Batteries/Chargers 040816

 (July 2004) Proper charging for LiIon batteries
From the IC charger supplier’s viewpoint, many Lithium-ion charge features can be provided to the charger designer from Voltage ranges, measurement accuracies, high duty cycles and ability to suppress noise form ceramic capacitors with popular inductor sizes.
Portable Design, June 2004, p 22
 (July 2004) How much time before recharging your battery pack
Semiconductor vendors offer sophisticated gas-gauge IC algorithms to maximize recharging and also compensate for aging effects. Difficulty in determining charge content is amplified by varying rates of discharge. Updating capacity algorithms use methods such as cycle counts, coulomb counting, and ever improving impedance measuring techniques.
Portable Design, June 2004, p. 26
 (July 2004) Avoid pitfalls when recharging batteries to ensure long life.

An excellent overview of charging for Nickel and Lithium-ion based chemistries is presented. This article should be in every battery designer’s notebook. The considerations for  delta V and delta T in nickel charging are presented. False peaks, temperature conditions, charge times and even some consideration of aging are presented.
Portable Design,  June 2004, pp. 18-28
(Febuary 2004) Chips Aid Battery Backup In Industrial Applications
Linear Technology is building a singel cell, stand alone Lithium-ion battery charger for long life industrial backup batteryu applications. The chip only charges to 4.0 Volts instead of the popular 4.2 Volts to slow the aging process and allow operation to 3 years or more.

AMI offers achip which measures power failure durations for up to 5 hours with one second resolution. Current consumption is less than one microAmp.
Electronic Design, November 24, 2003, p 34
Q: What is the battery fuel gauge? When the `smart' battery was introduced in the 1990s, one of the main objectives was being able to communicate with battery.
Q: What are considerations for discharging at high and low temperature
Advancements in battery rapid-testing : April 2003 Not just a concept to provide greater information about battery charge conditions,Electrochemical Impedance Spectroscopy (EIS) now provides data to show superior perofrmance. The electrochemical characteristics of a battery are determined by applying an AC potential at varying frequencies and measuring the current response of the lectrochemical cell.