Patents by Inventor Kohki Tamura
Kohki Tamura 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: 4810597Abstract: In a fuel cell having a fuel electrode, an oxidant electrode, and an electrolyte which is located between both the electrodes, a methanol concentration control device is disposed, at a pipe which supplies the fuel to the fuel cell for controlling the amount of the methanol in the pipe by detecting the open-circuit voltage of the unit cell or the open-circuit potential of the oxidant cell at the methanol concentration control device.Type: GrantFiled: March 7, 1985Date of Patent: March 7, 1989Assignee: Hitachi, Ltd.Inventors: Teruo Kumagai, Tatsuo Horiba, Tomoichi Kamo, Seiji Takeuchi, Kazuo Iwamoto, Kunko Kitami, Kohki Tamura
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Patent number: 4699853Abstract: A unit cell is formed by a plurality of sub-unit cells as a result of dividing each of the electrodes and electrolytic plate into a plurality of parts. That is, the electrodes and the electrolytic plate are each divided into two parts by electrolytic plate support portions projected from the surfaces of separators. The support portions are pressed in contact with the end portions of the electrolytic plate so as to support the electrolytic plate and seal the reaction gas, preventing it from leaking. The electrolyte support portions of the separators can be provided with electrolyte supply paths, through which the electrolyte is supplied and impregnated into the electrolytic plate. The electrolyte can be supplied via the apertures provided in the separators, to the electrolyte supply paths.Type: GrantFiled: March 12, 1986Date of Patent: October 13, 1987Assignee: Hitachi, Ltd.Inventors: Hideo Okada, Sigeru Okabe, Yoshio Iwase, Masato Takeuchi, Kohki Tamura
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Patent number: 4656735Abstract: A fuel cell provided with an electrolyte retaining plate made of electrical insulating long fibers such as lithium aluminate long fibers which have preferably a length of 100 to 400 .mu.m and a diameter of 1 to 4 .mu.m, are interlocked each other and have vacant spaces for filling an electrolyte can be constructed and operated safely without damaging the electrolyte retaining plate for a long period of time.Type: GrantFiled: April 23, 1986Date of Patent: April 14, 1987Assignee: Hitachi, Ltd.Inventors: Hideo Okada, Masato Takeuchi, Sigeru Okabe, Hiroshi Tobita, Shimpei Matsuda, Kohki Tamura, Fumito Nakajima
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Patent number: 4643957Abstract: In a fuel cell comprising a pair of counterposed gas-diffusible electrodes, an electrolyte-retaining, porous matrix provided between and in contact with the electrodes, a fuel chamber for feeding a gaseous fuel to the anode of the pair of the electrodes and an oxidizing agent chamber for feeding a gaseous oxidizing agent to the cathode of the pair of the electrodes, the cell performance is remarkably prevented from lowering by making the electrolyte saturated absorption amount of the cathode smaller than that of the anode, thereby preventing migration of the electrolyte in the electrolyte-retaining matrix.Type: GrantFiled: April 11, 1985Date of Patent: February 17, 1987Assignee: Hitachi, Ltd.Inventors: Seizi Takeuchi, Tomoichi Kamo, Tatsuo Horiba, Kunko Kitami, Toshikatsu Mori, Toshiki Kahara, Jinichi Imahashi, Akio Honji, Masato Takeuchi, Kohki Tamura
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Patent number: 4555452Abstract: In operating a fuel cell comprising an oxidizing agent chamber subject to supply of an oxidizing agent gas and a fuel chamber subjected to supply of a fuel gas, sintering of noble metal particles such as platinum black as an electrode catalyst can be prevented from sintering by connecting the fuel cell to an outside auxiliary load circuit and controlling the unit cell voltage to not more than 0.80 V at start or discontinuation to operate the fuel cell or during the operation of the fuel cell when an outside load becomes too low due to fluctuation of the outside load. The fuel cell performance can be improved thereby.Type: GrantFiled: March 7, 1985Date of Patent: November 26, 1985Assignee: Hitachi, Ltd.Inventors: Toshiki Kahara, Toshikatsu Mori, Jinichi Imahashi, Akio Honji, Kohki Tamura
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Patent number: 4550067Abstract: The disclosure is concerned with a secondary cell comprising a positive electrode, a negative electrode, a liquidous electrolyte layer interposed between the electrodes, said electrolyte containing a dopant consisting of an anion and a cation, means for electrically insulating the electrodes, and an envelope for enclosing and for air-tightly sealing the electrodes and the electrolyte.The positive electrode or the negative electrode is made of a material, such as, phthalocyanine complexes, metal porphyrin complexes, chalcogenides of transition metals and an electrically conductive polymeric material such as polyacetylene.The secondary cell of the present invention has a long service life because of its good durability to charge and discharge operations.Type: GrantFiled: June 20, 1984Date of Patent: October 29, 1985Assignee: Hitachi, Ltd.Inventors: Tatsuo Horiba, Kazunori Fujita, Shinpei Matsuda, Kohki Tamura
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Patent number: 4493878Abstract: This invention is a fuel element for liquid fuel cell characterized in that a liquid fuel is rendered to assume a non-fluidized state by either physical means or chemical means, and is returned back to the initial liquid fuel at any time by physical means or chemical means.Type: GrantFiled: April 7, 1983Date of Patent: January 15, 1985Assignee: Hitachi, Ltd.Inventors: Tatsuo Horiba, Kazuo Iwamoto, Hidejiro Kawana, Kazunori Fujita, Kohki Tamura
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Patent number: 4478917Abstract: A methanol fuel cell with an electrolyte ion exchange membrane integrated with an oxidizer electrode containing water-repellent particles on one side of the membrane and with a hydrophilic fuel electrode containing no water-repellent particles on the other side thereof and with less contact resistance between the ion exchange membrane and the electrodes and a three-phase boundary readily formable in the oxidizer electrode.Type: GrantFiled: March 25, 1983Date of Patent: October 23, 1984Assignee: Hitachi, Ltd.Inventors: Kazunori Fujita, Kohki Tamura, Hidejiro Kawana, Kazuo Iwamoto, Tatsuo Horiba
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Patent number: 4457987Abstract: A liquid fuel cell including an anode made of carbon powders, which contains therein an electrode catalyzer and is adapted to be supplied with a liquid fuel, a cathode supplied with oxygen, and a separator interposed between the anode and the cathode. In order to improve cell performance, the anode is formed from carbon powders bonded with a binder, the carbon powders having particle sizes passing through a 50 Tyler mesh screen, in which at least thirty percent by volume of the carbon powders are unable to pass through a 100 Tyler mesh screen.Type: GrantFiled: September 17, 1982Date of Patent: July 3, 1984Assignee: Hitachi, Ltd.Inventors: Tatsuo Horiba, Seizi Takeuchi, Kohki Tamura, Go Kawamura, Tetsuichi Kudo
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Patent number: 4446210Abstract: A fuel cell electrode being substantially free from cracks on the surface of catalyst layer on the electrode and having a good electrode performance under the atmospheric pressure or under pressure when assembled into a fuel cell, which comprises a gas-diffusing electroconductive substrate with continued pores and a water-repellent catalyst layer comprising electroconductive submicron particles having a catalyst, electroconductive materials each having a volume 10.sup.3 -10.sup.10 as large as the volume of the largest particle of the submicron particles and, if necessary, having a catalyst, and a water-repellent polymer as a binder, the electroconductive submicron particles and the electroconductive materials being provided in a mixing ratio by volume of the former to the latter of 95-50 to 5-50.Type: GrantFiled: April 8, 1982Date of Patent: May 1, 1984Assignee: Hitachi, Ltd.Inventors: Hideo Okada, Jinichi Imahashi, Seizi Takeuchi, Sigeru Okabe, Toshiki Kahara, Kenzo Ishii, Masato Takeuchi, Shimpei Matsuda, Kohki Tamura, Hiroshi Tobita
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Patent number: 4436794Abstract: In a molten carbonate fuel cell, an anode or cathode is made of a sintered material containing a nickel oxide and/or cobalt oxide and a rare earth element oxide. This anode or cathode has a high activity and is stable at high temperatures.Type: GrantFiled: March 26, 1982Date of Patent: March 13, 1984Assignee: Hitachi, Ltd.Inventors: Masato Takeuchi, Hideo Okada, Hirosi Tobita, Sigeru Okabe, Shinpei Matsuda, Munehiko Tonami, Kohki Tamura, Fumito Nakajima
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Patent number: 4407905Abstract: Fuel cell with improved and stabilized electrode performance having at least one gas diffusion electrode, where the gas diffusion electrode comprises an electronconductive, gas-permeable substrate and an electrode catalyst uniformly distributed on the substrate, the electrode catalyst comprising colonies each consisting of not more than 20 primary particles of noble metal each having a size of 10-30 A and being uniformly distributed and deposited on carrier powder.Type: GrantFiled: October 14, 1981Date of Patent: October 4, 1983Assignee: Hitachi, Ltd.Inventors: Seizi Takeuchi, Kenzo Ishii, Toshiki Kahara, Jinichi Imahashi, Masato Takeuchi, Hideo Okada, Sigeru Okabe, Shimpei Matsuda, Fumito Nakajima, Hirosi Tobita, Kohki Tamura
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Patent number: 4390603Abstract: A methanol fuel cell wherein a positive electrode and a negative electrode are disposed in contact with a solid film which exhibits a hydrogen ion- and/or hydronium ion-conductivity.The methanol permeability coefficient of the solid film of the methanol fuel cell is at most 1.times.10.sup.-6 mol/(mol/l).min.cm.sup.2.Type: GrantFiled: May 21, 1982Date of Patent: June 28, 1983Assignee: Hitachi, Ltd.Inventors: Hidejiro Kawana, Tatsuo Horiba, Kazuo Iwamoto, Kazunori Fujita, Kohki Tamura
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Patent number: 4324828Abstract: A positive plate composite agent consisting of a mixture of manganese dioxide, carbon powder and polytetrafluoroethylene powder is press-molded at a pressure in the range of 1 to 5 t/cm.sup.2. The resulting molded article is then pulvertized into massive particles having a particle size ranging from 0.03 to 15 mm.sup.3. The massive particles are then press-molded into a positive plate having a predetermined shape at a pressure in the range of 0.2 to 1 t/cm.sup.2.There is thus obtained a positive plate of an enclosed type battery which comprises a portion consisting of the compactly formed massive particles of the positive plate composite agent and a portion consisting of the coarsely formed small particles of the composite agent interposed between the massive particles so as to define paths or voids for the passage of an electrolyte.Type: GrantFiled: June 6, 1980Date of Patent: April 13, 1982Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.Inventors: Noboru Ebato, Toshiki Kahara, Kohki Tamura
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Patent number: 4297231Abstract: Disclosed is a process for producing a positive electrode for a non-aqueous electrolytic cell. Manganese dioxide is heat-treated at a temperature between 250.degree. and 400.degree. C. The heat-treated manganese dioxide is next mixed with a conducting agent and binder. The binder is suspended in water by means of non-ionic surface active agent, and the mixture is heat-treated at a temperature between 180.degree. and 350.degree. C. and then pressured molded into a positive electrode. This production process allows the provision of a positive electrode for a non-aqueous electrolytic cell of excellent discharge characteristics.Type: GrantFiled: December 28, 1979Date of Patent: October 27, 1981Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.Inventors: Toshiki Kahara, Kohki Tamura, Noboru Ebata, Fumio Sato, Tomio Yoshida
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Patent number: 4262063Abstract: A fuel cell using an electrolyte-soluble fuel in which a solid film exhibiting a hydrogen ion- and/or hydronium ion-conducitivty is provided on the surface of an air electrode close to an electrolyte containing the fuel is disclosed.The solid film transmits hydrogen ions and hydronium ions, but it does not transmit water and oxygen in substance. Therefore, the leakage of electrolyte and the variation of the composition ratio of the electrolyte are not feared, so that the fuel cell can be used for a long time.Type: GrantFiled: May 22, 1979Date of Patent: April 14, 1981Assignee: Hitachi, Ltd.Inventors: Tetsuichi Kudo, Go Kikuchi, Hidehito Obayashi, Kohki Tamura
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Patent number: 4259415Abstract: A primary battery comprises a negative active material such as lithium, a positive active material and a non-aqueous electrolyte, wherein the positive active material further comprises a main positive active material such as manganese dioxide which takes main part in a primary discharge reaction together with the negative active material through the non-aqueous electrolyte and a precursor such as vanadium pentoxide or lead dioxide which takes part in the primary discharge reaction and produces a sub-positive active material, which takes part in a secondary discharge reaction.Type: GrantFiled: September 11, 1979Date of Patent: March 31, 1981Assignees: Hitachi, Ltd., Hitachi Chemical Co. Ltd.Inventors: Kohki Tamura, Toshiki Kahara, Tatsuo Horiba, Noboru Ebato, Osamu Asai
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Patent number: 4197366Abstract: This invention relates to a non-aqueous electrolyte cell having an improved utilization of manganese dioxide. The utilization of manganese dioxide of a conventional non-aqueous electrolyte cell comprising a negative active material which comprises lithium, sodium or the like; a positive active material which comprises manganese dioxide; and a non-aqueous electrolyte can be greatly improved by limiting the particle sizes of manganese dioxide powder, carbon powder and optional binder powder contained in the positive mass to, respectively, up to 30 .mu.m, up to 5 .mu.m and up to 3 .mu.m.Type: GrantFiled: August 10, 1978Date of Patent: April 8, 1980Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.Inventors: Kohki Tamura, Toshiki Kahara, Tatuo Horiba, Noboru Ebato
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Patent number: 4101718Abstract: In a battery of the structure laminated with plural cells a frame of the battery is divided into three equal spaces by barriers of insulating material. One of the spaces is a cathode active material chamber, another of the spaces is an anode active material, and the other is an electrolyte chamber. Cathode and anode plates are attached to one ends of the respective cathode active material and electrolyte chambers. The anode active material chamber is divided at one end thereof by an insulating partition plate formed integral with the frame. The plural frames attached with these anode and cathode plates are accumulated to form plural unit cells in such a manner that the chamber for the electrolyte of the frame of certain layer is disposed between the chambers for two materials different in the fore and aft layers from each other.Type: GrantFiled: April 1, 1977Date of Patent: July 18, 1978Assignees: Hitachi Chemical Company, Ltd., Hitachi, Ltd.Inventors: Kohki Tamura, Kazuo Iwamoto