The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 2001
Filed:
Jul. 23, 1998
Katsuhiko Mori, Hirakata, JP;
Yoshihiro Kashihara, Osaka, JP;
Yasushi Hirakawa, Moriguchi, JP;
Kazuo Saito, Kadoma, JP;
Kazuhiko Watanabe, Kadoma, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention relates to an explosion-proof seal plate for a sealed cell and a production method thereof and aims at providing an explosion-proof seal plate and production method thereof, wherein problems of a risk of explosion of a cell due to an excessive pressure inside the cell caused by abnormal generation of a gas through a chemical reaction accompanying over charge or erroneous use of the cell or damaging of electronic equipment using the cell as the power source are solved, ignition and other accidents can be prevented with a high accuracy by reliably cutting off an electric current when the cell internal pressure increases, and the increase in the resistance due to permeation of an electrolyte can be limited. In order to accomplish this aim, the present invention provides a thin portion,having a breaking strength of 18-24 kg/cm,in the central portion of an upper metallic foil,made of aluminum and a thin portion,having a breaking strength of 10-13 kg/cm,in the central portion of a lower metallic foil,made of aluminum, wherein the diameter A of the thin portion,of the upper metallic foil and the diameter B of the thin portion,of the lower metallic foil,satisfy the relation AB. The two metallic foils are welded at the central portions with an insulating gasket interposed, and encased in a metallic case,made of aluminum having 4 vent holes, on top of which a temperature dependent resistor,and a metallic cap,having 4 vent holes are then placed. A seal plate is obtained by sealing the periphery of the metallic case,, with which it is possible to prevent accidents such as ignition and explosion of a cell by reliably allowing internal gas to exhaust in the event of generation of a large volume of gas under an abnormal condition of a sealed cell.