[KariK]

Just saw an article in Car and Driver:
http://www.caranddriver.com/reviews.../concept_central/2011_chevrolet_volt_car_news
where they interviewed Larry Burns:

"Second-Gen Work Under Way
Meanwhile, Burns says work is already under way on the second generation. He declines to give a timeframe."

So now we get to start dreaming about that as well. I know what I want: bigger electric motor, same battery capacity but smaller size so a 5 person car, and a more efficient, cheaper ICE/generator combo, leading to a cheaper, more powerful car.

 

[Jason M. Hendler]

The ICE / generator is already cost reduced, as ICE's have been manufactured for decades, as well as generator / alternators, so I don't see much progress there.

The greatest cost reduction will be in both the capital and recurring costs of batteries. You will pay less for them, and they will save you more and more money by displacing petroleum.

 

[Koz]

Yes, batteries, Power Electronics, and perhaps motor are low hanging fruit. I thought they should have been designing the E-Flex with a more powerful motor from the start. They could have still kept the same performance in the Volt and just not use all of the power. This would result is slightly better efficiency for hard acceleration plus they could scale it up for more vehicle types as well as high performance versions. I don't think there is much downside to a 160KW motor.

 

[KariK]

I quite agree, Koz. Jason, I hope there are new ways to integrate the ICE and the generator, like a micro-turbine or an ICE where the generator coils are around the ICE pistons, which have magnets in them. Once there is a market for hundreds of thousands of units, there will be enormous pressure to bring costs down. I think right now the Volt ICE is a normal car ICE. In the future it needs to be integrated into the generator, somewhat different technology, isn't it?

 

[KariK]

Another thing GM could do is to shrink the battery pack size. If it is true that A123 has verified 7000 FULL cycles and has 87% capacity at 3500 cycles or ten years with a cycle per day
(http://www.a123systems.com/#/applications/phev/pchart2/),
that should be more than enough for ten years. So just change to a 12 kWh battery and run it between 10 and 2 kWh. You have (at least) the same range, but the car will be cheaper and lighter. In addition it will need less room for the batteries so please make it a 5 passenger car.

 

[Koz]

Another thing GM could do is to shrink the battery pack size. If it is true that A123 has verified 7000 FULL cycles and has 87% capacity at 3500 cycles or ten years with a cycle per day
(http://www.a123systems.com/#/applications/phev/pchart2/),
that should be more than enough for ten years. So just change to a 12 kWh battery and run it between 10 and 2 kWh. You have (at least) the same range, but the car will be cheaper and lighter. In addition it will need less room for the batteries so please make it a 5 passenger car.

I have been advocating allowing the driver to override the default lower SOC limit per drive when needed, but GM has to be careful hear. It's a little more compicated than the charts show, so expanding the useable battery % on a daily bases may cause issues for longevity (although 2 to 10 for A123 12kWh pack might be OK). Also, this is not practical in mountainous terrain. Coming upon a large climb with only 2KWh left in the pack is going to cause performance limitations a lot of times.

 

[RRRB]

Why 2 mode?

In the Car and Driver article, Burns is quoted as saying "For larger vehicles, GM’s two-mode hybrid system makes more sense. " Why would that be the case?

 

[Koz]

In the Car and Driver article, Burns is quoted as saying "For larger vehicles, GM’s two-mode hybrid system makes more sense. " Why would that be the case?

I think what makes more sense is that GM wants to believe that given the state of today's commercially available batteries, the larger vehicles are best addressed with two-mode hybrid. I don't know if this is accurate, but GM sure has a large investment in two-mode technology. The power requirements of large SUV's are much greater than small cars, especially when towing is factored in. With the power rich A123 cells, 2 motors, and a genset; I think they could make it work for not much more than the two-mode tech costs. What bothers me more is that minivans were lumped into this category. Minivans do not have such tremendous power needs. All that I think it would require to adapt the Volt's E-Flex drive train for a minivan would be ramping up the power electronics and motor to 160-180KW as well as adding 3-4KWh to the battery to keep 40AER (or leave battery capacity and settle for less AER). This is may be too costly for 2010 but should be doable in 2012-2013 timeframe.

 

[KariK]

Li-Ion + supercaps

Here is some more info on the second generation batteries:
http://www.greencarcongress.com/2008/05/gm-exploring-su.html#more

"General Motors is actively exploring the concept of combining supercapacitors and lithium-ion batteries in a next-generation energy storage system (ESS) for its E-Flex series of extended range electric vehicles (EREV).