Abstract: A rechargeable electrochemical cell is provided having a pressure-responsive apparatus for determining a charge termination point. In particular, a reversible pressure-responsive switch may be disposed in a cap at the open end of a rechargeable metal hydride cell. The reversible pressure-responsive switch may also contain a vent system for releasing the cell internal pressure. Alternatively, a rechargeable cell may include a strain gauge disposed in its outer surface whose resistance changes as the outer surface of the battery expands due to internal pressure accumulation during charging. Additionally, a rechargeable cell is used combination with a charging source that can supply constant voltage, constant current, alternating current, or voltage that varies between a minimum threshold and a maximum threshold.
Type:
Grant
Filed:
March 21, 2005
Date of Patent:
October 30, 2007
Assignee:
Spectrum Brands, Inc. ( FKA Rayovac Corporation)
Inventors:
William C. Bushong, Paul Cheeseman, Thomas Kaufman, Michael Root, Aaron Rositch, Marc L. Syvertsen, Viet H. Vu