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:
Mar. 12, 2002
Filed:
Nov. 20, 1998
Takayuki Yamahira, Fukushima, JP;
Ayaki Watanabe, Fukushima, JP;
Toshizou Kameishi, Nara, JP;
Koji Kihara, Nara, JP;
Other;
Abstract
An extremely safe non-aqueous electrolyte secondary cell free of explosions and which can promptly release the internal pressure in case of rise in the internal pressure. The non-aqueous electrolyte secondary cell has in its opening a cleavage valve obtained on bonding a metal foil to the opening. In case of rise in the internal pressure, the cleavage valve is cleft to release the pressure. In this cell, a value K corresponding to the internal volume in the cell in cm divided by the area of the opening in cm is set so that 40≦K≦350. By selecting the value K to a suitable value, the cleavage valve is in operation when the internal pressure reaches a predetermined value to release the pressure. The metal foil is produced by, for example, a electro-forming method or a cladding method. Preferably, a fluorine-based water-proofing agent is coated on the foil surface.