Electric cars are a pipe dream

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I think he's trying to make a point that we don't have to compromise on size and comfort, but it's not a great one. It only makes 40mpg over a short distance that that's only because it uses the grid to initially charge it's batteries. On long trips it makes 20mpg, which is fantastic for a 1959 Lincoln.
 
Skeptical said:
... However, battery technology is improving dramatically. I have posted references showing :
1. Lithium batteries can be made with ten times the energy storage of current models.
2. Lithium batteries can be made that recharge in minutes
3. Lithium batteries can be made that retain their ability to store energy for at least ten years.
In 20 years we will have lithium battery operated EV's that combine all three. ...
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Skeptical said:
... reference for higher capacity was post 367....
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There you read:
"Researchers at MIT have found that using specially treated thin layers of carbon nanotubes in batteries can boost the amount of power delivered per unit of weight by up to ten times. ..."

That is not energy storage up by factor of 10. (Your prediction 1.) I admitted and explained that getting charge and discharge rates much higher (Your prediction 2.) is possible* because they are roughly proportional to the surface area on very tiny scale. Porous electrodes or in this case nanotubes can greatly increase the active area compared to the gross scale area of the electrode plates.

Higher POWER is a statement about the discharge rate, not the density of energy storage. I strongly doubt that will ever even be doubled. Probably a 50% increase is beyond reach.

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* Sustained high power is not ever going to be increased much as heat is produced during both charging and discharge. Lots of mico-scale surface are will let driver get a great burst of power for passing etc. but not for rapidly climbing a long hill.
Billy T said:
{post 509} Perhaps 3 did not really mean it could store energy for 10 years, but intended to say it could be used to store and discharge energy for 10 years. I was predicting that no battery (or capacitor, for that matter) has such a low self discharge rate that it can store energy for 10 years. Hell even gasoline would get very "gummy" in that time and be nearly useless.
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Billy, I'm not so sure of your interpretation of this, but I'll do some research before saying so, but remember improper use of physics terms are often made by journalists.

BUT

Your point about the discharge rates seems to be off.
My 12V starter battery in my car will discharge enough current to weld metal if one shorts the positive terminal.

Similarly a Lithium battery can discharge so much current that it can generate sufficient heat to set things near it on fire if shorted.

I can hardly see someone claiming any kind of breakthrough for achiving what is already possible with these batteries, very high rates of discharge.

Arthur
 
adoucette said:
...
Your point about the discharge rates seems to be off. ...
I can hardly see someone claiming any kind of breakthrough for achieving what is already possible with these batteries, very high rates of discharge. Arthur
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I think you did not understand my point. Certainly one can briefly get huge power out of any battery with low internal impedance. For example a lead/acid car battery. They come rated with a "cranking capacity" (current or power, I forget) stated. What this is telling your is that for something like 5 to 10 seconds you can pull that power level out, but if you pull it out for 100+ seconds the heat will damage if not destroy the battery.

I tried to make this point clear by telling that more fine scale plate area would allow greater power in a burst, say for passing another car, but not for rapidly climbing a long hill.

I bet a fully charged 12V car battery shorted out by moderately heavy* copper jumper making solid contact with the battery terminals can deliver 100Kw for 0.1 seconds. I.e. deliver 10,000 Joules, which may be enough to melt the copper jumper.

Note, there will be something like 10,000 Joules of heat created in the battery too and it will be very concentrated near the plate and probably seriously damage the battery. If you use #0 wire or larger, and keep it well connected, you can destroy the battery in 10 seconds. I am just making up these numbers to illustrate the point that it the power time product that is heat limited. In most non-liquid electrolyte batteries it is the internal impedance that limits the power output level. (To make that the max power possible, the "short" / "load" should have the same resistance as the internal impedance. If it has less, then more than half of the chemical energy released will produce heat inside the battery.)

* Say #10 wire.
 
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Thanks, and I know that you can't sustain that kind of draw without damage, but that's my point, people really aren't trying to come up with ways to increase discharge rates, they are trying to come up with ways to increase battery storage capacity per unit of weight.

And if you go to the actual article, that's exactly what the seem to be claiming.

http://www.nature.com/nnano/journal/v5/n7/abs/nnano.2010.116.html

The electrode, which is several micrometres thick, can store lithium up to a reversible gravimetric capacity of ~200 mA h g−1 electrode while also delivering 100 kW kg electrode−1 of power and providing lifetimes in excess of thousands of cycles, both of which are comparable to electrochemical capacitor electrodes.
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Arthur
 
adoucette said:
... they are trying to come up with ways to increase battery storage capacity per unit of weight. And if you go to the actual article, that's exactly what they seem to be claiming.
http://www.nature.com/nnano/journal/v5/n7/abs/nnano.2010.116.html
Arthur
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I don't think they are claiming that at all. What they are claiming is with porous electrode structures they are getting closer to capacitor discharge rates. They did not say anything about the Joules / Kg storage. One thing mentioned in the free part of the paper was:

"{Improving} power output of lithium batteries by reducing lithium-ion diffusion distances." Let me tell more about this:

As there is an electric field near the electrode surface, it would be better to speak of the "reducing lithium-ion drift distances" not diffusion, but forget that terminology quibble. Reducing that distance is important as it will reduce the heat produced. I.e. as the ion drifts towards the electrode it is making many collisions and that is transferring energy it gained from the electric field to neutral atoms. I.e. some of the field’s energy is being converted into heat and a shorter drift distance will reduce the heat produced for each electron collected on the plate (or each ion neutralized on the other plate).

SUMMARY: although not speaking of the energy density, they are telling that their electrode will let you get a given high power level out longer before damage occurs. Stating this another way: They are working to let you get rapidly farther up the long hill before the self monitoring system turns down the output power to avoid battery damage.

BTW, we agree that increasing the energy storage density is the real goal, but as I stated earlier, without proof, doubling it is impossible and probably a 50% increase is beyond reach.
 
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Thanks,
I think you are right.

Found this rather simple explanation:

Definition of Energy Density and Power Density

Energy Density (Wh/kg) is a measure of how much energy a battery can hold. The higher the energy density, the longer the runtime will be. Lithium-ion with cobalt cathodes offer the highest energy densities. Typical applications are cell phones, laptops and digital cameras.
Power Density (W/kg) indicates how much power a battery can deliver on demand. The focus is on power bursts, such as drilling through heavy steel, rather than runtime. Manganese and phosphate-based lithium-ion, as well as nickel-based chemistries, are among the best performers. Batteries with high power density are used for power tools, medical devices and transportation systems.

An analogy between energy and power densities can be made with a water bottle. The size of the bottle is the energy density, while the opening denotes the power density. A large bottle can carry a lot of water, while a large opening can pore it quickly. The large container with a wide mouth is the best combination.


http://www.batteryuniversity.com/partone-5A.htm

Arthur
 
Ford will have the all electric Focus available in 2011 for the same price as the regular focus.
 
adoucette said:
GM is slated to start production runs of the Volt in November. They recently changed their Battery Range estimates to "25 to 50" ...
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Nissan's Leaf, already available but in the US when Volt starts to make, has a sticker price of $32,780 But after a federal tax credit of $7,500, the car will only set you back about $25,280. It will travel about 100 miles, but then needs to be where it can recharge as there is no on board gasoline engine generator.

BYD's F3DM, a plug-in hybrid promising about 60 miles of all-electric range and selling for around $22,000, was first offered to fleet buyers in late 2008.

It seems to me that the volt tried for two markets and will get none. I.e. If you want a second car to use in the city, buy the Leaf and save more than $8,000 up front expense. If you want a first car to occasionally make loger tirps in buy BYD's F3DM and save much more (not sure if the $2200 is the sticker price, but think it is) and go farther in the all electric mode in the city.
 
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The Volt will be on the US and European markets one year ahead of the F3DM, but certainly if those prices hold true the volt will have little market penetration after that.
 
Billy T said:
Nissan's Leaf, already available but in the US when Volt starts to make, has a sticker price of $32,780 But after a federal tax credit of $7,500, the car will only set you back about $25,280. It will travel about 100 miles, but then needs to be where it can recharge as there is no on board gasoline engine generator.

BYD's F3DM, a plug-in hybrid promising about 60 miles of all-electric range and selling for around $22,000, was first offered to fleet buyers in late 2008.

It seems to me that the volt tried for two markets and will get none. I.e. If you want a second car to use in the city, buy the Leaf and save more than $8,000 up front expense. If you want a first car to occasionally make loger tirps in buy BYD's F3DM and save much more (not sure if the $2200 is the sticker price, but think it is) and go farther in the all electric mode in the city.
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Ah, the Leaf is not yet available.
Nissan was supposed to start making them (in Japan) this month, but the first ones to US buyers will not be until December. Because of the Recharging infrastructure, which the GM Volt does not need, the Leaf is going to be targeted to just a few markets to start with, Washington, Oregon, California, Arizona, New York, Massachusetts, southern Florida and Tennessee. Where they got a grant from the US gov to subsidize the building of a lot of charging stations. The Leaf rollout to the US market will be slower because of the need for this support structure.

I personally think the GM Volt style technology will ultimately find more buyers, but early adoption figures should generate a lot of buyers for both cars.

Arthur
 
ElectricFetus said:
The Volt will be on the US and European markets one year ahead of the F3DM, but certainly if those prices hold true the volt will have little market penetration after that.
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Not so sure. (From Wiki)

Since March 29, 2010, BYD Auto began selling the F3DM to the general public in Shenzhen, Guangdong Province,[5][6] but only 28 units were sold during the first three months and all were sold to the Shenzhen local government.[21] Among the reasons cited for the slow sales are the lack of infrastructure to charge, the high battery cost, and also the batteries have been reported to be unreliable.[21]

Selling a Chinese car into the US market will require quite a bit of support infrastructure.

Arthur
 
adoucette said:
Not so sure. (From Wiki) Since March 29, 2010, BYD Auto began selling the F3DM to the general public in Shenzhen, Guangdong Province,[5][6] but only 28 units were sold during the first three months and all were sold to the Shenzhen local government.[21] Among the reasons cited for the slow sales are the lack of infrastructure to charge, the high battery cost, and also the batteries have been reported to be unreliable.[21]

Selling a Chinese car into the US market will require quite a bit of support infrastructure. Arthur
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I suspect that main reason why not selling well in China is their relative high cost, say compared to a Cherry car. The leaf is the one needing recharge stations and when the BYD hybrid does come to the US it will probably mainly sell in states the Leaf has establised recharge stations; but like the volt it can run on gasoline.

Cherry is soon building a plant in Brazil (for 100,000 cars/ per year as I recall). They already have a much smaller one in Argentina. I suspect it will be some years before you can buy a Cherry in USA.

BTW I don't understand wiki's comment about high battery cost - it is part of the car's price, is it not. Did you look at Wiki's Ref. 21"? The one casting doubt on BYD's batteries? They are the world's largest and most experienced maker of Li-ion batteries. If they can't make them last, who can?
 
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As to the reliability, I did check before, but the link didn't offer any more details than was in Wiki, but that might also be related to the high price of the battery issue. If it doesn't have a good warranty, then its cost is a factor.

Arthur
 
adoucette said:
As to the reliability, I did check before, but the link didn't offer any more details than was in Wiki, but that might also be related to the high price of the battery issue. If it doesn't have a good warranty, then its cost is a factor. Arthur
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Thanks, but my real interest is who is the link as I did not expect them to tell any hard data - how could they unless they are Chinese in China and servicing cars. I suspect that it an unfounded smear. (It is not just politicans that do that.) For example does the link have any connection to Chevy and the Volt?
 
The link from Wiki was to China Economic Review.
I don't think there is any connection to the Volt, besides, none of these car companies can make nearly as many cars as there are demand for them.

Leaf cut off its registration process at 20k, but they had said earlier that their first year production was only going to be around 5,000 cars.

I think they want to evaluate the car in day to day use before they commit a lot of them to the market.

Arthur
 
adoucette said:
The link from Wiki was to China Economic Review.... Arthur
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Thanks again. Here is their site: http://www.chinaeconomicreview.com/
and it has a search box in which I entered "BYD batteries"
Got a lot of hits, most recent ones about Warren Buffet's visit, but there was one that had "batteries reported to be unreliable" However when you open the article there is not a word about that. I am giving up, but still have doubts there is anything factual about what may be a slur.
 
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