Putting a Chill Into Battery Thermal Runaway

Charles Murray

July 28, 2011

1 Min Read
Putting a Chill Into Battery Thermal Runaway

Thermal runaway has never been far from the minds of design engineers who use lithium-ion batteries, especially since the first reports of laptop fires surfaced more than a decade ago.

Electronics suppliers are helping engineers prevent such problems with the introduction of new battery management integrated circuits that monitor voltage, temperature, and current conditions at the battery.

"The main condition is overvoltage," says Yevgen Barsukov, IP development manager for battery management systems at Texas Instruments. "Normal voltage for a lithium-ion battery is 4.2V. If the battery is charged to 4.3V or 4.4V, it can take you to a condition where you have thermal runaway."

TI's bq275xx family of battery management ICs provides protection for battery packages. The ICs, which measure just a couple of millimeters on a side, include a microcontroller, flash memory, random access memory, and an analog-to-digital converter. The devices serve as gauges for handheld devices such as cell phones, laptops, and tablets.

Both TI and Analog Devices make management units for electric vehicle batteries. In June, TI unveiled bq76PL536, a battery management unit targeted at rechargeable lithium-ion packs for EVs, hybrid vehicles, and power tools. Last year, Analog Devices rolled out the AD8280, which works with a series of high-voltage comparators to "look" for undesirable voltage or temperature conditions in vehicle battery packs.

"The idea is to monitor for voltage, temperature, and overcurrent conditions," Barsukov says. "If any of the conditions are exceeded, the battery management system will turn off the appropriate components."

For a related deep dive into high-energy rechargables, see our feature-length article, New Breed of Lithium Batteries.

About the Author(s)

Charles Murray

Charles Murray is a former Design News editor and author of the book, Long Hard Road: The Lithium-Ion Battery and the Electric Car, published by Purdue University Press. He previously served as a DN editor from 1987 to 2000, then returned to the magazine as a senior editor in 2005. A former editor with Semiconductor International and later with EE Times, he has followed the auto industry’s adoption of electric vehicle technology since 1988 and has written extensively about embedded processing and medical electronics. He was a winner of the Jesse H. Neal Award for his story, “The Making of a Medical Miracle,” about implantable defibrillators. He is also the author of the book, The Supermen: The Story of Seymour Cray and the Technical Wizards Behind the Supercomputer, published by John Wiley & Sons in 1997. Murray’s electronics coverage has frequently appeared in the Chicago Tribune and in Popular Science. He holds a BS in engineering from the University of Illinois at Chicago.

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