On Wed, 25 Jun 2008 17:56:29 -0400, "Peter Dohm"
wrote in
:

"Larry Dighera" wrote in message
.. .
On Wed, 25 Jun 2008 19:54:33 +0000 (UTC), Dylan Smith
wrote in
:

All the Li-Ion batteries that have burned have had causes, too. (Faulty
charging circuitry in the main).

I wouldn't expect faulty charging circuitry to be the main cause of
lithium batteries spontaneously catching fire.

Here is the cause of the massive Sony battery recall:

http://arstechnica.com/news.ars/post/20060928-7858.html
They cite microscopic metal particles that enter the battery
during the manufacturing process as the reason for the battery
failures. The particles, they say, come into contact with other
parts of the battery cell, causing the battery to short-circuit.
Sony claims that these batteries would normally just power off,
but in "rare cases" may overheat and cause flames.

IMHO, that is far more frightening than charging problems!

Peter

As technology advances and the energy density of batteries increases,
there is a higher probability of more spectacular failure modes.

Here are some more things to think about:

http://en.wikipedia.org/wiki/Lithium_ion_battery
Safety

Lithium-ion batteries can rupture, ignite, or explode when exposed
to high temperature environments, for example in an area that is
prone to prolonged direct sunlight.[40] Short-circuiting a Li-ion
battery can cause it to ignite or explode, and as such, any
attempt to open or modify a Li-ion battery's casing or circuitry
is dangerous. Li-ion batteries contain safety devices that protect
the cells inside from abuse, and, if damaged, can cause the
battery to ignite or explode.

Contaminants inside the cells can defeat these safety devices. For
example, the mid-2006 recall of approximately 10 million Sony
batteries used in Dell, Sony, Apple, Lenovo/IBM, Panasonic,
Toshiba, Hitachi, Fujitsu and Sharp laptops was stated to be as a
consequence of internal contamination with metal particles. Under
some circumstances, these can pierce the separator, causing the
cell to short, rapidly converting all of the energy in the cell to
heat resulting in an exothermic oxidizing reaction, increasing the
temperature to a few hundred degrees Celsius in a fraction of a
second.[41] This causes the neighboring cells to heat up, causing
a chain thermal reaction.

The mid-2006 Sony laptop battery recall was not the first of its
kind, however it was the largest to date. During the past decade
there have been numerous recalls of lithium-ion batteries in
cellular phones and laptops owing to overheating problems. In
October 2004, Kyocera Wireless recalled approximately 1 million
batteries used in cellular phones, due to counterfeit batteries
produced in Kyocera's name.[42] In December 2006, Dell recalled
approximately 22,000 batteries from the U.S. market.[43] In March
2007, Lenovo recalled approximately 205,000 9-cell lithium-ion
batteries due to an explosion risk. In August 2007, Nokia recalled
over 46 million lithium-ion batteries, warning that some of them
might overheat and possibly explode.[44] There was an incident in
the Philippines involving a Nokia N91, which uses the BL-5C
battery.[45]

It is possible to replace the lithium cobalt oxide cathode
material in li-ion batteries with lithiated metal phosphate
cathodes that are not as sensitive to temperature, and so are less
prone to explode. This also extends their shelf life. However,
currently these 'safer' li-ion batteries are mainly destined for
electric cars and other large-capacity battery applications, where
the safety issues are more critical. Unfortunately, a problem with
these 'safer' li-ion batteries is that lithiated metal phosphate
batteries hold only about 75 percent as much energy.[46]

Another option is to use manganese oxide or iron phosphate
cathode.




http://www.batteriesdigest.com/lithium_ion_recall.htm
The Apple recall of Computer Batteries

Lithium-ion batteries in computers were once again voluntarily
recalled in May 2005 when Apple, in conjunction with the U.S.
Product Safety Commission, said that an internal short in three
model notebooks could have battery cells which could overheat and
pose a fire hazard to consumers. Apple received six reports
worldwide of batteries overheating, including two in the United
States.

The batteries are said to be manufactured by LG Chem Ltd., of
South Korea.

The computers were sold through regional resellers, catalogers,
and Apple’s on-line retail stores with batteries from October 2004
through May 2005 for between $900 to $2,300. The batteries also
were sold separately for about $130.

Although Sony and LG chem have provided the bulk of Lithium-ion
batteries for Apple Computer, about 20 percent have been supplied
by DynaPack, a Taiwan-based company. According to an article in
the DigiTimes, DynaPack began shipments to Apple for its
Powerbook earlier this year and Simplo, another Taiwan-based
company will begin shipments to Apple starting at the end of the
year. (“Apple notebook battery recall may benefit Taiwan makers”
by Huang Kung Tien, Taipei; Jessie Shen, DigiTimes.com, 05/25/05)