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APPARATUS FOR CHARGING A LITHIUM ION BATTERY IN A NICKEL SYSTEM CHARGER

IP.com Disclosure Number: IPCOM000007780D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2002-Apr-23

Publishing Venue

Motorola

Related People

Authors:
Scott M. Garrett

Abstract

The problem of how to allow charging of a lith- ium ion based battery pack in a nickel cadmium/ metal hydride charger is currently broached by existing MicroTAC lithium ion batteries. These bat- teries contain circuitry comprising voltage sensing circuits and switches coupled in series with the lith- ium ion cell(s). In addition, the circuitry comprises a means for simulating a high temperature upon the cell voltage reaching some predetermined over- voltage threshold (typically 4.2V/cell). This fools the nickel system charger into terminating rapid charge, and keeps the cell(s) from experiencing an over- voltage condition. If the charger does not shut off within some time frame, such as, for example, two seconds, then the circuit opens a switch to electri- cally disconnect the battery from the charger.