Patents Assigned to Power Systems Co., Ltd.
  • Patent number: 7705567
    Abstract: A capacitor power source 1 including a plurality of capacitors comprises: an inflection-point voltage detection circuit (11) for detecting the inflection-point voltage of the capacitor based on a set voltage Vbot; an overvoltage detection circuit (12) for detecting the overvoltage Vful of the capacitor; and an initialization circuit (13) for putting charging current of the capacitor into bypass operation using initialization voltage Vini when an initialization mode is selected, wherein charging/discharging control is performed such that a discharging stop signal is generated based on a detection signal of the inflection-point voltage of any one of the plurality of capacitors, a charging stop signal is generated based on a detection signal of the overvoltage of any one of the plurality of capacitors, and an end signal of the initialization charging is generated based on a plurality of bypass operation signals.
    Type: Grant
    Filed: May 10, 2007
    Date of Patent: April 27, 2010
    Assignee: Power Systems Co., Ltd.
    Inventors: Michio Okamura, Atsushi Shimizu
  • Patent number: 7622898
    Abstract: A charging apparatus for electrically charging a capacitor storage type power source comprises a switching circuit for turning on/off the charge current, a current detection circuit for detecting the charge current, a voltage detection circuit for detecting the voltage of power source, a constant current control circuit for outputting an error amplifying signal according to the current value, a power control circuit for outputting an error amplifying signal according to the current value, the voltage value-and a power reference value, a constant voltage control circuit for outputting an error amplifying signal according to the voltage value and a voltage reference value, an OR circuit for selecting one of the error amplifying signals and a control circuit for generating a pulse width modulation signal according to the error amplifying signal output from the OR circuit to turn on/off the switching circuit and control the charge current.
    Type: Grant
    Filed: February 16, 2007
    Date of Patent: November 24, 2009
    Assignee: Power Systems Co., Ltd.
    Inventors: Masaaki Shimizu, Katsuji Mitsui, Masahiko Shimizu, Shinichi Yamamoto, Atsushi Shimizu, Masahiko Shinotsuka, Masaaki Yamagishi, Hiroshi Tsuji
  • Publication number: 20070279010
    Abstract: A capacitor power source 1 including a plurality of capacitors comprises: an inflection-point voltage detection circuit 11 for detecting the inflection-point voltage of the capacitor based on a set voltage Vbot; an overvoltage detection circuit 12 for detecting the overvoltage Vful of the capacitor; and an initialization circuit 13 for putting charging current of the capacitor into bypass operation using initialization voltage Vini when an initialization mode is selected, wherein charging/discharging control is performed such that a discharging stop signal is generated based on a detection signal of the inflection-point voltage of any one of the plurality of capacitors, a charging stop signal is generated based on a detection signal of the overvoltage of any one of the plurality of capacitors, and an end signal of the initialization charging is generated based on a plurality of bypass operation signals.
    Type: Application
    Filed: May 10, 2007
    Publication date: December 6, 2007
    Applicant: Power Systems Co., Ltd.
    Inventors: Michio Okamura, Atsushi Shimizu
  • Patent number: 7286334
    Abstract: The invention is intended to reduce expansion proportion of electric double layer capacitors by combining nonporous carbonaceous electrodes produced by a specific method with an electrolyte of a specific structure. Provided is an electric double layer capacitor comprising nonporous carbonaceous electrodes soaked in an organic electrolytic solution, wherein the organic electrolytic solution contains a pyrrolidinium compound salt as a solute, and wherein the carbonaceous electrodes are electrodes obtained by the method comprising a step of obtaining a carbon powder by prebaking a needle coke green powder under an inert atmosphere, baking the prebaked needle coke powder in the presence of alkali hydroxide under an inert atmosphere, and removing the alkali hydroxide; and a step of shaping the carbon powder.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: October 23, 2007
    Assignee: Power Systems Co., Ltd.
    Inventors: Hitoshi Nakamura, Michio Okamura
  • Publication number: 20070216425
    Abstract: A capacitor apparatus according to the present invention is configured to charge electric charge in capacitors C1 and C2 and discharge electric charge from the capacitors C1 and C2 at normal operation time. The capacitor apparatus includes an internal resistance detection means 2 for detecting the internal resistance value of the capacitors C1 and C2 and an inter-capacitor charging/discharging control means 1 for controlling charging/discharging operation between the capacitors C1 and C2. When the internal resistance detection means 2 detects a resistance value more than a predetermined value, the inter-capacitor charging/discharging control means 1 performs charging/discharging control between the capacitors C1 and C2 to cause the capacitors C1 and C2 to self-heat.
    Type: Application
    Filed: February 20, 2007
    Publication date: September 20, 2007
    Applicant: Power Systems Co., Ltd.
    Inventors: Michio Okamura, Takao Muto, Atsushi Shimizu
  • Publication number: 20070194759
    Abstract: A charging apparatus for electrically charging a capacitor storage type power source comprises a switching circuit for turning on/off the charge current, a current detection circuit for detecting the charge current, a voltage detection circuit for detecting the voltage of power source, a constant current control circuit for outputting an error amplifying signal according to the current value, a power control circuit for outputting an error amplifying signal according to the current value, the voltage value-and a power reference value, a constant voltage control circuit for outputting an error amplifying signal according to the voltage value and a voltage reference value, an OR circuit for selecting one of the error amplifying signals and a control circuit for generating a pulse width modulation signal according to the error amplifying signal output from the OR circuit to turn on/off the switching circuit and control the charge current.
    Type: Application
    Filed: February 16, 2007
    Publication date: August 23, 2007
    Applicant: Power Systems Co., Ltd.
    Inventors: Masaaki Shimizu, Katsuji Mitsui, Masahiko Shimizu, Shinichi Yamamoto, Atsushi Shimizu, Masahiko Shinotsuka, Masaaki Yamagishi, Hiroshi Tsuji
  • Publication number: 20070146968
    Abstract: The present invention provides a separator for insulating a positive electrode and a negative electrode, the separator having mechanical strength and oxidation-reduction resistance while being excellent in impregnatability with an electrolytic solution and ion mobility like conventional cellulose-containing separators for insulating a positive electrode and a negative electrode. A separator for insulating a positive electrode and a negative electrode, wherein the separator comprises a porous sheet containing cellulose and a latex with which the porous sheet is impregnated.
    Type: Application
    Filed: December 20, 2006
    Publication date: June 28, 2007
    Applicant: Power Systems Co., Ltd.
    Inventors: Hidetoshi Ohta, Keiichi Hayashi, Takashi Tanikawa, Atsushi Shimizu
  • Patent number: 7214249
    Abstract: An object of the present invention is to provide a method for conducting electric activation of an electric double layer capacitor, the method making it possible to increase the electrostatic capacitance and to decrease the internal resistance. The method is for conducting electric activation of an electric double layer capacitor in which nonporous carbonaceous electrodes containing graphite-like fine crystalline carbon are soaked in an organic electrolytic solution. The method at least comprises: charging the electric double layer capacitor at a constant current until the interelectrode voltage reaches a predetermined voltage which is not lower than the electrostatic capacitance developing voltage but lower than the rated voltage; conducting constant voltage charging for a predetermined time during which ions of solutes in the organic electrolytic solution are conceived to be adsorbed uniformly on the surface of the fine crystalline carbon at that predetermined voltage.
    Type: Grant
    Filed: August 4, 2006
    Date of Patent: May 8, 2007
    Assignee: Power Systems Co., Ltd.
    Inventors: Hidetoshi Ohta, Keiichi Hayashi, Takashi Tanikawa, Atsushi Shimizu
  • Publication number: 20070032031
    Abstract: An object of the present invention is to provide a method for conducting electric activation of an electric double layer capacitor, the method making it possible to increase the electrostatic capacitance and to decrease the internal resistance. The method is for conducting electric activation of an electric double layer capacitor in which nonporous carbonaceous electrodes containing graphite-like fine crystalline carbon are soaked in an organic electrolytic solution. The method at least comprises: charging the electric double layer capacitor at a constant current until the interelectrode voltage reaches a predetermined voltage which is not lower than the electrostatic capacitance developing voltage but lower than the rated voltage; conducting constant voltage charging for a predetermined time during which ions of solutes in the organic electrolytic solution are conceived to be adsorbed uniformly on the surface of the fine crystalline carbon at that predetermined voltage.
    Type: Application
    Filed: August 4, 2006
    Publication date: February 8, 2007
    Applicant: Power Systems Co., Ltd.
    Inventors: Hidetoshi Ohta, Keiichi Hayashi, Takashi Tanikawa, Atsushi Shimizu
  • Publication number: 20060245143
    Abstract: The objects of the present invention are to improve characteristics of electric double layer capacitors, such as energy density and charge-and-discharge rate, and to provide a positive electrode for electric double layer capacitors useful for the foregoing object, and a simple method for its production. Disclosed is a positive electrode for electric double layer capacitors, wherein the electrode comprises graphite particles having a specific surface area of less than 10 m2/g.
    Type: Application
    Filed: April 25, 2006
    Publication date: November 2, 2006
    Applicant: Power Systems Co., Ltd.
    Inventors: Hitoshi Nakamura, Takashi Tanikawa, Masaki Yoshio
  • Publication number: 20060238958
    Abstract: The objects of the present invention are to improve characteristics of electric double layer capacitors, such as energy density and charge-and-discharge rate, and to provide a positive electrode for electric double layer capacitors useful for the foregoing object, and a simple method for its production. Disclosed is a positive electrode for electric double layer capacitors comprising graphite-carbon composite particles, the graphite-carbon composite particle being composed of a graphite particle and a carbon layer covering the graphite particle.
    Type: Application
    Filed: April 24, 2006
    Publication date: October 26, 2006
    Applicants: Power Systems Co., Ltd., Masaki Yoshio, Mitsui Mining Company, Limited
    Inventors: Hitoshi Nakamura, Keiichi Hayashi, Hidetoshi Ohta, Taiji Nakagawa, Masaki Yoshio, Tatsuo Umeno
  • Patent number: 7019960
    Abstract: The invention provides an electric double-layer capacitor sealed up by a flexible casing material that ensures a release of pressure upon an increasing internal pressure. A pressure release valve (1) is attached to the flexible casing material. The pressure release valve (1) comprises a collar airtightly joined to the flexible casing material and a cylindrical portion (3) connected to the collar, extending out of a capacitor enclosure. The cylindrical portion (3) comprises an end part (5) having a self-closing passage (6) that is opening to the outside only upon a pressure release and is closed up in a normal state, and a channel (4) in communication with the interior of the capacitor enclosure.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: March 28, 2006
    Assignees: Power Systems Co., Ltd., Japan Gore-Tex Inc., Kokoku Intech Co., Ltd.
    Inventors: Michio Okamura, Hitoshi Nakamura, Kotaro Kobayashi
  • Publication number: 20050219797
    Abstract: The invention is intended to reduce expansion proportion of electric double layer capacitors by combining nonporous carbonaceous electrodes produced by a specific method with an electrolyte of a specific structure. Provided is an electric double layer capacitor comprising nonporous carbonaceous electrodes soaked in an organic electrolytic solution, wherein the organic electrolytic solution contains a pyrrolidinium compound salt as a solute, and wherein the carbonaceous electrodes are electrodes obtained by the method comprising a step of obtaining a carbon powder by prebaking a needle coke green powder under an inert atmosphere, baking the prebaked needle coke powder in the presence of alkali hydroxide under an inert atmosphere, and removing the alkali hydroxide; and a step of shaping the carbon powder.
    Type: Application
    Filed: March 21, 2005
    Publication date: October 6, 2005
    Applicant: Power Systems Co., Ltd.
    Inventors: Hitoshi Nakamura, Michio Okamura
  • Patent number: 6554875
    Abstract: A process for manufacturing an electric double-layer capacitor with an excellent property of preventing a short circuit between the electrodes, a better ionic permeability and a high strength is provided, said process comprising using, as a separator, a fiber sheet containing a fiber having fibrils and a fine polyester fiber having a fineness of not more than 0.45 dtex (decitex) and drying the separator at a specific temperature.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: April 29, 2003
    Assignees: Japan Vilene Co., Ltd., Power Systems Co., Ltd.
    Inventors: Fuminori Kimura, Takeshi Kobayashi, Kouji Kimura, Masahiko Shimizu