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CHARGER FEATURE TO PREVENT OVERCHARGE OF REINSERTED CHARGED BATTERY

IP.com Disclosure Number: IPCOM000009423D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Aug-22
Document File: 1 page(s) / 71K

Publishing Venue

Motorola

Related People

Joseph PatiƱo: AUTHOR [+3]

Abstract

Many means are used in present chargers to ter- minate fast rate charging of batteries as they finish to prevent overcharging. Typically, AT/At is the pri- mary means to terminate rapid charging, which monitors the rise in temperature slope, Temperature Cutoff (TCO) is primarily a back up technique, and Voltage CutOff (VCO) is used to terminate charging in the event that a fully charged battery is reinserted into the charger. Due to the temperature conditions in a vehicle environment, typically Temperature Cutoff is used along with Voltage Cutoff only. In Vehicular Adapter environments it is very common for the user to remove the battery fully charged for a very short period and reinsert it into the charger. This causes the charger to restart rapid charging the battery. If the Voltage Cutoff threshold is properly set, the charger will terminate the rapid charge sequence and trickle charge the battery instead and therefore avoid heating the battery. This heating of the battery adversely affects the battery's cycle life performance.

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Developments Technical 0 M M-ROLA

CHARGER FEATURE TO PREVENT OVERCHARGE OF REINSERTED CHARGED BATTERY

by Joseph Patifio, Robert Ford and Joseph Namm

  Many means are used in present chargers to ter- minate fast rate charging of batteries as they finish to prevent overcharging. Typically, AT/At is the pri- mary means to terminate rapid charging, which monitors the rise in temperature slope, Temperature Cutoff (TCO) is primarily a back up technique, and Voltage CutOff (VCO) is used to terminate charging in the event that a fully charged battery is reinserted into the charger. Due to the temperature conditions in a vehicle environment, typically Temperature Cutoff is used along with Voltage Cutoff only. In Vehicular Adapter environments it is very common for the user to remove the battery fully charged for a very short period and reinsert it into the charger. This causes the charger to restart rapid charging the battery. If the Voltage Cutoff threshold is properly set, the charger will terminate the rapid charge sequence and trickle charge the battery instead and therefore avoid heating the battery. This heating of the battery adversely affects the battery's cycle life performance.

  Because different battery chemistries attain dif- ferent voltage levels when fully charged, the Voltage Cutoff must be set in accordance with the chemistry battery being charged or it will not work properly. If the threshold is too high (example: NICad thresh- old selected when charging a NiMHi battery) then the battery will te...