Stan Beer
Thursday, 05 October 2006 14:18
IT Industry -
Strategy
Japanese computer maker Fujitsu has issued a recall of 287,000 Sony Lithium Ion notebook batteries, pushing the total number of defective Sony batteries to be replaced past the 7.5 million mark.
With six major notebook manufacturers already
contributing to a snowballing battery replacement bill approaching
US$300 million, Sony must be beginning to wonder when it will see the
light at the end of the tunnel.
The Sony Lithium Ion batteries at the root of the company's troubles in
past months are believed to contain small metal particles that can
under certain circumstances cause an internal short circuit, triggering
the batteries to overheat and catch fire.
The Lithium Ion batteries made by Sony and some other manufacturers
contain Cobalt Oxide which is used because of its high energy storage
properties.
However, Cobalt Oxide can become unstable if overcharged in the case of
an internal short. This in turn can lead to a dangerous feedback
heating process called thermal runaway which in extreme cases can cause
the batteries to explode into flames.
Some Lithium Ion battery manufacturers have opted to replace Cobalt
Oxide with less volatile Iron Phosphate, sacrificing about 25% of
battery storage capacity for the sake of safety.