is a cross-sectional view schematically showing a coin-shaped non-aqueous electrolyte secondary battery according to an embodiment of the present invention.
- FIG. 2 is a cross-sectional view schematically showing a coin-shaped non-aqueous electrolyte secondary battery according to another embodiment of the present invention.
- FIG. 3A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the discharge final voltage is 1.0 V, and the discharge current is 1 mA.
- FIG. 1 is a cross-sectional view schematically showing a coin-shaped non-aqueous electrolyte secondary battery according to an embodiment of the present invention.
- FIG. 2 is a cross-sectional view schematically showing a coin-shaped non-aqueous electrolyte secondary battery according to another embodiment of the present invention.
- FIG. 3A is a diagram for explaining an example of
- FIG. 3B is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is 1.0 V, and the discharge current is 7 mA.
- FIG. 4 is a diagram for explaining an example of a non-aqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining power characteristics and capacity characteristics of the non-aqueous electrolyte secondary battery.
- 1 is a graph showing the relationship between discharge current and capacity when discharging is performed at a molar concentration of 1 to 7 mol/L, a discharge current of 1 to 8 mA, and a discharge final voltage of 1.0 V.
- FIG. 1 is a graph showing the relationship between discharge current and capacity when discharging is performed at a molar concentration of 1 to 7 mol/L, a discharge current of 1 to 8 mA, and a discharge final voltage of 1.0
- FIG. 5A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining the effect of increasing the discharge capacity of the nonaqueous electrolyte secondary battery.
- FIG. 5B is a diagram for explaining an example of the nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining the effect of increasing the discharge capacity of the nonaqueous electrolyte secondary battery.
- FIG. 6A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 1 mA.
- FIG. 6A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 1 mA.
- FIG. 6B is a diagram for explaining an example of a non-aqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the non-aqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 7 mA.
- FIG. 7A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining the effect of increasing the discharge capacity of the nonaqueous electrolyte secondary battery. is 1 to 7 mol/L, and the final discharge voltage is 1.0 V.
- a graph showing the relationship between the discharge current and the relative value when the discharge capacity at a supporting salt concentration of 1 M is 1. is.
- FIG. 7B is a diagram for explaining an example of the nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining the effect of increasing the discharge capacity of the nonaqueous electrolyte secondary battery. is 1 to 7 mol/L, and the final discharge voltage is 2.0V. is.
- FIG. 8A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 1 mA.
- FIG. 8A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 1 mA.
- FIG. 8B is a diagram for explaining an example of the nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining capacity characteristics of the nonaqueous electrolyte secondary battery. is changed, the final discharge voltage is set to 1.0 V, and the discharge is performed at 7 mA.
- FIG. 9A is a diagram for explaining an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram for explaining the effect of increasing the discharge capacity of the nonaqueous electrolyte secondary battery. is 1 to 7 mol/L, and the final discharge voltage is 1.0 V.
- a graph showing the relationship between the discharge current and the relative value when the discharge capacity at a supporting salt concentration of 1 M is 1. is.
- FIG. 10A is a diagram illustrating an example of a nonaqueous electrolyte secondary battery according to the present invention, and is a diagram illustrating changes in internal resistance of a nonaqueous electrolyte secondary battery in a high temperature and high humidity storage test.
- FIG. 10B is a diagram illustrating an example of the nonaqueous electrolyte secondary battery according to the present invention, and is a diagram illustrating the rate of increase in internal resistance of the nonaqueous electrolyte secondary battery after the high-temperature and high-humidity storage test.
- FIG. 11A is a diagram illustrating an example of a non-aqueous electrolyte secondary battery according to the present invention, and is a diagram illustrating changes in the capacity of a non-aqueous electrolyte secondary battery over-discharged after a high-temperature and high-humidity storage test.
- FIG. 11B is a diagram illustrating an example of a non-aqueous electrolyte secondary battery according to the present invention, and is a diagram illustrating changes in the capacity of a non-aqueous electrolyte secondary battery over-discharged after a high-temperature, high-humidity storage test.
- the non-aqueous electrolyte secondary battery described in the present invention specifically comprises an active material used as a positive electrode or a negative electrode and an electrolytic solution contained in a container. , for example, can be applied to electrochemical cells such as lithium ion capacitors.
- the non-aqueous electrolyte secondary battery 1 of the first embodiment shown in FIG. 1 is a so-called coin (button) type battery.
- This non-aqueous electrolyte secondary battery 1 contains a positive electrode 10 containing a positive electrode active material and capable of intercalating and deintercalating lithium ions, and a negative electrode 20 containing a negative electrode active material and capable of intercalating and deintercalating lithium ions. , a separator 30 disposed between the positive electrode 10 and the negative electrode 20, a gasket 40 for sealing the storage space of the storage container 2, and an electrolytic solution 50 containing at least a supporting salt and an organic solvent. be.
- the non-aqueous electrolyte secondary battery 1 of the present embodiment includes a bottomed cylindrical positive electrode can 12 and an opening 12a of the positive electrode can 12, which is fixed with a gasket 40 interposed therebetween.
- a cylindrical (hat-shaped) negative electrode can 22 with a lid is provided, and the housing space is sealed by crimping the peripheral edge of the opening 12a of the positive electrode can 12 inward, that is, toward the negative electrode can 22. .
- a positive electrode 10 provided on the side of the positive electrode can 12 and a negative electrode 20 provided on the side of the negative electrode can 22 are arranged opposite to each other with a separator 30 interposed in the storage space sealed by the storage container 2 . It is Moreover, in the example shown in FIG. 1, a lithium foil 60 is interposed between the negative electrode 20 and the separator 30 . Further, as shown in FIG. 1 , the gasket 40 is narrowly inserted along the inner peripheral surface of the positive electrode can 12 and is connected to the outer periphery of the separator 30 to hold the separator 30 . Moreover, the positive electrode 10 , the negative electrode 20 and the separator 30 are impregnated with the electrolytic solution 50 filled in the storage container 2 .
- non-aqueous electrolyte secondary battery 1 of the example shown in FIG. It is electrically connected to the inner surface of the negative electrode can 22 via.
- the non-aqueous electrolyte secondary battery 1 including the positive electrode current collector 14 and the negative electrode current collector 24 as illustrated in FIG. 1 is described as an example. Without limitation, for example, a configuration in which the positive electrode can 12 also serves as a positive electrode current collector and the negative electrode can 22 also serves as a negative electrode current collector may be used.
- the non-aqueous electrolyte secondary battery 1 of the present embodiment is configured as described above, so that lithium ions move from one of the positive electrode 10 and the negative electrode 20 to the other, thereby accumulating (charging) electric charge, It can release (discharge) an electric charge.
- At least one of the positive electrode 10 and the negative electrode 20 is in the form of pellets containing an active material, a conductive aid, and a binder, and the separator 30 is glass fiber. non-woven fabric.
- PC propylene carbonate
- EC ethylene carbonate
- DME dimethoxyethane
- LiFSI lithium bis(fluorosulfonyl)imide
- the storage container 2 used in the non-aqueous electrolyte secondary battery 1 of the present embodiment includes a bottomed cylindrical positive electrode can 12 and an opening 12a of the positive electrode can 12 with a gasket, the details of which will be described later. and a negative electrode can 22 that is fixed via 40 and forms a housing space between itself and the positive electrode can 12 .
- the storage container 2 is a substantially coin-shaped (button-shaped) container in which the storage space is sealed by crimping the opening 12a of the positive electrode can 12 toward the negative electrode can 22 side. Therefore, the maximum inner diameter of the positive electrode can 12 is set larger than the maximum outer diameter of the negative electrode can 22 .
- the positive electrode can 12 that constitutes the storage container 2 is configured in a cylindrical shape with a bottom, and has a circular opening 12a in plan view.
- conventionally known materials can be used without any limitation. Examples thereof include stainless steels such as SUS316L and SUS329J4. do not have.
- a metal material other than stainless steel may be used for the positive electrode can 12 .
- the negative electrode can 22 is configured in a lidded cylindrical shape (hat shape), and the tip portion 22a thereof is configured to enter the positive electrode can 12 through the opening 12a.
- the material of the negative electrode can 22 similar to the material of the positive electrode can 12, conventionally known stainless steel can be mentioned. may employ other conventionally known stainless steel such as SUS304-BA.
- a metal material other than stainless steel may be used for the negative electrode can 20 .
- a clad material in which copper, nickel, or the like is pressed against stainless steel can be used for example.
- the plate thickness of the metal plate material used for the positive electrode can 12 and the negative electrode can 22 is generally about 0.1 to 0.3 mm. Can be configured.
- the tip portion 22a of the negative electrode can 22 has a shape folded along the outer surface of the negative electrode can 22, but it is not limited to this.
- the present invention can also be applied to the case of using the negative electrode can 22 having the end face of the metal plate as the tip portion 22a and not having the above-described folded shape.
- non-aqueous electrolyte secondary battery for example, 920 size (outer diameter ⁇ 9.5 mm x height 2.0 mm), batteries of various sizes can be mentioned.
- each battery element is arranged in the storage space of the storage container 2 in which the positive electrode can 12 and the negative electrode can 22 are sealed with an optimum structure. It has a structure excellent in durability, and can effectively prevent volatilization of the electrolytic solution 50 and invasion of moisture contained in the atmosphere into the battery. Therefore, even in a small coin-shaped non-aqueous electrolyte secondary battery, by combining the electrolyte solution 50 in which the composition of the organic solvent and the supporting salt is optimized and the battery structure, which will be described later in detail, High output characteristics and high capacity characteristics are obtained.
- non-aqueous electrolyte secondary battery 1 of the example shown in FIG. It is made into the structure which interposed and was insulated and sealed.
- this embodiment by adopting an insulating sealing structure in which the gasket 40 is interposed in an optimal arrangement between the cathode can 12 and the anode can 22, electrical insulation and sealing performance are further enhanced.
- the composition of the electrolytic solution 50 which will be described in detail later, even the coin-shaped non-aqueous electrolyte secondary battery 1, which is small as shown in the figure, exhibits excellent high output characteristics. and high capacity characteristics are obtained more remarkably.
- the gasket 40 is formed in an annular shape along the inner peripheral surface of the positive electrode can 12, and the tip portion 22a of the negative electrode can 22 is arranged inside the annular groove 41 thereof.
- Examples of materials for the gasket 40 include polypropylene resin (PP), polyphenyl sulfide (PPS), polyethylene terephthalate (PET), polyamide, liquid crystal polymer (LCP), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin.
- PP polypropylene resin
- PPS polyphenyl sulfide
- PET polyethylene terephthalate
- LCP liquid crystal polymer
- tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin examples include polypropylene resin (PP), polyphenyl sulfide (PPS), polyethylene terephthalate (PET), polyamide, liquid crystal polymer (LCP), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin.
- polyetheretherketone resin PEEK
- polyethernitrile resin PEN
- polyetherketone resin PEK
- polyarylate resin polybutylene terephthalate resin (PBT)
- polycyclohexanedimethylene terephthalate resin polyether Plastic resins such as sulfone resins (PES), polyaminobismaleimide resins, polyetherimide resins, and fluorine resins can be used.
- PES polyetheretherketone resin
- PBT polycyclohexanedimethylene terephthalate resin
- polyether Plastic resins such as sulfone resins (PES), polyaminobismaleimide resins, polyetherimide resins, and fluorine resins can be used.
- PES sulfone resins
- polyaminobismaleimide resins polyetherimide resins
- fluorine resins fluorine resins
- the gasket 40 it is also possible to suitably use a material obtained by adding glass fiber, mica whisker, fine ceramic powder, or the like to the above material in an amount of 30% by mass or less. By using such a material, it is possible to suppress large deformation of the gasket due to high temperature and prevent leakage of the electrolytic solution 50 .
- a sealant may be applied to the inner surface of the annular groove of the gasket 40 .
- a sealing agent asphalt, epoxy resin, polyamide resin, butyl rubber adhesive, or the like can be used. Also, the sealant is applied to the inside of the annular groove 41 and then dried before use.
- the gasket 40 is sandwiched between the positive electrode can 12 and the negative electrode can 22, and at least a portion of the gasket 40 is compressed. 1 can be reliably sealed and the gasket 40 is not broken.
- PC propylene carbonate
- EC ethylene carbonate
- DME dimethoxyethane
- LiFSI lithium bis(fluorosulfonyl ) contains 2 to 7 (mol/L) of imide
- Such electrolyte solution 50 is generally made by dissolving a supporting salt in a non-aqueous solvent such as an organic solvent, and its characteristics are determined in consideration of the heat resistance, viscosity, etc. required of the electrolyte solution 50 . be.
- the type and content of the supporting salts are also important in order to obtain high output characteristics capable of supplying a large current in a small coin-type non-aqueous electrolyte secondary battery. had to be adjusted to the optimum range.
- the organic solvent used in the electrolytic solution 50 contains PC and EC, which are cyclic carbonate solvents, and DME, which is a chain ether solvent, in an appropriate mixing ratio.
- PC and EC which are cyclic carbonate solvents
- DME which is a chain ether solvent
- the discharge capacity of the non-aqueous electrolyte secondary battery 1 is increased by using PC and EC, which have a high dielectric constant and a high solubility of the supporting salt, as the cyclic carbonate solvent.
- PC and EC have high boiling points, even if they are used or stored/stored in a high-temperature environment, they become electrolyte solutions that are difficult to volatilize.
- PC which has a lower melting point than EC, as a cyclic carbonate solvent in combination with EC, it is possible to improve low-temperature characteristics. Low-temperature characteristics are improved by using DME having a low melting point as the chain ether solvent. Also, since DME has a low viscosity, the electrical conductivity of the electrolytic solution is improved. Furthermore, DME solvates Li ions, thereby increasing the discharge capacity of the non-aqueous electrolyte secondary battery.
- the cyclic carbonate solvent has a structure represented by the following (chemical formula 1), and examples include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), trifluoroethylene carbonate (TFPC), chloro Ethylene carbonate (ClEC), trifluoroethylene carbonate (TFEC), difluoroethylene carbonate (DFEC), vinylene carbonate (VEC) and the like.
- PC and EC are used as the cyclic carbonate solvent having the structure represented by the following (chemical formula 1).
- R1, R2, R3, and R4 represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms, and a fluorinated alkyl group.
- R1, R2, R3, and R4 in the above (chemical formula 1) may be the same or different.
- a large discharge capacity can be obtained by using PC and EC, which have a high dielectric constant and a high supporting salt solubility, as the cyclic carbonate solvent.
- PC and EC since PC and EC have high boiling points, they become electrolytic solutions that are difficult to volatilize even when used or stored in a high-temperature environment.
- PC which has a lower melting point than EC, mixed with EC as the cyclic carbonate solvent, excellent low-temperature properties can be obtained.
- the chain ether solvent has a structure represented by the following (chemical formula 2), and examples thereof include 1,2-dimethoxyethane (DME) and 1,2-diethoxyethane (DEE).
- DME 1,2-dimethoxyethane
- DEE 1,2-diethoxyethane
- a chain ether solvent having a structure represented by the following (chemical formula 2) is used. , using DME, which readily solvates with lithium ions.
- R5 and R6 represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms, and a fluorinated alkyl group. Also, R5 and R6 may be the same or different.
- DME low-temperature characteristics are improved by using DME with a low melting point as the chain ether solvent. Also, since DME has a low viscosity, the electrical conductivity of the electrolytic solution is improved. Furthermore, since DME solvates Li ions, a large discharge capacity can be obtained as a non-aqueous electrolyte secondary battery.
- the blending ratio of the organic solvent is within the above range, the effect of improving the low-temperature characteristics can be obtained more significantly without impairing the capacity retention ratio at high temperatures or normal temperatures, as described above.
- PC propylene carbonate
- EC cyclic carbonate solvent
- the blending ratio of ethylene carbonate (EC), which is a cyclic carbonate solvent, in the organic solvent is at least the lower limit of the above range, the dielectric constant of the electrolytic solution 50 and the solubility of the supporting salt are enhanced, and the non-aqueous electrolyte two The discharge capacity of the next battery increases.
- EC has poor electrical conductivity due to its high viscosity, and its high melting point may reduce low-temperature properties if the content is too high. Limitation is preferred.
- the blending ratio of EC in the organic solvent within the above range, it is possible to suppress an increase in internal resistance in a low-temperature environment.
- the blending ratio of dimethoxyethane (DME), which is a chain ether solvent, in the organic solvent is at least the lower limit of the above range, a predetermined amount of DME with a low melting point is contained in the organic solvent, thereby improving the low-temperature characteristics.
- DME dimethoxyethane
- the organic solvent since DME has a low viscosity, it is possible to improve electric conductivity and to obtain a large discharge capacity by solvating Li ions.
- DME since DME has a low dielectric constant, it is not possible to increase the concentration of the supporting electrolyte. It is preferable to limit to below the upper limit.
- the mixing ratio of DME in the organic solvent within the above range, it is possible to suppress the voltage drop at the initial stage of discharge.
- lithium bis(fluorosulfonyl)imide (LiFSI) is used as the supporting salt used in the electrolytic solution 50, and the content in the electrolytic solution 50 is 2.
- the range is ⁇ 7 mol/L.
- the content of the supporting salt (LiFSI) in the electrolytic solution 50 can be determined within the above range, taking into consideration the type of the positive electrode active material described later.
- the organic solvent contained in the electrolytic solution 50 has the above composition, and LiFSI, which has excellent conductivity as a supporting salt, is included in the molar ratio within the above range, so that a small non-aqueous electrolyte like a coin is obtained. A large current can be obtained even with a secondary battery.
- the electrolytic solution 50 contains LiFSI at a molar ratio within the above range, it is possible to suppress the voltage drop in the initial stage of discharge within a certain range, so that sufficient discharge capacity is maintained even at mA level discharge. can.
- the detailed mechanism is not clear, by including the supporting salt made of the above lithium compound in the electrolytic solution 50 at an optimum molar concentration, even if the electrolytic solution deteriorates, the necessary and sufficient amount of lithium can be secured. As a result, it is possible to obtain the effect of suppressing the decrease in the discharge capacity even when the battery is stored and stored for a long period of time or when it is used for a long period of time.
- the concentration of the supporting salt in the electrolytic solution 50 is too high or too low, the battery characteristics may be adversely affected, so the above range is preferable.
- the concentration of the supporting salt in the electrolytic solution 50 that is, the concentration of LiFSI is 4 to 7 (mol/L).
- the concentration of LiFSI with excellent conductivity in the electrolyte solution 50 is within the above range, after storing the non-aqueous electrolyte secondary battery under conditions of high temperature, high humidity and overdischarge The electrical characteristics of the battery, more specifically, the effect of improving the overdischarge characteristics can be obtained. As a result, even when overdischarge occurs, the effect of preventing deterioration of the non-aqueous electrolyte secondary battery can be obtained. Similarly, the internal resistance of the non-aqueous electrolyte secondary battery can be effectively reduced by setting the concentration of LiFSI in the electrolytic solution 50 within the above range, although the detailed mechanism is not clear.
- the electrolytic solution 50 preferably contains 3 to 4 (mol/L) of LiFSI, which is a supporting salt.
- LiFSI LiFSI
- the organic solvent used in the electrolyte solution 50 has the above composition, so that the viscosity of the electrolyte solution increases particularly in a low temperature environment of room temperature to ⁇ 30 to ⁇ 40° C. can be prevented, and the hindrance of movement of electric charges can be suppressed. This improves the discharge characteristics in a low-temperature environment, making it possible to maintain a sufficient discharge capacity over a wide temperature range.
- the positive electrode 10 is not particularly limited as long as it contains a positive electrode active material made of lithium manganese oxide, and conventionally known materials in this field can be used.
- a positive electrode active material made of lithium manganese oxide
- conventionally known materials in this field can be used.
- the positive electrode 10 in addition to the positive electrode active material described above, polyacrylic acid as a binder and graphite or the like as a conductive agent are mixed, and the mixture is made into pellets, for example.
- Examples of the positive electrode active material contained in the positive electrode 10 include LiMn 2 O 4 having a spinel crystal structure and lithium manganese oxides such as Li 4 Mn 5 O 12 .
- lithium manganese oxides a part of Mn is particularly Those substituted with Co are preferred.
- the discharge characteristics are further improved, and the output characteristics are high.
- the effect of further stabilizing the capacity characteristics can be obtained.
- the positive electrode active material made of lithium manganese oxide having the above composition for the positive electrode 10
- the small button-type nonaqueous electrolyte secondary battery 1 as described above can be used in a wide range of applications. Operation in a temperature range becomes possible, and excellent high-output characteristics and high-capacity characteristics are obtained more remarkably.
- the positive electrode active material may contain not only one kind of the above lithium manganese oxides, but also a plurality of them.
- the particle size (D50) is not particularly limited, and is preferably 0.1 to 100 ⁇ m, more preferably 10 to 50 ⁇ m, and further preferably 20 to 40 ⁇ m. preferable. If the particle size (D50) of the positive electrode active material is less than the lower limit of the preferred range, the reactivity of the non-aqueous electrolyte secondary battery increases when exposed to high temperatures, making it difficult to handle. , the discharge rate may decrease.
- the "particle diameter (D50) of the positive electrode active material" in the present invention means a particle diameter measured using a conventionally known laser diffraction method and means a median diameter.
- the content of the positive electrode active material in the positive electrode 10 is determined in consideration of the discharge current and discharge capacity required for the non-aqueous electrolyte secondary battery 1, and is preferably 50 to 95% by mass, for example. If the content of the positive electrode active material is equal to or higher than the lower limit of the preferred range, sufficient discharge current and discharge capacity can be easily obtained, and if it is equal to or lower than the preferred upper limit, the positive electrode 10 can be easily formed. .
- the positive electrode 10 may contain a conductive aid (hereinafter, the conductive aid used in the positive electrode 10 may be referred to as a "positive conductive aid").
- positive electrode conductive aids include carbonaceous materials such as furnace black, ketjen black, acetylene black, and graphite.
- the positive electrode conductive aid one of the above may be used alone, or two or more thereof may be used in combination.
- the content of the positive electrode conductive aid in the positive electrode 10 is preferably 1 to 25% by mass, more preferably 2 to 15% by mass. If the content of the positive electrode conductive aid is at least the lower limit of the preferred range, sufficient conductivity can be easily obtained.
- the positive electrode 10 can easily provide a sufficient discharge capacity.
- the positive electrode 10 may contain a binder (hereinafter, the binder used for the positive electrode 10 may be referred to as a “positive electrode binder”).
- the positive electrode binder conventionally known substances can be used. ), polyvinyl alcohol (PVA), etc. Among them, polyacrylic acid is preferred, and cross-linked polyacrylic acid is more preferred.
- the positive electrode binder may be used alone or in combination of two or more of the above.
- polyacrylic acid for the positive electrode binder it is preferable to adjust the polyacrylic acid to pH 3 to 10 in advance.
- an alkali metal hydroxide such as lithium hydroxide or an alkaline earth metal hydroxide such as magnesium hydroxide can be used.
- the content of the positive electrode binder in the positive electrode 10 can be, for example, 1 to 20% by mass.
- the size of the positive electrode 10 is determined according to the size of the non-aqueous electrolyte secondary battery 1 .
- the thickness of the positive electrode 10 in the state of being housed inside the positive electrode can 12 is also determined according to the size of the non-aqueous electrolyte secondary battery 1. In the case of a coin type for backup, the thickness is about 300 to 1000 ⁇ m.
- the positive electrode 10 can be manufactured by a conventionally known manufacturing method.
- a positive electrode active material, optionally a positive electrode conductive aid, and at least one of a positive electrode binder are mixed to form a positive electrode mixture, and this positive electrode mixture is
- the pressure for forming the positive electrode 10 by the pressure molding is determined in consideration of the type of the positive electrode conductive aid, and can be set to 0.2 to 5 ton/cm 2 , for example.
- the positive electrode current collector 14 a conventionally known one can be used, for example, one made of a conductive resin adhesive or the like using carbon as a conductive filler.
- the positive electrode 10 and the negative electrode 20 is configured in a pellet shape, as described above.
- the pellet-shaped positive electrode 10 is placed in the inner bottom portion 12b of the positive electrode can 12, and is formed in a ring shape in plan view, the details of which will be described later. Arranged in the through-hole part.
- between the inner bottom portion 12b of the positive electrode can 12 and the positive electrode 10 that is, between the positive electrode current collector 14 and the positive electrode 10 disposed on the inner bottom portion 12b of the positive electrode can 12 in the example shown in FIG.
- the positive electrode 10 and the inner bottom portion 12b are bonded via the positive electrode current collector 14 .
- the negative electrode 20 used in the present embodiment includes SiO X (0 ⁇ X ⁇ 2) as a negative electrode active material.
- a mixture of an appropriate binder, polyacrylic acid as a binder, and graphite as a conductive aid can be used in the form of pellets, for example.
- the negative electrode active material used for the negative electrode 20 examples include SiO or SiO 2 , that is, silicon oxide represented by the above SiO x (0 ⁇ X ⁇ 2). By using the silicon oxide having the above composition for the negative electrode active material, the non-aqueous electrolyte secondary battery 1 can be used at a high voltage, and the cycle characteristics are improved.
- the negative electrode 20 further includes Li—Al alloy, Si, WO 2 and WO 3 , which are alloy-based negative electrodes other than carbon. may contain at least one of By using the above material as the negative electrode active material for the negative electrode 20, the reaction between the electrolytic solution 50 and the negative electrode 20 is suppressed during charge/discharge cycles, the decrease in capacity can be prevented, and the cycle characteristics can be improved.
- the negative electrode 20 contains a negative electrode active material made of SiO x (0 ⁇ X ⁇ 2) in which at least a part of the surface is coated with carbon (C), the conductivity of the negative electrode 20 is improved, and particularly at low temperatures. An increase in internal resistance in the environment is suppressed. As a result, the voltage drop at the beginning of discharge is suppressed, the high-capacity characteristics including the initial capacity are more stabilized, and a large current can be stably supplied, resulting in the effect of more stable high-output characteristics. .
- the SiO x (0 ⁇ X ⁇ 2) is used as the negative electrode active material, at least part of the surface of the particles made of SiO x (0 ⁇ X ⁇ 2) should be covered with carbon. It is preferable that the entire surface is covered from the point that the above effect becomes more remarkable.
- the method for coating the surface of the SiO x (0 ⁇ X ⁇ 2) particles with carbon is not particularly limited, but examples include physical vapor deposition (PVD) using a gas containing an organic substance such as methane or acetylene, or , chemical vapor deposition (CVD), and the like.
- PVD physical vapor deposition
- CVD chemical vapor deposition
- the particle diameter (D50) is not particularly limited, but is, for example, 0.1 to 30 ⁇ m. It is preferably 1 to 10 ⁇ m, more preferably 1 to 10 ⁇ m. If the particle diameter (D50) of the negative electrode active material is within the above range, the conductivity is maintained even when the negative electrode expands or contracts when the non-aqueous electrolyte secondary battery is charged and discharged. The deterioration of the charge/discharge characteristics such as is suppressed.
- the particle size (D50) of the negative electrode active material is less than the lower limit of the preferred range, for example, when the non-aqueous electrolyte secondary battery is exposed to high temperatures, the reactivity increases, making it difficult to handle. If the upper limit is exceeded, the discharge rate may decrease.
- the particle diameter (D50) of the negative electrode active material (SiO x (0 ⁇ X ⁇ 2)) described in this specification means that carbon is present on at least part of the surface of SiO x (0 ⁇ X ⁇ 2). Particle size in the coated state.
- the negative electrode active material in the negative electrode 20 contains both lithium (Li) and SiOx (0 ⁇ X ⁇ 2), and the molar ratio (Li/SiOx) thereof is 3.5 . More preferably, it ranges from 7 to 4.9. As described above, the negative electrode active material contains both lithium (Li) and SiO 2 X , and the molar ratio thereof is set within the above range, thereby obtaining the effect of preventing abnormal charging and the like.
- the molar ratio (Li/SiO x ) is less than 3.7, the amount of Li is too small. For example, when used or stored/stored for a long period of time in a high temperature environment, Li becomes insufficient, and the discharge capacity decreases. descend. On the other hand, if the above molar ratio (Li/SiO x ) exceeds 4.9, there is a possibility that abnormal charging will occur due to excessive Li content. In addition, since the metal Li remains without being incorporated into SiO 2 X , the internal resistance may increase and the discharge capacity may decrease.
- the molar ratio (Li/SiO x ) in the above range is set by selecting a more appropriate range according to the type of the positive electrode active material contained in the positive electrode 10 described above. is more preferred.
- the molar ratio (Li/SiO x ) in the negative electrode active material is more preferably in the range of 4.0 to 4.7.
- the molar ratio (Li/SiO x ) in the negative electrode active material is more preferably in the range of 3.9 to 4.9.
- the molar ratio (Li/SiO x ) of the negative electrode active material within a range corresponding to the type of the positive electrode active material, the above-described increase in initial resistance is suppressed, and abnormal charging and the like are prevented.
- the content of the negative electrode active material in the negative electrode 20 is determined in consideration of the discharge capacity and the like required for the non-aqueous electrolyte secondary battery 1.
- the content is preferably 50% by mass or more, more preferably 60 to 80% by mass.
- the negative electrode 20 when the content of the negative electrode active material made of the above material is equal to or higher than the lower limit value of the preferred range, a sufficient discharge capacity can be easily obtained. becomes easier.
- the negative electrode 20 may contain a conductive aid (hereinafter, the conductive aid used in the negative electrode 20 may be referred to as "negative conductive aid”).
- the negative electrode conductive aid is the same as the positive electrode conductive aid.
- the negative electrode 20 may contain a binder (hereinafter, the binder used for the negative electrode 20 may be referred to as "negative electrode binder”).
- negative electrode binders include polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), polyacrylic acid (PA), carboxymethyl cellulose (CMC), polyimide (PI), and polyimideamide (PAI). Acrylic acid is preferred, and crosslinked polyacrylic acid is more preferred.
- the negative electrode binder may be used alone or in combination of two or more of the above.
- polyacrylic acid for the negative electrode binder
- the pH can be adjusted by, for example, adding an alkali metal hydroxide such as lithium hydroxide or an alkaline earth metal hydroxide such as magnesium hydroxide.
- the content of the negative electrode binder in the negative electrode 20 is, for example, 1 to 20% by mass.
- the shape (for example, pellet shape), size, and thickness of the negative electrode 20 are the same as those of the positive electrode 10 .
- a lithium foil 60 is provided on the surface of the negative electrode 20, that is, between the negative electrode 20 and the separator 30 described later.
- the above material is used as the negative electrode active material, and if necessary, a negative electrode conductive aid such as graphite and/or a negative electrode binder are mixed to prepare a negative electrode mixture,
- a method of pressure-molding the negative electrode mixture into a pellet shape such as a disk shape can be used.
- the pressure when the negative electrode 20 is pressure-molded is determined in consideration of the type of the negative electrode conductive aid, and can be, for example, 0.2 to 5 ton/cm 2 .
- the same material as that of the positive electrode current collector 14 can be used for the negative electrode current collector 24 .
- At least one of the positive electrode 10 and the negative electrode 20 is configured in a pellet shape.
- the pellet-shaped negative electrode 20 is placed inside the negative electrode can 22 in the through-hole of the gasket 40 which is configured in a ring shape in plan view, as in the case of the positive electrode 10 . Place in part.
- the negative electrode current collector 24 and the pellet-shaped negative electrode are arranged between the inner top portion 22b of the negative electrode can 22 and the negative electrode 20, that is, in the inner top portion 22b of the negative electrode can 22 in the example shown in FIG.
- the negative electrode 20 and the inner top portion 22b are bonded via the negative electrode current collector 24 by disposing a conventionally known conductive adhesive between the electrodes 20 .
- the lithium foil 60 is placed on the surface of the negative electrode 20 after the negative electrode 20 is placed inside the negative electrode can 22 .
- the separator 30 is interposed between the positive electrode 10 and the negative electrode 20, and an insulating film having high ion permeability, excellent heat resistance, and predetermined mechanical strength is used.
- the separator 30 is made of glass fiber non-woven fabric. Glass fiber has excellent mechanical strength and high ion permeability. Therefore, by using a glass fiber non-woven fabric for the separator 30, it is possible to reduce the internal resistance and improve the discharge capacity.
- the thickness of the separator 30 is determined in consideration of the size of the nonaqueous electrolyte secondary battery 1, the material of the separator 30, and the like, and can be, for example, about 5 to 300 ⁇ m.
- non-aqueous electrolyte secondary battery 1 of the present embodiment by combining the configuration in which the composition of the electrolytic solution 50 is optimized and the configuration in which the arrangement structure of each battery element inside the storage container 2 is optimized, It is possible to realize a non-aqueous electrolyte secondary battery 1 that is compact, yet has excellent high-output characteristics and also has excellent high-capacity characteristics.
- a non-aqueous electrolyte secondary battery according to a second embodiment of the present invention will be described below with reference to FIG.
- the same reference numerals are used for configurations similar to those of the non-aqueous electrolyte secondary battery 1 according to the first embodiment shown in FIG. The detailed description may be omitted in some cases.
- the non-aqueous electrolyte secondary battery 100 of the present embodiment is a coin (button) type battery, similar to the non-aqueous electrolyte secondary battery 1 of the first embodiment shown in FIG.
- a positive electrode 110 containing a positive electrode active material and capable of intercalating and deintercalating lithium ions, a negative electrode 120 containing a negative electrode active material and capable of intercalating and deintercalating lithium ions, the positive electrode 110 and the negative electrode 120 are contained in the storage container 102.
- a separator 130 arranged between them, a gasket 140 for sealing the storage space of the storage container 102, and an electrolytic solution 50 containing at least a supporting salt and an organic solvent are provided.
- the positive electrode 110 is arranged so that the storage container 102 covers the entire surface of the inner bottom portion 112b of the positive electrode can 112, and the inner portion 112c of the positive electrode can 112 and the positive electrode 110 It differs from the non-aqueous electrolyte secondary battery 1 of the first embodiment in that it is insulated and sealed with a gasket 140 interposed between it and the negative electrode can 122 .
- non-aqueous electrolyte secondary battery 100 of the present embodiment by adopting the insulation sealing structure as described above, electrical insulation and sealing performance are enhanced. Further, as will be described later in detail in Examples, even a small coin-type non-aqueous electrolyte secondary battery can provide even more excellent high output characteristics and high capacity characteristics.
- the electrolytic solution 50 having the same composition as that of the non-aqueous electrolyte secondary battery 1 of the first embodiment can be used.
- the composition of the electrolyte solution 50 is the same as that of the non-aqueous electrolyte secondary battery 1 of the first embodiment with respect to the composition ratio of the organic solvent, but the content of the supporting salt LiFSI is changed to A range of 2 to 3 (mol/L) is more preferable.
- the present embodiment employs a structure in which the positive electrode 110 having a larger outer shape than the first embodiment is provided, and the positive electrode 110 is arranged so as to cover the entire surface of the inner bottom portion 112b of the positive electrode can 112.
- the distance between the negative electrode 120 and the positive electrode 110 increases due to the internal structure of the battery.
- the distance from the vicinity of the peripheral portion of the positive electrode 110 increases.
- it is thought that the above effects are likely to be exhibited when an electrolytic solution having a lower concentration and a lower viscosity than in the first embodiment is used. be done.
- the composition of the electrolytic solution 50 is optimized and each By combining with the configuration in which the arrangement structure of the battery elements is optimized, the battery is small, yet has excellent high output characteristics and excellent high capacity characteristics.
- a non-aqueous electrolyte secondary battery having a coin-shaped structure using a positive electrode can and a negative electrode can made of stainless steel and having a storage container in which these are crimped is provided.
- the invention is not limited to this.
- the present invention can also be applied.
- the configuration according to the present invention can also be applied to electrochemical cells such as lithium ion capacitors.
- the non-aqueous electrolyte secondary battery 1 of the present embodiment can supply a large current over a wide temperature range, can maintain a sufficient discharge capacity even at a mA level discharge, and can be small in size but has a high capacity. Since it provides output characteristics and high capacity characteristics, it is suitable for use not only as a backup power source in various electronic devices, but also as a main power source that requires a high current.
- the non-aqueous electrolyte secondary battery 1,100 according to the embodiment of the present invention, first, as the electrolyte solution 50, PC and EC are used as organic solvents in an optimum ratio, so that a wide temperature range can be achieved.
- the electrical conductivity of the electrolytic solution 50 is improved because the low-temperature properties are improved by using the DME in an optimum ratio, while the operation is possible at .
- the electrolytic solution 50 contains LiFSI as a supporting salt in an optimum range, so that both high output characteristics and high capacity characteristics are obtained.
- a coin-shaped (920 type) non-aqueous electrolyte secondary battery (lithium secondary battery) having an outer diameter of ⁇ 9.5 mm and a thickness of 2.0 mm as shown in the cross-sectional view of FIG. 1 was fabricated.
- An organic solvent was adjusted at a blending ratio (% by volume) described below, and an electrolytic solution was prepared by dissolving a supporting salt in this organic solvent.
- a mixed solvent was prepared.
- LiFSI lithium bis(fluorosulfonyl)imide
- lithium manganese oxide Li 1.14 Co 0.06 Mn 1.80 O 4
- the negative electrode 20 SiO powder having the entire surface coated with carbon (C) was prepared and used as a negative electrode active material. Then, this negative electrode active material was mixed with graphite as a conductive agent and polyacrylic acid as a binder in a ratio of 75:20:5 (mass ratio), respectively, to obtain a negative electrode mixture. Next, 11.5 mg of the obtained negative electrode mixture was pressure-molded at a pressure of 2 ton/cm 2 to form disc-shaped pellets having a diameter ( ⁇ ) of 6.3 mm and a thickness (t) of 0.2 mm. Pressed.
- the positive electrode current collector 14 and the negative electrode current collector 24 shown in FIG. A non-aqueous electrolyte secondary battery was produced by imparting the function of a negative electrode current collector.
- the separator 30 was placed on the lithium foil 60 crimped onto the negative electrode 20 , and a polypropylene gasket 40 was placed in the opening of the negative electrode can 22 .
- the positive electrode can 12 and the negative electrode can 22 were filled with a total of 30 ⁇ L per battery of the electrolytic solution prepared by the above procedure.
- the above-described members constituting the non-aqueous electrolyte secondary battery were prepared, and the positive electrode can 12 was prepared. and the negative electrode can 22 was filled with the electrolytic solution.
- the negative electrode unit was crimped to the positive electrode unit so that the separator 30 was in contact with the positive electrode 10 . Then, after the positive electrode can 12 and the negative electrode can 22 are sealed by fitting the opening of the positive electrode can 12, they are allowed to stand still at 25° C. for 7 days, and the concentration of the supporting salt (LiFSI) contained in the electrolytic solution increases.
- Example 11 to 17 In Experimental Examples 11 to 17, as shown in FIG. A coin-shaped non-aqueous electrolyte secondary battery having a structure in which a gasket 140 was interposed between the negative electrode can 122 and an insulating and sealed structure was produced. Further, in Experimental Examples 11 to 17, electrolyte solutions having the following compositions were prepared to fabricate non-aqueous electrolyte secondary batteries. In this experimental example, a coin-shaped (920 type) non-aqueous electrolyte secondary battery (lithium secondary battery) having an outer diameter of ⁇ 9.5 mm and a thickness of 2.0 mm as shown in the cross-sectional view of FIG. 2 was fabricated.
- 920 type non-aqueous electrolyte secondary battery lithium secondary battery
- electrolytic solutions having the same compositions as those prepared in Experimental Examples 1 to 7 were used as the electrolytic solutions.
- the positive electrode 110 commercially available lithium manganese oxide (Li 1.14 Co 0.06 Mn 1.80 O 4 ), which is the same as the positive electrode active material used in Experimental Examples 1 to 7, is added with graphite as a conductive aid. , and polyacrylic acid as a binder were mixed in the same ratio to obtain a positive electrode mixture.
- 115 mg of the obtained positive electrode material mixture was pressurized with a pressure of 2 ton/cm 2 to form a disk-shaped pellet having a diameter ( ⁇ ) of 8.9 mm and a thickness (t) of 0.67 mm.
- the negative electrode 120 similarly to the negative electrode active material used in Experimental Examples 1 to 7, SiO powder whose entire surface is coated with carbon is prepared, and graphite as a conductive agent is attached to this negative electrode active material.
- Polyacrylic acid was mixed at the same ratio as an agent to prepare a negative electrode mixture.
- 15.1 mg of the obtained negative electrode mixture was pressure-molded at a pressure of 2 ton/cm 2 and added to disc-shaped pellets having a diameter ( ⁇ ) of 6.7 mm and a thickness (t) of 0.25 mm. Pressed.
- the positive electrode can 112 and the negative electrode can 122 were filled with a total of 30 ⁇ L per battery of the electrolytic solution prepared by the above procedure.
- electrolytic solutions Example 11 to 17: concentrations similar to those in Experimental Examples 1 to 7
- each of the above-mentioned each constituting the non-aqueous electrolyte secondary battery was used.
- the members were prepared, and the positive electrode can 112 and the negative electrode can 122 were filled with the electrolytic solution.
- FIGS. 7A and 7B the effect of increasing the capacity when the concentration of the supporting salt contained in the electrolytic solution is changed is shown in FIGS. 7A and 7B.
- electrolytic solutions having the same compositions as those prepared in Experimental Examples 1 to 7 and Experimental Examples 11 to 17 were used as the electrolytic solutions.
- the positive electrode 110 a positive electrode active material made of commercially available lithium manganese oxide (Li 4 Mn 5 O 12 ), graphite as a conductive aid, polyacrylic acid as a binder, and lithium manganese oxide: graphite.
- Polyacrylic acid 90:8:2 (mass ratio) to prepare a positive electrode mixture.
- 98.6 mg of the obtained positive electrode mixture was pressurized with a pressure of 2 ton/cm 2 to form a disk-shaped pellet having a diameter ( ⁇ ) of 8.9 mm and a thickness (t) of 0.67 mm. did.
- a negative electrode active material made of SiO powder not coated with carbon was prepared, and graphite as a conductive agent and polyacrylic acid as a binder were added to the negative electrode active material in a ratio of 54:44, respectively. 2 (mass ratio) to prepare a negative electrode mixture.
- 15.1 mg of the obtained negative electrode mixture was pressure-molded at a pressure of 2 ton/cm 2 and added to disc-shaped pellets having a diameter ( ⁇ ) of 6.7 mm and a thickness (t) of 0.25 mm. Pressed.
- the positive electrode can 112 and the negative electrode can 122 were filled with a total of 30 ⁇ L per battery of the electrolytic solution prepared by the above procedure.
- a non-aqueous electrolyte secondary battery were prepared, and the positive electrode can 112 and the negative electrode can 122 were filled with the electrolytic solution.
- the negative electrode unit was crimped to the positive electrode unit so that the separator 130 was in contact with the positive electrode 110, so that the opening of the positive electrode can 112 was fitted to the positive electrode can 112 and the negative electrode can. 122 was sealed, and allowed to stand at 25° C. for 7 days to obtain non-aqueous electrolyte secondary batteries of Experimental Examples 21 to 27 having different concentrations of supporting salt (LiFSI) contained in the electrolyte.
- LiFSI supporting salt
- the conditions for the high-temperature, high-humidity storage test were as follows: the non-aqueous electrolyte secondary batteries in Experimental Examples 31 to 37 were short-circuited via a resistor of 18 k ⁇ to be in an over-discharged state, and in this state, the temperature was 60 ° C. and the humidity was 90%. At RH, the test was performed for each period of 7 days, 14 days, 21 days, 28 days and 40 days. The internal resistance was measured by an AC method at a frequency of 1 kHz.
- HHTS high temperature and high humidity storage test
- the positive electrode 110 is arranged so as to cover the entire surface of the inner bottom portion 112b of the positive electrode can 112, and the inner portion 112c of the positive electrode can 112, the positive electrode 120, and the negative electrode can 122 are insulated and sealed by interposing a gasket 140.
- Experimental Examples 11 to 17 in which experiments were conducted by changing the content of LiFSI contained in the electrolyte using a non-aqueous electrolyte secondary battery having a structure (see FIG. 2), the graphs of FIGS. 6A and 6B , it was confirmed that when the LiFSI content was in the range of 2 to 5 mol/L (Experimental Examples 12 to 15), a large discharge capacity was obtained.
- FIG. 2 it has the same structure as the non-aqueous electrolyte secondary batteries of Experimental Examples 11 to 17, and the composition of the positive electrode active material used for the positive electrode 110 and the negative electrode active material used for the negative electrode 120
- Experimental Examples 21 to 27 in which the particle structure and the composition of the negative electrode mixture were changed, the LiFSI content was in the range of 2 to 5 mol/L as shown in the graphs of FIGS. 25), it was confirmed that a large discharge capacity can be obtained.
- Experimental Examples 21 to 27 it was confirmed that a very large discharge capacity can be obtained especially when the content of LiFSI contained in the electrolyte is 2 to 3 mol/L (Experimental Examples 22 and 23). did it. Further, as shown in the graphs of FIGS.
- a non-aqueous electrolyte secondary battery having a structure in which a gasket 40 is interposed between the inner bottom portion 12b and inner portion 12c of the positive electrode can 12 and the negative electrode can 22 for insulation and sealing.
- FIG. 1 in Experimental Examples 31 to 37 in which experiments were performed by changing the content of LiFSI contained in the electrolyte, especially when the content of LiFSI was in the range of 4 to 7 mol / L In (Experimental Examples 34 to 37), it was confirmed that the internal resistance was about 180 ⁇ to 315 ⁇ , which was greatly reduced. From the curve shown in the graph of FIG. 10A, in Experimental Examples 34 to 37, the increase in internal resistance was suppressed regardless of the storage period of 7 days, 14 days, 21 days, 28 days, or 40 days. It is clear that
- the non-aqueous electrolyte secondary battery of the present invention According to the non-aqueous electrolyte secondary battery of the present invention, a large current can be supplied over a wide temperature range, a sufficient discharge capacity can be maintained even at a mA level discharge, and although it is small, it has high output characteristics and high capacity. characteristics are obtained. Therefore, by applying the present invention to, for example, a non-aqueous electrolyte secondary battery used in the field of various electronic devices, it can be used as a main power source in addition to a backup power source, thereby enabling various electronic devices. It can contribute to miniaturization and performance improvement of similar devices.
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Abstract
Description
本出願は、2021年2月26日に日本に出願された特願2021-030396号に基づき、優先権を主張し、その内容をここに援用する。
また、通常、支持塩の濃度が高すぎると充分な放電容量が得られ難くなることから、特許文献1では、支持塩の濃度が0.6~1.4mol/Lとされている。
この結果、まず、(化学式1)で表される環状カーボネート溶媒としてエチレンカーボネート(EC)及びプロピレンカーボネート(PC)を用いることで、特に、高温下における容量維持率を良好に維持できることを見出した。
また、(化学式2)で表される鎖状エーテル溶媒として、ジメトキシエタン(DME)を用いることにより、常温下における容量を確保しながら、特に、低温特性を向上させることができることを見出した。
さらに、上記のEC、PC及びDMEの混合比を調整することで、特に低温環境下において放電容量を維持できる効果が顕著に得られることを見出した。
具体的には、まず、環状カーボネート溶媒として、誘電率が高く、支持塩の溶解性が高いPC及びECを用いることにより、大きな放電容量を得ることが可能となる。また、PC及びECは、沸点が高いことから、仮に高温環境下で使用又は保管した場合であっても、揮発し難い電解液となる。
また、環状カーボネート溶媒として、ECよりも融点が低いPCを、ECと混合して用いることにより、低温特性を向上させることが可能となる。
また、鎖状エーテル溶媒として、融点の低いDMEを用いることにより、低温特性が向上する。また、DMEは低粘度なので、電解液の電気伝導性が向上する。さらに、DMEは、Liイオンに溶媒和することにより、非水電解質二次電池の放電容量が大きくなる。
さらに、電解液に用いる支持塩として、導電性に優れたLiFSIを上記範囲のモル比で含むものを用いることにより、小型の非水電解質二次電池であっても大電流が得られる。また、電解液が、LiFSIを上記範囲のモル比で含むことにより、放電初期の電圧降下を一定の範囲で抑制することができることから、充分な放電容量を維持できる。
さらに、組成が最適化された電解液と、内部における各電池要素の配置構造が最適化された構成とを組み合わせることにより、小型でありながら、高出力特性に優れるとともに、高容量特性にも優れた非水電解質二次電池を提供することが可能となる。
以下、本発明の第1の実施形態に係る非水電解質二次電池1について、図1を参照して説明する。
図1に示す第1の実施形態の非水電解質二次電池1は、いわゆるコイン(ボタン)型の電池である。この非水電解質二次電池1は、収納容器2内に、正極活物質を含みリチウムイオンを吸蔵・放出可能な正極10と、負極活物質を含み、リチウムイオンを吸蔵・放出可能な負極20と、正極10と負極20との間に配置されたセパレータ30と、収納容器2の収容空間を密封するためのガスケット40と、少なくとも支持塩及び有機溶媒を含む電解液50とを備え、概略構成される。
また、図1に示すように、ガスケット40は、正極缶12の内周面に沿って狭入されるとともに、セパレータ30の外周と接続され、セパレータ30を保持している。
また、正極10、負極20及びセパレータ30には、収納容器2内に充填された電解液50が含浸している。
そして、非水電解質二次電池1は、電解液50が、有機溶媒として、プロピレンカーボネート(PC)、エチレンカーボネート(EC)及びジメトキシエタン(DME)からなる混合溶液を、体積比で{PC:EC:DME}={0.5~1.5:0.5~1.5:1~3}の範囲で含有し、且つ、支持塩として、リチウムビス(フルオロスルホニル)イミド(LiFSI)を2~7(mol/L)で含有する。
図1に示すように、本実施形態の非水電解質二次電池1に用いられる収納容器2は、有底円筒状の正極缶12と、正極缶12の開口部12aに、詳細を後述するガスケット40を介在して固定され、正極缶12との間に収容空間を形成する負極缶22とを備える。収納容器2は、正極缶12の開口部12aを負極缶22側にかしめることで収容空間が密封されてなる、概略コイン型(ボタン型)の容器とされている。このため、正極缶12の最大内径は、負極缶22の最大外径よりも大きい寸法とされている。
ガスケット40は、図1に示すように、正極缶12の内周面に沿って円環状に形成され、その環状溝41の内部に負極缶22の先端部22aが配置される。
本実施形態の非水電解質二次電池1に用いられる電解液50は、上述したように、有機溶媒として、プロピレンカーボネート(PC)、エチレンカーボネート(EC)及びジメトキシエタン(DME)からなる混合溶液を、体積比で{PC:EC:DME}={0.5~1.5:0.5~1.5:1~3}の範囲で含有し、且つ、支持塩として、リチウムビス(フルオロスルホニル)イミド(LiFSI)を2~7(mol/L)で含有するものである。
このような電解液50は、通常、支持塩を、有機溶媒等の非水溶媒に溶解させたものからなり、電解液50に求められる耐熱性や粘度等を勘案して、その特性が決定される。
また、環状カーボネート溶媒として、ECよりも融点が低いPCを、ECと混合して用いることにより、低温特性を向上させることが可能となる。
また、鎖状エーテル溶媒として、融点の低いDMEを用いることにより、低温特性が向上する。また、DMEは低粘度なので、電解液の電気伝導性が向上する。さらに、DMEは、Liイオンに溶媒和することにより、非水電解質二次電池の放電容量が大きくなる。
本実施形態においては、特に、導電率向上の観点に加え、さらに、常温下における容量を確保しながら低温特性を向上させる観点から、下記(化学式2)で表される構造の鎖状エーテル溶媒として、リチウムイオンと溶媒和しやすいDMEを用いる。
一方、PCは、ECに較べて誘電率が低いことから支持塩の濃度を高められないため、含有量が多過ぎると大きな放電容量が得られ難くなる可能性があることから、その配合比率を上記範囲の上限以下に制限することが好ましい。
一方、ECは、粘度が高いことから電気伝導性に乏しく、また、融点が高いことから含有量が多過ぎると低温特性が低下する可能性があるため、その配合比率を上記範囲の上限以下に制限することが好ましい。
さらに、有機溶媒中におけるECの配合比率を上記範囲とすることにより、低温環境下における内部抵抗の上昇を抑制することが可能となる。
一方、DMEは誘電率が低いことから支持塩の濃度を高められないため、含有量が多過ぎる場合には大きな放電容量が得られ難くなる可能性があることから、その配合比率を上記範囲の上限以下に制限することが好ましい。
さらに、有機溶媒中におけるDMEの配合比率を上記範囲とすることにより、放電初期の電圧降下を抑制することが可能となる。
電解液50中における、導電性に優れたLiFSIの濃度が上記範囲であることにより、詳細なメカニズムは明らかではないが、高温高湿且つ過放電の条件で非水電解質二次電池を保存した後の電気的特性、具体的には過放電特性が良好となる作用が得られる。これにより、過放電が生じた場合であっても、非水電解質二次電池の劣化を防止できる効果が得られる。同様に、詳細なメカニズムは明らかではないが、電解液50中におけるLiFSIの濃度が上記範囲であることで、非水電解質二次電池の内部抵抗を効果的に低減できる。
正極10としては、リチウムマンガン酸化物からなる正極活物質を含有するものであれば、特に限定されず、従来からこの分野で公知のものを用いることができる。また、正極10としては、上記の正極活物質に加え、さらに、結着剤としてポリアクリル酸を、導電助剤としてグラファイト等を混合して、例えば、ペレット状としたものを用いることができる。
また、本実施形態では、正極活物質として、上記のリチウムマンガン酸化物のうちの1種のみならず、複数を含有していても構わない。
正極活物質の粒子径(D50)が、上記好ましい範囲の下限値未満であると、非水電解質二次電池が高温に曝された際に反応性が高まるために扱いにくくなり、また、上限値を超えると、放電レートが低下するおそれがある。
なお、本発明における「正極活物質の粒子径(D50)」とは、従来公知のレーザー回折法を用いて測定される粒子径であって、メジアン径を意味する。
正極導電助剤としては、例えば、ファーネスブラック、ケッチェンブラック、アセチレンブラック、グラファイト等の炭素質材料が挙げられる。
正極導電助剤は、上記のうちの1種を単独で用いてもよく、あるいは、2種以上を組み合わせて用いてもよい。
また、正極10中の正極導電助剤の含有量は、1~25質量%が好ましく、2~15質量%がより好ましい。正極導電助剤の含有量が、上記の好ましい範囲の下限値以上であれば、充分な導電性が得られやすくなる。また、電極をペレット状に成型する場合に成型しやすくなる。一方、正極10中の正極導電助剤の含有量が、上記好ましい範囲の上限値以下であれば、正極10による充分な放電容量が得られやすくなる。
正極バインダとしては、従来公知の物質を用いることができ、例えば、ポリテトラフルオロエチレン(PTFE)、ポリフッ化ビニリデン(PVDF)、スチレンブタジエンゴム(SBR)、ポリアクリル酸(PA)、カルボキシメチルセルロース(CMC)、ポリビニルアルコール(PVA)等が挙げられ、中でも、ポリアクリル酸が好ましく、架橋型のポリアクリル酸がより好ましい。
また、正極バインダは、上記のうちの1種を単独で用いてもよく、あるいは、2種以上を組み合わせて用いてもよい。
なお、正極バインダにポリアクリル酸を用いる場合には、ポリアクリル酸を、予め、pH3~10に調整しておくことが好ましい。この場合のpHの調整には、例えば、水酸化リチウム等のアルカリ金属水酸化物や水酸化マグネシウム等のアルカリ土類金属水酸化物を用いることができる。
正極10中の正極バインダの含有量は、例えば、1~20質量%とすることができる。
また、正極缶12の内部に収容した状態における正極10の厚さも、非水電解質二次電池1の大きさに応じて決定され、非水電解質二次電池1が、例えば、各種電子機器向けのバックアップ用のコイン型のものである場合には、300~1000μm程度とされる。
例えば、正極10の製造方法としては、正極活物質と、必要に応じて正極導電助剤、及び、正極バインダのうちの少なくとも何れかと、を混合して正極合剤とし、この正極合剤を、例えば、円板状等のペレット形状に加圧成形する方法が挙げられる。
上記の加圧成形によって正極10を形成する場合の圧力は、正極導電助剤の種類等を勘案して決定され、例えば0.2~5ton/cm2とすることができる。
本実施形態で用いられる負極20は、負極活物質として、SiOX(0<X<2)を含むものが挙げられる。負極20としては、上記の負極活物質に加え、さらに、適当なバインダと、結着剤としてポリアクリル酸を、導電助剤としてグラファイト等を混合したものを、例えばペレット状として用いることができる。
また、負極20は、負極活物質として、上記のSiOx(0<X<2)に加え、さらに、炭素以外の合金系負極である、Li-Al合金、Si、WO2及びWO3のうちの少なくとも何れかを含有していてもよい。
負極20に、負極活物質として上記材料を用いることで、充放電サイクルにおける電解液50と負極20との反応が抑制され、容量の減少を防止でき、サイクル特性が向上する効果が得られる。
なお、上記のSiOx(0<X<2)を負極活物質に用いる場合、SiOx(0<X<2)からなる粒子の表面の少なくとも一部が炭素によって被覆されていればよいが、表面全体が被覆されていることが、上記効果がより顕著になる点から好ましい。
一方、上記のモル比(Li/SiOX)が4.9を超えると、Liが多過ぎることから、充電異常が発生する可能性がある。また、金属LiがSiOXに取り込まれずに残存することから、内部抵抗が上昇して放電容量が低下する可能性がある。
負極20において、上記材料からなる負極活物質の含有量が、上記好ましい範囲の下限値以上であれば、充分な放電容量が得られやすく、また、上限値以下であれば、負極20を成形するのが容易になる。
負極20は、バインダ(以下、負極20に用いられるバインダを「負極バインダ」ということがある)を含有してもよい。
負極バインダとしては、ポリフッ化ビニリデン(PVDF)、スチレンブタジエンゴム(SBR)、ポリアクリル酸(PA)、カルボキシメチルセルロース(CMC)、ポリイミド(PI)、ポリイミドアミド(PAI)等が挙げられ、中でも、ポリアクリル酸が好ましく、架橋型のポリアクリル酸がより好ましい。
また、負極バインダは、上記のうちの1種を単独で用いてもよく、あるいは、2種以上を組み合わせて用いてもよい。なお、負極バインダにポリアクリル酸を用いる場合には、ポリアクリル酸を、予め、pH3~10に調整しておくことが好ましい。この場合のpHの調整は、例えば、水酸化リチウム等のアルカリ金属水酸化物や水酸化マグネシウム等のアルカリ土類金属水酸化物を添加することで行うことができる。
負極20中の負極バインダの含有量は、例えば1~20質量%とされる。
また、図1に示す非水電解質二次電池1においては、負極20の表面、即ち、負極20と後述のセパレータ30との間にリチウムフォイル60を設けている。
負極20を加圧成形する場合の圧力は、負極導電助剤の種類等を勘案して決定され、例えば0.2~5ton/cm2とすることができる。
セパレータ30は、正極10と負極20との間に介在され、大きなイオン透過度を有するとともに耐熱性に優れ、かつ、所定の機械的強度を有する絶縁膜が用いられる。
本実施形態においては、セパレータ30として、ガラス繊維の不織布からなるものを用いる。ガラス繊維は、機械強度に優れるとともに、大きなイオン透過度を有するため、セパレータ30にガラス繊維の不織布を採用することで、内部抵抗を低減して放電容量の向上を図ることが可能となる。
セパレータ30の厚さは、非水電解質二次電池1の大きさや、セパレータ30の材質等を勘案して決定され、例えば5~300μm程度とすることができる。
以下、本発明の第2の実施形態に係る非水電解質二次電池について、図2を参照して説明する。
なお、以下に説明する第2の実施形態の非水電解質二次電池100において、図1に示した第1の実施形態に係る非水電解質二次電池1と類似した構成については、同じ符号を付して説明する場合があるとともに、その詳細な説明を省略する場合がある。
一方、本実施形態においては、電解液50の組成が、有機溶媒の組成比については第1の実施形態の非水電解質二次電池1と同じとする一方、支持塩であるLiFSIの含有量を2~3(mol/L)の範囲とすることがより好ましい。
本実施形態の非水電解質二次電池100において、上記のような電池構造と電解液50の組成とを組み合わせることで、上記効果が得られる詳細なメカニズムは不明である。しかしながら、本実施形態では、第1の実施形態に比べて外形が大きな正極110を備え、正極缶112における内底部112bの全面を覆うように正極110が配置された構造を採用している。これにより、電池内部の構造上、負極120と正極110との間の距離が大きくなることから、例えば、正極缶112よりも小型である負極缶122の内部に配置された負極120の周縁部近傍と、正極110の周辺部近傍との間の距離が大きくなる。本実施形態においては、上記のような構造を採用することで、第1の実施形態よりも低濃度且つ粘度が小さな電解液を用いた場合に、上記効果が発現しやすくなるためではないかと考えられる。
本実施形態においては、非水電解質二次電池の一実施形態として、ステンレス鋼製の正極缶と負極缶とを用い、これらをかしめた収納容器を備えるコイン型構造の非水電解質二次電池を挙げて説明したが、本発明はこれに限定されるものではない。例えば、セラミックス製の容器本体の開口部が、金属製の封口部材を用いたシーム溶接等の加熱処理によって、セラミックス製の蓋体で封止された構造の非水電解質二次電池に、本発明を適用することも可能である。
本実施形態の非水電解質二次電池1は、上述したように、幅広い温度範囲にわたって大電流を供給できるとともに、mAレベルの放電であっても十分な放電容量を維持でき、小型でありながら高出力特性且つ高容量特性が得られるものなので、例えば、各種電子機器におけるバックアップ用の電源の他、高電流が要求されるメイン電源としても好適に用いられる。
以上説明したように、本発明の実施形態である非水電解質二次電池1,100によれば、まず、電解液50として、有機溶媒にPC及びECを最適な比率で用いることで幅広い温度範囲における動作が可能になるとともに、DMEを最適な比率で用いることで低温特性が向上するので、電解液50の電気伝導性が向上する。これに加えて、電解液50が、支持塩としてLiFSIを最適範囲で含有することにより、高出力特性及び高容量特性の両方が得られる。
さらに、組成が最適化された電解液50と、収納容器2の内部における各電池要素の配置構造が最適化された構成とを組み合わせることにより、小型のコイン型電池でありながら、高出力特性に優れるとともに、高容量特性にも優れた非水電解質二次電池1,100を提供することが可能となる。
[実験例1~7]
実験例1~7においては、図1に示すような、収納容器2が、正極缶12の内底部12b及び内側部12cと負極缶22との間にガスケット40を介在させて絶縁封止された構造を有する、コイン型の非水電解質二次電池を作製した。なお、実験例1~7では、以下に示す組成で電解液を調製し、非水電解質二次電池を作製した。
本実験例では、図1に示す断面図において、外形がφ9.5mm、厚さが2.0mmのコイン型(920タイプ)の非水電解質二次電池(リチウム二次電池)を作製した。
以下に説明する配合比率(体積%)で有機溶媒を調整し、この有機溶媒に支持塩を溶解させることで電解液を調製した。
まず、有機溶媒として、プロピレンカーボネート(PC)、エチレンカーボネート(EC)、及び、ジメトキシエタン(DME)を、体積比で{PC:EC:DME}={1:1:2}の割合で混合することで、混合溶媒を調整した。
次いで、得られた混合溶媒に、支持塩として、リチウムビス(フルオロスルホニル)イミド(LiFSI)を、1~7M(1~7mol/L)の範囲で、1Mステップで変更して溶解させることで、支持塩濃度がそれぞれ異なる7種類(実験例1~7)の電解液を調製した。
正極10として、まず、正極活物質である市販のリチウムマンガン酸化物(Li1.14Co0.06Mn1.80O4)に、導電助剤としてグラファイトを、結着剤としてポリアクリル酸を、リチウムマンガン酸化物:グラファイト:ポリアクリル酸=95:4:1(質量比)の割合で混合して正極合剤とした。
次いで、得られた正極合剤56mgを、2ton/cm2の加圧力で加圧し、直径(φ)=5.8mm、厚み(t)=0.8mmの円板形ペレットに加圧成形した。
そして、正極ユニットにおける正極缶12の開口部12aの内側面にシール剤を塗布した。
次いで、得られた負極合剤11.5mgを、2ton/cm2の加圧力で加圧成形し、直径(φ)=6.3mm、厚み(t)=0.2mmの円板形ペレットに加圧成形した。
そして、ペレット状の負極20上に、さらに、直径(φ)=5.8mm、厚み(t)=0.42mmの円板状に打ち抜いたリチウムフォイル60を圧着し、リチウム-負極積層電極とした。
これら、各実験例の非水電解質二次電池は、上記のように、電解液に含まれる支持塩の量がそれぞれ異なるものであり、また、そのサンプル数(作製数)nを、各々、n=3とした。
各支持塩濃度とされた実験例1~7の非水電解質二次電池について、放電電流を1.0mA及び7.0mAとしたときの、各々の放電容量を測定した。この際の放電終止電圧は1.0Vとし、その結果を、図3A(放電電流:1.0mA)及び図3B(放電電流:7.0mA)のグラフにそれぞれ示した。
実験例11~17においては、図2に示すような、収納容器102が、正極缶112における内底部112bの全面を覆うように正極110が配置され、正極缶112の内側部112c及び正極110と負極缶122との間にガスケット140を介在させて絶縁封止された構造を有する、コイン型の非水電解質二次電池を作製した。また、実験例11~17においては、以下に示す組成で電解液を調製し、非水電解質二次電池を作製した。
本実験例では、図2に示す断面図において、外形がφ9.5mm、厚さが2.0mmのコイン型(920タイプ)の非水電解質二次電池(リチウム二次電池)を作製した。
また、正極110としても、実験例1~7で用いた正極活物質と同じ市販のリチウムマンガン酸化物(Li1.14Co0.06Mn1.80O4)に、導電助剤としてグラファイトを、結着剤としてポリアクリル酸を、同じ割合で混合して正極合剤とした。
次いで、得られた正極合剤115mgを、2ton/cm2の加圧力で加圧し、直径(φ)=8.9mm、厚み(t)=0.67mmの円板形ペレットに加圧成形した。
そして、正極ユニットにおける正極缶112の開口部112aの内側面にシール剤を塗布した。
次いで、得られた負極合剤15.1mgを、2ton/cm2の加圧力で加圧成形し、直径(φ)=6.7mm、厚み(t)=0.25mmの円板形ペレットに加圧成形した。
そして、ペレット状の負極120上に、さらに、直径(φ)=6.1mm、厚み(t)=0.38mmの円板状に打ち抜いたリチウムフォイル160を圧着し、リチウム-負極積層電極とした。
これら実験例11~17の非水電解質二次電池は、そのサンプル数(作製数)nを、各々、n=3とした。
実験例21~27においても、図2に示すような、収納容器102が、正極缶112における内底部112bの全面を覆うように正極110が配置され、正極缶112の内側部112c及び正極110と負極缶122との間にガスケット140を介在させて絶縁封止された構造を有する、コイン型の非水電解質二次電池を作製した。また、実験例21~27においては、以下に示す組成で電解液を調製し、非水電解質二次電池を作製した。
本実験例でも、図2に示す断面図において、外形がφ9.5mm、厚さが2.0mmのコイン型(920タイプ)の非水電解質二次電池(リチウム二次電池)を作製した。
また、正極110としては、市販のリチウムマンガン酸化物(Li4Mn5O12)からなる正極活物質に、導電助剤としてグラファイトを、結着剤としてポリアクリル酸を、リチウムマンガン酸化物:グラファイト:ポリアクリル酸=90:8:2(質量比)の割合で混合して正極合剤とした。
次いで、得られた正極合剤98.6mgを、2ton/cm2の加圧力で加圧し、直径(φ)=8.9mm、厚み(t)=0.67mmの円板形ペレットに加圧成形した。
そして、正極ユニットにおける正極缶112の開口部112aの内側面にシール剤を塗布した。
次いで、得られた負極合剤15.1mgを、2ton/cm2の加圧力で加圧成形し、直径(φ)=6.7mm、厚み(t)=0.25mmの円板形ペレットに加圧成形した。
そして、ペレット状の負極120上に、さらに、直径(φ)=6.1mm、厚み(t)=0.38mmの円板状に打ち抜いたリチウムフォイル160を圧着し、リチウム-負極積層電極とした。
これら実験例21~27の非水電解質二次電池も、そのサンプル数(作製数)nを、各々、n=3とした。
実験例31~37においては、図1に示すような、収納容器2が、正極缶12の内底部12b及び内側部12cと負極缶22との間にガスケット40を介在させて絶縁封止された構造を有する、実験例1~7と同様の仕様とされたコイン型の非水電解質二次電池を作製した。即ち、実験例31~37においても、実施例1~7に対応した同様の組成で電解液を調製し、図1に示す断面図において、外形がφ9.5mm、厚さが2.0mmのコイン型(920タイプ)の非水電解質二次電池(リチウム二次電池)を作製した。
なお、上記の内部抵抗は、周波数1kHzの交流法によって測定した。
そして、高温高湿保存試験後の非水電解質二次電池を、初期容量と同じ条件で充放電させた値を試験後の放電容量とし、初期容量に対する容量維持率を求めた。
図3A及び図3Bのグラフに示すように、正極缶12の内底部12b及び内側部12cと負極缶22との間にガスケット40を介在させて絶縁封止された構造を有する非水電解質二次電池(図1を参照)を用い、電解液に含まれるLiFSIの含有量を変更して実験を行った実験例1~7では、LiFSIの含有量が2~5mol/Lの範囲である場合(実験例2~5)において、大きな放電容量が得られることが確認できた。特に、電解液に含まれるLiFSIの含有量が3~4mol/Lである場合(実験例3,4)には、非常に大きな放電容量が得られることが確認できた。このことは、図4に示した、放電電流と容量との関係を示すグラフからも明らかである。
また、図5A及び図5Bのグラフに示すように、実験例1~7では、LiFSIの含有量が2~5mol/Lの範囲である場合(実験例2~5)において大きな容量アップ効果が見られ、特に、放電終止電圧が1.0Vである場合には、電解液に含まれるLiFSIの含有量が3~4mol/Lであると(実験例3,4)、より大きな容量アップ効果が得られることが確認できた。
また、図7A及び図7Bのグラフに示すように、実験例11~17においても、LiFSIの含有量が2~5mol/Lの範囲である場合(実験例12~15)において大きな容量アップ効果が見られ、特に、電解液に含まれるLiFSIの含有量が2~3mol/Lであると(実験例12,13)、より大きな容量アップ効果が安定して得られることが確認できた。
また、図9A及び図9Bのグラフに示すように、実験例21~27においても、LiFSIの含有量が2~5mol/Lの範囲である場合(実験例22~25)において大きな容量アップ効果が見られ、特に、電解液に含まれるLiFSIの含有量が2~3mol/Lであると(実験例22,23)、より大きな容量アップ効果が得られることが確認できた。
より詳細には、図11A及び図11Bのグラフに示すように、保存期間が28日又は40日の何れの場合であっても、初期容量と比較して十分な放電容量(保存後容量)を有していることがわかる。また、実験例34~37では、高温高湿環境且つ過放電の状態で保存した後の容量維持率が、保存期間が28日の場合は68%~93%、保存期間が40日の場合は45%~85%と、従来の非水電解質二次電池に比べて高い容量維持率を示していることがわかる。
また、上記の実施例(実験例31~37)の結果より、電解液に用いる支持塩として、導電性に優れたLiFSIを上記範囲のモル比で含むものを用い、さらに、内部における各電池要素の配置構造が最適化された構成を組み合わせることで、高温高湿且つ過放電の条件で非水電解質二次電池を保存した後の電気的特性(過放電特性)がさらに良好となるので、過放電が生じた場合であっても、非水電解質二次電池の劣化をより効果的に防止することが可能となることが明らかである。
2,102…収納容器
10,110…正極
12,112…正極缶
12a,112a…開口部
12b,112b…内底部
12c,112c…内側部
14,114…正極集電体
20,120…負極
22,122…負極缶
22a…先端部
22b,122b…内頂部
24…負極集電体
30…セパレータ
40…ガスケット
41…環状溝
50…電解液
60…リチウムフォイル
Claims (9)
- 正極活物質を含む正極と、
負極活物質を含む負極と、
前記正極と前記負極との間に配置されるセパレータと、
有機溶媒及び支持塩を含む電解液と、
前記正極、前記負極、前記セパレータ、及び前記電解液が内部の収容空間に配置される収納容器と、を含み、
前記正極及び前記負極のうちの少なくとも一方が、活物質、導電助剤、及びバインダを含むペレット状とされており、
前記セパレータがガラス繊維の不織布からなり、
前記電解液は、前記有機溶媒として、プロピレンカーボネート(PC)、エチレンカーボネート(EC)及びジメトキシエタン(DME)からなる混合溶液を、体積比で{PC:EC:DME}={0.5~1.5:0.5~1.5:1~3}の範囲で含有し、且つ、前記支持塩として、リチウムビス(フルオロスルホニル)イミド(LiFSI)を2~7(mol/L)で含有することを特徴とする非水電解質二次電池。 - 前記電解液が、前記支持塩であるリチウムビス(フルオロスルホニル)イミド(LiFSI)を4~7(mol/L)で含有することを特徴とする請求項1に記載の非水電解質二次電池。
- 前記収納容器は、
有底円筒状の正極缶と、
前記正極缶の開口部にガスケットを介在して固定され、前記正極缶との間に収容空間を形成する負極缶と、を備え、
前記正極缶の開口部を前記負極缶側にかしめることで前記収容空間が密封されてなる、コイン型容器であることを特徴とする請求項1又は請求項2に記載の非水電解質二次電池。 - 前記収納容器は、前記正極缶の内底部及び内側部と前記負極缶との間に、前記ガスケットを介在させて絶縁封止された構造であることを特徴とする請求項3に記載の非水電解質二次電池。
- 前記電解液が、前記支持塩であるリチウムビス(フルオロスルホニル)イミド(LiFSI)を3~4(mol/L)で含有することを特徴とする請求項4に記載の非水電解質二次電池。
- 前記収納容器は、前記正極缶における内底部の全面を覆うように前記正極が配置され、前記正極缶の内側部及び前記正極と前記負極缶との間に、前記ガスケットを介在させて絶縁封止された構造であることを特徴とする請求項2に記載の非水電解質二次電池。
- 前記電解液が、前記支持塩であるリチウムビス(フルオロスルホニル)イミド(LiFSI)を2~3(mol/L)で含有することを特徴とする請求項6に記載の非水電解質二次電池。
- 前記正極は、前記正極活物質として、少なくとも、Li1+xCoyMn2-x-yO4(0≦x≦0.33、0<y≦0.2)からなるリチウムマンガン酸化物を含むことを特徴とする請求項1~請求項7の何れか一項に記載の非水電解質二次電池。
- 前記負極は、前記負極活物質として、表面の少なくとも一部が炭素で被覆されたSiOX(0<X<2)を含むことを特徴とする請求項1~請求項8の何れか一項に記載の非水電解質二次電池。
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WO2016143543A1 (ja) | 2015-03-12 | 2016-09-15 | セイコーインスツル株式会社 | 非水電解質二次電池 |
JP2017224430A (ja) * | 2016-06-14 | 2017-12-21 | セイコーインスツル株式会社 | 非水電解質二次電池 |
JP2021030396A (ja) | 2019-08-28 | 2021-03-01 | 株式会社アルプスツール | 棒材取り扱い機の自動運転準備方法 |
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2022
- 2022-01-28 JP JP2023502214A patent/JPWO2022181207A1/ja active Pending
- 2022-01-28 CN CN202280016378.3A patent/CN116998038A/zh active Pending
- 2022-01-28 KR KR1020237022236A patent/KR20230150782A/ko unknown
- 2022-01-28 EP EP22759248.2A patent/EP4261926A1/en active Pending
- 2022-01-28 WO PCT/JP2022/003367 patent/WO2022181207A1/ja active Application Filing
- 2022-01-28 US US18/259,931 patent/US20240088445A1/en active Pending
- 2022-02-11 TW TW111105019A patent/TW202304039A/zh unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2016143543A1 (ja) | 2015-03-12 | 2016-09-15 | セイコーインスツル株式会社 | 非水電解質二次電池 |
JP2017224430A (ja) * | 2016-06-14 | 2017-12-21 | セイコーインスツル株式会社 | 非水電解質二次電池 |
JP2021030396A (ja) | 2019-08-28 | 2021-03-01 | 株式会社アルプスツール | 棒材取り扱い機の自動運転準備方法 |
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JPWO2022181207A1 (ja) | 2022-09-01 |
EP4261926A1 (en) | 2023-10-18 |
CN116998038A (zh) | 2023-11-03 |
TW202304039A (zh) | 2023-01-16 |
US20240088445A1 (en) | 2024-03-14 |
KR20230150782A (ko) | 2023-10-31 |
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