On Mon, Nov 05, 2018 at 02:59:50PM +1300, RussellMc wrote:
> On Mon, 5 Nov 2018 at 13:56, James Cameron <quozl@laptop.org> wrote:
>=20
> > Thanks, interesting.
> >
> > Specific electrolyte additives and temperature control in the field
> > are critical to product longevity.
> >
> > Paraphrasing a new rule of use; minimise temperature while battery
> > voltage is high.
> >
> > Or even simpler; minimise voltage, and minimise temperature.
> >
> > He describes the underlying causes and methods to test for the
> > mechanism of degradation.  Measuring the heat gain or loss during a
> > cycle is nice.
>=20
> I'm not intuitively comfortable with his assertion that cycle life is wel=
l
>  (if not linearly) correlated with coulombic efficiency.
>=20
> LiFePO4 at least start at somewhere over 99% when new and IMPROVE with ti=
me.

Hmm, my reading was the reverse.  Coulombic inefficiency as a result
of the undesired reactions.  These reactions may decrease in extent
after a few cycles, but they have begun.

> (Note that although Li cell charge/discharge energy efficiency is high
> compared to most otrher systems, coulombic and energy efficiencies do not
> track well, alas.)

p.s. "surface" is often rendered as "service" during the
transcription.

--=20
James Cameron
http://quozl.netrek.org/
--=20
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