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New Material Transforms Car Bodies Into Batteries
MikeChino writes "As battery manufacturers race to produce more efficient lithium-ion batteries for electric vehicles, some scientists are looking to make the cars themselves a power source. Researchers are currently developing a new auto body material that can store and release electrical energy like a battery. Once perfected, scientists hope the substance will replace standard car bodies, making vehicles up to 15 percent lighter and significantly extending the range of electric vehicles."
According to TFA their plan is to make the body panels act as one plate of a huge capacitor. I can't even begin to list all the technical flaws in their proposal; just reading it made my head hurt. They really should run their promotional pieces past a real engineer before spreading them all over the net.
Physorg is a tarpit. Here's the REAL original article.
http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_5-2-2010-10-26-39
There is also the issue of having an electrical grid that can handle that. Charging a battery in minutes with enough power to get you hundreds of miles takes a non-trivial amount of power, no matter how good your battery is.
You don't draw it from the grid. You draw it from a battery bank. The battery bank is in turn trickle-charged from the grid.
And in case anyone's curious, yes, they do make extremely high power chargers. TARDEC got one last year that does 800kW. I don't know how much that one cost, but ones in the ~250kW range are typically ~$125k-ish (and about the size of a vending machine). That may sound like a lot, but then again, a gas station generally costs $1-2m to build, and you have to pay for tear-down at end of life (tearing down a charger is a net gain, from scrap). Plus, expect prices to fall over time.
Chargers that big generally require that their connectors or even their cables be cooled. Which makes me wonder when we'll see the next logical step in that evolution -- having the charger provide coolant for the battery pack instead of the EV providing it. After all, why make the EV haul around a powerful cooling system when your charger already has one and is already bringing coolant all the way to the vehicle? All the vehicle should need is a connector for the coolant and ducting for it to travel through. If you use something like supercritical CO2 as a coolant, you won't even have to worry about coolant contamination or residual coolant being left over in the system.
The current fast-charging pseudo-standard, TESCO, doesn't do that, though. But in the future, I expect we'll ultimately see it.
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!
I mentioned the worst and the best. Do I really need to spell out all of the midpoints?
Cellulosic ethanol is estimated at up to 1,500 gallons/acre/year. At 30mpg, that's 45,000 miles/acre/year.
Ausra's proposed 177MW Carrizo solar thermal plant was to be situated on 640 acres. That's 277kW/acre. Assuming a capacity factor of about 0.3 (clear skies, heliostat), that's about 727,000,000 Wh/acre/year. At 250Wh/mi, that's ~2,900,000 miles/acre/year.
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!
What really matters is what the resulting cost is.
1) Land use absolutely *does* matter. As does water use, fertilizer use, etc. It matters for wildlife habitat (incl. rainforest), for food production, for algal blooms, for countless things.
2) From a cost perspective, solar thermal wins there, too. EVs are really cheap to run. Even if cellulosic ethanol could manage to sell for the same price as gasoline (and note that 30mpg ethanol is notably better than 30mpg gasoline, in the above calculations) -- say, $3/gal -- it would be 10 cents per mile. Even if you had to pay 20 cents per kWh for the solar thermal (most next-gen solar thermal is predicting less than that), rather than the US national average for electricity of 10 cents per kWh residential (and notably less for industrial power), that would be five cents per mile.
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!
Dear god, if you drive 700-800 miles without stopping to rest or eat, please don't do it when I'm on the road!
I'm sure some semi-truck drivers have done it. For us regular drivers, who stop and rest after 350 miles, will the car be recharged in 12 hours? That depends on how standardized, and available charging is. The average motel today probably would bill extra, if it were even possible (big parking lots, no outlets, etc.) or if unattended charging was allowed.
But, I'm not trying to be a kill-joy. I'd love to have an electric car or motorcycle with a range of between 40 and 80 miles. I'm an electronics engineer, so I'd even have fun building my own solar and wind power to charge it.
On that note, I've recently done some comparisons between rechargeable batteries and capacitors.
To summarize: batteries win with normal approaches (low cost and complexity), but high voltage capacitors have the best performance and greater usable energy capacity. Technically capacitors should outlast batteries. And, in theory, a high voltage capacitor is simpler to build than either a supercap or battery, so the cost could be lower in mass production.
I used the SI unit Joules, instead of Wh, because it's easier to visually compare numbers greater than 1, as opposed to using enginnering notation for milli, micro, nano, and pico.
The following information doesn't take into account usable energy, because that's dependent on how the things are used. A capacitor will outperform a battery in high current usage. Capacitors can also be totally discharged to 0V without being damaged and batteries cannot (most battery Ah ratings take that into account).
Convert Watt-hours to Watt-seconds (Joules)
E=W*3600
Convert battery to Joules
The product of voltage V, amp hours Ah and 60 squared, is Joules E (watts per second)
E=V*A*3600
Convert capacitor to Joules
Half of Farads multiplied by the square of Voltage
E=0.5*F*V^2
Fun math:
One Kilowatt Hour is 3.6MJ (3,600,000J, 1000Wh*3600)
A single AA NiMH is 10.4KJ (10,368J)
A L-ion 3.7V 4Ah is 53.28KJ (53,280J)
A 16V, 100F capacitor is 12.8KJ (12,800J)
A 12V 40Ah battery is 1.728MJ (1,728,000J) (Two 12V 40Ah batteries are nearly 1KWh, 3.456MJ)
A (real) 6.5KV, 9500uF capacitor is 200.7KJ (200,700J) ~ a 1x1x2 foot sized industrial capacitor
A (theoretical) 26KV, 9500uF capacitor is 3.2MJ (3,200,000J)
A (theoretical) 300KV, 1000uF capacitor is 90MJ (90,000,000J, 25KWh)
All the capacitors are physically bulkier than batteries, typically twice the size or worse for a given amount of Joules.
Recently pulled from wikipedia
http://en.wikipedia.org/wiki/Battery_(electricity)
Secondary Battery Chemistries
NiCd 1.2V 0.14 MJ/Kg
Lead Acid 2.1V 0.14 MJ/Kg (0.1232 MJ/Kg, found for real battery)
NiMH 1.2V 0.36 MJ/Kg
NiZn 1.6V 0.36 MJ/Kg
L-ion 3.6V 0.46 MJ/Kg (0.635 MJ/Kg, found for real battery)
*Zinc-Air 1.55 1.35-1.65 MJ/Kg
(*electrical or mechanical recharging is possible)
Aluminum-Air is similar to Zinc-Air, but I don't much have information on it.
Interesting bit of information about capacitors (as battery substitutes)
A 1V, 2F capacitor is 1J (Linear)
A 2V, 1F capacitor is 2J (Exponential)
A 1V, 10F capacitor is 5J (L)
A 1V, 20F capacitor is 10J (L)
A 10V, 1F capacitor is 50J (E)
A 20V, 1F capacitor is 200J (E)
High voltage capacitors are capable of storing more energy than high farad capacitors. Because an increase in voltage is an exponential increase in energy, and an increase in farads is a linear increase in energy.
Supercaps are safer to work near, cheaper, and physically smaller (but heavier) than high voltage capacitors. Unless I'm mistaken, the highest voltage capacitor type is a vacuum capacitor (vacuum is the dielectric) hence it being potentially more lightweight than any other type of capacitor.