This isn't a big deal, since the basic properties of all these battery chemistries are known. My understanding (and I am open to correction if I am out of date) is that of the commercialized rechargeable batteries, the lithium-ion ones leak least, the NiCADs next, and the NiMH the most of all. But the lithium ones cost the most, the NiMH the next, and the NiCADs least. Of course all of that may change in the future. (The so-called rechargeable alkalines are out of the running for a variety of reasons.) The lithium batteries can also store the most energy per unit volume (or unit weight), making them a good choice for hybrids, except for cost. In fact, for today's hybrids (and I have a newly acquired Ford Escape, so not much experience with it), neither capacity nor leakage is very important (up to a point, of course), because the batteries are being constantly recharged. The basic advantage of the hybrid is that the electric motor is available to give a torque boost when you need it, making it possible to install a smaller, faster running, and more efficient internal combustion engine than would otherwise be compatible with the performance we American drivers demand. Other benefits (like regenerative braking) follow once you've gone that route, but it is the small fast efficient IC engine that is most important. Am I wrong?

Hal

 

The lithium batteries can also store the most energy per unit volume (or unit >> weight), making them a good choice for hybrids, except for cost.

Well many of the posts here are about folks trying to stay in EV mode longer. Reasons for not being able to are, traffic patterns, terrain, and oops, time to regen via the ICE. Longer times between regen cycles means more EV avalability for the folks who have the ideal conditions.

The assist helps in getting the sticker mpg but EV mode gets you higher. There are times where I could have gone an additional 2 miles or so in EV but the ICE kicked in.

 

A bigger/lighter battery wouldn't change that, unless it was large enough to always be charged from coal-burning power plants . And in that case, you'd really have an electric vehicle rather than a hybrid, and probably a very polluting one at that.

I think the Ford team did a good job with all the various compromises. I admit I'd like a more powerful traction motor, one that could supply power beyond 40 mph, and a bigger battery so that I could make more use of EV mode, but those things would cost more and/or weigh more. And, of course, a bigger battery would need the engine to run more or harder to charge it.

 

Check this out:

"Researchers at MIT have developed a new type of lithium battery that could become a cheaper alternative to the batteries that now power hybrid electric cars. "

http://www.innovations-report.de/htm...cht-55384.html

 

I never implied a bigger battery, just a more efficient lighter battery. More capacity relates to the charge it can hold and not the size. Hardifeh's link shows that.

Now time to Google for the carbon nano-tube technology I was describing to to recapture leakage.

 

Yes, I assumed that you meant bigger capacity. And I don't think that increased capacity will do much until it is so high that we can just plug it in and dispense with the gasoline engine.

 

Geeked out for 15 minutes and this is what I got. Read up...I think this may be the next wave until something better comes along.

Okay, a NASA description
http://www.grc.nasa.gov/WWW/RT2001/5000/5410hepp1.html

Hmmm, storage increases utilizing ultracapacitor configurations with nanotubes
http://web.mit.edu/newsoffice/2006/batteries-0208.html

A Primer with references to this
http://www.ciwmb.ca.gov/WPW/Power/ElectricStor.htm

more from MIT
http://www.greencarcongress.com/2006...rbon_nano.html
http://www.sciencedaily.com/releases...0216232807.htm

A more Environmentally friendly solution being greenlighted for development acceleration (basically, a non-cobalt solution)
http://www.azonano.com/news.asp?newsID=1486

Whoa, more tech with pics
http://nano.anl.gov/ADC2005/pdfs/abs...DC0117_Yap.pdf

Wonderfully geeky whitepaper UNC on how to make the best nanotubes for this application
http://www.physics.unc.edu/~zhou/mur...L.abinitio.pdf

More, another article stating that this is the way to go
http://www.sciencedaily.com/releases...0118094512.htm

 

Well, think of it this way...the capacity increases, it can be quickly recharged, increased power means smaller ICE engine is needed (20hp?) which runs much less since it's only need is to recharge and it can run at full capacity, which an ICE is most efficient, thus maximum fuel savings without being a plug in EV vehicle.

 

I just don't think that works. For one thing, a high-speed highway trip will still require a decent sized gasoline engine--a bigger one, actually, if the battery is actually heavier and the traction motor bigger, etc.

I just don't know if a bigger capacity battery will make a big difference in a hybrid. It will make a huge difference in a pure electric vehicle, but I think we face diminishing returns with hybrids as far as battery capacity goes.

 

And by then we'll be back to burning coal or gas or (even worse) oil, to get the electricity to put into our cars to avoid burning oil.