Current hybrid car batteries are made from nickel metal hydride batteries(NiMH), but carmakers are saying the next generation of hybrid batteries will be made from lithium-ion(Li-Ion). They also say the next step in hybrid cars will be plug-in hybrid vehicles (PHEV) that can be plugged in overnight and can run on electric power alone (i.e. off the battery pack) for up to 40 miles at a time.
Why Switch to Li-Ion Batteries?
But why do they need to switch? There are several reasons:
A Li-ion battery weighs about half as much as a NiMH battery. That can add up to big fuel economy gains for a hybrid car. Weight can be more telling on a mpg rating than almost any other factor thrown into a car.
Cost is also a big factor. Nickel futures on the London Metal Exchange is over $36,000 a ton. That's down from a high of $51,800 in May. Lithium has risen to about $8,000 a ton in March. That number will climb once hybrid cars start using Li-Ion batteries in large batches, but for now that's quite a difference in price.
Lithium is also abundant in Chile (currently the main supplier), North America and Russia. And, according to stories I've seen, there's still some unexploited regions with plenty of reserves.
Why haven't they switched, yet?
So, given Li-Ion batteries are more powerful, weigh less and are cheaper to build, why haven't they started building them, yet?
Lithium-ion batteries are currently found in smaller packs in laptops and cell phones. But researchers at big and small battery companies are still researching the most reliable, and more importantly, the safest way to put several batteries together to make a large enough battery pack to power a hybrid car. You've heard about how Sony had to recall some laptops for combusting, right? Now imagine that happening in a hybrid car.
What about lead?
It's good enough for my gas car, why isn't it good enough for a hybrid?
Lead seems to be out of the running. The heaviest of the three choices, it seems to be eliminated from the running before it has even gotten started.