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Originally Posted by kuhlka
Sorry, I should have been more specific. I was referring to the recent breakthroughs with graphene supercapacitors. The research scientists are claiming they hold as much charge as Lithium, except charge in a fraction of the time.
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Those are pretty cool, but I'd always be a bit wary of putting too much faith in press releases, at least until there are some actual products out there using them.
Quote:
Originally Posted by kuhlka
Everything I've read about regenerative braking is that even at low to moderate braking force the current batteries aren't able to absorb/charge-up all of that power.
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That's not so much a limitation of the technology as it is a limitation of the implementation used in most modern hybrids. The Porsche 918 Spyder can regeneratively brake at 0.50G, which will take you from 60 to 0 in 5.5 seconds. Yes, for truly hard braking, it still has to use the brakes, but for the majority of braking around town, that seems perfectly adequate. Other cars could do something similar, but it all depends on how they want to set up their electric motor, controller, and batteries (and what current, both charging and discharging, they want to design it for).
Quote:
Originally Posted by kuhlka
Considering graphene doesn't require an electrolyte, it should mean we don't need gigantic 1-ton batteries to make a car go 100 miles on a charge. Also, even if it takes 10 minutes to charge the batteries, that's no big deal for a road trip and a comparable charge time to fossil fuel fill-ups if you take into account a piss break and grabbing a drink from the shop.
The Super Supercapacitor | Brian Golden Davis on Vimeo |
Even if it matches the energy density of lithium, you'd still need ~1klb of capacitors to get a ~200-250mi range. As for the 10 minute charge? That still requires (using the same estimated capacity as in my calculations above) a 180kW charger, pushing something like 400A of current. This is admittedly getting down to the level that the wires are of a nearly reasonable size, at least, but it's still an awful lot of power to be pushing around, especially with multiple cars charging at once. Also, this isn't that much better than what the Tesla can already do with the superchargers, which can provide about 200 miles of range in a 30-40 minute charge (vs your proposed 100 miles in 10).