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Toyota Hybrid X Concept
Don't expect any impressive MPG gains in the next generation Toyota Prius

Toyota's next generation Prius likely won't have the spectacular boost in fuel economy that was once expected. In late May, the Japanese newspaper Nikkan Koyogo reported that Toyota was considering nixing the idea of putting lithium-ion batteries in the next generation Prius. The newspaper stated that there were concerns within the company about the safety of lithium-ion batteries -- something that Sony is already well aware of.

The Wall Street Journal confirmed today that the next-generation Prius will not use lithium-ion battery technology -- at least for the first few years. The lithium-ion batteries that were to be used in the Prius would have been provided by Panasonic EV Energy Company.

The Prius will instead continue to use nickel-metal hydride batteries -- albeit in a higher capacity form to boost mileage over the current generation vehicle.

Toyota's decision to not use lithium-ion battery technology could be a big break for General Motors. GM has long been in Toyota's shadow when it comes to hybrid technology, but the company is looking to reverse its fortunes in the coming years.

The company has launched its new "mild hybrid" Saturn Aura Green Line sedan and is nearing the release of dual-mode hybrid Chevrolet Tahoe and GMC Yukon full-size SUVs. GM's coup de grâce, however, could be the upcoming Saturn Vue Green Line mid-sized crossover.

In 2009, the Saturn Vue Green Line will be equipped with a 2-mode hybrid powertrain and plug-in capabilities. Owners will be able to charge their vehicle overnight via a standard 110-volt outlet and drive 10 miles on fully charged lithium-ion batteries before the internal combustion engine takes over. In addition, GM says that its plug-in hybrid Vue Green Line is good for 70MPG.

All hope is not lost for the Prius in the quest for increased fuel economy. Current and future Prius owners can always look to third-parties to retrofit their vehicles with lithium-ion batteries. Lithium Technology Corporation has produced a lithium-ion battery pack (comprised of 63 LTC LiFePO4 cells) for the current Prius. When coupled with a plug-in system, fuel economy jumps from 46MPG combined to 125MPG.



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GOOD DECISION!!!
By buz9er on 6/14/2007 12:56:34 PM , Rating: 4
Guys, Toyota is totally right to continue using NIMH batteries over Li-Ion, for at least 3 VERY IMPORTANT reasons:

1- Batterie life: Li-Ion can loose up to 15-20% of their maximum energy capacity EACH YEAR... (Don't believe me? Look it up!) I don't want to have to buy new batteries every 2-4 years... My 2000 Prius still works flawlessly and has the same fuel efficiency as when I bought it...

2- Li-Ion battery are great for gadgets you're constantly charging up (like a cell phone you charge even if the battery's not dead yet), but they have another disadvantage: you cannot use their full capacity if you want to be able to reuse them: if you discharge a Li-Ion cell completely, there's a good chance you will never be able to charge it again; this is known as "deep discharge state". That is why you usually have to stop draining power from a cell when the voltage drops.

3- Li-Ion batteries are very sensity to temperature, especially concerning permanent capacity loss: the higher the non-operating temperature is, the higher the capacity loss is... any idea how hot your car gets when parked in the sun? ;)

The main thing here is that Toyota decided to use a more durable and more dependable battery technology, and every one should be pleased. Not that new cell technology will never be used, only that NiMH was the better choice here :)




RE: GOOD DECISION!!!
By DEredita on 6/14/2007 1:59:07 PM , Rating: 2
Also, it could be that Toyota doesn't want to risk a major recall if the Li-Ion batteries have issues. Toyota is looking at what can be a major expensive engine recall campaign with their Tundra series. They've had at least 20 trucks have their camshafts snap, this requires that the entire engine be replaced. They'll most likely land on their feet after the Tundra, but I doubt they could afford another fiasco like it.


RE: GOOD DECISION!!!
By DLeRium on 6/14/2007 2:40:43 PM , Rating: 1
I suggest you do a little reading before talking about NiMH batteries and Li-Ion. Li-Ion is the high end of all rechargeable batteries. They are not prone to the "memory effect" at all. NiMH batteries are. With that said, EVERY rechargeable battery loses a bit of their total charge each time they are charged. Don't believe me? It's simple physics. You're going to be depleting something everytime. There's no free unlimited energy.

Li-Ions are used in laptops, cell phones, ipods, etc, and they are damn expensive. NiMH's performance isn't any better either.

The fact is I'm sure Toyota is addressing these issues, and there are plenty of concerns over rechargeable batteries.


RE: GOOD DECISION!!!
By Madzombie on 6/16/2007 5:20:05 PM , Rating: 2
Lithium Ion batteries lose their capacity over time, even if not in use. They also lose their capacity much faster at higher temperatures. I saw a site somewhere that compared capacity drops of Li-Ion batteries after 12 months when stored at different temperatures. The most extreme example was a battery kept at 60 degrees C and fully charged. It went down to ~70% capacity in 3 months. If you live in a hot climate and drive a lot (heat is still produced by the engine even if it's an efficient electrical one) then the Li-Ion batteries will need replacing after only 2-3 years. NI-MH batteries often last much longer than this. Not only is battery replacement an additional cost, it's also terrible for the environment, as all the waste Li-Ion batteries need to be dumped somewhere or recycled (not sure if this is even possible).


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