The Envia batteries tested by ARPA-E were 45-Ah units. Kapadia said that a 100-mile electric sedan would need approximately 120 of the cells. A full battery pack for such a vehicle could be air-cooled or liquid-cooled, he said.
Envia, which has an interdisciplinary team of 13 PhDs in areas of material science and electrochemistry, has done all the battery's design work itself, starting in 2007.
"We've never used off-the-shelf components for our batteries," Kapadia said. "A battery is just as good as its components, and all of the components are ours."
For a close look at GM's Chevy Volt, go to the Drive for Innovation site and follow the cross-country journey of EE Life editorial director, Brian Fuller. In the trip sponsored by Avnet Express, Fuller is taking the fire-engine-red Volt to innovation hubs across America, interviewing engineers, entrepreneurs, innovators, and students as he blogs his way across the country.
:-) while I agree you should treat your CD's/DVD's that way, they are incredably tolerant of scratches etc. because of a combination of good error correction algorithms and some cleaver schemes to deal with complete loss of signal. Where as a scratch on vinyl produces a click which is spectrally different from the content, a CD player extends the last detected audio level which barely changes the spectral content and so goes largely unnoticed. One thing CD's don't like is exposure to sulphur. High sulphur paper can blacken the silver reflective layer causing much more significant effects than a few scratches might.
tekochip: I mentioned in a previous comment that I have a tin ear that can't tell the difference between the sound quality of vinyl versus digital. I've been told for years that digital can't measure up to vinyl and I wondered why vinyl didn't sound better to me. Your comment is heartening -- maybe my assessment of sound quality isn't as bad as I was led to believe. Thanks.
I agree, Chuck. I kept my vinyl records. A few years ago, I went through them with the idea of selling them on eBay. But they were in terrible shape with scratches everywhere, so I didn't bother. Meanwhile, my CDs hold up well.
Suddenly vinyl is becoming trendy. It's true that the sound quality was really quite good just as it was phased out, but it comes nowhere close a CD. I am a musician, and I remember the first digitally recorded, digitally mastered and digitally reproduced album I heard. Like many people it was "Brothers in Arms" by Dire Straits. The sound was breath taking, simply awe inspiring, and made me rush out and buy a better amplifier because now I needed better signal to noise performance.
Then there came MP3s. We went from dynamic range that stretched the limits of the cables carrying the signal, to the squishy sound of a Diamond Rio (I bought the first MP3 player I could get my hands on). Engineers are used to trade-offs and this was a big one, as consumers traded quality for convenience. Storage size went from 10MB a minute to 1MB or less depending on the quality you could tolerate, which was now less than the quality of vinyl. More than a decade has passed and now consumers download more music than purchase media content. Sure enough, one day my kids came to me and said that vinyl records had the best sound. We listened to some vinyl and then I put on a full digital CD and they too were awe inspired, since they had grown up listening to music through an iPod and small diaphragm speakers that they crammed into their ears.
Well, I've written too much, but it's a topic near and dear to my heart. The bottom line is that digital audio has the capability of taking our breath away with quality as good as the source, but marketplace convenience has yielded quality comparable to a cassette.
Next topic, vacuum tubes? Much like a candle, nothing warms my heart like the flickering, blue glow from a pair of 6L6s.
My rather limited record supply had very few vinyl records without scratches, pops and hissing. One of the advantages of CDs is that I can get my hands around the outer perimeter of the CD without touching the playing surface. As a result, my CDs -- even the older ones -- are in far better condition than any of my similarly-aged vinyl records.
Good point, Nancy. I have found CDs to be very convenient. Digital music also has another big advantage -- it doesn't deteriorate. While it may not have the full audio range and depth of vinyl, there are no pops and hissing after 1000 plays. Since vinyl is based on friction, it's pretty much inevitable the vinyl recording will lose its fine sound in time.
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