I have read that Li-Ion EV battery systems have a
shorter lifespan (6 to 10 years) than the current
NiMH EV battery sytems.(10-20 years) . For example,
HyMotion's Plug-in Add-on Li-Ion EV battery
system to the Prius II (2005-2009) is rated for
only about 6 to 8 years before it must be replaced.
Toyota's NiMH EV traction battery system is
warranted for 8 years but reports that I've been
reading suggest it is engineered to last atleast
20 years and upto 300,000 miles. The key to
NiMH EV battery lifespan technology is the
computer managing the NiMH battery's power
levels and recharging process. I've read that
NiMH and Li-ion battery recharging characteristics
are different so the same methodology that
has been able to extend the life of the NiMH
EV batteries would not work for the Li-Ion EV
batteries. It is this same lifespan-warranty
Li-Ion EV battery technical challenge that has
been holding up the introduction of the Chevy Volt.
I would be interested in knowing whether
Toyota has solved this *reported* technical
challenge given the new battery chemistry.
I'm just happy I got a 2004 Prius after reading that. :)