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April 11, 2007


John F.

"It is also a good selling point to show that PHEVs and EVs can help lower our energy costs"

I don't think so. You're overlooking how expensive battery charge cycles are.

Today's lithium batteries are good for perhaps 1000 charge cycles, and cost between $400 and $1500 per kWh of capacity. Even if you assumed the low end of that range, and that you could get 1000 deep discharge cycles, the capital cost of a charge cycle is therefore a minimum of $0.40/kWh. In other words, every time you send electricity to the battery and retrieve it later, you're adding 40 cents/kWh to its cost. That's many times the difference between peak and off-peak electricity prices. You'd be selling at a huge loss even if you could charge the batteries with free electricity.

Some selling point. Batteries will have to drop in price by about 90% before this application makes any sense. Maybe we'll get there someday, but I'm not aware of any battery technology in the pipeline that comes close, with the possible exception of the shadowy EESU, if that ever realizes its hype.

No, Altair and A123 don't have a battery appropriate for this application. Their breakthrough is power density, not energy density or cost/Wh. They do claim more and deeper charge cycles, but not enough to make them economical for load balancing the grid.

These limitation in battery cost/capacity is the reason why today's hybrids are carefully engineered to protect their expensive batteries from premature degradation, making sure that they stay in the 60-85% charge range. No one in their right mind would plug it into the grid and let the power company wear their extremely expensive batteries out years before they otherwise would.


Well EEStor isn't that shadowy.
They got former IBM executives as their executives.

They got the same venture capital firm as Google, Amazon.com, and Ebay.

And their technology has been verified by multiple sources:



But yeah, you are correct. Cycle life just isn't good enough with NanoLithium. (Especially with A123, maaybe with Altair)


Link to the article

John F.

"Shadowy" probably isn't the right word. Connotes disreputability, which is not what I meant. Perhaps "opaque" is more apropos. Extraordinary claims require a lot of transparency to be credible. I agree that their list of big backers provides some credibility. On the other hand, the Kleiner Perkins quote I read did say they considered it a "high risk" investment.

I looked at the numbers for Altair and A123 again. I can't find a good number for charge cycles from A123, and I've seen multiple charge cycle claims for Altair, but if you accept the high numbers for them, they may have a PHEV load balancing application someday.


The above page says "10x cycle life vs. conventional Li-ion". But the sidebar says "over 1000 cycles". They don't say what they consider to be the number for "conventional Li-ion", but supposing it's 500, that's 5000 for A123. But why then claim only "over 1000 cycles"? Yes, that is "over", but it's a LOT over. Why wouldn't they write something more like "over 4000"? I suspect they wrote "1000" because there's some reason why they couldn't write a higher number there.

So they're probably out for load balancing. But Altair, if you accept the more optimistic claims of 15,000 charge cycles, could be a load balancing option if they could sell their packs for, say, $14,000 (about 3 cents/kWh).

I've seen that $14K dollar figure tossed around as a long-term target, but I haven't seen it from Altair, so that may simply be based on the optimistic assumption that they'll cost no more than the cheapest current lithiums.

Carl Hage

An interesting thread-- the amortized battery cost is often neglected in EV discussions. Based on approximate current prices, specs for the Tesla yield ~$.012/mile at the special PG&E EV night rate ($.021 regular off-peak), but battery cost comes out to about ~$.27/mile.

Still cheaper than gas for a Hummer or Lamborghini, but hopefully battery cost will go down by the time the packs need replacing.



A123systems promises 2,000 cycles for their DeWalt power tools. Power tools are a very demanding application, as they'll get run down to 0% charge at max discharge rates, and then up to 100% while still hot, and there's no cooling of any sort.

Automotive apps, where you can have sophisticated charge and temp management, should get much, much higher cycle life. I suspect they'll do 5,000 cycles easily at 100% discharge, and much more at lower levels - almost certainly they'll have leftover cycles at the end of the life of the car, making V2G attractive.


Tesla says their battery pack costs $400/Kwh. They estimate a minimum of 500 cycle life (and hope for much more), which gives $.80/kwh. At 215 watt-hours per mile (Tesla's spec) that's about $.17/mile for battery costs. At $.05/night-time kwhr, power costs about $.01/mile (as you calculated), for a total of $.18.


John F,

RE: "I've seen that $14K dollar figure tossed around as a long-term target, but I haven't seen it from Altair, so that may simply be based on the optimistic assumption that they'll cost no more than the cheapest current lithiums."

In ALTI's last conference call, Grotcher stated that current costs is about $2/wh. So the 35 Nanosafe would be about $70,000. Which is about right with all the contracts prices stated. They estimate through volume that the cost will be about $.33/wh. So the 35 Nanosafe than would cost $11,550. $14000 is a nice safe conservitaive number based on the previous statement from Grotcher that through volume the Nanosafe would cost about $400/kwh... so the 35 Nanosafe would be $14000.


Well even if A123 can get a paltry 5000 (rather than it's DeWalt 2000)

AltairNano offers 15,000 cycles :O

This one may actually do the trick.


Heh, reading that link even further.

15000 cycles just brings it down to 85% capacity.
Plenty of workhorse left in it after that :P

So maximum possible cycle life, who knows.
Maybe 90,000 something cycles :P

Energy Lover

Only the utility industry would look to the auto industry to help with Grid reliability.

I think this idea is generally cool, but it may lead to instabilities: shifting of peak loads, unreliable peaking, loss through inversion, etc. Hybrids have a good enough story on their own, lets not hang the utility industry around their neck.

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Batteries/Hybrid Vehicles