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. 31, 2005
Filed:
May. 21, 2003
Philip H. Burrus, Iv, Lilburn, GA (US);
Guoping Deng, Lawrenceville, GA (US);
Edmond Louie, Snellville, GA (US);
Philip H. Burrus, IV, Lilburn, GA (US);
Guoping Deng, Lawrenceville, GA (US);
Edmond Louie, Snellville, GA (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A current interrupt device for rechargeable, electrochemical cells having a safety valve, insulating spacer and a thin metal plate for coupling to an electrode assembly is provided. The thin metal plate electrically couples to the safety valve by way of a conductive polymer, preferably having a positive temperature coefficient characteristic. The positive temperature coefficient characteristic is such that the impedance of the polymer increases with increasing temperature. In normal operation, the polymer conducts current. In high current situations, where internal components heat due to parasitic resistances, the polymer becomes an insulator and disconnects the cell from the exterior can. When gasses build within the cell, the safety valve deforms, thereby causing the safety valve to separate from the thin metal plate. Once the safety valve and thin metal plate have separated, the electrode assembly is electrically isolated from the exterior can.