I believe Ni-MH batteries do a fine job for non-plug-in applications with fewer cost & cooling complications.

 

^^ yeah I'd assume cost is the biggest reason

 

first all of all, all of the info in that article is just made up anyway.

as to the nimh vs lion in general, i am not sure... everyone is saying that battery is lighter and smaller a lot but all these lion hybrids are heavier and use more space than Toyota Hybrids with nimh.

You could probably get some improvements but question is how for how much. For instance in Prius v for Japan and Europe, they use Li-ion batteries and MPG is exactly the same. On the other hand, GS450h with nimh batteries has 8hp less battery output than M35h with lion. So is 8hp a lot? Maybe.

Positive for nimh is that they are really, really, really reliable. Li-ions are unknown quantity.

At the same time, Toyota is buying lithium ore mines around the world right now, so the switch is coming eventually... they may invent different chemistry for the battery before they start using it though.