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View Full Version : Plug-In Hybrids: What is the state of the art?


xcel
02-21-2007, 11:18 PM
Many challenges face the world’s automakers. (http://www.toyota.com/html/hybridsynergyview/2007/winter/plugin.html?url=readmore)

http://www.cleanmpg.com/photos/data/501/NREL_EnergyCS_PHEV.jpgToyota Motor Company - Feb. 21, 2007

EnergyCS’ PHEV capable Prius II - Not quite ready for the average consumer?

The idea seems simple enough: Just add a cord and a plug to a Prius so you can charge its battery on ordinary household electric current overnight. Then, use only the battery power to make the short round-trips to work, school or the store. That would save lots of gas, and the charging could be done mainly at night, when utility rates are cheaper. When driving longer distances, the engine kicks in and the vehicle operates on gasoline, much like today’s Hybrid Synergy Drive® vehicles.

This inspiring idea has caught the public’s attention as an energy-security measure that uses domestic and potentially renewable resources. Not surprisingly, it has prompted questions to automakers about when the first commercial plug-in hybrid can be expected. As the leading maker of hybrid vehicles, responsible for three out of four sold in the United States last year, Toyota receives many of these questions.

Toyota believes plug-in hybrid vehicles are an appealing technology offering possibilities for energy diversity. Depending on electric power sources, they may offer reductions in both emissions and fuel consumption. Reaching this vision, however, will require breakthroughs in battery technology, including capacity, durability and cost. At present, plug-in hybrid vehicles are not commercially feasible.

It’s about batteries

An earlier edition of Hybrid Synergy View pointed out that much of the “magic” that makes hybrid vehicles work involves high-voltage battery technology. Bill Reinert, national manager in the Advanced Technology Group at Toyota Motor Sales, U.S.A., says, “It all comes back to the battery. If you want to run longer and farther on electric power alone, it means a bigger battery. It means charging a battery more fully and discharging it more completely. And, it means provisions for cooling or ventilation in order to give the batteries longer life.”

“You have to decide what you want and what you’re willing to give up,” says Reinert. “A bigger battery might mean less space for passengers or luggage, for example. And a much more costly battery could mean a very long payback period for the investment in a fuel-saving plug-in system.”

So, Reinert concludes that a great deal of work is being done in storage battery technology, but much more remains.

Designing a system

Doug Coleman, advanced technology vehicle manager in Toyota’s Vehicle Operations Group, says a system that allows the driver to stay in electric mode is referred to as having AER, or “all-electric range.” He explains that this kind of system may not be the first one that reaches commercial production.

“To achieve the acceleration, highway speeds and hill-climbing abilities most motorists demand,” Coleman says, “an AER system might need not only a more powerful battery but a bigger motor and related electronics as well. This could make it uneconomical to produce -- too costly for mass distribution.”

“It’s possible,” he adds, “that a plug-in hybrid might use a blended system of plug-in battery power and engine power that doesn’t force the engine to be shut down. A car like that could use a less powerful motor and battery because its computer would engage the engine when more power is needed, much like a Prius does today.”

The blended approach, Coleman explains, could give the vehicle owner the fuel savings and the emissions reduction he or she is looking for without a lot of extra cost.

Other design challenges

Bill Reinert believes an effective plug-in hybrid system would not only have to be commercially practical, it would also need to be so reliable as to be warranted, like present-day Toyota hybrids, for up to 10 years or 150,000 miles. This, he states, would be especially challenging if the batteries were more deeply discharged, which could shorten battery life. He says a global company like Toyota must also make its system compatible with the variety of household electric currents and different electric receptacles and connections used worldwide.

No magic bullet yet

Reinert concludes that none of the plug-in hybrid systems thus far demonstrated by scientists and entrepreneurs meet all the challenges of commercial acceptability. Those challenges, he says, include size, weight, performance, durability and cost. But if these can be overcome, there may well be a bright future for the plug-in hybrid.

msantos
02-21-2007, 11:28 PM
Yep. That appears to be the common conclusion: Mass produced plug-ins are likely remain an unrealistic prospect.

Oh well...

Cheers;

MSantos

Pravus Prime
02-21-2007, 11:51 PM
Yep. That appears to be the common conclusion: Mass produced plug-ins are likely remain an unrealistic prospect.

Oh well...

Cheers;

MSantos


And the PHEV Saturn Vue?
:flag:

msantos
02-22-2007, 12:00 AM
And the PHEV Saturn Vue?
:flag:

Sorry for appearing to ignore the Vue and others...

I too read the numerous GM press releases as well as some of the analysts reports. However, I really would like the analysts to be wrong - at least this one time.

In any case, do you know what numbers is GM targetting for that platform?

Cheers;

MSantos

xcel
02-22-2007, 12:05 AM
Hi MSantos:

___The PHEV capable Saturn VUE DualMode is currently being tested with a 7 kWh Li-Ion pack (both the A123 Systems and JCI/SAFT packs are/have been installed) with ~ 50% of their available SoC for propulsion.

___Is that what you were asking about?

___Good Luck

___Wayne

msantos
02-22-2007, 06:20 AM
Hi Wayne;

No, I was referring to the projected production numbers. The biggest concern in some circles continues to boil down to this very simple metric.
So far, I don't think anyone is denying that these vehicles can be produced, instead the problem appears to be feasibility for mass production. For some, the supporting indicators just don't appear to be there, at least not yet. Fortunately, demand does not appear to be one of those indicators.

Anyhow... It would be really nice to be wrong. :)

Cheers;

MSantos

xcel
02-22-2007, 06:32 AM
Hi MSantos:

___Who knows? I do not believe GM has a clue as to the demand of the 08/09 Saturn VUE DualMode PHEV? The supply question looks promising however as A123 Systems already produce more then .5 million Li-Ion cel’s a month and can ramp that number up 2 to 3 fold in short order. With a 2 + year lead time, Cel supply should not be a problem but demand is a wild card depending on what GM charges for the state of the art system?

___I think GM will only warranty the DualMode PHEV pack for either 8 years/80K miles or 5 years/100 K miles following their current non-hybrid/hybrid warranty strategy. It is less expensive to forego PZEV status and avoid the 10 year/150K mile warranty in the clean states w/ a ULEV or SULEV rating. At least that is what I suspect GM will do?

___Good Luck

___Wayne

msantos
02-22-2007, 07:17 AM
Speaking of GM, here's another encouraging article:

http://autoshow.en.autos.sympatico.msn.ca/autoshow/cias2007/Article.aspx?cp-documentid=3042490


Cheers;

MSantos



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