OT: Lithium-ion over-current videos

  • Thread starter Thread starter George Macdonald
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George Macdonald

I'd heard about counterfeit Li-ion batteries exploding but those are err,
spectacular. The links are in the Techflicks sidebar at the top right of
the page http://www.edn.com/article/CA514947.html. Note: Windows
Mediaplayer refuses to do the video for an .AVI over a network so you'll
likely have to DL first.

Anyway, thought those might be of interest.
 
George said:
I'd heard about counterfeit Li-ion batteries exploding but those are err,
spectacular. The links are in the Techflicks sidebar at the top right of
the page http://www.edn.com/article/CA514947.html. Note: Windows
Mediaplayer refuses to do the video for an .AVI over a network so you'll
likely have to DL first.

Anyway, thought those might be of interest.
Click to expand...

Well, the reason they explode are not them being counterfeit,
but them missing two level protection agains overcharge, short-circuit
etc which is present in all UL-compliant Li-ion battery packs.
It is well known that Li-ion battery will very reproduceable explode
if overcharged above 4.5V (or overheated above 150C by for example
short-circuit). That is the reason why there is no consumer size (like
AA) Li-ion batteries.

Regards,
Evgenij
 
Well, the reason they explode are not them being counterfeit,
D'OH!

but them missing two level protection agains overcharge, short-circuit
etc which is present in all UL-compliant Li-ion battery packs.
It is well known that Li-ion battery will very reproduceable explode
if overcharged above 4.5V (or overheated above 150C by for example
short-circuit). That is the reason why there is no consumer size (like
AA) Li-ion batteries.
Click to expand...

Read the article.
 
Evgenij Barsukov said:
Well, the reason they explode are not them being counterfeit,
but them missing two level protection agains overcharge, short-circuit
etc which is present in all UL-compliant Li-ion battery packs.
It is well known that Li-ion battery will very reproduceable explode
if overcharged above 4.5V (or overheated above 150C by for example
short-circuit). That is the reason why there is no consumer size (like
AA) Li-ion batteries.
Click to expand...

In the case of the particular batteries in the story, the reason they
lacked the overcurrent (etc) protection is that they were counterfeit.
 
Joe said:
In the case of the particular batteries in the story, the reason they
lacked the overcurrent (etc) protection is that they were counterfeit.
Click to expand...

The point being is, there is no particular reason why counterfeiters
could not make batteries with all the protections included, considering
that reference designs of proper battery packs are published on the
web and all the ICs are catalogue parts.
It takes (1) a compatible battery manufacturer (which by itself is
not illegal as have been indicated by recent precident giving case with
Lexmark printer cartidges) + (2) a sloppy or intentionaly dishonest one
to violate UL-standards (that would provide for absent safety elements)
to create a dangerous battery.
It is true that for the end user, there is no way to know if
component (2) is present (unless an autentication IC is used in the pack
and he can be assured that pack is made by original manufacturer). It
could be argued however that there could be such thing as "reputable"
compatible battery manufacturer who the end-user would trust to make a
proper battery, even with a clear knowledge that battery is not
made by original maker.

Regards,
Evgenij
 
Evgenij Barsukov said:
The point being is, there is no particular reason why counterfeiters
could not make batteries with all the protections included, considering
that reference designs of proper battery packs are published on the
web and all the ICs are catalogue parts.
It takes (1) a compatible battery manufacturer (which by itself is
not illegal as have been indicated by recent precident giving case with
Lexmark printer cartidges) + (2) a sloppy or intentionaly dishonest
one to violate UL-standards (that would provide for absent safety
elements) to create a dangerous battery.
Click to expand...

This is all true. However, from reading the article I get the
impression that the batteries were not just compatible, but in fact
counterfeit: they had trademarks claiming to have been made by or for
the phone manufacturer, but had not used those trademarks under
license. When that happens, the presumption is that the parts are
indeed second-rate.

Over in the auto parts world (where I spend a lot of my hobby time and
money), it's well known that third party parts are frequently at least
as good as and frequently better than "factory" parts. However,
counterfeit parts (represented as being from the factory, without
licensing the trademarks) are almost certainly shoddy, below-spec
junk.
It is true that for the end user, there is no way to know if
component (2) is present (unless an autentication IC is used in the
pack and he can be assured that pack is made by original
manufacturer). It could be argued however that there could be such
thing as "reputable" compatible battery manufacturer who the end-user
would trust to make a proper battery, even with a clear knowledge that
battery is not
made by original maker.
Click to expand...

Of course. In fact, when I bought replacement batteries for my own
cell phone, they were quite clearly not made by Samsung, and the
manufacturer claimed only that they were "for SAM i300" (I'd feel
better about them if they had *some* manufacturer's name on them;
again, my experience over in the auto parts world and also in the
computer memory world is that parts with a name -- any name! -- on
them are normally higher quality than parts without). No idea whether
they actually have the protective circuitry we're talking about here,
but they haven't blown up yet!
 
It is true that for the end user, there is no way to know if
Of course. In fact, when I bought replacement batteries for my own
cell phone, they were quite clearly not made by Samsung, and the
manufacturer claimed only that they were "for SAM i300" (I'd feel
better about them if they had *some* manufacturer's name on them;
again, my experience over in the auto parts world and also in the
computer memory world is that parts with a name -- any name! -- on
them are normally higher quality than parts without). No idea whether
they actually have the protective circuitry we're talking about here,
but they haven't blown up yet!
Click to expand...

Well, to put it simplified somewhat, protective circuit is only kicks in if
1) for single cell situation (e.g. 3.6V nominal battery) charger fails
to maintain constant voltage mode at 4.2V
or
2) for multy-cell situatin (e.g. 7.2V or above nominal battery), some
of the cells state of charge is higher than others and so single cell
exceeds 4.2V even if the pack voltage provided by charger is correct.

So you might be using your pack for a while without a problem even
without protection, but than either charger fails, of some of the cells
becomes disbalanced, and - BANG (big red fireball)!

Regards,
Evgenij
 
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