The lowly capacitor and AFS Trinity

http://afstrinity.com/company/milestones.htm

Two notable milestones:

Plug-in Hybrid Program Milestones
AFS Trinity Power has developed patented technology that makes it possible for plug-in hybrid electric vehicles to achieve 150 MPG, go 40 miles in all-electric mode, and use gasoline for additional unlimited miles in hybrid mode. Below are various plug-in hybrid program milestones along the way.


November 17, 2008 - AFS Trinity Power Corporation reported independent test results demonstrating that the company's "Extreme Hybrid" technology that utilizes batteries in combination with ultracapacitors will enable a plug in hybrid vehicle using the system to have a useful life that is 6 times greater than plug ins that use lithium batteries alone -- 150,000 miles for an AFS Trinity Extreme Hybrid versus 25,000 miles for a conventional plug in hybrid that uses lithium ion batteries alone. (Press Announcement I Related New York Times Article in PDF)

Lithium ion batteries, properly managed, can easily
achieve 1,000 full charge/discharge and many more
not-so-deep cycles. The stated range of the upcoming
commercial EVs is something like 75 entirely-reasonable
miles. This makes the lifetime of the lithium battery
at least 75,000 miles and quite likely, a lot more.

Plus, what the ultracapacitor does for you is allow
very fast capture of the electricity that is regenerated
when the car suddenly slows down. In stop-n-go traffic,
this is a very useful thing as it means you won't be
discharging and recharging the battery for each small
start-n-stop; instead, you'll be charging and discharging
the ultracapacitor and while it doesn't store a lot of
elecricity, it's lifetime (for our purposes) is essen-
tially unlimited. But on the highway, where you're
simply constantly running at more-or-less the same
speed, at most, coasting from time to time, the
ultracapacitor won't be any advantage.

Tesha

The batteries were severely under-estimated on useful lifetime.

The traction battery in the Prius is a relatively small Nickel/Metal-Hydride
battery and the hybrid drive control computer manages its charge over a
very narrow range of values, something like 40 to 60% of full charge at
all times. So that battery is living a battery's version of the Life of Riley,
ideal for a long, long life.

By comparison, the batteries in EVs will be a different chemistry (Lithium-
based) and will be subject to much larger charge/discharge cycles (perhaps
100% down to, occasionally, 20 or even 10% and then back again. That's a
much more-stressful life for a battery but I still have confidence that the car
control systems will manage to get a good life out of the battery packs.

Tesha

I forgot the Prius was NiMh, not Li