Patents by Inventor Masaki YAMAKAJI

Masaki YAMAKAJI 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).

  • Publication number: 20240038966
    Abstract: A positive electrode for a nonaqueous secondary battery including an active material layer which has sufficient electron conductivity with a low ratio of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery including an active material layer which is highly filled with an active material, id est, including the active material and a low ratio of a conductive additive. The active material layer includes a plurality of particles of an active material with a layered rock salt structure, graphene that is in surface contact with the plurality of particles of the active material, and a binder.
    Type: Application
    Filed: October 5, 2023
    Publication date: February 1, 2024
    Inventors: Takahiro KAWAKAMI, Masaki YAMAKAJI, Mako MOTOYOSHI, Rika YATABE
  • Patent number: 11888113
    Abstract: A gel electrolyte and a separator are provided between the positive electrode current collector and the negative electrode current collector. The plurality of positive electrode current collectors and the plurality of negative electrode current collectors are stacked such that surfaces of negative electrodes with which active material layers are not coated or surfaces of positive electrodes with which active material layers are not coated are in contact with each other.
    Type: Grant
    Filed: September 8, 2021
    Date of Patent: January 30, 2024
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Yumiko Yoneda, Masaki Yamakaji, Ryota Tajima, Masaaki Hiroki
  • Publication number: 20230327207
    Abstract: A storage battery includes positive and negative electrodes and an electrolytic solution. The negative electrode includes a first element and carbon. The first element is any of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium. The negative electrode includes an active material and a first layer in contact with a surface of the active material. The first layer has a thickness of 10 nm to 1000 nm inclusive. The electrolytic solution contains first and second cations. The first cation is one or more of a lithium ion, a sodium ion, a calcium ion, and a magnesium ion. The second cation is an imidazolium cation or a tertiary sulfonium cation.
    Type: Application
    Filed: May 1, 2023
    Publication date: October 12, 2023
    Inventors: Nobuhiro INOUE, Masaki YAMAKAJI, Jun ISHIKAWA, Kazuhei NARITA
  • Publication number: 20230178813
    Abstract: An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode including a positive active material layer of 5 mAh/cm2 or more in capacity density per unit area; a negative electrode including metallic lithium; and a nonaqueous electrolyte including an ionic liquid and a fluorinated ether.
    Type: Application
    Filed: June 4, 2021
    Publication date: June 8, 2023
    Inventor: Masaki YAMAKAJI
  • Patent number: 11670807
    Abstract: To provide a lithium-ion storage battery or electronic device that is flexible and highly safe. One embodiment of the present invention is a flexible storage battery including a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, an exterior body that surrounds the positive electrode, the negative electrode, and the separator, and a wiring provided along the exterior body. At least part of the wiring is more easily breakable by deformation than the exterior body. The wiring is more vulnerable to deformation than the exterior body and thus damaged earlier than the exterior body. Damage to the wiring is detected and an alert is sent to a user; thus, the use of the storage battery can be stopped before the exterior body is damaged.
    Type: Grant
    Filed: December 9, 2020
    Date of Patent: June 6, 2023
    Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Masaki Yamakaji, Junpei Momo, Ryota Tajima, Takahiro Kasahara
  • Publication number: 20230041532
    Abstract: A positive electrode for a nonaqueous secondary battery including an active material layer which has sufficient electron conductivity with a low ratio of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery including an active material layer which is highly filled with an active material, id est, including the active material and a low ratio of a conductive additive. The active material layer includes a plurality of particles of an active material with a layered rock salt structure, graphene that is in surface contact with the plurality of particles of the active material, and a binder.
    Type: Application
    Filed: October 19, 2022
    Publication date: February 9, 2023
    Inventors: Takahiro KAWAKAMI, Masaki YAMAKAJI, Mako MOTOYOSHI, Rika YATABE
  • Publication number: 20230028401
    Abstract: An aspect of the present invention is a nonaqueous electrolyte energy storage device that includes a negative electrode including a lithium alloy and a nonaqueous electrolyte containing a fluorinated solvent, in which the lithium alloy contains silver, and the content of silver with respect to the total content of lithium and silver in the lithium alloy is 3% by mass or more and 20% by mass or less. Another aspect of the present invention is a nonaqueous electrolyte energy storage device that includes a negative electrode including a lithium alloy and a nonaqueous electrolyte including a lithium salt containing fluorine, in which the lithium alloy contains silver, and the content of silver with respect to the total content of lithium and silver in the lithium alloy is 3% by mass or more and 20% by mass or less.
    Type: Application
    Filed: October 7, 2020
    Publication date: January 26, 2023
    Inventor: Masaki YAMAKAJI
  • Patent number: 11515517
    Abstract: A positive electrode for a nonaqueous secondary battery including an active material layer which has sufficient electron conductivity with a low ratio of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery including an active material layer which is highly filled with an active material, id est, including the active material and a low ratio of a conductive additive. The active material layer includes a plurality of particles of an active material with a layered rock salt structure, graphene that is in surface contact with the plurality of particles of the active material, and a binder.
    Type: Grant
    Filed: December 11, 2019
    Date of Patent: November 29, 2022
    Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Takahiro Kawakami, Masaki Yamakaji, Mako Motoyoshi, Rika Yatabe
  • Patent number: 11495826
    Abstract: To provide a graphene compound having an insulating property and an affinity for lithium ions. To increase the molecular weight of a substituent included in a graphene compound. To provide a graphene compound including a chain group containing an ether bond or an ester bond. To provide a graphene compound including a substituent containing one or more branches. To provide a graphene compound including a substituent including at least one of an ester bond and an amide bond.
    Type: Grant
    Filed: May 22, 2020
    Date of Patent: November 8, 2022
    Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventor: Masaki Yamakaji
  • Patent number: 11437622
    Abstract: To provide a manufacturing method of graphene oxide that allows mass production through a relatively simple process, at low costs, and with safety and efficiency. A hydrogen peroxide solution, sulfuric acid, and flake graphite are put in a reaction container, and the mixture is stirred to obtain expansion graphite. The synthesized expansion graphite is washed not with pure water but with a saturated aqueous solution of magnesium sulfate (MgSO4) or an organic solvent, whereby a large amount of sulfuric acid is contained between graphite layers. The expansion graphite is subjected to heat treatment or microwave irradiation to form expanded graphite, and a graphite layer is peeled by ultrasonic treatment and then oxidized to form a graphene compound.
    Type: Grant
    Filed: February 24, 2021
    Date of Patent: September 6, 2022
    Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Yumiko Yoneda, Teppei Oguni, Takuya Miwa, Masaki Yamakaji, Ayae Tsuruta
  • Publication number: 20220115668
    Abstract: A graphene oxide used as a raw material of a conductive additive for forming an active material layer with high electron conductivity with a small amount of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery using the graphene oxide as a conductive additive is provided. The graphene oxide is used as a raw material of a conductive additive in a positive electrode for a nonaqueous secondary battery and, in the graphene oxide, the atomic ratio of oxygen to carbon is greater than or equal to 0.405.
    Type: Application
    Filed: December 20, 2021
    Publication date: April 14, 2022
    Inventors: Hiroatsu TODORIKI, Mikio YUKAWA, Yumiko SAITO, Masaki YAMAKAJI, Rika YATABE, Tatsuya IKENUMA
  • Publication number: 20220059824
    Abstract: A positive electrode for a secondary battery which enables both good battery characteristics and electrode strength at a predetermined level, a secondary battery, and a method for fabricating the positive electrode for a secondary battery are provided. The positive electrode for a secondary battery includes a current collector and an active material layer over the current collector. The active material layer includes an active material, graphene, and a binder. A carbon layer is on a surface of the active material. The proportion of the graphene in the active material layer is greater than or equal to 0.1 wt % and less than or equal to 1.0 wt %.
    Type: Application
    Filed: August 30, 2021
    Publication date: February 24, 2022
    Inventors: Masaki YAMAKAJI, Takahiro KAWAKAMI, Mako MOTOYOSHI, Rika YATABE
  • Publication number: 20210408593
    Abstract: A gel electrolyte and a separator are provided between the positive electrode current collector and the negative electrode current collector. The plurality of positive electrode current collectors and the plurality of negative electrode current collectors are stacked such that surfaces of negative electrodes with which active material layers are not coated or surfaces of positive electrodes with which active material layers are not coated are in contact with each other.
    Type: Application
    Filed: September 8, 2021
    Publication date: December 30, 2021
    Inventors: Yumiko YONEDA, Masaki YAMAKAJI, Ryota TAJIMA, Masaaki HIROKI
  • Patent number: 11121405
    Abstract: A gel electrolyte and a separator are provided between the positive electrode current collector and the negative electrode current collector. The plurality of positive electrode current collectors and the plurality of negative electrode current collectors are stacked such that surfaces of negative electrodes with which active material layers are not coated or surfaces of positive electrodes with which active material layers are not coated are in contact with each other.
    Type: Grant
    Filed: November 21, 2017
    Date of Patent: September 14, 2021
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Yumiko Yoneda, Masaki Yamakaji, Ryota Tajima, Masaaki Hiroki
  • Patent number: 11108038
    Abstract: A positive electrode for a secondary battery which enables both good battery characteristics and electrode strength at a predetermined level, a secondary battery, and a method for fabricating the positive electrode for a secondary battery are provided. The positive electrode for a secondary battery includes a current collector and an active material layer over the current collector. The active material layer includes an active material, graphene, and a binder. A carbon layer is on a surface of the active material. The proportion of the graphene in the active material layer is greater than or equal to 0.1 wt % and less than or equal to 1.0 wt %.
    Type: Grant
    Filed: June 27, 2016
    Date of Patent: August 31, 2021
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masaki Yamakaji, Takahiro Kawakami, Mako Motoyoshi, Rika Yatabe
  • Publication number: 20210210794
    Abstract: To provide a lithium-ion storage battery or electronic device that is flexible and highly safe. One embodiment of the present invention is a flexible storage battery including a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, an exterior body that surrounds the positive electrode, the negative electrode, and the separator, and a wiring provided along the exterior body. At least part of the wiring is more easily breakable by deformation than the exterior body. The wiring is more vulnerable to deformation than the exterior body and thus damaged earlier than the exterior body. Damage to the wiring is detected and an alert is sent to a user; thus, the use of the storage battery can be stopped before the exterior body is damaged.
    Type: Application
    Filed: December 9, 2020
    Publication date: July 8, 2021
    Inventors: Masaki YAMAKAJI, Junpei MOMO, Ryota TAJIMA, Takahiro KASAHARA
  • Publication number: 20210202945
    Abstract: To provide a manufacturing method of graphene oxide that allows mass production through a relatively simple process, at low costs, and with safety and efficiency. A hydrogen peroxide solution, sulfuric acid, and flake graphite are put in a reaction container, and the mixture is stirred to obtain expansion graphite. The synthesized expansion graphite is washed not with pure water but with a saturated aqueous solution of magnesium sulfate (MgSO4) or an organic solvent, whereby a large amount of sulfuric acid is contained between graphite layers. The expansion graphite is subjected to heat treatment or microwave irradiation to form expanded graphite, and a graphite layer is peeled by ultrasonic treatment and then oxidized to form a graphene compound.
    Type: Application
    Filed: February 24, 2021
    Publication date: July 1, 2021
    Inventors: Yumiko Yoneda, Teppei Oguni, Takuya Miwa, Masaki Yamakaji, Ayae Tsuruta
  • Publication number: 20210175507
    Abstract: The positive electrode active material layer includes a plurality of particles of a positive electrode active material and a reaction mixture where reduced graphene oxide is bonded to a polymer having a functional group as a side chain. The reduced graphene oxide has a sheet-like shape and high conductivity and thus functions as a conductive additive by being in contact with the plurality of particles of the positive electrode active material. The reaction mixture serves as an excellent binder since the reduced graphene oxide is bonded to the polymer. Therefore, even a small amount of the reaction mixture where the reduced graphene oxide is covalently bonded to the polymer excellently serves as a conductive additive and a binder.
    Type: Application
    Filed: February 18, 2021
    Publication date: June 10, 2021
    Inventors: Masaki YAMAKAJI, Kuniharu NOMOTO
  • Publication number: 20210151758
    Abstract: An object is to improve the characteristics of a power storage device such as a charging and discharging rate or a charge and discharge capacity. The grain size of particles of a positive electrode active material is nano-sized so that a surface area per unit mass of the active material is increased. Specifically, the grain size is set to greater than or equal to 10 nm and less than or equal to 100 nm, preferably greater than or equal to 20 nm and less than or equal to 60 nm. Alternatively, the surface area per unit mass is set to 10 m2/g or more, preferably 20 m2/g or more, further, the crystallinity of the active material is increased by setting an XRD half width to greater than or equal to 0.12° and less than 0.17°, preferably greater than or equal to 0.13° and less than 0.16°.
    Type: Application
    Filed: January 28, 2021
    Publication date: May 20, 2021
    Inventors: Takahiro KAWAKAMI, Masaki YAMAKAJI
  • Patent number: 10944110
    Abstract: To provide a manufacturing method of graphene oxide that allows mass production through a relatively simple process, at low costs, and with safety and efficiency. A hydrogen peroxide solution, sulfuric acid, and flake graphite are put in a reaction container, and the mixture is stirred to obtain expansion graphite. The synthesized expansion graphite is washed not with pure water but with a saturated aqueous solution of magnesium sulfate (MgSO4) or an organic solvent, whereby a large amount of sulfuric acid is contained between graphite layers. The expansion graphite is subjected to heat treatment or microwave irradiation to form expanded graphite, and a graphite layer is peeled by ultrasonic treatment and then oxidized to form a graphene compound.
    Type: Grant
    Filed: June 27, 2019
    Date of Patent: March 9, 2021
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Yumiko Yoneda, Teppei Oguni, Takuya Miwa, Masaki Yamakaji, Ayae Tsuruta