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GM Unveils Second Propulsion System for Chevrolet Volt: A Fuel Cell Variant

Cutaway drawing of the Volt fuel cell variant. Click to enlarge.

At the Shanghai Auto Show, GM unveiled a second propulsion system for the Volt concept under the aegis of the E-Flex electric drive family: a hydrogen fuel cell variant that uses GM’s new fifth-generation fuel cell system as its primary power source.

This second variant of the E-Flex system combines the new 80 kW fuel cell stack with an 8 kWh (50 kW peak power) lithium-ion battery to provide up to 300 miles (483 km) of petroleum- and emissions-free electric driving. The Volt fuel cell variant is plug-in capable, adding up to 20 additional miles (34 km) of range each time it is charged.

The two Volts, battery-dominant with ICE range extender on the left, fuel-cell centric on the right. Click to enlarge.

Unlike the first Volt propulsion system, which is battery-dominant with a small combustion engine range extender, the second system is fuel-cell centric, and uses a blended operating strategy to augment its range and power with a battery pack that is half the size of that in the first Volt.

A different configuration under E-Flex in which a smaller fuel cell would function as the range extender to a larger battery pack is also possible. (This is the approach Ford took with its HySeries concept. Earlier post.) However, this is not the design that GM implemented in the second variant of the Volt.

The E-Flex system is a flexible all-electric production vehicle architecture that can be configured to run on electricity from a number of sources.  It was first shown in January at the North American International Auto Show in the Chevrolet Volt concept vehicle. The first Volt concept is a plug-in series hybrid electric vehicle that has a 40 mile all electric range and uses a small bio-fuel engine with a generator to extend its range to 640 miles (1,030 km). (Earlier post.)

We think electrically driven vehicles are really going to be a big part of the solution to the energy and environmental challenges that our vehicles face.  We’re talking about purely electrically driven vehicles, not a hybrid, not mechanically driven.  And this really sets the stage for diverse energy sources in simpler vehicles.

When we talk about electrically driven vehicles, we're really talking about what GM calls E-flex.  It has a common drive architecture, electric drive component, and electric drive architecture.

The key is to be able to create and store electricity onboard the vehicle, and you can store electricity obviously by plugging the car in and storing electricity in a battery.  And you can create electricity by running an engine generator or by using a fuel cell.  So the key enabling technologies here are engines and generators and batteries and fuel cells and hydrogen storage and the plug in capability that they offer.  And then because electricity and hydrogen can be generated from a range of energy sources, we can have all that diversity with a very simple, common E-flex electric drive architecture, so that really helps from a business standpoint. 

—Larry Burns, GM Vice President Research & Development and Strategic Planning

The fuel cell variant shares many parts with the first version of the Volt, such as the front electric drive component.

The 5th generation fuel cell system in the Volt. Click to enlarge.

GM’s fifth-generation fuel cell system is half the size of its predecessor, and provides the same power and performance. The fourth-generation system currently powers the Chevrolet Sequel concept vehicle. To double the specific output of the fourth-generation system, GM worked with different material sets and then improved efficiency and improved yield from each square inch of material inside the cells.

Our improvements are in management of all of those gasses and the water flows, [and] the selection of the materials to make that whole membrane electrode assembly center. It’s a system. The real key is in the controls.

—Larry Burns

The Sequel stores 8 kg of hydrogen and delivers a range of 300 miles (483 km). The fuel cell Volt—a lighter vehicle—will also deliver a range of 300 miles, but with only 4.0 kg of hydrogen (75 miles/kg) stored at 10,000 psi in two Type IV tanks.

The front drive motor offers a maximum 70 kW of power, with 250 Nm (184 lb-ft) of torque. The Volt fuel cell variant also showcases GM’s two third-generation wheel hub motors, packaged inside the rear wheels to add torque for all-wheel electric drive capability. The new motor technology reduces mass and produces more power (25 kw and 500 Nm /368 lb-ft per motor) compared to the first generation shown in 2003.

The fuel-cell Volt accelerates from 0 to 60 in 8 to 8.5 seconds, and has a burst top speed of 120 mph, with a continuous top speed of 100 mph.

A variety of other technological advancements and lightweight materials contribute to the efficiency of the Volt. With an estimated curb weight of 3,500 pounds (1,588 kg), it weighs 30% less than the Sequel. The fuel cell propulsion system is packaged entirely under the hood and is equivalent in size to a four-cylinder engine with automatic transmission.

The Volt also features molded GE plastic panels on the fenders, window glazings, instrument panel and steering wheel, which offer between 30% and 50% weight reduction per part. The car is fitted with low rolling resistance tires.

The global economy is going to grow 3% or 4% per year, and there’s a correlation with that economic growth to the demand for energy growing at about 2% per year. 

You know you compound 2% over 10 years, that’s 25%.  That puts you right in the range of the efficiency gains that you get from a hybrid, right in the range of what it would be energy efficient-wise versus a gas engine, and right in the range of what most people think can be teased out of the internal combustion engine going forward.  So we really need to look at alternatives in addition to just efficiency improvements to solve this problem.

So we really think now is the time to face the reality.  We have to find solutions to the energy and environmental challenges that automobiles face.  We have to do it in General Motors simply as a matter of business. If we don’t, there are real concerns about the growth of our industry being capped and that’s not a good thing for our industry.

And at General Motors, our strategy is pretty simple.  We want to displace petroleum, displace oil, reduce the amount of oil that’s being consumed, and we think the key to doing that is through energy diversity.  By having a wide variety of energy pathways made available for automobiles, we can grow our business and we have the chance of growing our business sustainably going forward.

We’ve become increasingly confident that we can meet the automotive competitive targets that we've set for the [hydrogen fuel cell] technology, $50 per kilowatt, 150,000-mile life, with a 300-mile range. But before this technology can be made widely available, governments, energy suppliers and infrastructure companies around the world need to collaborate with GM and the auto industry to develop a market for fuel cell vehicles and hydrogen fuel.

—Larry Burns



That's nice Mr. Burns.

But, since the station down the street still only sells petroleum byproducts, I'd still prefer the version that runs on dead dinosaurs, thanks.


GM is saying in effect 'we can't give you a large battery with a cheap engine so we'll swap it for a small battery with an expensive engine'. They need to offer an improvement in averaged well-to-wheels efficiency for this idea to go anywhere.


how many times does it need to said that oil does not
come from dead dinosaurs.

Also, lemmings don't kill themselves but still that phrase is repeated over and over.


3500 lbs. using lightweight materials in a small four-seater. Someone please tell me that this is progress.


They are at it again: vapor and ads; the future is right around the corner! Right! GM and Ford, Big Auto, always advertise the future while producing the past. These companies are in the business of controlling the auto industry just like Big Oil controls the American energy industry. If we all decided to keep and maintain our current personal cars and to wait until the H2 car is available from GM, GM would go out of business. That may not be a bad thing.


$50/kW is $4000 for a 80kW stack. Oddly enough, that's almost exactly the difference in announced price between a 4-cylinder 2008 Altima and the 3.5L V6 version, so calling it an "expensive engine" is a bit of a red herring...

Yah, cost vs. MSRP, I know, and the V6 is better equipped, but it's in the ballpark...


The first Volt was all smoke & mirrors this one is.....what? Heavy smoke & no mirror?

George K

To all you negative nells out there:
Folks, GM is going to build the Volt!!!
Get over it.


Look, there's a lot of energy money riding on H2 since the petro biz sees it as their next fuel. So GM announces the concept and challenges the oil guys to build an infrastructure. According to some on this site mobile H2 tanker/pumps could roll onto any dinosaur station lot overnight.

These cars will sell to fleet operators first and help establish localized H2 distribution. What's the big huff - consumers will want the LiIon version until the FC fuel issues shakes out. Don't like H2? Don't buy it.

Jeff R

I was right there with this concept until the last line. If hydrogen under pressure turns out to be the most effective way to store energy on a vehicle, okay, but are they really still talking about a hydrogen distribution system? Why not have gas stations make hydrogen on site from electricity and water? Can someone clarify what the last sentence by Mr. Burns is supposed to mean? Surely he's not dreaming of hydrogen being piped or trucked from a central plant...


I agree sounds to me like" We want to lock you all into another
form of road fuel so GM and it buddies can sit back and watch
while the bucks roll in , rather than use an already exsisting
network ",

James White

And GM tells us they can't build a conventional gasoline or diesel series hybrid Volt because of insufficient battery technology, but yet they continue touting hydrogen fuel cells? Ya, right.


As I said fuel cells are improving fast. Just 2 gens and what 2-3 years amd the cell grew in power droppef alot in size and cost increased in lifespan.

Amd they still have years before deadline. How good will the next few gens get? Witch gen starts mass production?

Gona be fun finding out. Thats the real fun.. we will see so many interesting things in our life.. ubless we die soon;/


The battery packaging has changed. Anybody have any input on this change and who created it?


Does it run ? Im seeing only words and pictures and mockups. Any way to see it running ?

::The fuel-cell Volt accelerates from 0 to 60 in 8 to 8.5 seconds, and has a burst top speed of 120 mph

Where and when exactly was this tested ? Can we see it, please ?
How is the one with gas engine doing ? Can we see it, please ?


fool cells

Tony Belding

There is a good reason why GM chose to show the hydrogen fuel cell version in China. The Chinese have ambitious plans to build 300 new nuclear power plants. Those plants could use high-temperature electrolysis to convert steam into hydrogen; it's probably the most efficient way to make hydrogen without reforming fossil fuels.

GM's plan is to make versions of the E-Flex that can tap into whatever fuels become popular in different parts of the world. That means hydrogen in China, ethanol in Brazil, diesel or biodiesel in Europe, and I think the USA is still up in the air. Even a pure battery-electric version could be cooked up relatively easily, if the market goes in that direction.

I think GM's plans have some shortcomings (and the Chevy Volt, as it has been shown thus far, is an automotive abomination), but at least there is some method to what they're doing, and I think they are pretty serious about wanting to do it. They have seen the writing on the wall, and they must be aware the Japanese are also quietly researching this stuff.

Let's give some credit. . . GM are way ahead of Ford, DaimlerChrysler and VW, to name a few. Those companies have thinking stuck in the 1990s when they were all fighting against CARB and alternative fuels.

Mark A

Right on, Tony Belding. GM is on the right track here, and should be given credit for what they are trying to offer. At least they are not offering something, and putting a "Hemi" label on it to try to get it to sell!!

But this is all mostly unproven technology, and involve many other companies independent of GM, to succeed. GM, and Chevy, must be cautious in their offerings, or suffer irrepairable damage to their image. Remember the earlier Tesla story about their cars weight gain/range decrease? Minimal damage to them. But Tesla can play on a different, unlevel playing field from GM, and still be given credit that any major automaker would not get.

And as far as you guys worrying about the hydrogen issue here, keep in mind where this offering was unveiled. CHINA! A much different regulatory "atmosphere" there, than here in the USA. Perhaps it would be much easier to introduce and develop there, than here in the "overly-litigating" USA, and then trickle the technology back here after its liabilities are eliminated.

For the condensed opinion, its a good story all around. If you dont like it, ignor it, or, vote for your preference with your checkbook.


Why is it when Honda and Toyota work with Fuel Cells, many here break their own arms trying to pat them on the back, and then when GM does it, GM is considered evil-incarnate? Scroll down the articles right now and see that their is currently an article about a Hydrogen Highlander. I guess that is perfectly acceptable for Toyota to look into Hydrogen because they can do no wrong.

Personally, I like the idea of Hydrogen, if its infrastructure issues can be worked out over time. I do feel in this case, GM should be prioritizing by putting the gasoline gen set version on the front burner to get all issues worked out, and FCV's on the back burner for the time being. That may already be the case too--we don't know that for sure. One poster here mentioned that this FCV version was shown in China since they might be closer to a Hydrogen economy than the rest of the world. I thought that was a good point. If that proves to be true, then the FCV version of the Volt being shown in Shanghai was probably a good move.

Greg woulf

Finally some voices of reason.

GM is on the right track, and they showed a different version fast, which shows that they really mean flexible in terms of power source to the electric motor.

If you put away hate for GM from the EV-1 and all the false hype would this be a good step? I think for most it would be seen that way.

A car that can run on any fuel source is ideal with all the changes coming.


This is a lot of B.S. Hype..
3500 pounds = are they Nuts , and supposedly with light
materials ??
If they could remember Aerodynamics , they would be
able to meet the guidelines with Better design alone.
And git rid of some Garbage - cut that 3500 down
to less than 2500 = bonus...
Send that 'Hummer' somewhere else.. We do NOT want it..


The main thing that GM is missing is any kind of out-of-the-box thinking. To me this thing is just vaporware - they are trying to tease us and convince us that in the future GM will still be relevant. In the meantime, others are doing far more revolutionary things.

In my eyes, GM is still headed for bankruptcy....


Schmeltz, show me ONE person here praising Honda or Toyota for their FC prototypes or their hybrid SUV's.

(Seems I made the same point last week, but some folks didn't get the memo.)


Hmm... it took GM just about 10 years to realize the vision Toyota Managers had already in 1995...

Cool stuff, really; Just listen up, electricity, in whatever form, will drive future vehicles.

(I doubt that GM runs it's own electric motor R&D department, own semiconductor manufacturing plant, and invests heavy in custom-built semiconductors for use in electric drivetrains. Guess who is... And guess who announced significant progress in bringing SiC (silicium carbide) production costs down. SiC can operate un-cooled next to internal combustion engines, and also next to the waste heat of fuel cells, or zebra batteries, without deratings in power or life at those temps (>250 °C at the junction, compared to <140° with Si).


Wow! This technology will probably come to market soon after GM goes bankrupt.

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