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Subject: Re: BATTERY-FAQ and the FM
From: Nix (nix_at_esperi.demon.co.uk)
Date: 2003-06-08


On Fri, 6 Jun 2003, Martin stipulated:
> NOW JOHN.....READ THIS BELOW
>
> The development of Lithium-Ion (Li-Ion) based batteries retained
> the beneficial electrochemical properties of metallic lithium without
> exhibiting most of the safety drawbacks. However, care must still be
> taken to not overcharge a Li-Ion battery. Overcharging results in the
> formation of pure lithium metal, which can react and cause overheating,
> fire and even explosions in extreme cases.

Correct.

(This comes from the Cadex `Batteries for a Portable World' book,
right? I think I recognise the phraseology.)

> Most Li-Ion batteries
> have built in safety mechanisms such as pressure actuated
> electrical disconnect to prevent the most drastic consequences, but
> careful circuit design must still be done to ensure that the battery is
> not overcharged. At the very least, the battery will be damaged and
> have a shorter lifetime.

This is what the LTC1734 chip is for. It works. Believe me, you'd know if
it didn't; `venting with flame' isn't something you'd fail to
notice. `Small explosion' is a better description.

(Looks cool, but it's a good idea to make sure you don't care about the
batteries in question and that they're not in something you care about
:) )

-- 
`It is an unfortunate coincidence that the date locarchive.h was
 written (in hex) matches Ritchie's birthday (in octal).'
               -- Roland McGrath on the libc-alpha list



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