It's the Batteries, Stupid!

[vfx]

Traditional lithium-ion batteries have high discharge rates that are problematic for automotive applications.

http://web.archive.org/web/20071011123250/www.teslamotors.com/blog2/?p=39

Through the process of developing the Tesla Roadster and in previous ventures, we have really become experts in battery technology, particularly Li-ion. ...
There are several factors that affect Li-ion cycle life. Some are physical and are built into the cells at the time of manufacture and so they can’t be changed. ...

The other factors affecting cycle life are tied to how the cell is used. In particular:

Avoiding very high and very low states of charge. Voltages over 4.15V/cell (about 95 percent state of charge [SOC]) and voltages below 3.00V/cell (about 2 percent SOC) cause more stress on the insides of the cell (both physical and electrical).

Avoiding very high charge rates. Charging faster than about C/2 (two hour charge) can reduce the cell’s life.

Avoiding charging at temperatures below 0° C. (Our design heats the pack before charging at cold temperatures.)

Avoiding very high discharge rates. (Our pack has been designed such that even at maximum discharge rate, the current required from each cell is not excessive.)

 

[JRP3]

The quote says that lithium batteries have high discharge rates, and that it's a problem for automotive applications. If a cell can safely provide a high discharge rate, how is that a problem? You want a high discharge rate in an automotive cell, or more accurately you want a discharge rate appropriate for the demands of the system. You can use a small cell with a high C rate or a larger cell with a lower C rate, and end up with the same performance.

 

[ChargeIt!]

I have a feeling by high-discharge rate they meant to be referring to self-discharge rate (no load) ... and that would be in error too.

 

[PopSmith]

http://web.archive.org/web/20071011123250/www.teslamotors.com/blog2/?p=39

Here's the non-archive link: :biggrin:

http://www.teslamotors.com/blog/bit-about-batteries

 

[vfx]

Here's the non-archive link: :biggrin:

http://www.teslamotors.com/blog/bit-about-batteries

Yeah but that's Martinless...

 

[PopSmith]

Yeah but that's Martinless...

True...the formatting also doesn't look as good compared to the archived one you linked to.

 

[teslaspotter]

AH it is nice to see that Seeking Alpha at least knows of Stan. I like to think that it was because of the corporate response to his good work that EV builders started investigating Li-ion tech. I'd like to see Chevron try and pull out all the cell phone and laptop batteries off the market! lol!

 

[dpeilow]

DuPont introduces Energain li-ion battery separator; claims it boosts power 30%

 

[Iz]

DuPont introduces Energain li-ion battery separator; claims it boosts power 30%

The power vs. energy density reader comments notwithstanding, there will always be on-going improvements in battery performance. Given that, we should expect TM to incorporate something similar into the ESS pack for Model S and future Roadsters. That 230-mile pack should be closer to 300 by 2012. The 300 closer to 400.

 

[vfx]

Tesla predicted (and is in some ways relying on this)
http://green.autoblog.com/2010/08/31/lithium-ion-battery-prices-may-tumble-19-percent-in-2010-or-h/

 

[mt2]

Tesla predicted (and is in some ways relying on this)
http://green.autoblog.com/2010/08/31/lithium-ion-battery-prices-may-tumble-19-percent-in-2010-or-h/

Yes, but this is not the kind of price reduction we'd hope for. As oversupply diminishes and small players are driven out of the market, prices will climb back up. I hope that technology advances will keep pace so costs are reduced and prices will stabilize lower.

 

[Brent]

Tesla predicted (and is in some ways relying on this)
http://green.autoblog.com/2010/08/31/lithium-ion-battery-prices-may-tumble-19-percent-in-2010-or-h/

And then the NY Times comes out with this:

“Lithium ion, which clearly is the best battery technology today, is flat, completely flat since 2003,” Mr. Wilcke said last week at a gathering in San Francisco attended by executives from I.B.M. and Better Place, a Silicon Valley electric car infrastructure company.

I'm not sure what Wilcke means by "flat."

 

[vfx]

Batteries for Battery Powered Cars Are More Environmentally Friendly Than Expected

http://www.sciencedaily.com/releases/2010/08/100830120945.htm

Now, for the first time, a team of Empa scientists have made a detailed life cycle assessment (LCA) or ecobalance of lithium-ion (Li-ion) batteries, in particular the chemically improved (i.e. more environmentally friendly) version of the ones most frequently used in electric vehicles.

Researchers at Empa's "Technology and Society Laboratory" decided to find out for sure. They calculated the ecological footprints of electric cars fitted with Li-ion batteries, taking into account all possible relevant factors, from those associated with the production of individual parts all the way through to the scrapping of the vehicle and the disposal of the remains, including the operation of the vehicle during its lifetime.

The study shows that the electric car's Li-ion battery drive is in fact only a moderate environmental burden. At most only 15 per cent of the total burden can be ascribed to the battery (including its manufacture, maintenance and disposal).

The conclusion drawn by the Empa team: a petrol-engined car must consume between three and four liters per 100 kilometers (or about 70 mpg) in order to be as environmentally friendly as the e-car studied, powered with Li-ion batteries and charged with a typical European electricity mix.

 

[JRP3]

I'm not sure what Wilcke means by "flat."

I guess "flat" means vastly improved and much cheaper. Can he really be unaware of the advances in lithium technology? Maybe he needs to stick his head outside the lab once in a while.

 

[edo]

I'm not sure what Wilcke means by "flat."

The only way he can be right is if he means "prismatic" /tongue/. The acceleration of advances might be "flat" too.

 

[mt2]

Let's put it in context -

Mr. Wilcke’s team at the Almaden Research Center of I.B.M. in San Jose, Calif., is trying to develop a new battery technology called lithium air that could allow a car to go 500 miles on a single charge.

 

[eledille]

http://www.sciencedaily.com/releases/2010/08/100830120945.htm

vfx: very nice. I particularly liked the conclusion that running the electric car on 100% coal power only worsened its environmental impact by 13%, while running it on 100% hydro gave a 40% improvement. I.e. the electric car is better than almost any ICE even on 100% coal power, but on hydro, wind or solar, it has almost no environmental impact at all.

 

[bobw]

“Lithium ion, which clearly is the best battery technology today, is flat, completely flat since 2003,” Mr. Wilcke said last week at a gathering in San Francisco attended by executives from I.B.M. and Better Place, a Silicon Valley electric car infrastructure company.

The article is about how Moore's Law doesn't apply to batteries.

Because batteries are so closely associated with the computer industry some people assume batteries will improve in the same way that integrated circuit density doubles every 18 to 24 months.

He's saying that lithium ion technology improvement has leveled off. It's "flat".

Somebody clipped what Winfried Wilcke said just before that out of the article, destroying the context.

 

[edo]

vfx: very nice. I particularly liked the conclusion that running the electric car on 100% coal power only worsened its environmental impact by 13%, while running it on 100% hydro gave a 40% improvement. I.e. the electric car is better than almost any ICE even on 100% coal power, but on hydro, wind or solar, it has almost no environmental impact at all.

Interestingly, these numbers are very close to those Tesla came up with in their white paper. (If I remember correctly, they did 100% coal and national average mix)

 

[stopcrazypp]

The article is about how Moore's Law doesn't apply to batteries.

Because batteries are so closely associated with the computer industry some people assume batteries will improve in the same way that integrated circuit density doubles every 18 to 24 months.

He's saying that lithium ion technology improvement has leveled off. It's "flat".

Somebody clipped what Winfried Wilcke said just before that out of the article, destroying the context.

"Journalists" today like to do that. The more sensation the better. I guess it is the "blog" culture that affects that.

However it is true compared to the early years of li-ion (which is only 10-20 years ago), the improvements have leveled off. "Flat" makes it sound like it is no longer improving; in reality it still is improving with smaller slope. From Tesla's graph, cell prices really are basically flat, but cell density improvements are continuing (we have evidence from Panasonic's new cells).