Patents by Inventor Tomohiko Yokoyama

Tomohiko Yokoyama 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: 20150255766
    Abstract: An object of the present invention is to safely discharge gases to the outside of a battery even when the gases are generated in a sealed secondary battery. In the sealed secondary battery according to the present invention, an electrode group (4) formed by winding a positive electrode plate (1) and a negative electrode plate (2) with a separator (3) interposed therebetween or formed by stacking the positive electrode plate (1) and the negative electrode plate (2) one on top of another with the separator (3) interposed therebetween is housed in a battery case (5). The sealed secondary battery includes an insulating plate (8) and a sealing body (10). The insulating plate (8) is disposed on an end surface of the electrode group (4) on an opening side of the battery case (5). The sealing body (10) seals the opening of the battery case and includes a cap (14). The cap (14) and the insulating plate (8) respectively have a first opening (14a) and a second opening (8a).
    Type: Application
    Filed: September 18, 2013
    Publication date: September 10, 2015
    Applicant: SANYO ELECTRIC CO., LTD.
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Kyosuke Miyata, Koki Inoue
  • Publication number: 20150236316
    Abstract: The battery is sealed by a sealing member including a safety valve for exhausting the gas generated in the battery to the outside of the battery when the pressure in the battery is increased. A part of the sealing member is formed of a member having a melting point lower than that of high-temperature gas generated in the abnormal time and having a ratio of an area of an opening of the battery case to an area of a gas exhaust hole is 3.0×10?5 or more and 9.1×10?3 or less.
    Type: Application
    Filed: September 26, 2013
    Publication date: August 20, 2015
    Inventors: Keisuke Shimizu, Masato Fujikawa, Tomohiko Yokoyama, Kyosuke Miyata, Koki Inoue
  • Patent number: 9093704
    Abstract: The non-aqueous electrolyte secondary battery of the present invention is provided with an electrode plate group and a non-aqueous electrolyte, the electrode plate group including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, a positive electrode lead connected to the positive electrode, and a negative electrode lead connected to the negative electrode. The energy density of the electrode plate group is 750 Wh/L or higher by volume, and the cross-sectional area of at least one of the positive electrode lead and the negative electrode lead is 5.5×10?5 to 1.2×10?2 cm2.
    Type: Grant
    Filed: November 19, 2008
    Date of Patent: July 28, 2015
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Tomohiko Yokoyama, Hideharu Takezawa, Masato Fujikawa, Shinji Kasamatsu
  • Patent number: 9088031
    Abstract: A battery module 100 includes a plurality of cells 10, wherein a cooling unit 20 in which a coolant is sealed is disposed in the vicinity of the cells 10, the coolant is liquid adjusted to have a viscosity within the range of 2 Pa·s to 350 Pa·s, and the cooling unit 20 includes an unsealable portion 23 which is partially unsealed to release the coolant when at least one of the cells 10 abnormally generates heat.
    Type: Grant
    Filed: July 20, 2011
    Date of Patent: July 21, 2015
    Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Shunsuke Yasui, Daisuke Kishii
  • Publication number: 20150155535
    Abstract: Disclosed is a sealed secondary battery including: a case having an opening, and housing an electrode group including a positive electrode, a negative electrode, and a separator; an insulating plate disposed near the opening and between the opening and the electrode group within the case; and a sealing unit sealing the opening of the case. The sealing unit includes a first conductor plate, a second conductor plate, and a valve mechanism interposed therebetween. The first conductor plate is disposed on the exterior side of the case, and the second conductor plate is disposed on the interior side of the case. The first conductor plate has a first hole having an opening area S1 (mm2), the insulating plate has a second hole having an opening area S2 (mm2), and S1 and S2 satisfy the inequality: (3/t+12) mm2?S1<S2, where a coefficient t corresponds to a wall thickness (mm) of the case.
    Type: Application
    Filed: July 2, 2013
    Publication date: June 4, 2015
    Inventors: Masato Fujikawa, Akihiro Maeda, Tomohiko Yokoyama, Keisuke Shimizu
  • Publication number: 20150010793
    Abstract: A cylindrical lithium ion battery in which an electrode group formed by winding a positive electrode and a negative electrode is housed in a battery case is disclosed. A sealing plate seals an opening of the battery case. An insulating plate having a plurality of openings is provided on a side of the electrode group closer to the sealing plate. The plurality of openings include a first hole with a largest opening area, and a plurality of second holes with opening areas smaller than the opening area of the first hole. An opening ratio of the first hole is 12% or more and 40% or less; a sum of opening ratios of the second holes is 0.3% or more and 10% or less; and a total opening ratio of all the openings is 20% or more and 50% or less.
    Type: Application
    Filed: December 28, 2012
    Publication date: January 8, 2015
    Applicant: PANASONIC CORPORATION
    Inventors: Tomohiko Yokoyama, Yoshiyuki Muraoka, Takahiro Fukuoka, Kyosuke Miyata
  • Publication number: 20140377599
    Abstract: An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween is housed in a battery case, and a sealing plate seals an opening of the battery case. The sealing plate includes an upper metal plate, a valve, and a lower metal plate that are stacked, an insulating plate is placed on a portion of the electrode group near the opening of the battery case, one of the positive electrode plate or the negative electrode plate of the electrode group is connected to the lower metal plate through a lead, the lower metal plate and the insulating plate have a first opening and a second opening, respectively, and a ratio of S2/S1 is within the range of 1.8-3.3, where S1 represents an area of the first opening, and S2 represents an area of the second opening.
    Type: Application
    Filed: September 28, 2012
    Publication date: December 25, 2014
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa
  • Patent number: 8871369
    Abstract: A hermetic battery including: a safety valve through which gas generated in the battery due to increase in pressure in the battery is discharged outside the battery, wherein the safety valve includes a first safety valve 9a, 10 which is operated at a first operating pressure, and a second safety valve 15a which is operated at a second operating pressure higher than the first operating pressure, a rate at which the gas is discharged while the second safety valve 15a is operated is higher than a rate at which the gas is discharged while the first safety valve 9a, 10 is operated, and the first safety valve 9a, 10 is closed at least while the second safety valve 15a is operated.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: October 28, 2014
    Assignee: Panasonic Corporation
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Yasunari Sugita
  • Publication number: 20140308550
    Abstract: A battery pack 200 including a plurality of cells 100, in which the plurality of cells 100 are arranged so as to be oriented in the same direction, the cells 100 each have a first safety valve and a second safety valve whose operating pressure is higher than an operating pressure of the first safety valve, the first safety valve of each cell 100 is connected to a first exhaust passage 50, the second safety valve of each cell 100 is connected to a second exhaust passage 60, and the first exhaust passage 50 is spatially separated from the second exhaust passage 60.
    Type: Application
    Filed: November 12, 2012
    Publication date: October 16, 2014
    Applicant: PANASONIC CORPORATION
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa
  • Patent number: 8846235
    Abstract: A battery module including: a plurality of aligned cells, wherein a cooling unit accommodating a cooling agent is provided in a vicinity of the cells, part of the cooling unit is a vulnerable section having a relatively low compressive strength, and the vulnerable section is unsealed when heat is abnormally generated in at least one of the cells.
    Type: Grant
    Filed: December 29, 2011
    Date of Patent: September 30, 2014
    Assignee: Panasonic Corporation
    Inventors: Tomohiko Yokoyama, Masato Fujikawa, Keisuke Shimizu, Shunsuke Yasui, Daisuke Kishii
  • Patent number: 8673471
    Abstract: Provided is a highly safe portable electronic device having a secondary battery as a power source, and including a housing, an electronic device body housed in the housing, and a battery housing portion housed in the housing, in which a surface is inhibited from being locally heated to high temperature. In the portable electronic device, the battery housing portion is a molding with a battery fitting portion for fitting the secondary battery therein, and the battery fitting portion has provided on its surface a heat-insulating layer having a thickness of from 500 to 3000 ?m and a thermal conductivity of 0.2 W/m·K or lower.
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: March 18, 2014
    Assignee: Panasonic Corporation
    Inventors: Tomohiko Yokoyama, Hideharu Takezawa, Kazuya Iwamoto, Taisuke Yamamoto
  • Patent number: 8592067
    Abstract: A battery pack includes: a plurality of secondary batteries; a housing for containing the secondary batteries; and at least one heat insulating layer for separating the secondary batteries from one another. The at least one heat insulating layer includes a foam material capable of foaming at a first predetermined temperature of 110° C. or more and less than 200° C. When the foam material foams, gas bubbles are produced in the heat insulating layer, so that the thickness of the heat insulating layer increases. The battery pack thus has excellent safety, exhibiting a high heat insulation effect in the event of abnormal heat generation of the batteries.
    Type: Grant
    Filed: June 7, 2010
    Date of Patent: November 26, 2013
    Assignee: Panasonic Corporation
    Inventors: Tomohiko Yokoyama, Keisuke Shimizu, Masato Fujikawa
  • Patent number: 8592076
    Abstract: A battery pack includes: a plurality of batteries; a housing for containing the batteries; and at least one partition plate for separating the batteries from one another. The at least one partition plate includes a metal mesh and a heat insulating layer disposed on each side of the metal mesh. The heat insulating layer includes a foam material capable of foaming at a temperature of 110° C. or more and 200° C. or less, so that the thickness of the heat insulating layer increases when the foam material foams. Even when one of the batteries contained in the battery pack generates abnormal heat, the conduction of the heat to other batteries can be effectively suppressed.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: November 26, 2013
    Assignee: Panasonic Corporation
    Inventors: Yasunari Sugita, Tomohiko Yokoyama, Keisuke Shimizu, Masato Fujikawa
  • Patent number: 8586233
    Abstract: Provided is a highly safe portable electronic device having a secondary battery as a power source, and including a package, an electronic device body housed in the package, and a battery housing portion housed in the package, in which even if the content melts due to an extremely significant impact applied thereto, discharge of a melt is inhibited. In the portable electronic device, the battery housing portion is a molding with a battery fitting portion for fitting the secondary battery therein, and the battery fitting portion has a covering layer, which includes a temperature suppression layer and a block layer, provided on its surface.
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: November 19, 2013
    Assignee: Panasonic Corporation
    Inventors: Hideharu Takezawa, Tomohiko Yokoyama, Kazuya Iwamoto, Taisuke Yamamoto
  • Publication number: 20130095356
    Abstract: Batteries 100 are accommodated in a case 20, wherein the batteries 100 each include an opening portion 8a for releasing gas produced in an associated one of the batteries to outside the battery, the case 20 is partitioned into an accommodation section 50 configured to accommodate the batteries 100 and an exhaust passage 60 configured to expel the gas released from at least one of the opening portions 8a of the batteries 100 to outside the case 20, the opening portions 8a of the batteries 100 are allowed to communicate with the exhaust passage 60 through sealed connection passages 40, and a one-way open valve 70 which is configured to open only along a direction from the opening portion 8a of the battery 100 to the exhaust passage 60 is provided in an intermediate portion or at an end of each of the connection passages 40.
    Type: Application
    Filed: May 31, 2011
    Publication date: April 18, 2013
    Applicant: Panasonic Corporation
    Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Keisuke Naito
  • Patent number: 8389153
    Abstract: A battery including: a battery case having a bottom, a side wall, and an upper opening; an electrode assembly; an electrolyte; and a sealing plate covering the upper opening of the battery case accommodating the electrode assembly and the electrolyte, the electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a gasket is interposed between an opening-edge portion of the battery case and the sealing plate, a first resistive layer is disposed between the opening-edge portion of the battery case and the gasket, or a second resistive layer is disposed between the sealing plate and the gasket. The first or second resistive layer contains a mixture of a particulate inorganic oxide and a binder. This configuration makes it possible to prevent a short circuit between the battery case and the sealing plate even when the gasket is broken.
    Type: Grant
    Filed: June 1, 2009
    Date of Patent: March 5, 2013
    Assignee: Panasonic Corporation
    Inventors: Masato Fujikawa, Tomohiko Yokoyama
  • Publication number: 20130040173
    Abstract: A battery pack comprising: a secondary battery including a safety valve; a gas absorption portion including a gas absorbent represented by zeolite and a container hermetically enclosing the gas absorbent; and a case housing the secondary battery and the gas absorption portion. The safety valve is configured to discharge a gas produced in the secondary battery at the time of abnormality. The container includes a principal surface facing the safety valve, for example, and when the gas is discharged, the container is unsealed by rupturing of at least the principal surface of the container by an effect of heat or pressure of the gas.
    Type: Application
    Filed: November 4, 2011
    Publication date: February 14, 2013
    Applicant: PANASONIC CORPORATION
    Inventors: Tomohiko Yokoyama, Masato Fujikawa, Akiko Yuasa
  • Publication number: 20120301757
    Abstract: In a rectangular battery, a lead 9L connected to an electrode plate having a first polarity is connected to a battery case 1 which is an external terminal having the first polarity. A lead 11L connected to an electrode plate having a second polarity is connected to an external terminal 25 having the second polarity, through a connection plate 29. A distance between the battery case 1 and the connection plate 29 at at least one end of the battery case 1 in a long-side direction is equal to or less than the half of the width of the battery case 1 in a short-side direction thereof.
    Type: Application
    Filed: December 15, 2010
    Publication date: November 29, 2012
    Inventors: Tomohiko Yokoyama, Kazuki Endo, Masato Fujikawa
  • Patent number: 8318347
    Abstract: In a lithium ion secondary battery including a flat-plate electrode assembly which is configured by stacking the positive electrode, the separator, and the negative electrode in the thickness direction thereof, each of the positive electrode and the negative electrode includes a current collector and an active material layer. Each of the current collector includes a substantially rectangular current collector body, a heat radiating portion, and a lead portion, and the heat radiating portions are projected toward the outside of the electrode assembly so as not to overlap with each other in the thickness direction of the electrode assembly. In this way, heat caused inside the lithium ion secondary battery can be diffused efficiently to the outside, and safety of the lithium ion secondary battery can be further increased, without complicating the battery structure and decreasing mechanical strength of the battery.
    Type: Grant
    Filed: October 8, 2008
    Date of Patent: November 27, 2012
    Assignee: Panasonic Corporation
    Inventors: Tomohiko Yokoyama, Masato Fujikawa, Hideharu Takezawa, Shinji Kasamatsu
  • Patent number: 8318337
    Abstract: A battery includes an electrode assembly including a first electrode and a second electrode, a non-aqueous electrolyte, a battery case, a first lead connecting the first electrode with a bottom of the battery case, a seal member sealing an opening of the battery case, and a second lead connecting the second electrode with the seal member. At least one of the first lead and the second lead has a high resistant portion that has a higher resistance than the other portions per unit length. The high resistant portion is disposed at a position of the first lead closer to the first electrode than the portion connected to the bottom of the battery case or at a position of the second lead closer to the second electrode than the portion connected to the seal member. The high resistant portion is in contact with the battery case or the seal member.
    Type: Grant
    Filed: July 7, 2009
    Date of Patent: November 27, 2012
    Assignee: Panasonic Corporation
    Inventors: Tomohiko Yokoyama, Masato Fujikawa