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:
May. 13, 2003
Filed:
Aug. 30, 1999
Kouichi Satoh, Osaka, JP;
Naoya Nakanishi, Osaka, JP;
Kazuyasu Fujiwara, Osaka, JP;
Toshiyuki Nohma, Osaka, JP;
Ikuo Yonezu, Osaka, JP;
Sanyo Electric Co., LTD, Osaka, JP;
Abstract
A secondary cell comprises a gastight can having a cylinder and a lid fixed to an opening portion of the cylinder, and a secondary cell element accommodated in the can . The lid is fixedly provided with a gas vent closure in the form of a disk and having a diaphragm openable upon the internal pressure of the can exceeding a predetermined value. The gas vent closure has an outer peripheral portion welded to an opening edge defining a through bore formed in the lid . The lid is formed in a front surface thereof with a circumferential groove surrounding the welded portion of the gas vent closure , and a diminished portion is provided between the groove and the welded portion for reducing the sectional area of a heat flow path for the heat of welding to pass therethrough. The lid thus constructed makes it possible to weld the vent closure to the lid free of defects such as pinholes or cracks.