WO2015111494A1 - 全固体電池の使用 - Google Patents
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- WO2015111494A1 WO2015111494A1 PCT/JP2015/050903 JP2015050903W WO2015111494A1 WO 2015111494 A1 WO2015111494 A1 WO 2015111494A1 JP 2015050903 W JP2015050903 W JP 2015050903W WO 2015111494 A1 WO2015111494 A1 WO 2015111494A1
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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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
- H01M10/0562—Solid materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
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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
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
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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
- H01M2220/00—Batteries for particular applications
- H01M2220/10—Batteries in stationary systems, e.g. emergency power source in plant
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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
- H01M2220/00—Batteries for particular applications
- H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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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
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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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to the use of all solid state batteries.
- a liquid electrolyte such as an organic solvent using a flammable organic solvent as a diluent solvent has been conventionally used as a medium for moving ions.
- a battery using such an electrolytic solution may cause problems such as leakage of the electrolytic solution, ignition, and explosion.
- Patent Document 1 US Pat. No. 8,831,264
- Patent Document 2 JP 2009-516359 A disclose a positive electrode having a thickness of greater than about 4 ⁇ m and less than about 200 ⁇ m, and a solid electrolyte having a thickness of less than about 10 ⁇ m.
- the positive electrode disclosed in these documents seems to use a non-oriented positive electrode active material.
- Patent Document 3 Japanese Patent Laid-Open No. 2012-009193
- Patent Document 4 Japanese Patent Laid-Open No. 2012-009194
- Patent Document 5 Japanese Patent No.
- Patent Document 6 Japanese Patent Laid-Open No. 2011-051800 discloses that the addition of Al in addition to Li, La, and Zr, which are basic elements of LLZ, can improve the density and lithium ion conductivity.
- Patent Document 7 Japanese Patent Application Laid-Open No. 2011-073962 discloses that lithium ion conductivity can be further improved by adding Nb and / or Ta in addition to Li, La and Zr, which are basic elements of LLZ.
- Patent Document 8 Japanese Patent Laid-Open No. 2011-073963 includes Li, La, Zr, and Al, and the density can be further improved by setting the molar ratio of Li to La to 2.0 to 2.5. Is disclosed.
- a volatile memory such as a DRAM is used as a main memory of a computer or a server.
- DRAMs are frequently used in computers and servers in recent years because of their extremely high processing speed.
- volatile memory such as DRAM has the characteristic that stored data is lost when power supply is interrupted, so that servers for core systems are prepared for power failure such as power failure or instantaneous voltage drop.
- UPS uninterruptible power supply
- a power generation device are also provided. By taking these measures, the system can be restored without any delay in the event of a power failure.
- these devices are configured on the assumption that power is supplied to the entire device such as a server, they are large-scale devices and are generally juxtaposed as devices separate from the devices such as the server.
- DRAM having a capacitor as a smaller backup power source is commercially available.
- examples of the product of the DRAM with the capacitor include ArxCis-NV TM manufactured by Viking Technology and NVDIMMs manufactured by Micron.
- Such a DRAM with a capacitor has a function of transmitting data stored in the DRAM to a non-volatile memory (for example, a NAND flash memory) using power temporarily supplied from the capacitor in the event of a power failure such as a power failure or instantaneous voltage drop. Therefore, stored data can be held in the nonvolatile memory even after the electrode supply from the capacitor is interrupted. When the power supply abnormality is finished and the power supply is resumed, the stored data in the nonvolatile memory is returned to the DRAM, so that the system can be quickly recovered.
- a non-volatile memory for example, a NAND flash memory
- the inventors of the present invention can obtain battery performance with high capacity and energy density by increasing the thickness of the oriented polycrystal, and We have obtained knowledge that the characteristics can be utilized to the maximum in the use of backup power source for volatile memory in devices such as computers and servers.
- the object of the present invention is to provide a useful application that takes full advantage of the characteristics of an all-solid-state battery using an oriented polycrystal as a positive electrode active material, in particular the advantages of small size, high energy density and high safety. There is to do.
- As a backup power source for at least one device selected from the group consisting of a computer, a laptop computer, a portable computer, a pocket computer, a workstation, a supercomputer, computer peripheral hardware, and a server of an all-solid-state battery comprising Use of is provided.
- FIG. 1 It is a schematic cross section which shows an example of the all-solid-state battery which can be used for this invention. It is a figure which shows the backup power supply output waveform example of 4GB capacity
- the vertical axis represents current, and the horizontal axis represents time.
- A) is a conventional example using an NVDIMM super capacitor as a backup power source
- (b) is an example of the present invention using a battery of a battery backup DRAM as a backup power source.
- (C) is an example of the present invention using a hybrid backup power source combining an all solid state battery and a bypass capacitor.
- A indicates a state where data is copied from the DRAM to the flash memory
- B indicates a state where the DRAM holds data in the self-refresh mode
- C indicates data stored in the DRAM. Indicates a state in which is disappearing. It is a backup power supply output waveform in the backup system of Example B1. It is a backup power supply output waveform in the backup system of Example B2. It is an equivalent circuit diagram in the backup system of Example C3. It is a backup power supply output waveform in the backup system of Example C3.
- FIG. 1 schematically shows an example of an all solid state battery according to the present invention.
- An all solid state battery 10 shown in FIG. 1 includes a positive electrode layer 14 having a positive electrode active material 12, a solid electrolyte layer 16 made of a lithium ion conductive material, and a negative electrode layer 20 having a negative electrode active material 18.
- the solid electrolyte layer 16 is sandwiched between the positive electrode layer 14 and the negative electrode layer 20.
- the positive electrode active material 12 is an oriented polycrystal formed of a plurality of lithium transition metal oxide particles oriented in a certain direction.
- the all-solid-state battery disclosed in Patent Documents 1 and 2 has a problem that even if the positive electrode layer is formed thick, the increase in capacity and energy density cannot be obtained as expected. . This is considered to be because, in Patent Documents 1 and 2, since the positive electrode active material used for the positive electrode layer is not oriented, it is difficult to efficiently insert and remove lithium ions over the entire thickness of the thick positive electrode layer. . For example, it may happen that lithium existing on the side of the thick positive electrode layer away from the solid electrolyte cannot be sufficiently extracted.
- the positive electrode active material 12 is an oriented polycrystal composed of a plurality of lithium transition metal oxide particles oriented in a certain direction, even if the positive electrode active material is provided thick, the entire thickness of the positive electrode layer is not affected. In addition, it is easy to remove and insert high-efficiency lithium ions, and the capacity improvement effect brought about by the thick positive electrode active material can be maximized. For example, lithium existing on the side of the thick positive electrode layer away from the solid electrolyte can be sufficiently extracted. Such an increase in capacity can greatly improve the energy density of the all-solid-state battery. That is, according to the all solid state battery of the present invention, battery performance with high capacity and energy density can be obtained. Therefore, it is possible to realize a highly safe all-solid battery having a high capacity and a high energy density while being relatively thin or small.
- the all solid state battery has an energy density of 700 Wh / L or more, a thickness of 5 mm or less, and a vertical and horizontal dimension of 100 mm or less, respectively.
- the all solid state battery has an energy density of 600 Wh / L or more, a thickness of 2 mm or less, and a vertical and horizontal size of 50 mm or less, respectively.
- the all solid state battery has an energy density of 500 Wh / L or more, a thickness of 1 mm or less, and a length and a width of 50 mm or less, respectively.
- the all solid state battery has an energy density of 250 Wh / L or more, a thickness of 0.5 mm or less, and a length and a width of 50 mm or less, respectively.
- the energy density is 100 Wh / L or more
- the thickness is 0.3 mm or less
- the length and width are each 50 mm or less.
- the all solid state battery has an energy density of 100 to 1,000 Wh / L, a thickness of 0.1 to 10 mm, and a length and width of 5 to 100 mm, respectively.
- the all-solid-state battery has an energy density of 250 to 700 Wh / L, a thickness of 0.3 to 5 mm, and a length and a width of 10 to 50 mm, respectively.
- the all-solid-state battery 10 of the present invention capable of realizing a high capacity and a high energy density while being relatively thin or small has been difficult or assumed to be an actual application of the all-solid-state battery until now. It can be advantageously applied in various applications that have not been used.
- high capacity and high energy density which leads to thinning or miniaturization
- high safety by not using a flammable electrolyte
- high weather resistance for example, operating at 80 ° C or higher
- a high-voltage battery can be configured by using an all-solid battery having a stack structure in which such unit batteries are stacked.
- the present inventors include computers, laptop computers, portable computers, pocket computers, workstations, supercomputers, computer peripheral hardware, And a use as a backup power source in at least one device selected from the group consisting of servers (hereinafter referred to as a computer or the like).
- a computer or the like
- DRAMs including capacitors as small backup power supplies are commercially available (for example, ArxCis-NV TM from Viking Technology and NVDIMMs from Micron).
- Such a DRAM with a capacitor has a function of transmitting data stored in the DRAM to a non-volatile memory (for example, a NAND flash memory) using power temporarily supplied from the capacitor in the event of a power failure such as a power failure or instantaneous voltage drop. Therefore, stored data can be held in the nonvolatile memory even after the electrode supply from the capacitor is interrupted. When the power supply abnormality is finished and the power supply is resumed, the stored data in the nonvolatile memory is returned to the DRAM, so that the system can be quickly recovered.
- a non-volatile memory for example, a NAND flash memory
- a commercially available DRAM with a capacitor has a structure in which a stacked body of a DRAM mounting substrate, a mounting substrate of a nonvolatile memory, and a capacitor are connected via a long electric cord.
- the DRAM reaches a very high temperature (for example, about 95 ° C.) when it is in operation, and in consideration of safety and reliability, it is desirable to place the capacitor at a low temperature position as far as possible from the DRAM and the nonvolatile memory. Because it is.
- a liquid battery or capacitor containing an electrolytic solution may cause problems such as ignition or deterioration when exposed to a high temperature of about 95 ° C.
- liquid batteries and capacitors are considerably larger (especially considerably thicker) than memory mounting substrates, and long electrical cords are also required for their wiring. It is necessary to secure extra in the device.
- the all solid state battery of the present invention in addition to high capacity and high energy density (which leads to thinning or miniaturization), high safety (flammable electrolyte solution is used. It has various advantageous properties such as high weather resistance (for example, operable even at 80 ° C. or higher) and long life (due to not using an electrolyte that deteriorates in a high temperature environment). Therefore, the all-solid-state battery of the present invention can function safely and reliably even when exposed to a high temperature of about 95 ° C., and is also suitable for thinning or miniaturization. As a result, a memory such as a DRAM is mounted. It can be placed on or near (eg adjacent to) the substrate.
- a memory such as a DRAM
- the all solid state battery of the present invention may be attached to a heat sink of a memory such as a DRAM, or may be attached to a part of a substrate so as not to overlap with a memory such as a DRAM.
- the all solid state battery is located in the immediate vicinity of the memory such as the DRAM, so that the power supply from the all solid state battery can be reduced when the power supply is abnormal. Loss can be made more quickly and contributes to improved performance as a backup power source. Therefore, according to the all-solid-state battery of the present invention, it is possible to provide an extremely useful backup power source that is excellent in safety and reliability, is low in cost, and is suitable for space saving in an apparatus such as a computer.
- an apparatus such as a computer includes at least one board on which a volatile memory and a non-volatile memory are connected so as to be able to transmit data to each other.
- An all solid state battery is disposed in the vicinity (for example, adjacent) in connection with the volatile memory and / or the nonvolatile memory.
- the volatile memory and the non-volatile memory are each mounted on separate substrates, and these mounting substrates may be stacked to form a stacked substrate, or the volatile memory and the non-volatile memory may be mounted on a single substrate.
- the memory mounting board is particularly preferably in the form of a memory module in which a plurality of volatile memories and / or a plurality of nonvolatile memories are arranged.
- the all-solid-state battery supplies power to the volatile memory and nonvolatile memory for a certain period of time in the event of power failure (such as a power failure or instantaneous voltage drop), and transfers the data in the volatile memory to the nonvolatile memory.
- power failure such as a power failure or instantaneous voltage drop
- the nonvolatile memory can be stored in a non-volatile memory, thereby avoiding the loss of data in the volatile memory.
- highly important data can be reliably preserved by the nonvolatile memory without being affected by a failure of the uninterruptible power supply (UPS) or the power generation device.
- UPS uninterruptible power supply
- system recovery can be performed in seconds by rapid transmission of data between memories, and as a result, data recovery from a hard disk that requires a long time (for example, 30 minutes to 1 hour) becomes unnecessary.
- an apparatus such as a computer is provided with a substrate on which a volatile memory is mounted, and the all solid state battery is volatile on (or adjacent to) the substrate. It may be arranged in connection with a memory. That is, it is good also as a structure which does not have a non-volatile memory.
- the memory mounting board is particularly preferably in the form of a memory module in which a plurality of volatile memories are arranged.
- the all-solid-state battery can temporarily avoid the loss of data in the volatile memory by supplying power to the volatile memory for a certain period of time in the event of power failure (such as a power failure or instantaneous voltage drop). it can.
- the all solid state battery of the present invention can have a high capacity, it can supply power for a relatively long time, preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 15 minutes or more.
- self-refreshing data updating at a constant cycle
- self-refreshing for holding stored data can be continuously performed.
- 90% of power outages will be restored in less than 5 minutes, and if so, it will take more than 5 minutes as described above.
- the all solid state battery of the present invention that can be configured to be able to supply power over 90% or more, in some cases, almost all blackouts continue to be supplied with power until recovery and hold stored data during that time Therefore, the utility value is extremely high as a backup power source. Moreover, it is sufficient to supply power only to a volatile memory (for example, DRAM), which is one of the components, not to the entire device such as a computer, so that data can be maintained with a minimum amount of power. It is. Therefore, in some cases, it is possible to eliminate the need for an uninterruptible power supply (UPS) or a power generation device that is a large-scale device. It goes without saying that a plurality of all solid state batteries may be provided in accordance with the required power supply time.
- a volatile memory for example, DRAM
- UPS uninterruptible power supply
- a power generation device that is a large-scale device.
- the positive electrode active material 12 is an oriented polycrystal formed of a plurality of lithium transition metal oxide particles oriented in a certain direction. This certain direction is preferably a lithium ion conduction direction. Typically, the positive electrode active material 12 has a specific crystal plane of each particle oriented in a direction from the positive electrode layer 14 toward the negative electrode layer 20. Configured as a layer.
- the particles contained in the positive electrode active material 12 are composed of a lithium transition metal oxide.
- the lithium transition metal oxide preferably has a layered rock salt structure or a spinel structure, and more preferably has a layered rock salt structure.
- the layered rock salt structure has a property that the oxidation-reduction potential decreases due to occlusion of lithium ions and the oxidation-reduction potential increases due to elimination of lithium ions, and a composition containing a large amount of Ni is particularly preferable.
- the layered rock salt structure is a crystal structure in which transition metal layers other than lithium and lithium layers are alternately stacked with an oxygen atom layer interposed therebetween, that is, an ion layer and lithium ions of transition metals other than lithium.
- lithium-transition metal composite oxides having a layered rock salt structure include lithium nickelate, lithium manganate, nickel / lithium manganate, nickel / lithium cobaltate, cobalt / nickel / lithium manganate, cobalt / manganese Examples of these materials include Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ag, Sn, and the like. One or more elements such as Sb, Te, Ba, Bi and the like may be further included.
- the lithium transition metal oxide is Li x M1O 2 or Li x (M1, M2) O 2 (where 0.5 ⁇ x ⁇ 1.10, M1 is selected from the group consisting of Ni, Mn, and Co).
- M2 is Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ag, Sn, Sb,
- M1 is Ni and Co
- M2 is a composition that is at least one selected from the group consisting of Mg, Al, and Zr, more preferably Li x (M1, M2) O 2 , and M1 is Ni and Co.
- M2 is Al
- the proportion of Ni in the total amount of M1 and M2 is preferably 0.6 or more in atomic ratio. Any of such compositions can take a layered rock salt structure.
- a ceramic having a Li x (Ni, Co, Al) O 2 -based composition in which M1 is Ni and Co and M2 is Al may be referred to as NCA ceramics.
- a lithium transition metal oxide represented by Li x M1O 2 and having a composition in which M1 is Ni, Mn and Co, or M1 is Co is also preferable.
- the positive electrode active material 12 is an oriented polycrystal composed of a plurality of lithium transition metal oxide particles.
- the lithium transition metal oxide particles are preferably particles formed in a plate shape having a thickness of about 2 to 100 ⁇ m.
- the specific crystal plane described above is a (003) plane, and the (003) plane is oriented in a direction from the positive electrode layer 14 toward the negative electrode layer 20.
- the (101) plane or the (104) plane other than the (003) plane may be oriented along the plate surface of the positive electrode active material 12.
- Patent Document 3 Japanese Patent Laid-Open No. 2012-009193
- Patent Document 4 Japanese Patent Laid-Open No. 2012-009194
- Patent Document 5 Japanese Patent No. 4745463
- the oriented polycrystalline body constituting the positive electrode active material 12 is suitable for making it thicker than the non-oriented polycrystalline body.
- the thickness of the oriented polycrystal is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, and further preferably 25 ⁇ m or more.
- the upper limit of the thickness is not particularly limited, it can be said that it is practically 500 ⁇ m or less, more realistically 200 ⁇ m or less, and practically 100 ⁇ m or less.
- the positive electrode active material 12 is preferably formed in a sheet shape.
- a preferred method for producing a positive electrode active material (hereinafter referred to as a positive electrode active material sheet) formed in the form of a sheet will be described later.
- the positive electrode active material 12 may be constituted by a single positive electrode active material sheet, or a plurality of small pieces obtained by dividing the positive electrode active material sheet may be arranged in layers to constitute the positive electrode active material 12. May be.
- the lithium ion conductive material constituting the solid electrolyte layer 16 is a garnet-based ceramic material, a nitride-based ceramic material, a perovskite-based ceramic material, a phosphate-based ceramic material, a sulfide-based ceramic material, or a polymer.
- it is at least one selected from the group consisting of garnet ceramic materials, nitride ceramic materials, perovskite ceramic materials, and phosphate ceramic materials.
- garnet based ceramic materials include Li—La—Zr—O based materials (specifically, Li 7 La 3 Zr 2 O 12 etc.), Li—La—Ta—O based materials (specifically, Li 7 La 3 Ta 2 O 12 ), and the like.
- Patent Document 6 Japanese Patent Laid-Open No. 2011-051800
- Patent Document 7 Japanese Patent Laid-Open No. 2011-073962
- Patent Document 8 Japanese Patent Laid-Open No. 2011-073963. Publications
- An example of a nitride ceramic material is Li 3 N.
- perovskite ceramic materials include Li—La—Zr—O based materials (specifically, LiLa 1-x Ti x O 3 (0.04 ⁇ x ⁇ 0.14), etc.).
- phosphate ceramic materials include lithium phosphate, nitrogen-substituted lithium phosphate (LiPON), Li—Al—Ti—PO, Li—Al—Ge—PO, and Li—Al—Ti—.
- Si—P—O specifically, Li 1 + x + y Al x Ti 2 ⁇ x Si y P 3 ⁇ y O 12 (0 ⁇ x ⁇ 0.4, 0 ⁇ y ⁇ 0.6), etc. may be mentioned.
- a particularly preferable lithium ion conductive material is a garnet-based ceramic material in that a reaction does not occur even when it is in direct contact with negative electrode lithium.
- an oxide sintered body having a garnet type or a garnet type-like crystal structure containing Li, La, Zr and O is excellent in sinterability and easily densified, and has high ionic conductivity. This is preferable.
- a garnet-type or garnet-like crystal structure of this type of composition is called an LLZ crystal structure, and is referred to as an X-ray diffraction file No. of CSD (Cambridge Structural Database). It has an XRD pattern similar to 422259 (Li 7 La 3 Zr 2 O 12 ). In addition, No.
- the constituent elements are different and the Li concentration in the ceramics may be different, so the diffraction angle and the diffraction intensity ratio may be different.
- the molar ratio Li / La of Li to La is preferably 2.0 or more and 2.5 or less, and the molar ratio Zr / La to La is preferably 0.5 or more and 0.67 or less.
- This garnet-type or garnet-like crystal structure may further comprise Nb and / or Ta. That is, by replacing a part of Zr of LLZ with one or both of Nb and Ta, the conductivity can be improved as compared with that before the substitution.
- the substitution amount (molar ratio) of Zr with Nb and / or Ta is preferably set such that the molar ratio of (Nb + Ta) / La is 0.03 or more and 0.20 or less.
- the garnet-based oxide sintered body preferably further contains Al, and these elements may exist in the crystal lattice or may exist in other than the crystal lattice.
- the amount of Al added is preferably 0.01 to 1% by mass of the sintered body, and the molar ratio Al / La to La is preferably 0.008 to 0.12.
- Patent Document 6 Japanese Patent Laid-Open No. 2011-051800
- Patent Document 7 Japanese Patent Laid-Open No. 2011-073962
- Patent Document 8 Japanese Patent Laid-Open No. 2011-073963
- lithium ion conductive material a phosphoric acid-based ceramic material can be cited, and among these, nitrogen-substituted lithium phosphate (LiPON) is preferable.
- LiPON nitrogen-substituted lithium phosphate
- the dimensions of the solid electrolyte layer 16 are not particularly limited, but the thickness is preferably 0.0005 mm to 0.5 mm, more preferably 0.001 mm to 0.2 mm, and still more preferably, from the viewpoint of charge / discharge rate characteristics and mechanical strength. Is 0.005 to 0.1 mm.
- the method for forming the solid electrolyte layer 16 various particle jet coating methods, solid phase methods, solution methods, gas phase methods, and direct bonding methods can be used.
- the particle jet coating method include an aerosol deposition (AD) method, a gas deposition (GD) method, a powder jet deposition (PJD) method, a cold spray (CS) method, and a thermal spraying method.
- the aerosol deposition (AD) method is particularly preferable because it can form a film at room temperature, and does not cause a composition shift during the process or formation of a high resistance layer due to a reaction with the positive electrode plate.
- the solid phase method include a tape lamination method and a printing method.
- the tape lamination method is preferable because the solid electrolyte layer 16 can be formed thin and the thickness can be easily controlled.
- the solution method include a hydrothermal synthesis method, a sol-gel method, a precipitation method, a microemulsion method, and a solvent evaporation method.
- the hydrothermal synthesis method is particularly preferable in that it is easy to obtain crystal grains having high crystallinity at a low temperature.
- microcrystals synthesized using these methods may be deposited on the positive electrode or may be directly deposited on the positive electrode.
- the gas phase method examples include laser deposition (PLD) method, sputtering method, evaporation condensation (PVD) method, gas phase reaction method (CVD) method, vacuum deposition method, molecular beam epitaxy (MBE) method and the like.
- the laser deposition (PLD) method is particularly preferable because there is little composition deviation and a film with relatively high crystallinity can be easily obtained.
- the direct bonding (direct bonding) method is a method in which the surfaces of the solid electrolyte layer 16 and the positive electrode active material 12 formed in advance are chemically activated and bonded at a low temperature. For activation of the interface, plasma or the like may be used, or chemical modification of a functional group such as a hydroxyl group may be used.
- Negative electrode active material may be any of various known negative electrode active materials that can be used in an all-solid lithium battery.
- the negative electrode active material 18 include lithium metal, a lithium alloy, a carbonaceous material, and lithium titanate (LTO).
- the negative electrode active material 18 is formed by forming a thin film of lithium metal or a metal alloying with lithium on the negative electrode current collector 24 (copper foil or the like) by vacuum deposition, sputtering, CVD, or the like. It can be produced by forming a layer of lithium metal or a metal alloying with lithium.
- the positive electrode layer 14 preferably includes a positive electrode active material 12 and a positive electrode current collector 22 formed on the end surface of the positive electrode active material 12 opposite to the solid electrolyte layer 16.
- the negative electrode layer 20 preferably includes a negative electrode active material 18 and a negative electrode current collector 24 formed on the end surface of the negative electrode active material 18 opposite to the solid electrolyte layer 16.
- materials constituting the positive electrode current collector 22 and the negative electrode current collector 24 include platinum (Pt), platinum (Pt) / palladium (Pd), gold (Au), silver (Ag), aluminum (Al), Examples thereof include copper (Cu) and ITO (indium-tin oxide film).
- Container The container 26 is not particularly limited as long as it can accommodate a unit battery or a stack in which a plurality of unit batteries are stacked in series or in parallel.
- the container 26 can adopt a relatively simple container form.
- a chip form for mounting on an electronic circuit or a laminate cell form for example, a multilayer product of aluminum (Al) / polypropylene (PP) for thin and wide space applications can be employed.
- raw material particles particles obtained by appropriately mixing particles of compounds such as Li, Co, Ni, and Mn so that the composition after synthesis is a positive electrode active material LiMO 2 having a layered rock salt structure. Used. Alternatively, raw material particles having a composition of LiMO 2 (synthesized particles) can be used.
- LiMO 2 is obtained by further reacting the fired molded body with the lithium compound after the firing process of the molded body.
- a lithium compound may be added in an excess of 0.5 to 30 mol%.
- 0.001 to 30 wt% of a low melting point oxide such as bismuth oxide or a low melting point glass such as borosilicate glass may be added.
- the raw material particles are formed into a sheet-like self-supporting compact. That is, the “self-supporting molded body” typically can maintain the shape of a sheet-shaped molded body by itself. In addition, even if it alone can not keep the shape of the sheet-like molded body, it may be attached to any substrate or formed into a film and peeled off from this substrate before or after firing, Included in “self-supported compact”.
- a doctor blade method using a slurry containing raw material particles can be used.
- a drum dryer may be used for forming a formed body, in which a slurry containing a raw material is applied onto a heated drum and the dried material is scraped off with a scraper.
- a disk drier can be used for forming the formed body, in which a slurry is applied to a heated disk surface, dried and scraped with a scraper.
- the hollow granulated body obtained by setting the conditions of a spray dryer suitably can also be regarded as the sheet-like molded object with a curvature, it can be used suitably as a molded object.
- an extrusion molding method using a clay containing raw material particles can also be used as a molding method of the molded body.
- the slurry is applied to a flexible plate (for example, an organic polymer plate such as a PET film), and the applied slurry is dried and solidified to form a molded product, and the molded product and the plate are peeled off. By doing so, you may produce the molded object before baking of a plate-like polycrystalline particle.
- a flexible plate for example, an organic polymer plate such as a PET film
- inorganic particles may be dispersed in a suitable dispersion medium, and a binder, a plasticizer, or the like may be added as appropriate.
- the slurry is preferably prepared so as to have a viscosity of 500 to 4000 cP, and is preferably degassed under reduced pressure.
- the molded body obtained in the molding process is placed on a setter and fired, for example, in a molded state (a sheet state).
- the firing step may be one in which a sheet-like formed body is appropriately cut and crushed and placed in a sheath and fired.
- the raw material particles are mixed particles before synthesis, synthesis, further sintering and grain growth occur in this firing step.
- a molded object is a sheet form
- the grain growth of the thickness direction is restricted. For this reason, after the grains have grown until the number of crystal grains becomes one in the thickness direction of the compact, grain growth proceeds only in the in-plane direction of the compact. At this time, a specific crystal plane which is stable in terms of energy spreads on the sheet surface (plate surface). Therefore, a film-like sheet (self-supporting film) oriented such that a specific crystal plane is parallel to the sheet surface (plate surface) is obtained.
- the (101) plane and (104) plane which are crystal planes in which lithium ions can enter and exit satisfactorily, can be oriented so as to be exposed on the sheet surface (plate surface).
- the (h00) plane which becomes the (104) plane when reacted with a lithium compound to form LiMO 2 , It can be oriented so as to be exposed on the sheet surface (plate surface).
- the firing temperature is preferably 800 ° C to 1350 ° C.
- the firing time is preferably between 1 and 50 hours. If it is shorter than 1 hour, the degree of orientation becomes low. On the other hand, if it is longer than 50 hours, energy consumption becomes too large.
- the firing atmosphere is appropriately set so that decomposition does not proceed during firing.
- the volatilization of lithium proceeds, it is preferable to arrange lithium carbonate or the like in the same sheath to create a lithium atmosphere.
- firing is preferably performed in an atmosphere having a high oxygen partial pressure.
- a positive electrode active material film oriented so as to be exposed to the surface is obtained.
- lithium is introduced by sprinkling the orientation sheet lithium nitrate so that the molar ratio Li / M of Li and M is 1 or more and heat-treating.
- the heat treatment temperature is preferably 600 ° C. to 800 ° C. At a temperature lower than 600 ° C., the reaction does not proceed sufficiently. At a temperature higher than 800 ° C., the orientation deteriorates.
- a positive electrode active material sheet using LiCoO 2 particles can be produced, for example, as follows. First, a green sheet containing Co 3 O 4 and Bi 2 O 3 is formed. This green sheet is fired at a temperature in the range of 900 to 1300 ° C. for a predetermined time, so that it is an independent thin film sheet made up of a large number of plate-like Co 3 O 4 particles oriented (h00) in the particle plate surface direction. (Self-supporting film) is formed.
- “(h00) orientation” indicates that the (h00) plane is oriented so as to be parallel to the plate surface.
- the “independent” sheet refers to a sheet that can be handled as a single unit independently of other supports after firing. That is, the “independent” sheet does not include a sheet that is fixed to another support (substrate or the like) by firing and integrated with the support (unseparable or difficult to separate).
- the amount of material existing in the thickness direction is extremely small compared to the particle plate surface direction, that is, the in-plane direction (direction perpendicular to the thickness direction). Few.
- the grain growth direction is limited to the in-plane two-dimensional direction. This reliably promotes grain growth in the surface direction. In particular, even if the thickness of the green sheet is relatively thick, such as about 100 ⁇ m or more, the grain growth in the plane direction is more surely promoted by promoting the grain growth as much as possible. At this time, only particles having a crystal plane having the lowest surface energy in the plane of the green sheet selectively grow in a flat shape (plate shape) in the in-plane direction.
- plate-like crystal grains made of CoO having a large aspect ratio and a specific crystal plane (here, (h00) plane) oriented in the grain plate plane direction are obtained by sheet firing. Furthermore, it is oxidized from CoO to Co 3 O 4 in the process of lowering the temperature. In this case, Co 3 O 4 plate-like crystal grains in which a specific crystal plane (here, (h00) plane) is oriented in the grain plate plane direction are obtained by taking over the orientation orientation of CoO. During the oxidation from CoO to Co 3 O 4 , the degree of orientation tends to decrease.
- a thin film (self-supporting film) is formed in which the number of crystal grains in the thickness direction is substantially one.
- the meaning of “substantially one crystal grain in the thickness direction” does not exclude that a part (for example, end portions) of crystal grains adjacent in the plane direction overlap each other in the thickness direction.
- This self-supporting film can be a dense ceramic sheet in which a large number of thin plate-like particles as described above are bonded without gaps.
- Lithium is introduced into the Co 3 O 4 particles by mixing the (h00) -oriented Co 3 O 4 ceramic sheet obtained by the above process and Li 2 CO 3 and heating the mixture for a predetermined time.
- a sheet for the film-like positive electrode active material 12 having the (003) plane oriented in the direction from the positive electrode layer 14 to the negative electrode layer 20 and the (104) plane oriented along the plate surface is obtained.
- the “independent” sheet refers to a sheet that can be handled by itself independently from another support after firing. That is, the “independent” sheet does not include a sheet that is fixed to another support (substrate or the like) by firing and integrated with the support (unseparable or difficult to separate).
- the amount of the material existing in the thickness direction is very small compared to the plate surface direction, that is, the in-plane direction (direction orthogonal to the thickness direction).
- the grain growth direction is limited to the in-plane two-dimensional direction. This reliably promotes grain growth in the surface direction.
- the grain growth in the plane direction is more surely promoted by promoting the grain growth as much as possible. That is, the grain growth in the plane direction of the grains parallel to the plate surface direction, that is, the in-plane direction (direction orthogonal to the thickness direction) is promoted preferentially.
- a large number of thin plate-like particles oriented so that a specific crystal plane is parallel to the plate surface of the particles are formed at the grain boundary portion.
- a free-standing film bonded in the plane direction can be obtained. That is, a self-supporting film is formed so that the number of crystal grains in the thickness direction is substantially one.
- the meaning of “substantially one crystal grain in the thickness direction” does not exclude that a part (for example, end portions) of crystal grains adjacent in the plane direction overlap each other in the thickness direction.
- This self-supporting film can be a dense ceramic sheet in which a large number of thin plate-like particles as described above are bonded without gaps.
- the (h00) -oriented (Ni, Co, Al) O ceramic sheet obtained by the above-described process and lithium nitrate (LiNO 3 ) are mixed and heated for a predetermined time, thereby (Ni, Co, Al). ) Lithium is introduced into the O particles. Thereby, the Li (Ni 0.75 Co 0 for the film-like positive electrode active material 12 in which the (003) plane is oriented in the direction from the positive electrode layer 14 to the negative electrode layer 20 and the (104) plane is oriented along the plate surface. .2 Al 0.05 ) O 2 sheet is obtained.
- a raw material containing a Li component, a La component and a Zr component is fired to obtain a primary fired powder for ceramic synthesis containing Li, La, Zr and oxygen.
- the primary fired powder obtained in the first firing step is fired to synthesize a ceramic having a garnet-type or garnet-like crystal structure containing Li, La, Zr, and oxygen.
- Li component, La component and Zr component These various components are not particularly limited, and various metal salts such as metal oxides, metal hydroxides, and metal carbonates containing the respective metal components can be appropriately selected and used.
- Li 2 CO 3 or LiOH can be used as the Li component
- La (OH) 3 or La 2 O 3 can be used as the La component
- ZrO 2 can be used as the Zr component.
- oxygen is usually included as an element constituting a part of a compound containing these constituent metal elements.
- the raw material for obtaining the ceramic material can contain a Li component, a La component, and a Zr component to such an extent that an LLZ crystal structure can be obtained from each Li component, La component, Zr component, and the like by a solid phase reaction or the like.
- the Li component, La component and Zr component can be used in a composition close to 7: 3: 2 or a composition ratio.
- the Li component includes an amount increased by about 10% from the molar ratio equivalent amount based on the stoichiometry of Li in LLZ, and the La component and the Zr component are each in an LLZ molar ratio. It can contain so that it may become the quantity equivalent to.
- the molar ratio of Li: La: Zr is 7.7: 3: 2.
- the molar ratio is about 3.85: about 3: about 2 when Li 2 CO 3 : La (OH) 3 : ZrO 2 , and Li 2 CO 3 :
- the molar ratio is about 3.85: about 1.5: about 2
- LiOH: La (OH) 3 : ZrO 2 is about 7.7: about 3: about 2.
- LiOH: La 2 O 3 : ZrO 2 it is about 7.7: about 1.5: about 2.
- a known raw material powder preparation method in the synthesis of ceramic powder can be appropriately employed.
- the mixture can be mixed uniformly by putting it into a reiki machine or a suitable ball mill.
- the first firing step is a step of obtaining a primary fired powder for facilitating the thermal decomposition of at least the Li component and the La component to easily form the LLZ crystal structure in the second firing step.
- the primary fired powder may already have an LLZ crystal structure.
- the firing temperature is preferably 850 ° C. or higher and 1150 ° C. or lower.
- the first baking step may include a step of heating at a lower heating temperature and a step of heating at a higher heating temperature within the above temperature range. By providing such a heating step, a more uniform ceramic powder can be obtained, and a high-quality sintered body can be obtained by the second firing step.
- the heat treatment step constituting the first firing step is preferably performed by a heat treatment step of 850 ° C. or more and 950 ° C. or less and a heat treatment step of 1075 ° C. or more and 1150 ° C. or less. More preferably, a heat treatment step of 875 ° C. to 925 ° C.
- the first baking step the total heating time at the maximum temperature set as the heating temperature as a whole is preferably about 10 hours to 15 hours. In the case where the first baking step is composed of two heat treatment steps, it is preferable that the heating time at the maximum temperature is about 5 to 6 hours.
- the first firing step can be shortened by changing one or more components of the starting material.
- an LLZ component containing Li, La and Zr is heated at a maximum temperature in a heat treatment step of 850 ° C. or more and 950 ° C. or less.
- the heating time can be 10 hours or less. This is because LiOH used as a starting material forms a liquid phase at a low temperature, and thus easily reacts with other components at a lower temperature.
- a 2nd baking process can be made into the process of heating the primary baking powder obtained at the 1st baking process at the temperature of 950 degreeC or more and 1250 degrees C or less.
- the primary firing powder obtained in the first firing step is fired, and finally a ceramic having an LLZ crystal structure that is a composite oxide can be obtained.
- an LLZ component including Li, La, and Zr is heat-treated at a temperature of 1125 ° C. or higher and 1250 ° C. or lower.
- Li 2 CO 3 is used as the Li raw material, it is preferable to perform heat treatment at 1125 ° C. or higher and 1250 ° C. or lower.
- the temperature of the second firing step can be lowered by changing one or more components of the starting material.
- an LLZ constituent component including Li, La, and Zr can be heat-treated at a temperature of 950 ° C. or higher and lower than 1125 ° C. This is because LiOH used as a starting material forms a liquid phase at a low temperature, and thus easily reacts with other components at a lower temperature.
- the heating time at the heating temperature in the second firing step is preferably about 18 hours or more and 50 hours or less. When the time is shorter than 18 hours, the formation of the LLZ ceramics is not sufficient.
- the primary fired powder is pressure-molded using a well-known press technique to give a desired three-dimensional shape (for example, a shape and size that can be used as a solid electrolyte of an all-solid battery)
- a desired three-dimensional shape for example, a shape and size that can be used as a solid electrolyte of an all-solid battery
- the molded body containing the primary fired powder is fired and sintered in the second firing step, it is preferable to carry out the process so that the molded body is buried in the same powder. By doing so, the loss of Li can be suppressed and the change in composition before and after the second firing step can be suppressed.
- the molded body of the raw material powder is usually buried in the raw material powder in a state where the raw material powder is spread and placed. By carrying out like this, reaction with a setter can be suppressed.
- the curvature at the time of baking of a sintered compact can be prevented by pressing a molded object with a setter from the upper and lower sides of a filling powder as needed.
- the primary fired powder compact can be sintered without being embedded in the same powder. This is because the loss of Li is relatively suppressed and the reaction with the setter can be suppressed by lowering the temperature of the second baking step.
- the solid electrolyte layer 16 having an LLZ crystal structure can be obtained.
- the solid electrolyte layer having a crystal structure and containing aluminum is obtained by carrying out either or both of the first firing step and the second firing step in the presence of an aluminum (Al) -containing compound. You may make it manufacture.
- This backup system includes a volatile memory, a non-volatile memory, an all-solid battery, and control means.
- the volatile memory and the nonvolatile memory are connected to each other so as to be able to transmit data.
- the all-solid-state battery is connected to a volatile memory and a non-volatile memory, and can supply data to the volatile memory continuously or intermittently when the power supply is abnormal to hold data in the volatile memory.
- the control means is a means that is connected in parallel with the all-solid-state battery and can intermittently supply the peak current to the volatile memory when the power supply is abnormal.
- This control means is non-volatile for each divided amount of data in the volatile memory, either through the peak current or through the peak current and the current from the all-solid battery that is temporarily increased accompanying it.
- the data is intermittently transferred to the memory and stored in the nonvolatile memory, whereby the data in the volatile memory is gradually accumulated in the nonvolatile memory.
- the data in the volatile memory is maintained for as long as possible in the event of a power failure, enabling instantaneous data restoration at the time of power restoration, while reducing the output of the all-solid-state battery due to an unexpected delay in power restoration.
- the risk of data loss can be avoided or minimized by copying data intermittently and cumulatively to the non-volatile memory.
- the volatile memory is typically a DRAM. Therefore, the following description will be given by taking the DRAM as an example, but it is needless to say that other volatile memories may be used.
- the nonvolatile memory is typically a flash memory (for example, a NAND flash memory). Therefore, the following description will be given by taking the flash memory as an example, but it goes without saying that other nonvolatile memories may be used. Nor.
- FIG. 2 (c) shows an example of the power output waveform of the hybrid backup system according to the present invention in which an all solid state battery and a bypass capacitor as a control means are combined.
- FIG. 2 shows a power output waveform example (a) using the above-described NVDIMM supercapacitor as a backup power source, and a power output waveform example (b) using a battery backup DRAM battery as a backup power source. ) Is also shown. Note that all of the power supply output waveform examples shown in FIG. 2 assume a 4 GB capacity memory module, and the vertical axis corresponds to the current value, and the horizontal axis corresponds to time.
- the data in the DRAM is copied to the flash memory at a time within the time indicated by “A” in the figure. .
- the peak current (7A in FIG. 2) is supplied from the supercapacitor simultaneously with the occurrence of the power stop (this is the starting point of time (0 seconds)), and within a predetermined time (in FIG. 2 (a)). 0 to 30 seconds), the data is copied all at once from the volatile memory DRAM to the nonvolatile memory flash memory. Then, after the predetermined time elapses, data in the DRAM is lost (see “C” in the figure).
- the time when this data is copied is a time during which the voltage of the NVDIMM can be maintained at a voltage equal to or higher than a threshold (for example, 3.3 V) at which data can be transmitted to the flash memory. It is desirable to complete the copy to memory (otherwise data in the DRAM that was not copied to the flash memory will be lost). Therefore, a supercapacitor having a large capacity is used so that a high peak current sufficient to copy a large amount of data to the flash memory at a time can be supplied. However, as described above, the supercapacitor is so large that it cannot be mounted on the memory module, and is inferior in heat resistance. In addition, even if the power is stopped within 1 minute, data in the DRAM is lost. Therefore, it takes time (for example, several tens of seconds) to return data from the flash memory to the DRAM when the power is restored.
- a threshold for example, 3.3 V
- the data in the DRAM is stored within a relatively long time indicated by “B” in the figure. It is kept as it is. This is because the life of data in the DRAM is extended by operating in a power saving mode (for example, a self-refresh mode) specialized for data retention.
- the battery supplies a low current (for example, 11 mA) which is the minimum necessary for extending the life of data in the DRAM, thereby delaying the battery exhaustion and waiting for the power supply to recover during that time.
- a conventional battery having a low heat-resistant temperature and low energy density is used, it is difficult to mount it in a memory module, and there is a problem that data in the DRAM is lost when the power supply is stopped beyond the backup possible time.
- the backup system includes a hybrid power source that combines an all-solid-state battery and control means (in the illustrated example, a bypass capacitor is provided). It is what was used.
- This hybrid power supply supplies a peak current intermittently (that is, at a constant cycle) by a control means having a bypass capacitor after the power supply is stopped.
- the peak current from the bypass capacitor can provide a voltage higher than a threshold (for example, 3.3 V) at which data can be transmitted from the DRAM to the flash memory as in the case of FIG.
- the peak current value is divided into n times (n is an integer of 2 or more, preferably 5 or more, more preferably 10 or more, more preferably 100 or more) and copied to the flash memory.
- the peak current due to the supercapacitor (a) can be set to be significantly low, 1 / n (7 / n (A) in FIG. 2).
- the control means (comprising a bypass capacitor in the illustrated example) is connected in parallel with the all-solid-state battery, the all-solid-state battery follows its inherent electrochemical properties as the peak current is generated from the control means. A current temporarily increased with a slight time lag is supplied to the DRAM. This is because the all-solid-state battery functions to compensate for the charge lost by the control means (especially the bypass capacitor) with the generation of the peak current, so that the increase in current by the all-solid-state battery follows the generation of the peak current.
- the current supplied from the all-solid-state battery is temporarily increased by the peak current provided by the control means, so that the amount of data in the DRAM displayed as “A” in the figure is divided (ie, A sufficient time can be secured for copying to the flash memory every 1 / n).
- the peak current supplied from the control means is a relatively high current that is instantaneously supplied and thus decays quickly, another relatively high current is supplied from the all solid state battery to compensate for the decay. It is supplied with a slight delay, and the time displayed as “A” in the figure can be made much longer than in the case of the capacitor alone as shown in FIG.
- the data in the volatile memory is intermittently transferred to the nonvolatile memory for each divided amount through the peak current and the current from the all-solid battery that temporarily increases accompanying the peak current.
- the data in the volatile memory can be gradually stored in the non-volatile memory. This operation is repeated until the copying of all the data in the volatile memory to the nonvolatile memory is completed.
- the sum of the peak current and the current from the all-solid battery temporarily increased accompanying therewith attenuates at a constant period, thereby
- the transfer of data in the volatile memory to the non-volatile memory is intermittently suspended, during which time the volatile memory is preferably operated in a power saving mode using current supplied from the all-solid-state battery.
- a power saving mode is a self-refresh mode (a mode in which only data is maintained with a minimum power) for holding stored data in a DRAM. In this way, data in a volatile memory such as a DRAM can be retained as long as possible (ie, the life can be extended) while minimizing the power consumption of the all-solid-state battery.
- the supply of current from the all-solid-state battery to the volatile memory is the power source as indicated by “B” in FIG. It is preferable to continue until recovery or the battery runs out, during which the data in the volatile memory is also retained in the power saving mode.
- the power saving mode displayed as “B” in FIG. 2C by appropriately monitoring the power state, the backup data from the nonvolatile memory is not used when the power is restored. The system can be instantly restored using only the data in the volatile memory.
- the data in the volatile memory is held for as long as possible in the event of a power failure, while enabling instantaneous data recovery when the power is restored, Data is intermittently and cumulatively copied to a non-volatile memory in preparation for a dead battery due to an unexpected delay in power recovery, thereby making it possible to avoid or minimize the risk of data loss. Therefore, highly important data can be reliably preserved in the volatile memory and / or the nonvolatile memory without being affected by the failure of the uninterruptible power supply (UPS) or the power generation device.
- UPS uninterruptible power supply
- the control means includes a bypass capacitor, and that the peak current is supplied from the bypass capacitor.
- the bypass capacitor has an advantage that a high peak current can be supplied in a shorter time than an all solid state battery. Further, since the bypass capacitor requires only 1 / n of the capacitance compared to the super capacitor, it can be mounted on a substrate (for example, a memory module) including a volatile memory and / or a nonvolatile memory or in the vicinity thereof.
- the control means may be configured to supply the peak current using the parasitic capacitance of the circuit, component and / or device to which the backup system is connected. In this case, although the peak current is small, no bypass capacitor is required. It can be.
- Example A1 An all solid state battery 10 having the configuration shown in FIG. 1 was produced.
- the positive electrode active material 12 has a layered rock salt structure and the composition is Li (Ni 1/3 Co 1/3 Mn 1/3 ) O 2 (hereinafter referred to as NCM), and the (003) plane is from the positive electrode layer 14.
- NCM Li (Ni 1/3 Co 1/3 Mn 1/3 ) O 2
- a positive electrode active material sheet oriented in the direction toward the negative electrode layer 20 was produced. The thickness of the positive electrode active material sheet was 30 ⁇ m.
- a solid electrolyte layer 16 was formed on the sheet-like positive electrode active material 12.
- the lithium ion conductive material constituting the solid electrolyte layer 16 a ceramic material having a garnet crystal structure made of Li 7 La 3 Zr 2 O 12 (hereinafter referred to as LLZ-Al) to which Al is added was used.
- the thickness of the solid electrolyte layer 16 was 10 ⁇ m.
- the negative electrode active material 18 was made of lithium metal and had a thickness of 10 ⁇ m.
- the positive electrode current collector 22 was composed of an aluminum foil having a thickness of 10 ⁇ m, and the negative electrode current collector 24 was composed of a copper foil having a thickness of 10 ⁇ m.
- a laminate composed of these components was obtained as a unit cell.
- This unit battery was laminated with a multilayer product of aluminum (Al) / polypropylene (PP).
- the size (vertical x horizontal) of the all-solid battery thus obtained as viewed from above was 20 mm x 30 mm, and the thickness of the all-solid battery was 0.24 mm.
- Example A2 The unit cells obtained in Example A1 were stacked in parallel to produce a battery with a capacity of 100 mAh.
- the energy density was determined in the same manner as in Example A1, it was 650 Wh / L.
- Example A3 The unit batteries obtained in Example A1 were stacked in parallel to produce a battery with a capacity of 300 mAh. When the energy density was determined in the same manner as in Example A1, it was 750 Wh / L.
- Example A4 A lithium ion conductive material constituting the solid electrolyte layer 16 was LiPON, and the thickness of the solid electrolyte layer 16 was 5 ⁇ m. This unit cell was laminated and covered in the same manner as in Example A1. The size (vertical x horizontal) of the all-solid battery thus obtained as viewed from above was 20 mm x 30 mm, and the thickness of the all-solid battery was 0.24 mm. When the volume energy density of the obtained all solid state battery was determined in the same manner as in Example A1, the capacity was 20 mAh and the energy density was 542 Wh / L.
- Example 5 The unit batteries obtained in Example A4 were stacked in parallel to produce a battery with a capacity of 100 mAh. When the energy density was determined in the same manner as in Example A4, it was 650 Wh / L.
- Example 6 The unit batteries obtained in Example A4 were stacked in parallel to produce a battery with a capacity of 300 mAh. When the energy density was determined in the same manner as in Example A1, it was 750 Wh / L.
- the size and performance of the battery shown in Table 1 are extremely suitable for various applications including a backup power source for volatile memory in an apparatus such as a computer.
- a backup power source for volatile memory in an apparatus such as a computer.
- the size and performance of the battery considered by the applicant to be desired in some applications such as a volatile memory backup power supply are shown in Table 2 below.
- For volatile memory backup power supply applications connect all the solid-state batteries to the volatile memory on or near (for example, adjacent to) the board on which the volatile memory is mounted according to the required power supply time. Can also be arranged. It can be seen that the all-solid-state battery of the present invention is extremely promising for various uses including those shown in Table 2.
- Table 2 includes applications with extremely high capacity such as electric vehicles, such high capacity can be realized by stacking unit cells in parallel.
- Example B1 An example of applying the volatile memory backup system using the all-solid-state battery of the present invention for NVDIMM (nonvolatile memory module) applications will be described below.
- this example is an example characterized in that the transfer of all data in the DRAM is completed within 30 minutes.
- the NVDIMM specifications, DRAM operating conditions, and all-solid battery specifications assumed in this example are as follows.
- ⁇ NVDIMM prerequisites> -Memory size: 4GB -Memory configuration: 8-chip 4G-bit DRAM; Consists of one chip of 32Gbit flash memory-DIMM board size: 133.35mm x 24.00mm (DDR3 standard) ⁇ Operating conditions for transferring all data at once from DRAM to flash memory (active mode)> -Voltage: 3.3V -Current: 4A (average), 7A (peak) -Time: 34 seconds-Energy: 0.125 Wh ( 3.3V x 4A x 34 seconds / 3600) ⁇ Operating conditions of DDR3 idle mode> -Power for one DRAM chip: 0.55W (Voltage: 3.3V, Current 0.167A) ⁇ Operating conditions of DDR3 self-refresh mode> -Output: 37mW for 8 chips of DRAM (Voltage: 3.3V, Current 0.011A) -Output: 32mW for 7 chips of DRAM (Voltage:
- the backup power supply output waveform in this example is shown in FIG.
- the backup system according to this example completes the transfer of the data in the DRAM to the flash memory in about 25 minutes and 50 seconds, and then the DRAM operates in the self-refresh mode for about 82.6 hours. Hold the data in the DRAM. Therefore, copying of data to the flash memory, which is a non-volatile memory, is completed in a relatively short time of about 30 minutes to prepare for the all-solid-state battery running out, and after that, it is stored in the DRAM for about 82.6 hours or more. Can also hold data. Meanwhile, power supply system monitoring for confirming whether or not power supply is restored is performed every block (30 seconds) of data transfer for 1 second, thereby enabling instantaneous data restoration upon power restoration.
- Approximate values for various conditions in this example are as follows.
- -Power system monitoring per block 1 second (interrupt signal from the power supply when power is restored can be accepted in this 1 second)
- Example B2 Another example in which the volatile memory backup system using the all-solid-state battery of the present invention is applied for NVDIMM (nonvolatile memory module) applications will be described below.
- this example is an example in which a battery having a size smaller than that of Example B1 is employed and data transfer from the DRAM to the flash memory is performed in a longer time.
- the NVDIMM specifications, DRAM operating conditions, and all-solid battery specifications assumed in this example are as follows.
- ⁇ NVDIMM prerequisites> -Memory size: 4GB -Memory configuration: 8-chip 4G-bit DRAM; Consists of one chip of 32Gbit flash memory-DIMM board size: 133.35mm x 24.00mm (DDR3 standard) ⁇ Operating conditions for transferring all data at once from DRAM to flash memory (active mode)> -Voltage: 3.3V -Current: 4A (average), 7A (peak) -Time: 34 seconds-Energy: 0.125 Wh ( 3.3V x 4A x 34 seconds / 3600) ⁇ Operating conditions of DDR3 idle mode> -DRAM chip power: 0.55W (Voltage: 3.3V, Current 0.167A) ⁇ Operating conditions of DDR3 self-refresh mode> -Output: 37mW for 8 chips of DRAM (Voltage: 3.3V, Current 0.011A) -Output: 32mW for 7 chips of DRAM (Voltage: 3.3V
- the backup power supply output waveform in this example is shown in FIG.
- the backup system according to this example completes the transfer of the data in the DRAM to the flash memory in about 2.80 hours, and then the DRAM operates in the self-refresh mode for about 16.9 hours. Hold the data in the DRAM. Therefore, while using a relatively small all-solid-state battery, copying of data to the flash memory, which is a non-volatile memory, is completed in about 2.80 hours to prepare for the all-solid-state battery running out. Data can be held in DRAM for 9 hours. Meanwhile, power supply system monitoring for confirming whether or not power supply is restored is performed every block (30 seconds) of data transfer for 1 second, thereby enabling instantaneous data restoration upon power restoration.
- Approximate values for various conditions in this example are as follows.
- -Power system monitoring per block 1 second (The interrupt signal from the power supply when power is restored can be accepted in this 1 second.)
- Example C1 An example in which the all-solid-state battery is applied to the backup of DIMM (Dual Inline Memory Module) which is a volatile memory is shown below.
- the specifications of the DIMM and the specifications of the all-solid battery assumed in this example are as follows. ⁇ Prerequisite specifications for DIMM> -DDR3 8GB DIMM (manufactured by Samsung Electronics, M393B1G70QH0-YH9 / K0) -Voltage: 1.35V -Self-refresh current: 0.3A ⁇ Specifications of all-solid battery> -Energy density: 400Wh / L -Battery size: 20mm x 60mm x 5mm -C rate available for data transfer: 0.25C
- the backup system of this example has a configuration in which the all solid state battery is connected to the DIMM, and operates the DIMM in a self-refresh mode by a current supplied from the all solid state battery.
- Approximate values for various conditions in this example are as follows.
- the data in the DIMM can be retained for 5.92 hours.
- 95% of power supply abnormalities are restored within 4 hours.
- the backup system of this example with a total backup time of 5.92 hours can cope with almost all power supply abnormalities (95% or more) even though it has a very simple configuration that does not use non-volatile memory. It can be said that there is.
- Example C2 An example of a pack-up system configured in the same manner as in Example C1 except that a DIMM having a specification different from that in Example C1 is adopted is shown below.
- the DIMM employed in this example has a lower power consumption than the DIMM employed in Example 1.
- the specifications of the DIMM and the specifications of the all-solid battery assumed in this example are as follows.
- the data in the DIMM can be retained for 5.56 hours.
- 95% of power supply abnormalities are restored within 4 hours.
- the backup system of this example which has a total backup time of 5.56 hours, can cope with almost all power supply abnormalities (95% or more) even though it has a very simple configuration that does not use non-volatile memory. It can be said that there is.
- Example C3 Another example in which the volatile memory backup system using the all-solid-state battery of the present invention is applied for NVDIMM (nonvolatile memory module) applications will be described below.
- this example is an example in which the roles of the all solid state battery and the bypass capacitor are clearly distinguished by switching the all solid state battery with a switch.
- the NVDIMM specifications, DRAM operating conditions, and all solid state battery specifications assumed in this example are as follows.
- ⁇ NVDIMM prerequisites> -NVDIMM (8GB DDR3) (manufactured by Netlist, NV3848HAT17-000NL000) -Memory size: 8GB -Memory configuration: 18 chip 4G bit DDR3 DRAM; 2 chip 32Gbit NAND flash memory-DIMM board size: 133.35mm x 24.00mm (DDR3 standard) ⁇ Operating conditions for data transfer from DRAM to flash memory by supercapacitor *> -Voltage: 5.4V (2.7V capacitor connected in series) -Current: 2.5A -Time: 34 seconds-Energy: 0.128 Wh ( 5.4 V x 2.5 A x 34 seconds / 3600) (value calculated from the case of a super capacitor) * Note that the above assumes a supercapacitor specification as a precondition.
- an all solid state battery is used instead of the supercapacitor.
- FIG. 5 shows an equivalent circuit that realizes a hybrid operation in which data transfer from the DRAM to the flash memory and DRAM storage in the self-refresh mode are combined under the above-mentioned preconditions. Main symbols shown in the equivalent circuit diagram of FIG. 5 will be described below.
- -R 1 resistance to reduce peak output current from all solid state batteries (inductors are also available)
- C 1 Bypass capacitor for applying current for data transfer from DRAM to flash memory-Z: Equivalent impedance (variable) of DRAM and flash memory (3.7 / 3.3 and 3.7 / 1.35) DC / DC converter)
- I 3 (i) During data transfer from DRAM to flash memory, current is 3.6 A (voltage is 3.7 V) (reference: 2.5 A (voltage: 5.4 V) for supercapacitor) , (Ii) While the DRAM is in the self-refresh mode and the flash memory is not accessed, the current is 0.11 A (voltage is 3.7 V) (reference: in the case of the 8 GB DDR3 DIMM used in Example C1, the current is 0.1. 3A (Voltage is 1.35V))
- FIG. 6 shows the backup power supply output waveform of this example, which is realized according to the above-described preconditions in the equivalent circuit shown in FIG.
- the peak current supplied from the bypass capacitor flows through the circuit for 0.1 second, and the divided data is transferred from the DRAM to the flash memory. Since 1 is turned off, no current is supplied from the all solid state battery. Subsequently, the switch SW 1 is switched to ON, current from the all-solid-state cell flows in 30 seconds circuitry, while maintaining the data in the DRAM to operate the DRAM in the self refresh mode, charging the bypass capacitor. Then, the charging of the bypass capacitor is completed after 30 seconds, and the switch SW 1 is turned off again. In the same manner as described above, the data is transferred from the DRAM to the flash memory (0.1 second), and then in the self-refresh mode. The operation (30 seconds) is repeated alternately.
- the backup system of this example after the transfer of the data in the DRAM to the flash memory is completed in 2.8 hours, the DRAM operates in the self-refresh mode for 2.8 hours. Retain data. Therefore, copying of data to flash memory, which is a non-volatile memory, is completed in 2.8 hours to prepare for all-solid-state battery depletion, and data can be retained in DRAM for 2.8 hours thereafter. it can.
- the backup system of this example which has a total DRAM storage time of 5.6 hours, has almost all power supply abnormalities (95% or more). It can be said that it can be handled at the DRAM level. Even after 5.6 hours, the system can be restored based on the data already copied in the flash memory. That is, the loss of data can be effectively avoided regardless of the time until the power is restored.
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Abstract
Description
リチウムイオン伝導材料で構成される固体電解質層と、
負極活物質を有する負極層と、
を備えた全固体電池の、コンピュータ、ラップトップ・コンピュータ、可搬式コンピュータ、ポケットコンピュータ、ワークステーション、スーパーコンピュータ、コンピュータ周辺ハードウェア、及びサーバからなる群から選択される少なくとも一つの装置におけるバックアップ電源としての使用が提供される。
本発明は、全固体電池の各種用途における使用に関する。図1に、本発明による全固体電池の一例を模式的に示す。図1に示される全固体電池10は、正極活物質12を有する正極層14と、リチウムイオン伝導材料で構成される固体電解質層16と、負極活物質18を有する負極層20とを備えてなり、固体電解質層16を正極層14と負極層20とで挟み込んだ構成となっている。そして、正極活物質12は、一定の方向に配向された複数のリチウム遷移金属酸化物粒子からなる配向多結晶体である。上述したように、特許文献1及び2に開示される全固体電池にあっては、正極層を厚く形成したとしても、期待したほど容量及びエネルギー密度の増加が得られないとの問題があった。これは、特許文献1及び2では正極層に用いる正極活物質が配向されていないため、厚い正極層の厚さ全体にわたった高効率なリチウムイオンの脱挿入がしづらいためであると考えられる。例えば、厚い正極層の固体電解質から離れた側に存在するリチウムを十分に取り出せないことが起こりうる。この点、正極活物質12は一定の方向に配向された複数のリチウム遷移金属酸化物粒子からなる配向多結晶体であるため、正極活物質を厚く設けても、正極層の厚さ全体にわたった高効率なリチウムイオンの脱挿入がしやすく、厚い正極活物質によってもたらされる容量向上効果を最大限に引き出すことができる。例えば、厚い正極層の固体電解質から離れた側に存在するリチウムも十分に取り出すことができる。かかる容量の向上によって、全固体電池のエネルギー密度をも大いに向上することができる。すなわち、本発明の全固体電池によれば、容量及びエネルギー密度の高い電池性能が得られる。したがって、比較的薄型ないし小型でありながらも、高い容量と高いエネルギー密度を有する安全性が高い全固体電池を実現することができる。
正極活物質12は、一定の方向に配向された複数のリチウム遷移金属酸化物粒子からなる配向多結晶体である。この一定の方向は、リチウムイオンの伝導方向であるのが好ましく、典型的には、正極活物質12は、各粒子の特定の結晶面が正極層14から負極層20に向かう方向に配向された層として構成される。
固体電解質層16を構成するリチウムイオン伝導材料は、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、リン酸系セラミックス材料、硫化物系セラミックス材料、又は高分子系材料で構成されるのが好ましく、より好ましくは、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、及びリン酸系セラミックス材料からなる群から選択される少なくとも一種である。ガーネット系セラミックス材料の例としては、Li-La-Zr-O系材料(具体的には、Li7La3Zr2O12など)、Li-La-Ta-O系材料(具体的には、Li7La3Ta2O12など)が挙げられ、特許文献6(特開2011-051800号公報)、特許文献7(特開2011-073962号公報)及び特許文献8(特開2011-073963号公報)に記載されているものも用いることができ、これらの文献の開示内容は参照により本明細書に組み込まれる。窒化物系セラミックス材料の例としては、Li3N。ペロブスカイト系セラミックス材料の例としては、Li-La-Zr-O系材料(具体的には、LiLa1-xTixO3(0.04≦x≦0.14)など)が挙げられる。リン酸系セラミックス材料の例としては、リン酸リチウム、窒素置換リン酸リチウム(LiPON)、Li-Al-Ti-P-O,Li-Al-Ge-P-O、及びLi-Al-Ti-Si-P-O(具体的には、Li1+x+yAlxTi2-xSiyP3-yO12(0≦x≦0.4、0<y≦0.6)など)が挙げられる。
負極活物質18は、全固体リチウム電池に使用可能な公知各種の負極活物質であってよい。負極活物質18の好ましい例としては、リチウム金属、リチウム合金、炭素質材料、チタン酸リチウム(LTO)等が挙げられる。好ましくは、負極活物質18は、負極集電体24(銅箔等)の上に、リチウム金属あるいはリチウムと合金化する金属の薄膜を真空蒸着法、スパッタリング法、CVD法等で形成して、リチウム金属あるいはリチウムと合金化する金属の層を形成することにより作製することができる。
正極層14は、正極活物質12と、該正極活物質12の固体電解質層16と反対側の端面に形成された正極集電体22とを備えるのが好ましい。また、負極層20は、負極活物質18と、該負極活物質18の固体電解質層16と反対側の端面に形成された負極集電体24とを備えるのが好ましい。正極集電体22及び負極集電体24を構成する材料の例としては、白金(Pt)、白金(Pt)/パラジウム(Pd)、金(Au)、銀(Ag)、アルミニウム(Al)、銅(Cu)、ITO(インジウム-錫酸化膜)等が挙げられる。
容器26は、単位電池又はそれを複数個直列若しくは並列に積層させたスタックを収容可能な容器であれば特に限定されない。特に、全固体電池10は電解液の漏れの懸念が無いため、容器26は比較的簡素な容器形態を採用可能である。例えば、電子回路に実装するためのチップ形態や、薄く幅広の空間用途のためのラミネートセル形態(例えばアルミニウム(Al)/ポリプロピレン(PP)の複層品)が採用可能である。
正極活物質シートの好ましい製造方法について以下に説明する。
原料粒子としては、合成後の組成が層状岩塩構造を有する正極活物質LiMO2となるように、Li、Co、Ni、Mnなどの化合物の粒子を適宜混合したものが用いられる。あるいは、原料粒子として、LiMO2の組成からなるもの(合成済みのもの)を用いることができる。
原料粒子を、シート状の自立した成形体に成形する。すなわち、「自立した成形体」は、典型的には、それ単体でシート状の成形体の形状を保つことができるものである。なお、それ単体ではシート状の成形体の形状を保つことができないものであっても、何らかの基板上に貼り付けたり成膜したりして焼成前又は焼成後に、この基板から剥離したものも、「自立した成形体」に含まれる。
この焼成工程においては、成形工程で得られた成形体は、例えば、成形されたそのままの状態(シート状態)で、セッターに載せて焼成される。あるいは、焼成工程は、シート状の成形体を適宜切断、破砕したものを、鞘に入れて焼成するものであってもよい。
LiCoO2粒子を用いた正極活物質シートは、例えば以下のようにして製造することができる。先ず、Co3O4とBi2O3とを含有したグリーンシートを形成する。このグリーンシートを900~1300℃の範囲内の温度で所定時間焼成することで、粒子板面方向に(h00)配向した多数の板状のCo3O4粒子からなる、独立した薄膜状のシート(自立膜)を形成する。ここで、「(h00)配向」とは、(h00)面が板面と平行となるように配向したことを示す。なお、この焼成の際に、ビスマスは揮発することでシートから除去され、Co3O4は還元されてCoOに相変態する。ここで、「独立した」シート(自立膜)とは、焼成後に他の支持体から独立して単体で取り扱い可能なシートのことをいう。すなわち、「独立した」シートには、焼成により他の支持体(基板等)に固着されて当該支持体と一体化された(分離不能あるいは分離困難となった)ものは含まれない。このように薄膜(自立膜)状に形成されたグリーンシートにおいては、粒子板面方向すなわち面内方向(厚さ方向と直交する方向)に比べて、厚さ方向に存在する材料の量がきわめて少ない。このため、厚さ方向に複数個の粒子がある初期段階には、ランダムな方向に粒成長する。一方、粒成長が進み厚さ方向の材料が消費されると、粒成長方向は面内の二次元方向に制限される。これにより、面方向への粒成長が確実に促進される。特に、グリーンシートの厚さが100μm程度もしくはそれ以上と比較的厚めであっても粒成長を可能な限り大きく促進したりすることで、面方向への粒成長がより確実に促進される。また、このとき、表面エネルギーの最も低い結晶面をグリーンシートの面内に持つ粒子のみが選択的に面内方向へ扁平状(板状)に粒成長する。その結果、シート焼成により、アスペクト比が大きく、特定の結晶面(ここでは(h00)面)が粒子板面方向に配向したCoOからなる板状結晶粒子が得られる。さらに、温度が下がる過程で、CoOからCo3O4に酸化される。その際に、CoOの配向方位が引き継がれることで、特定の結晶面(ここでは(h00)面)が粒子板面方向に配向したCo3O4板状結晶粒子が得られる。CoOからCo3O4への酸化の際に、配向度が低下しやすい。これは、CoOとCo3O4の結晶構造及びCo-Oの原子間距離が大きく異なることから、酸化、すなわち、酸素原子が挿入される際に、結晶構造が乱れやすいためである。従って、配向度をなるべく低下しないように適宜条件を選択することが好ましい。例えば、降温速度を小さくすることや、所定の温度で保持することや、酸素分圧を小さくすることが好ましい。そして、このグリーンシートを焼成することで、特定の結晶面が粒子板面方向に配向した薄板状の多数の粒子が、粒界部にて面方向に結合した薄膜(自立膜)が得られる。すなわち、実質的に厚さ方向についての結晶粒子の個数が1個となるような薄膜(自立膜)が形成される。ここで、「実質的に厚さ方向についての結晶粒子の個数が1個」の意義は、面方向に隣り合う結晶粒子の一部分(例えば端部)が厚さ方向に互いに重なり合うことを排除しない。この自立膜は、上述のような薄板状の多数の粒子が隙間なく結合した、緻密なセラミックスシートとなり得る。上述の工程によって得られた、(h00)配向したCo3O4セラミックスシートと、Li2CO3とを混合して、所定時間加熱することで、Co3O4粒子にリチウムが導入される。これにより、(003)面が正極層14から負極層20の方向に配向し、(104)面が板面に沿って配向した膜状の正極活物質12用のシートが得られる。
Lip(Nix,Coy,Alz)O2粒子を用いた正極活物質シートは、例えば以下のようにして製造することができる。先ず、NiO粉末とCo3O4粉末とAl2O3粉末とを含有するグリーンシートを形成し、このグリーンシートを1000℃~1400℃の範囲内の温度で、大気雰囲気で所定時間焼成することで、(h00)配向した多数の板状の(Ni,Co,Al)O粒子からなる、独立した膜状のシート(自立膜)が形成される。ここで、助剤としてMnO2、ZnO等を添加することにより、粒成長が促進され、結果として板状結晶粒子の(h00)配向性を高めることができる。ここで、「独立した」シートとは、焼成後に他の支持体から独立して単体で取り扱い可能なシートのことをいう。すなわち、「独立した」シートには、焼成により他の支持体(基板等)に固着されて当該支持体と一体化された(分離不能あるいは分離困難となった)ものは含まれない。このように自立膜状に形成されたグリーンシートにおいては、板面方向、すなわち、面内方向(厚さ方向と直交する方向)に比べて、厚さ方向に存在する材料の量がきわめて少ない。このため、厚さ方向に複数個の粒子がある初期段階には、ランダムな方向に粒成長する。一方、粒成長が進み厚さ方向の材料が消費されると、粒成長方向は面内の二次元方向に制限される。これにより、面方向への粒成長が確実に促進される。特に、グリーンシートの厚さが100μm程度もしくはそれ以上と比較的厚めであっても粒成長を可能な限り大きく促進したりすることで、面方向への粒成長がより確実に促進される。すなわち、表面エネルギーの低い面が板面方向、すなわち、面内方向(厚さ方向と直交する方向)と平行な粒子の面方向への粒成長が優先的に促進される。従って、上述のように膜状に形成されたグリーンシートを焼成することで、特定の結晶面が粒子の板面と平行となるように配向した薄板状の多数の粒子が、粒界部にて面方向に結合した自立膜が得られる。すなわち、実質的に厚さ方向についての結晶粒子の個数が1個となるような自立膜が形成される。ここで、「実質的に厚さ方向についての結晶粒子の個数が1個」の意義は、面方向に隣り合う結晶粒子の一部分(例えば端部)が厚さ方向に互いに重なり合うことを排除しない。この自立膜は、上述のような薄板状の多数の粒子が隙間なく結合した、緻密なセラミックスシートとなり得る。上述の工程によって得られた、(h00)配向した(Ni,Co,Al)Oセラミックスシートと、硝酸リチウム(LiNO3)とを混合して、所定時間加熱することで、(Ni,Co,Al)O粒子にリチウムが導入される。これにより、(003)面が正極層14から負極層20の方向に配向し、(104)面が板面に沿って配向した膜状の正極活物質12用のLi(Ni0.75Co0.2Al0.05)O2シートが得られる。
以下に固体電解質層16を構成するリチウムイオン伝導材料の代表例の一つである、Al添加LLZセラミックス焼結体の好ましい製造方法を説明する。
これらの各種成分は、特に限定されないで、それぞれの金属成分を含む、金属酸化物、金属水酸化物、金属炭酸塩等、各種金属塩を適宜選択して用いることができる。例えば、Li成分としてはLi2CO3又はLiOHを用い、La成分としてはLa(OH)3又はLa2O3を用い、Zr成分としてはZrO2を用いることができる。なお、酸素は、通常、これら構成金属元素を含む化合物の一部を構成する元素として含まれている。セラミックス材料を得るための原料は、各Li成分、La成分及びZr成分等から固相反応等によりLLZ結晶構造が得られる程度にLi成分、La成分及びZr成分を含むことができる。Li成分、La成分及びZr成分は、LLZの化学量論組成に従えば、7:3:2あるいは組成比に近似した組成で用いることができる。Li成分の消失を考慮する場合には、Li成分は、LLZにおけるLiの化学量論に基づくモル比相当量よりも約10%増量した量を含み、La成分及びZr成分は、それぞれLLZモル比に相当する量となるように含有することができる。例えば、Li:La:Zrのモル比が7.7:3:2となるように、含有することができる。具体的な化合物を用いた場合のモル比としては、Li2CO3:La(OH)3:ZrO2のとき、約3.85:約3:約2のモル比となり、Li2CO3:La2O3:ZrO2のとき、約3.85:約1.5:約2のモル比となり、LiOH:La(OH)3:ZrO2のとき、約7.7:約3:約2となり、LiOH:La2O3:ZrO2のとき、約7.7:約1.5:約2となる。なお、原料粉末の調製にあたっては、公知のセラミックス粉末の合成における原料粉末調製方法を適宜採用することができる。例えば、ライカイ機等や適当なボールミル等に投入して均一に混合することができる。
第1焼成工程は、少なくともLi成分やLa成分等の熱分解を行い第2焼成工程でLLZ結晶構造を形成しやくするための一次焼成粉末を得る工程である。一次焼成粉末は、LLZ結晶構造をすでに有している場合もある。焼成温度は、好ましくは、850℃以上1150℃以下の温度である。第1焼成工程は、上記温度範囲内において、より低い加熱温度で加熱するステップとより高い加熱温度で加熱するステップとを備えていてもよい。こうした加熱ステップを備えることで、より均一な状態なセラミックス粉末を得ることができ、第2焼成工程によって良質な焼結体を得ることができる。このような複数ステップで第1焼成工程を実施するときには、各焼成ステップ終了後、ライカイ機、ボールミル及び振動ミル等を用いて混練・粉砕することが好ましい。また、粉砕手法は乾式で行うことが望ましい。こうすることで、第2焼成工程により一層均一なLLZ相を得ることができる。第1焼成工程を構成する熱処理ステップは、好ましくは850℃以上950℃以下の熱処理ステップと1075℃以上1150℃以下の熱処理ステップを実施することが好ましい。さらに好ましくは875℃以上925℃以下(約900℃であることがより好ましい)の熱処理ステップと、1100℃以上1150℃以下(約1125℃であることがより好ましい)の熱処理ステップとする。第1焼成工程は、全体で加熱温度として設定した最高温度での加熱時間の合計として10時間以上15時間以下程度とすることが好ましい。第1焼成工程を2つの熱処理ステップで構成する場合には、それぞれ最高温度での加熱時間を5~6時間程度とすることが好ましい。一方で、出発原料の1つ又は複数の成分を変更することにより、第1焼成工程を短縮化することができる。例えば、LiOHを出発原料に含まれる成分の1つとして用いる場合、LLZ結晶構造を得るには、Li、La及びZrを含むLLZ構成成分を850℃以上950℃以下の熱処理ステップで最高温度での加熱時間を10時間以下にすることができる。これは、出発原料に用いたLiOHが低温で液相を形成するため、より低温で他の成分と反応しやすくなるからである。
第2焼成工程は、第1焼成工程で得られた一次焼成粉末を950℃以上1250℃以下の温度で加熱する工程とすることができる。第2焼成工程によれば、第1焼成工程で得た一次焼成粉末を焼成し、最終的に複合酸化物であるLLZ結晶構造を有するセラミックスを得ることができる。LLZ結晶構造を得るには、例えば、Li、La及びZrを含むLLZ構成成分を1125℃以上1250℃以下の温度で熱処理するようにする。Li原料としてLi2CO3を用いるときには、1125℃以上1250℃以下で熱処理することが好ましい。1125℃未満であるとLLZの単相が得られにくくLi伝導率が小さく、1250℃を超えると、異相(La2Zr2O7等)の形成が見られるようになりLi伝導率が小さく、また結晶成長が著しくなるため、固体電解質としての強度を保つことが難しくなる傾向があるからである。より好ましくは、約1180℃から1230℃である。一方で、出発原料の1つ又は複数の成分を変更することにより、第2焼成工程を低温化することができる。例えば、Li原料としてLiOHを出発原料に用いる場合、LLZ結晶構造を得るには、Li、La及びZrを含むLLZ構成成分を950℃以上1125℃未満の温度でも熱処理することができる。これは、出発原料に用いたLiOHが低温で液相を形成するため、より低温で他の成分と反応しやすくなるからである。第2焼成工程における上記加熱温度での加熱時間は18時間以上50時間以下程度であることが好ましい。時間が18時間よりも短い場合、LLZ系セラミックスの形成が十分ではなく、50時間よりも長い場合、埋め粉を介してセッターと反応しやすくなるほか、結晶成長が著しくサンプルとして強度を保てなくなるからである。好ましくは30時間以上である。第2焼成工程は、一次焼成粉末を周知のプレス手法を用いて加圧成形して所望の三次元形状(例えば、全固体電池の固体電解質として使用可能な形状及びサイズ)を付与した成形体とした上で実施することが好ましい。成形体とすることで固相反応が促進されるほか、焼結体を得ることができる。なお、第2焼成工程後に、第2焼成工程で得られたセラミックス粉末を成形体として、第2焼成工程における加熱温度と同様の温度で焼結工程を別途実施してもよい。第2焼成工程で一次焼成粉末を含む成形体を焼成して焼結させる場合、成形体を同じ粉末内に埋没させるようにして実施することが好ましい。こうすることでLiの損失を抑制して第2焼成工程前後における組成の変化を抑制できる。なお、原料粉末の成形体は、通常、原料粉末を敷き詰めた上に載置した状態で原料粉末内に埋没される。こうすることで、セッターとの反応を抑制することができる。また、必要に応じて成形体を埋め粉の上下からセッターで押さえ込むことにより、焼結体の焼成時の反りを防止することができる。一方で、第2焼成工程においてLi原料としてLiOHを用いる等して低温化した場合、一次焼成粉末の成形体を同じ粉末内に埋没させなくても焼結させることができる。これは、第2焼成工程が低温化したことで、Liの損失が比較的抑制され、またセッターとの反応を抑制することができるからである。
本発明の好ましい態様による全固体電池を用いた揮発性メモリ用バックアップシステムについて以下に説明する。このバックアップシステムは、揮発性メモリ、不揮発性メモリ、全固体電池、及び制御手段を備えてなる。揮発性メモリ及び不揮発性メモリは互いにデータ伝送可能に接続されてなる。全固体電池は、揮発性メモリ及び不揮発性メモリと接続され、電源異常時に揮発性メモリに電流を継続的又は間欠的に供給して揮発性メモリ中のデータを保持可能とする。制御手段は、全固体電池と並列に接続され、電源異常時にピーク電流を揮発性メモリに間欠的に供給可能な手段である。この制御手段は、ピーク電流を介して、又はピーク電流及びそれに付随して一時的に増大される全固体電池からの電流を介して、揮発性メモリ中のデータを分割された量ごとに不揮発性メモリに間欠的に転送して不揮発性メモリに保存させ、それにより揮発性メモリ中のデータを不揮発性メモリに徐々に蓄積させる。かかる構成によれば、電源異常時に揮発性メモリ中のデータをできるだけ長く保持して電源復旧時における瞬時のデータ復帰を可能とする一方で、電源復旧の想定外の遅延による全固体電池の出力低下に備えて不揮発性メモリにデータを間欠的かつ累積的にコピーしてデータ消失のリスクを回避又は最小化することができる。なお、揮発性メモリは典型的にはDRAMであり、それ故DRAMを例にとり以下の説明を行うが、その他の揮発性メモリであってもよいのは言うまでもない。また、不揮発性メモリは典型的にはフラッシュメモリ(例えばNAND型フラッシュメモリ)であり、それ故フラッシュメモリを例にとり以下の説明を行うが、その他の不揮発性メモリであってもよいのはいうまでもない。
図1に示される構成の全固体電池10を作製した。正極活物質12として、層状岩塩構造を有し、組成がLi(Ni1/3Co1/3Mn1/3)O2(以下、NCMという)である、(003)面が正極層14から負極層20に向かう方向に配向されている正極活物質シートを作製した。正極活物質シートの厚みは30μmとした。シート状の正極活物質12の上に固体電解質層16を形成した。固体電解質層16を構成するリチウムイオン伝導材料としては、Alが添加されたLi7La3Zr2O12(以下、LLZ-Alという)からなるガーネット系の結晶構造を有するセラミックス材料を用いた。固体電解質層16の厚みは10μmとした。負極活物質18は、リチウム金属で構成し、厚みは10μmとした。なお、正極集電体22を厚み10μmのアルミ箔にて構成し、負極集電体24を厚み10μmの銅箔にて構成した。これらの構成要素からなる積層体を単位電池として得た。この単位電池をアルミニウム(Al)/ポリプロピレン(PP)の複層品でラミネート外装した。こうして得られた全固体電池を上面からみたサイズ(縦×横)は20mm×30mmであり、全固体電池の厚みは0.24mmであった。
(E×C)/V (1)
(式中、Eは電圧(=3.9V)、Cは容量(mAh)、Vは電池体積(cm3)である。
例A1で得られた単位電池を並列に積層して、容量100mAhの電池を作製した。例A1と同様にしてエネルギー密度を求めたところ、650Wh/Lであった。
例A1で得られた単位電池を並列に積層して、容量300mAhの電池を作製した。例A1と同様にしてエネルギー密度を求めたところ、750Wh/Lであった。
固体電解質層16を構成するリチウムイオン伝導材料をLiPONとし、固体電解質層16の厚みを5μmとし、それ以外の構成は例1と同様の単位電池を得た。この単位電池を例A1と同様にラミネート外装した。こうして得られた全固体電池を上面からみたサイズ(縦×横)は20mm×30mmであり、全固体電池の厚みは0.24mmであった。得られた全固体電池の体積エネルギー密度を例A1と同様の方法で求めたところ、容量は20mAh、エネルギー密度は542Wh/Lであった。
例A4で得られた単位電池を並列に積層して、容量100mAhの電池を作製した。例A4と同様にしてエネルギー密度を求めたところ、650Wh/Lであった。
例A4で得られた単位電池を並列に積層して、容量300mAhの電池を作製した。例A1と同様にしてエネルギー密度を求めたところ、750Wh/Lであった。
本発明の全固体電池を用いた揮発性メモリ用バックアップシステムをNVDIMM(不揮発性メモリモジュール)用途向けに適用する一例を以下に示す。特に、本例は、DRAM中の全データの転送を30分以内に完了させることを特徴とする例である。本例で前提とするNVDIMMの仕様、DRAMの作動条件、及び全固体電池の仕様は以下のとおりである。
<NVDIMMの前提仕様>
‐ メモリサイズ:4GB
‐ メモリ構成:8チップの4GビットDRAMと、
1チップの32Gビットフラッシュメモリで構成
‐ DIMMボードサイズ:133.35mm×24.00mm(DDR3スタンダード)
<全データを一括でDRAMからフラッシュメモリへのデータ転送(アクティブモード)の作動条件>
‐ 電圧:3.3V
‐ 電流:4A(平均)、7A(ピーク)
‐ 時間:34秒
‐ エネルギー:0.125Wh(=3.3V×4A×34秒/3600)
<DDR3アイドルモードの作動条件>
- DRAM1チップ分の電力:0.55W(電圧:3.3V、電流0.167A)
<DDR3セルフリフレッシュモードの作動条件>
‐ 出力:DRAM8チップ分の37mW(電圧:3.3V、電流0.011A)
‐ 出力:DRAM7チップ分の32mW(電圧:3.3V、電流0.010A)
<全固体電池の仕様>
‐ エネルギー密度:400Wh/L
‐ 電池のサイズ:20mm×85mm×5mm
‐ データ転送に利用可能なCレート:0.25C
‐ 電池の利用可能エネルギー:3.4Wh(=400Wh/L×2cm×8.5cm×0.5cm/1000)
‐ 電池からの出力電流:0.257A(=3.4Wh/3.3V×(0.25C/1.0C))
‐ データ転送に要する時間:25分(=(0.125Wh/L)/3.3V/0.09A×60、0.09A=0.257A-0.167A))
‐ データ転送のためのブロック数:50(=25分/30秒、この30秒が1ブロックのデータ転送に要する時間であり、電源系統モニタリング用の時間を確保するため、34秒(DRAMの仕様によるデータ転送時間)よりも短くすべきである。)
‐ 1ブロック当たりの電源系統モニタリング:1秒(この1秒間に電源復旧時の電源からの割り込み信号を受容可能となる)
‐ 合計データ転送時間:25分50秒(=(30秒+1秒)×50=1550秒)
‐ データ転送のための合計エネルギー:0.365Wh(=0.257A×3.3V×1550秒/3600)
‐ データ転送後のセルフリフレッシュ時間:82.6時間(=(3.4Wh-0.365Wh)/0.037W-1550/3600)
本発明の全固体電池を用いた揮発性メモリ用バックアップシステムをNVDIMM(不揮発性メモリモジュール)用途向けに適用する他の一例を以下に示す。特に、本例は、例B1よりも小さいサイズの電池を採用し、DRAMからフラッシュメモリへのデータ転送をより長い時間で行う例である。本例で前提とするNVDIMMの仕様、DRAMの作動条件、及び全固体電池の仕様は以下のとおりである。
<NVDIMMの前提仕様>
‐ メモリサイズ:4GB
‐ メモリ構成: 8チップの4GビットDRAMと、
1チップの32Gビットフラッシュメモリで構成
‐ DIMMボードサイズ:133.35mm×24.00mm(DDR3スタンダード)
<全データを一括でDRAMからフラッシュメモリへのデータ転送(アクティブモード)の作動条件>
‐ 電圧:3.3V
‐ 電流:4A(平均)、7A(ピーク)
‐ 時間:34秒
‐ エネルギー:0.125Wh(=3.3V×4A×34秒/3600)
<DDR3アイドルモードの作動条件>
‐ DRAM1チップ分の電力:0.55W(電圧:3.3V、電流0.167A)
<DDR3セルフリフレッシュモードの作動条件>
‐ 出力:DRAM8チップ分の37mW(電圧:3.3V、電流0.011A)
‐ 出力:DRAM7チップ分の32mW(電圧:3.3V、電流0.010A)
<全固体電池の仕様>
‐ エネルギー密度:400Wh/L
‐ 電池のサイズ:20mm×60mm×5mm
‐ データ転送に利用可能なCレート:0.25C
‐ 電池の利用可能エネルギー:2.4Wh(=400Wh/L×2cm×6cm×0.5cm/1000)
‐ 電池からの出力電流:0.181A(=2.4Wh/3.3V×(0.25C/1.0C))
‐ データ転送に要する時間:2.71時間(=(0.125Wh/L)/3.3V/0.014A、0.014A=0.181A-0.167A)
‐ データ転送のためのブロック数:325(=2.71時間/30秒、この30秒が1ブロックのデータ転送に要する時間であり、電源系統モニタリング用の時間を確保するため、34秒(DRAMの仕様によるデータ転送時間)よりも短くすべきである。)
‐ 1ブロック当たりの電源系統モニタリング:1秒(この1秒間に電源復旧時の電源からの割り込み信号を受容可能となる。)
‐ 合計データ転送時間:2.80時間(=(30秒+1秒)×325)=10075秒)
‐ データ転送のための合計エネルギー:1.67Wh(=0.181A×3.3V×10075秒/3600)
‐ データ転送後のセルフリフレッシュ時間:16.9時間(=(2.4Wh-1.67Wh)/0.037W-2.80)
全固体電池を揮発性メモリであるDIMM(Dual Inline Memory Module)のパックアップに適用する一例を以下に示す。本例で前提とするDIMMの仕様及び全固体電池の仕様は以下のとおりである。
<DIMMの前提仕様>
‐ DDR3 8GB DIMM(Samsung Electronics製、M393B1G70QH0-YH9/K0)
‐ 電圧:1.35V
‐ セルフリフレッシュ電流:0.3A
<全固体電池の仕様>
‐ エネルギー密度:400Wh/L
‐ 電池のサイズ:20mm×60mm×5mm
‐ データ転送に利用可能なCレート:0.25C
‐ 電池の利用可能エネルギー:2.4Wh(=400Wh/L×2cm×6cm×0.5cm/1000)
‐ 電池からの出力電流:0.444A(=2.4Wh/1.35V×(0.25C/1.0C))(この電流値はセルフリフレッシュモード電流(0.3A)に適用可能である。)
‐ 合計バックアップ時間:5.92時間(=(2.4Wh/(1.35V×0.3A))
例C1とは異なる仕様のDIMMを採用したこと以外は、例C1と同様に構成したパックアップシステムの一例を以下に示す。本例で採用するDIMMは、例1で採用するDIMMよりも低消費電力化が図られたものである。本例で前提とするDIMMの仕様及び全固体電池の仕様は以下のとおりである。
<DIMMの前提仕様>
‐ DDR4 8GB DIMM(Micron製 MTA18ASF1G72PZ-8GB)
‐ 電圧:1.2V
‐ セルフリフレッシュ電流:0.18A
<全固体電池の仕様>
‐ エネルギー密度:400Wh/L
‐ 電池のサイズ:20mm×60mm×2.5mm
‐ データ転送に利用可能なCレート:0.25C
‐ 電池の利用可能エネルギー:1.2Wh(=400Wh/L×2cm×6cm×0.25cm/1000)
‐ 電池からの出力電流:0.25A(=1.2Wh/1.2V×(0.25C/1.0C))(この電流値はセルフリフレッシュモード電流(0.18A)に適用可能である。)
‐ 合計バックアップ時間:5.56時間(=(1.2Wh/(1.2V×0.18A))
本発明の全固体電池を用いた揮発性メモリ用バックアップシステムをNVDIMM(不揮発性メモリモジュール)用途向けに適用する他の一例を以下に示す。特に、本例は、全固体電池をスイッチによりオン・オフ切り替えすることで、全固体電池とバイパスコンデンサとの役割を明確に区別した例である。本例で前提とする、NVDIMMの仕様、DRAMの作動条件、及び全固体電池の仕様は以下のとおりである。
<NVDIMMの前提仕様>
‐ NVDIMM(8GB DDR3)(Netlist製、NV3848HAT17-000NL000)
‐ メモリサイズ:8GB
‐ メモリ構成:18チップの4GビットDDR3 DRAMと、
2チップの32GビットNAND型フラッシュメモリで構成
‐ DIMMボードサイズ:133.35mm×24.00mm(DDR3スタンダード)
<スーパーキャパシタ(※)によるDRAMからフラッシュメモリへのデータ転送の作動条件>
‐ 電圧:5.4V(2.7Vキャパシタの直列接続)
‐ 電流:2.5A
‐ 時間:34秒
‐ エネルギー:0.128Wh(=5.4V×2.5A×34秒/3600)(スーパーキャパシタの場合から算出した値)
※なお、上記は前提条件としてスーパーキャパシタの仕様を仮定したものであって、本例では上記スーパーキャパシタの代わりに全固体電池を使用する。
<DDR3セルフリフレッシュモードの作動条件(18チップによる)>
‐ 電圧:1.35V
‐ 電流:0.3A
<全固体電池の仕様>
‐ エネルギー密度:400Wh/L
‐ 電池のサイズ:20mm×80mm×4mm
‐ データ転送に利用可能なCレート:0.25C
上述した前提条件の下、DRAMからフラッシュメモリへのデータ転送と、セルフリフレッシュモードによるDRAM保存とを組み合わせたハイブリッド作動を実現する等価回路が図5に示される。図5の等価回路図に記される主な符号について以下に説明する。
‐ R1:全固体電池からのピーク出力電流を低減するための抵抗(インダクタも利用可能である)
‐ C1:DRAMからフラッシュメモリへのデータ転送のための電流を印加するバイパスコンデンサ
‐ Z:DRAM及びフラッシュメモリの等価インピーダンス(可変)(3.7/3.3及び3.7/1.35のDC/DCコンバータを備える)
‐ i3:(i)DRAMからフラッシュメモリへのデータ転送の間は、電流が3.6A(電圧は3.7V)(参考:スーパーキャパシタの場合は2.5A(電圧:5.4V))、
(ii)DRAMがセルフリフレッシュモードでありフラッシュメモリにアクセスが無い間は、電流が0.11A(電圧は3.7V)(参考:例C1で使用される8GB DDR3 DIMMの場合には電流0.3A(電圧は1.35V))
図5に示される等価回路において前述した前提条件に従い実現される、本例のバックアップ電源出力波形を図6に示す。図6に示されるように、本例によるバックアップシステムは、パイパスコンデンサから供給されるピーク電流が0.1秒間回路に流れてDRAMからフラッシュメモリへ、分割されたデータが転送され、その間、スイッチSW1がOFFとされるため、全固体電池からの電流は供給されない。続いて、スイッチSW1がONに切り替わり、全固体電池から電流が30秒間回路に流れ、DRAMをセルフリフレッシュモードで作動させてDRAM中のデータを保持しながら、バイパスコンデンサを充電する。そして、この30秒間を経てバイパスコンデンサの充電が完了し、再度、スイッチSW1がOFFに切り替わり、上記同様、DRAMからフラッシュメモリへのデータ転送(0.1秒間)、及びその後のセルフリフレッシュモードでの作動(30秒間)が順次交互に繰り返される。
(設計パラメータ)
‐ データ転送時間の34秒は340ステップに分割される(34秒=0.1秒×340秒)。
‐ バイパスコンデンサを電池で充電する時間は30秒である。
‐ C1の最小静電容量:0.9F(=0.36C/(3.7V-3.3V)
(例えば、村田製作所製EDLC(電気二重層キャパシタ)のサイズは1Fで14mm×30mm×3.7mm)
‐ 抵抗R1:8.3Ω(このR1の値は以下の式から算出される。
30秒=4×(時定数)(V1の99%が回復する時間)
=4×0.9F×R1
‐ i1の最大値:0.16A(=(3.7V-3.3V)/8.3Ω+0.11A)
‐ 電池に必要とされる合計エネルギー:1.42Wh(=(0.16A+0.11A)/2)×(30秒/3600)×3.7V×340ステップ
‐ 電池の利用可能エネルギー:2.56Wh(=400Wh/L×2cm×8cm×0.4cm/1000)(この値は、電池に必要とされる合計エネルギーである1.42Whよりも大きくする必要がある。)
‐ 電池のピーク出力電流:0.173A(=2.56Wh/3.7V×0.25(但し0.25はCレートである。)(この電流値は0.16Aよりも大きくする必要がある。)
‐ 合計データ転送時間:2.8時間(=(0.1秒+30秒)×340ステップ/3600)
‐ データ転送後のDRAM保存時間:2.8時間(電池の残存エネルギーは1.14WH=2.56-1.42Wh、2.8時間=1.14Wh(3.7V×0.11A)、セルフリフレッシュモードが適用される。)
‐ 合計DRAM保存時間:5.6時間(=2.8時間(合計データ転送時間)+2.8時間(データ転送後のDRAM保存時間))
Claims (29)
- 一定の方向に配向された複数のリチウム遷移金属酸化物粒子からなる配向多結晶体である正極活物質を有する正極層と、
リチウムイオン伝導材料で構成される固体電解質層と、
負極活物質を有する負極層と、
を備えた全固体電池の、コンピュータ、ラップトップ・コンピュータ、可搬式コンピュータ、ポケットコンピュータ、ワークステーション、スーパーコンピュータ、コンピュータ周辺ハードウェア、及びサーバからなる群から選択される少なくとも一つの装置におけるバックアップ電源としての使用。 - 前記装置が、互いにデータ伝送可能に接続された揮発性メモリ及び不揮発性メモリを実装した少なくとも1枚の基板を備えてなり、該基板上又はその近傍に前記全固体電池が前記揮発性メモリ及び/又は前記不揮発性メモリと接続して配置される、請求項1に記載の使用。
- 前記全固体電池が、電源異常時に前記揮発性メモリ及び前記不揮発性メモリに電力を一定時間供給して、前記揮発性メモリ中のデータを前記不揮発性メモリに転送して前記不揮発性メモリに保存させ、それにより前記揮発性メモリ中のデータの消失を回避する、請求項2に記載の使用。
- 前記装置が、揮発性メモリを実装した基板を備えてなり、該基板上又はその近傍に前記全固体電池が前記揮発性メモリと接続して配置される、請求項1に記載の使用。
- 前記全固体電池が、電源異常時に前記揮発性メモリに電力を一定時間供給して、前記揮発性メモリ中のデータの消失を一時的に回避する、請求項4に記載の使用。
- 前記全固体電池は、700Wh/L以上のエネルギー密度を有し、厚みが5mm以下であり、縦及び横の寸法がそれぞれ100mm以下である、請求項1~5のいずれか一項に記載の使用。
- 前記全固体電池は、600Wh/L以上のエネルギー密度を有し、厚みが2mm以下であり、縦及び横のサイズがそれぞれ50mm以下である、請求項1~5のいずれか一項に記載の使用。
- 前記全固体電池は、500Wh/L以上のエネルギー密度を有し、厚みが1mm以下であり、縦及び横がそれぞれ50mm以下である、請求項1~5のいずれか一項に記載の使用。
- 前記全固体電池は、250Wh/L以上のエネルギー密度を有し、厚みが0.5mm以下であり、縦及び横がそれぞれ50mm以下である、請求項1~5のいずれか一項に記載の使用。
- 前記全固体電池は、100Wh/L以上のエネルギー密度を有し、厚みが0.3mm以下であり、縦及び横がそれぞれ50mm以下である、請求項1~5のいずれか一項に記載の使用。
- 前記全固体電池は、100~1,000Wh/Lのエネルギー密度を有し、厚みが0.1~10mmであり、縦及び横がそれぞれ5~100mmである、請求項1~5のいずれか一項に記載の揮発性メモリ用バックアップシステム。
- 前記全固体電池は、250~700Wh/Lのエネルギー密度を有し、厚みが0.3~5mmであり、縦及び横がそれぞれ10~50mmである、請求項1~5のいずれか一項に記載の揮発性メモリ用バックアップシステム。
- 前記正極活物質を構成する前記配向多結晶体が5μm以上の厚さを有する、請求項1~12のいずれか一項に記載の使用。
- 前記正極活物質を構成する前記配向多結晶体が10μm以上の厚さを有する、請求項1~12のいずれか一項に記載の使用。
- 前記正極活物質を構成する前記配向多結晶体が25μm以上の厚さを有する、請求項1~12のいずれか一項に記載の使用。
- 前記一定の方向がリチウムイオンの伝導方向である、請求項1~15のいずれか一項に記載の使用。
- 前記所定方向が前記正極層から前記負極層に向かう方向である、請求項1~16のいずれか一項に記載の使用。
- 前記正極活物質は、各前記粒子の特定の結晶面が前記正極層から前記負極層に向かう方向に配向されている、請求項1~17のいずれか一項に記載の使用。
- 前記正極活物質に含まれる前記粒子が、層状岩塩構造又はスピネル構造を有する、請求項1~18のいずれか一項に記載の使用。
- 前記正極活物質に含まれる前記粒子が、層状岩塩構造を有する、請求項1~19のいずれか一項に記載の使用。
- 前記正極活物質に含まれる前記粒子が、LixM1O2又はLix(M1,M2)O2(式中、0.5<x<1.10、M1はNi,Mn及びCoからなる群から選択される少なくとも一種の遷移金属元素、M2はMg,Al,Si,Ca,Ti,V,Cr,Fe,Cu,Zn,Ga,Ge,Sr,Y,Zr,Nb,Mo,Ag,Sn,Sb,Te,Ba及びBiからなる群から選択される少なくとも一種の元素である)で表される組成を有する、請求項1~20のいずれか一項に記載の使用。
- 前記組成がLix(M1,M2)O2で表され、M1がNi及びCoであり、M2はMg,Al及びZrからなる群から選択される少なくとも一種である、請求項21に記載の使用。
- 前記組成がLixM1O2で表され、M1がNi,Mn及びCoであるか、又はM1がCoである、請求項21に記載の使用。
- 前記正極活物質に含まれる前記粒子が、Lip(Nix,Coy,Alz)O2(式中、0.9≦p≦1.3、0.6<x<0.9、0.1<y≦0.3、0≦z≦0.2、x+y+z=1)で表される組成の層状岩塩構造を有し、前記特定の結晶面が(003)面である、請求項18~22のいずれか一項に記載の使用。
- 前記固体電解質層を構成する前記リチウムイオン伝導材料が、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、リン酸系セラミックス材料、硫化物系セラミックス材料、又は高分子系材料で構成されている、請求項1~24のいずれか一項に記載の使用。
- 前記固体電解質層を構成する前記リチウムイオン伝導材料が、ガーネット系セラミックス材料であり、該ガーネット系セラミックス材料が、少なくともLi、La、Zr及びOを含んで構成されるガーネット型又はガーネット型類似の結晶構造を有する、請求項25に記載の使用。
- 前記ガーネット型又はガーネット型類似の結晶構造がNb及び/又はTaをさらに含んで構成される、請求項26に記載の使用。
- 前記ガーネット系セラミックス材料がAlをさらに含む、請求項26又は27に記載の使用。
- 前記正極層が、前記正極活物質と、該正極活物質の前記固体電解質層と反対側の端面に形成された正極集電体とを備え、且つ、前記負極層が、前記負極活物質と、該負極活物質の前記固体電解質層と反対側の端面に形成された負極集電体とを備えた、請求項1~28のいずれか一項に記載の使用。
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JP2015558817A JP6549041B2 (ja) | 2014-01-24 | 2015-01-15 | 全固体電池の使用 |
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JPWO2018087966A1 (ja) * | 2016-11-11 | 2019-11-14 | 日本碍子株式会社 | Ic用電源及びそれを備えた各種ic製品、icへの電力供給方法、並びにicの駆動方法 |
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JP6779221B2 (ja) * | 2015-10-15 | 2020-11-04 | 日本碍子株式会社 | 全固体リチウム電池 |
CN110521047A (zh) * | 2017-03-28 | 2019-11-29 | 株式会社村田制作所 | 全固态电池、电子设备、电子卡、可穿戴设备及电动车辆 |
WO2019049566A1 (ja) * | 2017-09-06 | 2019-03-14 | 日本碍子株式会社 | 微粒子検出素子及び微粒子検出器 |
US11959166B2 (en) | 2018-08-14 | 2024-04-16 | Massachusetts Institute Of Technology | Methods of fabricating thin films comprising lithium-containing materials |
KR102171623B1 (ko) | 2018-10-15 | 2020-10-29 | 주식회사 지2터치 | 최소의 터치 센서 제어 신호를 갖는 터치 스크린, 표시 장치 및 터치 스크린의 터치 스캔 방법 |
KR102575988B1 (ko) | 2021-04-22 | 2023-09-08 | 주식회사 지2터치 | 인터럽트 방식을 이용하여 저 소비 전력을 구현한 터치 스크린 및 이를 이용한 센싱 방법 |
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KR20160113596A (ko) | 2016-09-30 |
JPWO2015111494A1 (ja) | 2017-03-23 |
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