Friday, Sony's battery recall hit 7 million batteries - with Dell increasing their recall from 4.1 M to 4.2 M.
Earlier this month, a Thinkpad laptop power by one of the suspect batteries spontaneously burst into flames at LAX. A similar event took place in Japan last month, and another just reported event in Singapore in December of 2005. Most embarrassing is the one that caught fire at Yahoo headquarters - the "smoking" gun can be seen at Flickr here.
I remember when Li-ion batteries were new in the late 80s (or was it the early 90s), and one exploded in a cell phone in Japan. Li-ion technology has provided higher charging capacities and longer battery life, but has long been known as a more unstable chemical combination.
From Wikipedia:
Lithium batteries can provide extremely high currents and can discharge very rapidly when short-circuited. Although this is useful in applications where high currents are required, a too-rapid discharge of a lithium battery can results in overheating of the battery, rupture, and even explosion. Lithium-thionyl chloride batteries are particularly capable of this type of discharge. Consumer batteries usually incorporate overcurrent or thermal protection or vents in order to prevent explosion.
Because of the above risks, shipping and carriage of lithium batteries is restricted in some situations, particularly transport of lithium batteries by air.
Kuzhikalail M. Abraham, a lithium battery consultant with [8] E-Kem Sciences, says the computer industry's drive to increase battery capacity can test the limits of sensitive components such as the membrane separator, a polyethylene or polypropylene film that is only 20-25 µm thick. He points out that the energy density of lithium-ion batteries has more than doubled since they were introduced in 1991. "When you pack the battery with more and more material, the separator can undergo stress," he says.
Is this situation reminiscent of the automotive situation - where the world seems to think that energy comes for free? Have we neglected basic safety for the need for longer and longer battery life, and higher and higher unwired current capacities?
I think it is well past time to start investigating new battery technologies. I remember working on battery charging circuits for NiMH and Li-ion batteries when they were new as an analog applications engineer. If my rapid charging circuit was off a bit, I could physically see the batteries swell, and I knew I either had to flip the switch or hit the deck. Not good.
So far, there have been no injuries - this is pure luck.
These batteries have been referred to in the news media as "Zippo" batteries. In defense of the good people at Zippo , their products only ignite on demand - and then extinguish themselves immediately with no property damage. I am sure their marketing people are righteously "inflamed".
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