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).
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Patent number: 8309250Abstract: A battery includes an electrode group, a case, a sealing member, and a mesh portion. The electrode group includes a positive electrode, a negative electrode opposing the positive electrode, an electrolyte interposed between the positive electrode and the negative electrode. The case has an opening and contains the electrode group. The sealing member closes the opening of the case. The mesh portion is provided so as to face an exhaust hole formed in at least one of the case and the sealing member. The mesh is formed of a thermally conductive material to put off frame coming out of the exhaust hole, in case where the battery is so defective to ignite fire.Type: GrantFiled: March 3, 2009Date of Patent: November 13, 2012Assignee: Panasonic CorporationInventors: Hajime Nishino, Masato Fujikawa, Tomohiko Yokoyama, Mikinari Shimada
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Publication number: 20120258347Abstract: 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: ApplicationFiled: December 29, 2011Publication date: October 11, 2012Inventors: Tomohiko YOKOYAMA, Masato Fujikawa, Keisuke Shimizu, Shunsuke Yasui, Daisuke Kishii
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Publication number: 20120231317Abstract: 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: ApplicationFiled: July 20, 2011Publication date: September 13, 2012Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Shunsuke Yasui, Daisuke Kishii
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Publication number: 20120196163Abstract: 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: ApplicationFiled: April 7, 2011Publication date: August 2, 2012Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa, Yasunari Sugita
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Publication number: 20120171529Abstract: Disclosed is a battery pack including a battery and a cooling member for cooling the battery. The cooling member includes a coolant and a container enclosing the coolant. The container is capable of having a releasing port for releasing the coolant at a first temperature of 100° C. or more. The cooling member is arranged at a position that allows the coolant released from the releasing port of the container to spread on a principal surface of the battery. The coolant may include water, a surfactant, and a metallic soap. The coolant may further include a foaming accelerator capable of foaming at a temperature of 100° C. or more.Type: ApplicationFiled: June 14, 2011Publication date: July 5, 2012Inventors: Yasunari Sugita, Tomohiko Yokoyama, Keisuke Shimizu, Masato Fujikawa
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Publication number: 20120155001Abstract: A laminated film is used as a battery case to provide a secondary battery having high energy density and high strength. The secondary battery includes: a battery component 1; and an outer member for sealing the battery component 1, wherein the outer member includes a first layered sheet 2 having a first metal layer made of stainless steel and a first plastic layer, and a second layered sheet 3 having a second metal layer made of aluminum-based metal and a second plastic layer, the second layered sheet 3 is provided with a recess as a container part for containing the battery component 1, and the first plastic layer of the first layered sheet 2 and the second plastic layer of the second layered sheet 3 are thermally welded to seal the battery component 1.Type: ApplicationFiled: May 10, 2010Publication date: June 21, 2012Inventors: Masato Fujikawa, Tomohiko Yokoyama, Keisuke Shimizu
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Publication number: 20120148895Abstract: A cooling unit 20 is provided in the vicinity of a cell 10, and includes a sealed portion 22 formed by sealing a sheet 21. An easy-to-open portion 24 is provided in part of the sealed portion 22, and the easy-to-open portion 24 is opened when the cell 10 abnormally generates heat.Type: ApplicationFiled: June 22, 2011Publication date: June 14, 2012Inventors: Masato Fujikawa, Tomohiko Yokoyama, Keisuke Shimizu, Shunsuke Yasui, Daisuke Kishii
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Publication number: 20110195291Abstract: 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: ApplicationFiled: June 7, 2010Publication date: August 11, 2011Inventors: Tomohiko Yokoyama, Keisuke Shimizu, Masato Fujikawa
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Publication number: 20110159341Abstract: A battery pack 1 of the present invention includes: a secondary battery 2; a molded body 11 configured to store therein the secondary battery; a temperature increase suppressing layer 13 provided between the secondary battery and an inner surface of the molded body to suppress a temperature increase of an outer surface of the molded body; and a block layer 12 provided between the secondary battery and the temperature increase suppressing layer to block leakage from the secondary battery. With this, if a malfunction, such as a case where contents, such as a molten material, flows out from the secondary battery, occurs, the contents are prevented from flowing out to the outside of the battery pack, and the temperature increase of the surface of the battery pack is suppressed.Type: ApplicationFiled: August 31, 2009Publication date: June 30, 2011Inventors: Kazuya Iwamoto, Taisuke Yamamoto, Hideharu Takezawa, Tomohiko Yokoyama
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Publication number: 20110151297Abstract: A battery pack includes a plurality of batteries 12, and a pack case 13 containing the batteries 12. An electrode group is placed in a battery case 11, and an opening of the battery case 11 is sealed by a sealing plate 9. A first internal lead 6 electrically connected to one of positive and negative electrodes is connected to an inner bottom surface of the battery case 11. A second internal lead electrically connected to the other one of the positive and negative electrodes is connected to the sealing plate. The first internal lead 6 is arranged near an inner side surface of the battery case 11. Each of the batteries 12 is arranged in the pack case 13 with part of an outer side surface of the battery case 11 corresponding to the first internal lead 6 facing the inner side surface of the pack case 13.Type: ApplicationFiled: May 21, 2010Publication date: June 23, 2011Inventors: Keisuke Shimizu, Tomohiko Yokoyama, Masato Fujikawa
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Publication number: 20110064983Abstract: 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: ApplicationFiled: September 18, 2009Publication date: March 17, 2011Inventors: Tomohiko Yokoyama, Hideharu Takezawa, Kazuya Iwamoto, Taisuke Yamamoto
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Publication number: 20110064979Abstract: The opening of a cylindrical battery case 1 with a bottom is sealed by a seal assembly 5. The seal assembly 5 has an upper valve plate 13, a lower valve plate 15, and a bottom plate 16. The bottom plate 16 has inner gas vent holes 21. When the inner gas vent holes 21 are viewed from the axial direction of the battery case 1, at least a part of each inner gas vent hole 21 overlaps a valve-hole forming portion 15b of the lower valve plate 15. With this configuration, for example, even when an electrode assembly 20 is pushed up by increased internal pressure of the battery to push up the bottom plate 16, the valve hole is not closed.Type: ApplicationFiled: February 22, 2010Publication date: March 17, 2011Inventor: Tomohiko Yokoyama
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Publication number: 20110052971Abstract: In a battery, an electrode group (4) and an electrolyte are together sealed in a battery case (10). The electrode group (4) includes a positive electrode (1) and the negative electrode (2) which are wound or stacked with a separator (3) interposed therebetween. At least one of the positive electrode (1) and the negative electrode (2) includes a current collector (2A) and an active material layer (2B), and a lead (6) is electrically connected to an exposed portion (21) of the current collector (2A). The lead (6) is arranged to extend from the exposed portion (21) to the outside of the current collector (2A) such that the lead (6) straddles a first edge (21a) which is one of edges constituting the exposed portion (21), and is welded to the exposed portion (21) at a position close to the first edge (21a).Type: ApplicationFiled: November 5, 2009Publication date: March 3, 2011Inventors: Masato Fujikawa, Tomohiko Yokoyama, Mikinari Shimada
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Publication number: 20110026207Abstract: A portable electronic device of the present invention includes a package, an electronic device body, a battery housing portion including a battery fitting portion for fitting a secondary battery therein, a foaming agent-containing layer provided on a surface of the battery housing portion, and a secondary battery to be fitted in the battery fitting portion. The foaming agent-containing layer is normally thin and, in the event of the battery generating heat, the layer turns into a thicker foamed layer which exhibits superior thermal insulation properties. Thus, it is possible to provide a portable electronic device having the degree of freedom in design for size and thickness reduction achieved at a high level, while offering high-level safety and reliability.Type: ApplicationFiled: September 18, 2009Publication date: February 3, 2011Inventors: Hideharu Takezawa, Tomohiko Yokoyama, Kazuya Iwamoto, Taisuke Yamamoto
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Publication number: 20110020688Abstract: 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: ApplicationFiled: September 18, 2009Publication date: January 27, 2011Inventors: Hideharu Takezawa, Tomohiko Yokoyama, Kazuya Iwamoto, Taisuke Yamamoto
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Publication number: 20100330404Abstract: A PTC resistor according to the present invention comprises at least one PTC composition which comprises at least one resin and at least two conductive materials. The at least two conductive materials comprises at least two conductive materials different from each other. The at least one PTC composition may comprise a first PTC composition which comprises a first resin and at least one first conductive material and a second PTC composition which is compounded with the first PTC composition and comprises a second resin and at least one second conductive material. The at least one first conductive material is at least partially different from the at least one second conductive material. One of the first resin and the second resin may comprise a reactant resin and a reactive resin which is cross-linked with the reactant resin. The PTC resistor may comprise a flame retardant agent. The PTC resistor may comprise a liquid-resistant resin.Type: ApplicationFiled: February 9, 2009Publication date: December 30, 2010Applicant: Panasonic CorporationInventors: Hajime Nishino, Mikinari Shimada, Shinji Kasamatsu, Yasushi Hirakawa, Tomohiko Yokoyama
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Publication number: 20100273033Abstract: Positive and negative electrode plates are respectively joined to positive and negative electrode terminals through leads. At least one of the leads joined to the positive or negative electrode plate is made of a stack of first and second metal layers. The first metal layer has a resistance higher than that of the second metal layer. The second metal layer has a melting point lower than that of the first metal layer. When a short-circuit current flows in the secondary battery, current is concentrated in the second metal layer to cause a blowout of the second metal layer, and then, an increase in an heat generation amount due to an increase in a current density of a short-circuit current flowing in the first metal layer causes a blowout of the first metal layer, thereby causing a blowout of the lead to interrupt the short-circuit current.Type: ApplicationFiled: April 26, 2010Publication date: October 28, 2010Inventors: Masato FUJIKAWA, Tomohiko Yokoyama
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Publication number: 20100255359Abstract: The invention provides a battery pack and a battery-equipped device in which, even if a battery experiences an abnormal event to cause thermal runaway, and generates heat, temperature increase in the battery pack and batteries except for the battery which experienced the abnormal event can be prevented. For this purpose, a heat absorbing member 4 is arranged in space inside a battery pack 1 between a casing 2 and batteries 3. Even if one of the batteries 3 experiences thermal runaway, the heat absorbing member 4 absorbs heat generated by the battery 3, thereby preventing the thermal runaway from occurring in the other batteries 3.Type: ApplicationFiled: October 24, 2008Publication date: October 7, 2010Inventors: Yasushi Hirakawa, Hajime Nishino, Tomohiko Yokoyama
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Publication number: 20100227217Abstract: The present invention provides 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, wherein a gasket is interposed between an opening-edge portion of the battery case and the sealing plate, and a first highly-resistive layer is disposed between the opening-edge portion of the battery case and the gasket, or a second highly-resistive layer is disposed between the sealing plate and the gasket. This configuration makes it possible to prevent a short circuit between the battery case and the sealing plate from occurring even when the gasket is broken.Type: ApplicationFiled: June 1, 2009Publication date: September 9, 2010Inventors: Masato Fujikawa, Tomohiko Yokoyama
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Publication number: 20100136428Abstract: 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: ApplicationFiled: November 19, 2008Publication date: June 3, 2010Applicant: PANASONIC CORPORATIONInventors: Tomohiko Yokoyama, Hideharu Takezawa, Masato Fujikawa, Shinji Kasamatsu