Patents by Inventor Kenta Nakai
Kenta Nakai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11515537Abstract: An energy storage device includes a negative electrode having a negative active material layer containing amorphous carbon as an active material, a curve attained by determining a rate of change (dQ/dV) in a potential (V) of the amorphous carbon in a discharge capacity (Q) of the amorphous carbon per unit quantity based on a result attained by measuring the potential (V) with respect to the discharge capacity (Q) and representing the rate of change (dQ/dV) with respect to the potential (V) has one or more peaks in a range in which the potential of the amorphous carbon is 0.8 V or more and 1.5 V or less, and a potential of the negative electrode at time of full charge is 0.25 V or more with respect to a lithium potential.Type: GrantFiled: November 21, 2018Date of Patent: November 29, 2022Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Tomonori Kako, Akihiko Miyazaki, Masashi Takano, Kenta Nakai, Ukyo Harinaga
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Patent number: 11258065Abstract: An energy storage device includes: a positive electrode plate containing a positive composite layer including a positive active material capable of occluding and releasing a lithium ion; and a negative electrode plate containing a negative composite layer including a negative active material capable of occluding and releasing a lithium ion. A peak pore diameter Rp of the positive composite layer in a pore distribution measured by a mercury penetration method is 0.5 ?m or less, and a peak pore diameter Rn of the negative composite layer in a pore distribution measured by a mercury penetration method is 0.5 ?m or less. A ratio Rp/Rn of the peak pore diameter of the positive composite layer to the peak pore diameter of the negative composite layer is 0.60 or more and 1.70 or less.Type: GrantFiled: January 13, 2017Date of Patent: February 22, 2022Assignee: GS Yuasa International Ltd.Inventors: Shota Ito, Kenta Nakai, Akihiko Miyazaki, Tomonori Kako, Sumio Mori
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Publication number: 20210399347Abstract: Provided is a method for manufacturing an energy storage device including an electrode that has an active material layer, an electrolyte solution, and a case. According to the present embodiment, the method including injecting an electrolyte solution in a predetermined amount into a case is characterized in that the predetermined amount is an amount such that, an alkali metal or an alkaline earth metal at least partially comes into contact with a free electrolyte solution that is the electrolyte solution excluding the electrolyte solution soaking into the electrode assembly in the case, with the case housing therein: the alkali metal or the alkaline earth metal of an ion supply member that has the alkali metal or the alkaline earth metal disposed on a conductive member other than the active material layer; and an electrode assembly including the stacked electrode that has electrical conduction to the conducive member of the ion supply member.Type: ApplicationFiled: September 26, 2019Publication date: December 23, 2021Inventors: Taro YAMAFUKU, Kenta NAKAI, Jun OYAMA
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Publication number: 20200388845Abstract: An energy storage device includes a negative electrode having a negative active material layer containing amorphous carbon as an active material, a curve attained by determining a rate of change (dQ/dV) in a potential (V) of the amorphous carbon in a discharge capacity (Q) of the amorphous carbon per unit quantity based on a result attained by measuring the potential (V) with respect to the discharge capacity (Q) and representing the rate of change (dQ/dV) with respect to the potential (V) has one or more peaks in a range in which the potential of the amorphous carbon is 0.8 V or more and 1.5 V or less, and a potential of the negative electrode at time of full charge is 0.25 V or more with respect to a lithium potential.Type: ApplicationFiled: November 21, 2018Publication date: December 10, 2020Inventors: Tomonori KAKO, Akihiko MIYAZAKI, Masashi TAKANO, Kenta NAKAI, Ukyo HARINAGA
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Patent number: 10833349Abstract: An energy storage device includes: an electrode assembly which includes: an approximately rectangular positive electrode; an approximately rectangular negative electrode which is stacked alternately with the positive electrode; and a strip-like elongated separator having a base material layer and an inorganic layer which is made to overlap with the first base material layer, wherein the elongated separator is arranged between the positive electrode and the negative electrode, and the base material layer of the elongated separator faces the negative electrode in an opposed manner between the positive electrode and the negative electrode.Type: GrantFiled: March 14, 2016Date of Patent: November 10, 2020Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Kenta Nakai, Tomonori Kako, Akihiko Miyazaki, Sumio Mori
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Publication number: 20200144615Abstract: There is provided an energy storage device which can have a relatively high initial power and whereby it becomes possible to prevent the occurrence of electrodeposition of lithium even when a charge-discharge procedure is performed repeatedly at a high rate.Type: ApplicationFiled: November 6, 2018Publication date: May 7, 2020Inventors: Tomonori KAKO, Akihiko MIYAZAKI, Kenta NAKAI, Shota ITO
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Publication number: 20190027753Abstract: An energy storage device of which endurance capacity retention ratio is improved is provided. An energy storage device 10 includes: a positive electrode plate 12 containing a positive composite layer including a positive active material capable of occluding and releasing a lithium ion; and a negative electrode plate 13 containing a negative composite layer including a negative active material capable of occluding and releasing a lithium ion. A peak pore diameter Rp of the positive composite layer in a pore distribution measured by a mercury penetration method is 0.5 ?m or less, and a peak pore diameter Rn of the negative composite layer in a pore distribution measured by a mercury penetration method is 0.5 ?m or less. A ratio Rp/Rn of the peak pore diameter of the positive composite layer to the peak pore diameter of the negative composite layer is 0.60 or more and 1.70 or less.Type: ApplicationFiled: January 13, 2017Publication date: January 24, 2019Inventors: Shota ITO, Kenta NAKAI, Akihiko MIYAZAKI, Tomonori KAKO, Sumio MORI
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Patent number: 9905822Abstract: An energy storage unit having plural energy storage devices, each of which includes a container housing an electrode assembly and positive and negative electrode terminals electrically connected to the electrode assembly and extending from the container in the same direction, includes: a bus bar electrically connecting a first terminal, which is one of the positive electrode terminal and the negative electrode terminal of a first energy storage device included in the plural energy storage devices, and a second terminal, which is one of the positive electrode terminal and the negative electrode terminal of a second energy storage device included in the plural energy storage devices and opposite in polarity to the first terminal; a packing member interposed between the first terminal and the container of the first energy storage device; and an insulating member interposed between the bus bar and the container of the first energy storage device.Type: GrantFiled: December 2, 2013Date of Patent: February 27, 2018Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Sumio Mori, Tomonori Kako, Akihiko Miyazaki, Kenta Nakai
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Patent number: 9865855Abstract: An energy storage device includes a positive electrode, a negative electrode, and an insulating layer arranged between these electrodes to electrically insulate these electrodes. The negative electrode includes a composite layer containing active material particles. The composite layer of the negative electrode, and the positive electrode are arranged to face each other across the insulating layer. The insulating layer contains electrically insulating particles, and is made porous by a gap between these particles. The composite layer of the negative electrode is made porous by a gap between the active material particles, and “?0.8?Log B?Log A?1.0” is satisfied in which in a pore distribution of the composite layer, a pore peak diameter is represented by A (?m), and in a pore distribution of the insulating layer, a peak diameter is represented by B (?m).Type: GrantFiled: February 24, 2016Date of Patent: January 9, 2018Assignee: GS Yuasa International Ltd.Inventors: Akihiko Miyazaki, Kenta Nakai, Tomonori Kako, Sumio Mori
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Patent number: 9865878Abstract: An energy storage device includes a positive electrode, a negative electrode, and a nonaqueous electrolyte solution. The negative electrode includes an active material layer, and the active material layer has pores having a pore size of 0.1 ?m or more and 1.0 ?m or less, and a total volume of the pores is 0.26 cm3/g or more and 0.46 cm3/g or less.Type: GrantFiled: March 17, 2016Date of Patent: January 9, 2018Assignee: GS Yuasa International Ltd.Inventors: Kenta Nakai, Akihiko Miyazaki, Tomonori Kako, Sumio Mori
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Patent number: 9806376Abstract: Provided is an energy storage device including an electrolyte solution including a compound represented by the general formula (1), a compound represented by the general formula (2), and a compound represented by the general formula (3):Type: GrantFiled: August 24, 2015Date of Patent: October 31, 2017Assignee: GS Yuasa International Ltd.Inventors: Tomonori Kako, Sumio Mori, Akihiko Miyazaki, Kenta Nakai
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Patent number: 9761876Abstract: An energy storage device including a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the negative electrode includes a negative electrode active material layer containing a non-graphitizable carbon as a negative electrode active material, and the negative electrode active material has a negative electrode active material weight per unit volume of the negative electrode active material layer of 0.92 g/cc or more and 1.13 g/cc or less and a particle size D90 of 4.3 ?m or more and 11.5 ?m or less, the particle size D90 being a particle size in particle size distribution in which a cumulative volume is 90%.Type: GrantFiled: December 2, 2013Date of Patent: September 12, 2017Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Sumio Mori, Kenta Nakai, Akihiko Miyazaki, Tomonori Kako
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Energy storage device, energy storage apparatus, vehicle, and method for using energy storage device
Patent number: 9705119Abstract: An energy storage device comprises a positive electrode, a negative electrode, a separator arranged between the positive electrode and the negative electrode, and a nonaqueous electrolyte. The negative electrode has a negative substrate layer, and a negative composite layer arranged on the surface of the negative substrate layer. The separator has a separator substrate layer. The negative composite layer contains a non-graphitizable carbon having a particle diameter D50 of 2.0 ?m or more and 6.0 ?m or less. A corrected negative electrode density, which is defined as a value obtained by dividing, by a thickness of the separator substrate layer, a value obtained by multiplying a density of the negative composite layer by a thickness of the negative composite layer, is 1.2 (g/cm3) or more and 5.1 (g/cm3) or less.Type: GrantFiled: May 22, 2015Date of Patent: July 11, 2017Assignee: GS Yuasa International Ltd.Inventors: Akihiko Miyazaki, Sumio Mori, Tomonori Kako, Kenta Nakai -
Patent number: 9653714Abstract: An electric storage device is provided with an electrode assembly including a positive electrode plate and a negative electrode plate; a case for housing the electrode assembly; a positive-electrode external terminal arranged on an outer surface of the case and electrically connected to the positive electrode plate; a negative-electrode external terminal arranged on an outer surface of the case and electrically connected to the negative electrode plate; and a gas exhaust valve formed in a region of the case on the opposite side of a region where the positive-electrode external terminal and the negative-electrode external terminal are arranged.Type: GrantFiled: March 27, 2014Date of Patent: May 16, 2017Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Sumio Mori, Tomonori Kako, Akihiko Miyazaki, Kenta Nakai
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Patent number: 9455091Abstract: An electric storage device having a positive electrode, a negative electrode, a separator located between the positive electrode and the negative electrode, and a nonaqueous electrolyte. The positive electrode has a positive substrate layer, a positive composite layer containing a positive active material, and an undercoat layer located between the positive substrate layer and the positive composite layer. A density of the positive composite layer is 2.1 g/cm3 or more and 2.7 g/cm3 or less. The positive electrode has the rate of increase in sheet resistance after a solvent immersion test of 30% or less. The undercoat layer contains a binder selected from the group consisting of chitosan derivatives, cellulose derivatives and acrylic acid derivatives.Type: GrantFiled: September 26, 2014Date of Patent: September 27, 2016Assignee: GS Yuasa International Ltd.Inventors: Akihiko Miyazaki, Sumio Mori, Tomonori Kako, Kenta Nakai
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Publication number: 20160276667Abstract: An energy storage device includes a positive electrode, a negative electrode, and a nonaqueous electrolyte solution. The negative electrode includes an active material layer, and the active material layer has pores having a pore size of 0.1 ?m or more and 1.0 ?m or less, and a total volume of the pores is 0.26 cm3/g or more and 0.46 cm3/g or less.Type: ApplicationFiled: March 17, 2016Publication date: September 22, 2016Inventors: Kenta NAKAI, Akihiko MIYAZAKI, Tomonori KAKO, Sumio MORI
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Publication number: 20160276702Abstract: An energy storage device includes: an electrode assembly which includes: an approximately rectangular positive electrode; an approximately rectangular negative electrode which is stacked alternately with the positive electrode; and a strip-like elongated separator having a base material layer and an inorganic layer which is made to overlap with the first base material layer, wherein the elongated separator is arranged between the positive electrode and the negative electrode, and the base material layer of the elongated separator faces the negative electrode in an opposed manner between the positive electrode and the negative electrode.Type: ApplicationFiled: March 14, 2016Publication date: September 22, 2016Inventors: Kenta NAKAI, Tomonori KAKO, Akihiko MIYAZAKI, Sumio MORI
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Publication number: 20160248065Abstract: An energy storage device includes a positive electrode, a negative electrode, and an insulating layer arranged between these electrodes to electrically insulate these electrodes. The negative electrode includes a composite layer containing active material particles. The composite layer of the negative electrode, and the positive electrode are arranged to face each other across the insulating layer. The insulating layer contains electrically insulating particles, and is made porous by a gap between these particles. The composite layer of the negative electrode is made porous by a gap between the active material particles, and “?0.8?Log B?Log A?1.0” is satisfied in which in a pore distribution of the composite layer, a pore peak diameter is represented by A (?m), and in a pore distribution of the insulating layer, a peak diameter is represented by B (?m).Type: ApplicationFiled: February 24, 2016Publication date: August 25, 2016Inventors: Akihiko MIYAZAKI, Kenta NAKAI, Tomonori KAKO, Sumio MORI
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Patent number: 9397364Abstract: An electric storage device includes: an electrode assembly in which electrodes are wound such that paired curved portions and a straight portion connecting the paired curved portions are formed; a case which houses the electrode assembly, the case comprising a convex part protruding toward the straight portion of the electrode assembly to support the straight portion; and a support portion which supports the curved portion toward an inside of the electrode assembly.Type: GrantFiled: October 1, 2014Date of Patent: July 19, 2016Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Akihiko Miyazaki, Sumio Mori, Tomonori Kako, Kenta Nakai
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Patent number: 9350049Abstract: The electric storage device includes: an electrode assembly; and an electrolytic solution at least part of which is impregnated into the electrode assembly, wherein the electrode assembly includes, as electrode assembly forming members, at least a positive electrode and a negative electrode that face each other, and contains lithium carbonate, the electrolytic solution contains at least lithium hexafluorophosphate, at least one of the positive electrode and the negative electrode includes an active material layer containing a metal compound, the active material layer includes a peripheral area and an inner area inside the peripheral area, the electrode assembly includes a high-content part the ratio of lithium carbonate content of which is higher than that of the inner area.Type: GrantFiled: November 28, 2014Date of Patent: May 24, 2016Assignee: GS YUASA INTERNATIONAL LTD.Inventors: Kenta Nakai, Takeshi Sasaki