What Makes Lithium Ion Batteries Volatile?
Posted on behalf of RizkLaw on Feb 26, 2017 in Consumer Alerts
In the past two months three major manufacturers have issued recalls involving lithium-ion battery packs in their computers due to overheating and danger of combustion. What makes lithium-ion batteries volatile and why are they so often used in power electronics?
On January 2, 2017, following reports of battery packs overheating and melting, Toshiba expanded its recall of laptop computer battery packs due to burn and fire hazards from overheating. 91,000 units were previously recalled in the U.S. on March 30, 2016. About 83,000 units in the U.S., 10,000 units in Canada, and 5,000 units in Mexico were included in this January, 2017 recall.
On January 24, 2017, Hewlett Packard expanded its recall of lithium-ion batteries containing Panasonic cells used in HP notebook computers due to incidences of overheating, posing fire and burn hazards, and in one case causing property damage. The batteries are compatible with HP, Compaq, HP ProBook, HP ENVY, Compaq Presario, and HP Pavilion notebook computers, and were sold with computers between March 2013 and October 2016.
On February 7, 2017, although no incidents were reported, Sony expanded its recall of VAIO laptop computer Panasonic battery packs due to risk of burn and fire hazards from overheating. This recall added about 700 units to about 1,700 units it previously recalled on June 15, 2016. The expanded recall involves Panasonic lithium-ion battery packs installed in 18 models of Sony’s VAIO Series laptop computers. In 2006, millions of lithium-ion battery packs made by Sony were replaced after several hundred overheated and a few caught fire.
What Causes Lithium-Ion Batteries to Overheat?
Lithium is the least dense metallic element, making it able to pack more power in a small space than other types of battery. Lithium is also highly reactive, causing it to be combustible. In a lithium cell the electrolyte is a solution of lithium salts and organic solvents. When the battery is charged, lithium ions are driven from the electrolyte solution into a carbon anode, and when the battery is discharged ions flow back, creating a balancing flow of electrons in a circuit that powers the device.
If there is a small fault or damage in the extremely thin separators that keep the elements of the battery apart, an internal short-circuit can occur causing a build-up of heat and what is known as “thermal runaway,” in which the battery can burst into flame. Lithium batteries can also be damaged by using them in hot environments and by excessive discharging and charging. Running down a lithium-ion battery can also completely destroy it. For this reason, manufacturers have installed smart control systems to monitor battery temperature and regulate their charging and discharging.