Sean Korb via EV wrote:
This is the sort of thing where I should study the paper, read the dissents
and then give my completely unscientific opinion as if it were fact.
Yes indeed. :-)
Some basic physics: Imagine you're trying to invent a new battery. You
assume one molecule each of the two reactants. You calculate the voltage
(the difference between them in a table of electromotive forces). You
look up how many electrons the charge/discharge reaction will yield
(usually one or two). From the voltage and the current you calculate the
energy (watt-hours).
Now you calculate the weight (from their atomic weights). Divide energy
by weight, and put it in Wh/Kg. Holy cow! It's better than any real
battery! You're a genius! Quick, get your patent attorney, line up
investors, call the reporters to announce an "Incredible battery discovery!"
Not so fast. It turns out that just about any two molecules you pick
(even lead-acid) will have a theoretical yield higher than any practical
real-world battery. You didn't include anything for the separator,
conductors to collect the current and get it in/out, a case to put it
in, the inevitable internal resistance, what percentage of the molecules
will actually react, etc.
Real researchers know that you can't blindly scale up theoretical
studies and preliminary lab tests and expect it to predict full-size
product performance. But that doesn't stop them from saying things like,
"Theoretically, it could produce up to 200 Wh/Kg." But the reporters
will translate that into "Amazing new breakthrough battery yields more
energy than anything on the market!"
--
All children are born as engineers. Watch them at play. They're not
just playing; they're building and learning. They are engineering.
Then we get them in school and spend years squashing it out of them.
(Geoffrey Orsak, Southern Methodist University dean of engineering)
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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