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Re: [EVDL] Kokam / lithium "shelf life"

Eew... 4-5 years..what I remembered hearing... I asked kokam, who
stated that they are currently testing and have no info pertaining to
shelf life, they will send info as and when they get it. This was
today.

Im assuming this means the cells haven't been around long enough to get
a conclusive result?

They've been round at least 2 years, since that was when I made my first
enquiries with them.. cliff was already racing round a track with them
then... you'd think they could extrapolate a curve from 2+ years of
data...



-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Peter Gabrielsson
Sent: 07 November 2007 17:30
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Kokam / lithium "shelf life"

Shelf life is a function of cell voltage and temperature, store them
at lower voltage and keep them cool to maximize shelf life. The lower
voltage chemistries like A123 and Altair's batteries suffer less from
aging largely because of lower voltage.

The manufacturer is however the best source for this info...





Osmo S. <[email protected]> wrote:
> I believe this information comes from Philippe Borges, who wrote in
> March 2006:
>
> "i think no company will answer you (trustfully) on calendar life of
> their
> lithium batteries, because it's their major drawback.
> It's a fact than once assembled, it start to "self-destruct", worst
> if not
> used...
>
> This said one people aswered me, it was Kokam CEO himself during
> EVS21 :^)
> I asked about calendar life of their li-ion cells
> He told me something like: our cells are near new but we think you can
> expect arround 4-5 years calendar life before real capacity loss.
> I asked if capacity loss was significative
> he told me: under usual target 80% capacity left.
> I asked if half capacity loss was possible
> He told me: yes it's possible."
>
> Terveisin,
> Osmo
>
> Lawrie, Robin kirjoitti 7.11.2007 kello 18.01:
>
>
> > Ive heard persistent rumours that the Kokam Cells have a restricted
> > shelf life regardless of usage... is this the case? I cant even
> > remember
> > where I heard it... is this an issue with li-po cells in general?
> >
> > Cliff? You seem to be the man to ask..
> >
> > Ive been quoted a nice (its all relative) price on some 40 ah
> > cells, but
> > don't want to blow my load on some 2000+ cycle cells that only last
5
> > years regardless...
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
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>



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