[Ladogaboy]

After reading about GM's collaboration with Honda to build fuel cells in the United States, my mind immediately jumped to the Voltec power train. Is it possible that the next generation Volt could have a hydrogen fuel cell instead of a range extender? Or at least have it as an option?

Given the ~ 110 kW fuel cell stacks used in the likes of the Mirai, it seems like a perfectly suited option. Include a ~ 20 kWh usable battery pack, and you'd end up with an 80 mile PHEV with the option of using hydrogen fueling stations for long trips.

Obviously, this is a few years away, and the infrastructure would need to be built out to support it. But it seems like it could be an option in the future.

 

[llninja]

I sure hope not. It sounds too good to be true, put in hydrogen, emit water, save the planet. But I don't want a 10k psi tank in the vehicle. I don't want to park at an airport for a month long vacation and return to an empty tank. And I don't want to drive to California every time I want to fill up. The infrastructure isnt' there. The technology isn't there. And I'd much rather see Mr. Fusion than a hydrogen fuel cell. There need to be some very major breakthroughs to change my mind on this one

 

[bartin]

A fuel cell was explored as a range extender option from the very beginning because of the flexibility of the "skateboard" platform. It's possible this new collaboration changes the factors that led to the decision to not pursue the fuel cell for the first gen.

 

[Shivetya]

well all battery powered vehicles have serious limitations unless some amazing break through comes soon. they weigh to much for the power/range offered, recharging isn't swift compared to other fuels, and have performance issues in both very low and high temperatures. The biggest bogeyman is their weight for range

 

[Loboc]

An NG fuel cell would be more practical. NG can be stored at lower psi (even zero psi with some techs). NG is renewable as methane. (See Thunderdome). NG already has distribution.

I'd like to see H2, but, probably not in my lifetime.

Solid state batteries could make the dream of Hydrogen obsolete.

 

[saghost]

There's no technical reason GM couldn't do that. I sure hope they don't, however. Commercial hydrogen is much more expensive than gas, while being much less available and only slightly cleaner. And then there's the 10ksi bomb that's always in your car...

Fuel that's hard to find and requires planning defeats the entire purpose of the EREV concept - it'll be easier and more comfortable to live with a three hundred mile BEV than with a FCEREV.

On a more cynical note, FCEVs exist specifically to slow/spoil the EV revolution, and so folks making them aren't eager to allow their customers any EV experience. That's presumably why out of hundreds of fuel cell concepts over the years, there's exactly one plug in hybrid fuel cell car, an Audi from a few years ago - despite the fact that going PHEV would allow substantial reductions in cost and weight (the fuel cell itself is the most expensive part of the FCEV, and going PHEV would allow a stack that's half the size or less, designed to meet the continuous load instead of acceleration requirements.)

 

[mtp9302]

GM definitely can do it, they know how. As was mentioned, they thought about it with the E-Flex architecture right from start so they have a good handle on the pros and cons, but I don't think it would be to their benefit to do so for the reasons others have said.

Safety is not one of those reasons. The Fuel Cell Equinoxes were crash tested and proven safe. People need to stop thinking Hindenburg when they think of fuel cells. When done correctly, sitting on a tank of Hydrogen is no less safe than sitting on a tank of gasoline.

 

[maczr1]

Anyone that has owned a EV for any time and charges at home does not want to be tied to the man selling fuel again.
The man selling fuel knows this.

 

[saghost]

GM definitely can do it, they know how. As was mentioned, they thought about it with the E-Flex architecture right from start so they have a good handle on the pros and cons, but I don't think it would be to their benefit to do so for the reasons others have said.

Safety is not one of those reasons. The Fuel Cell Equinoxes were crash tested and proven safe. People need to stop thinking Hindenburg when they think of fuel cells. When done correctly, sitting on a tank of Hydrogen is no less safe than sitting on a tank of gasoline.

Except for the part where hydrogen requires far less initial energy (spark) to start it burning, and will burn/explode in a much wider range of concentrations, and then the little detail that the 10,000 psi tank can throw shrapnel through a city block without the fuel exploding just based on the compression energy if the tank fails, yes.

Oh, and keep in mind that every refueling cycle is doing fatigue damage to the fuel tanks due to pressure cycling. The Mirai says the tanks shouldn't be refueled after 5 years from the date of manufacture, presumably for that reason - I wonder what that maintenance is going to look like, stripping the whole high pressure system out and replacing it? Doesn't sound cheap...

(Gasoline can only explode between 1.4% and 7.6% concentration by volume in air. Hydrogen will burn from 4% to 94%, and detonate from 18% to 59% by volume.)

 

[DrMiguelitoLoveless]

Nope. H2 just isn't economical. Under the best circumstances it takes about 52kWh of electricity to create one kg of H2, which will allow you to drive 60 miles or so. The same amount of electricity allows your Volt to drive about 150 miles (though not all at once). So, once again, the math just doesn't work out for H2. With the arrival of the Bolt, you CAN put all 52kWh of electricity in it, and get almost two and a half times further on the same power, in a vehicle that costs about 25% less.

That said, why would GM replace the gasoline generator with an H2 fuel stack, thus immediately dooming the car to only be sold in areas where H2 fueling stations exists (at the moment 33 places in California and a handful of stations around DC)? An H2 fueling station costs around $2 million to build, whereas gas stations already exist, and charging stations are going up everywhere, and are far cheaper to build (also, you can charge your car at home).

To say the infrastructure isn't there is an understatement. The infrastructure is about a half trillion dollars from existing and I just don't see any company laying out that kind of cash when the basic fueling infrastructure for BEVs and PHEVs already exists and substantially less money will bring it up to spec for mass use.

A Volt FCEV isn't happening. The market just isn't there.

 

[DrMiguelitoLoveless]

well all battery powered vehicles have serious limitations unless some amazing break through comes soon. they weigh to much for the power/range offered, recharging isn't swift compared to other fuels, and have performance issues in both very low and high temperatures. The biggest bogeyman is their weight for range

And those issues are being addressed with each new iteration of battery. We are seeing improvements in energy density, reduction in costs and improvements chemistry (which makes them more resilient and faster charging). You already have vehicles coming in with 200+ miles range and fast chargers coming on line. These improvements and technologies will be in place and economically functional in the next few years.

The "amazing breakthroughs" have been the constant annual improvements in performance and the constant drop in price due to economies of scale. The Chinese are now looking to get into the battery market the way they got into the PV market, which drove the cost of solar panels from about $5 a watt to $0.50 a watt in ten years.

I don't see a problem

 

[DrMiguelitoLoveless]

Safety is not one of those reasons. The Fuel Cell Equinoxes were crash tested and proven safe. People need to stop thinking Hindenburg when they think of fuel cells. When done correctly, sitting on a tank of Hydrogen is no less safe than sitting on a tank of gasoline.

Absolutely true, but the problem is physics and economics. H2 is a poor storage medium for electricity. And that is what you are doing, expending lots of electricity to create hydrogen, which is then used to create electricity again, which then powers the motor. Instead, the same amount of electricity can go into a Li-on battery and propel an EV 2.5x as far as an FCEV.

 

[bjrosen]

I'd bet that it will never happen. There is no infrastructure for hydrogen and there is no reason to make the investment because there are no fuel cell cars, and without the infrastructure no one in their right mind would by a fuel cell car. Batteries have already won, the only technology that might challenge them at this point are supercapacitors which are have identical infrastructure requirements as batteries.

 

[mtp9302]

Except for the part where hydrogen requires far less initial energy (spark) to start it burning, and will burn/explode in a much wider range of concentrations, and then the little detail that the 10,000 psi tank can throw shrapnel through a city block without the fuel exploding just based on the compression energy if the tank fails, yes.

Oh, and keep in mind that every refueling cycle is doing fatigue damage to the fuel tanks due to pressure cycling. The Mirai says the tanks shouldn't be refueled after 5 years from the date of manufacture, presumably for that reason - I wonder what that maintenance is going to look like, stripping the whole high pressure system out and replacing it? Doesn't sound cheap...

(Gasoline can only explode between 1.4% and 7.6% concentration by volume in air. Hydrogen will burn from 4% to 94%, and detonate from 18% to 59% by volume.)

I hear what you are saying, no doubt pressurized Hydrogen is a volatile fuel. I also will readily admit I am a mechanical engineer, not good with chemistry, and apparently don't have knowledge of the ignition values of each fuel like you do so I'm not going to argue you that. Sealing Hydrogen is admittedly a tricky and expensive affair because it is such a light/small element. There is more potential there, so more protection is required. It does seem a little dramatic to say that a car with protection added such that it can pass NHTSA crash testing can also throw shrapnel through a city block, I have trouble believing both of those things are simultaneously true.

I had a front row seat to the Fuel Cell Equinoxes for 6 years. I saw a video from validation testing where a car was dropped on the Hydrogen tanks without incident. I forget from how high, but it was literally a junk automobile hanging from a crane high in the air and dropped on the Hydrogen storage system removed from the vehicle and sitting on the ground (so maybe 20-30 ft?). Cheap they are not, but their H2 storage system and its protection is extremely well thought out and proven safe in the same crash sequences that ICE cars are tested to.

Another thing to note: because Hydrogen is so small, leaks dissipate extremely quickly. How quick I don't have a number for, I would think orders of magnitude quicker than gas vapors. The presence of Hydrogen leaks is also monitored on these vehicles with multiple H2 sensors, so a leak is quickly caught and a DTC set. Cheap? Definitely not. Safe? Absolutely. Thus informed by what I've experienced, I still don't think a properly engineered H2 storage system and all of its safeguards/controls is any less safe than gasoline storage system and all of its safeguards/controls.

To your point about the tank life, I hadn't heard that the Mirai's tanks had this concern. I am not sure how their design compares to GMs or if this was an issue on GM's either. Either way, stripping the entire H2 system is not the same as replacing the H2 tank, there is more to that system than just a tank. I do agree that it doesn't sound cheap.

Common thread through all of this: GM can do this safely and has done it safely, but there are more cost-effective ways to move people around.

 

[DrMiguelitoLoveless]

Another issue, https://www.nace.org/Corrosion-Central/Corrosion-101/Hydrogen-Embrittlement/

 

[hellsop]

I'm not ready for it.

Gaseous refueling (setting aside the issue of access as an obviously solvable problem) at this point requires a certification class to do, plus takes about 20-30 minutes to fuel a vehicle that can then run on that fuel for about three hours at moderate speeds. Fueling a gas or diesel car takes five minutes that then grants about six hours of running at those same moderate speeds. For that amount of time fueling, you almost may as well buy that BEV instead.

(Now, would I consider a diesel-fueled Volt? Sure. Would I pay extra for one? Not much.)

 

[saghost]

To your point about the tank life, I hadn't heard that the Mirai's tanks had this concern. I am not sure how their design compares to GMs or if this was an issue on GM's either. Either way, stripping the entire H2 system is not the same as replacing the H2 tank, there is more to that system than just a tank. I do agree that it doesn't sound cheap.

Common thread through all of this: GM can do this safely and has done it safely, but there are more cost-effective ways to move people around.

My background is pretty similar actually, but I've done a fair amount of reading about hydrogen fuel cells which I hopefully have down right.

Fatigue life issues should affect the entire high pressure side, not just the tanks - the pressure regulator and everything upstream of it, although of course different parts have different safe lives.

To my mind, it's kinda like Nuclear Power. If the engineers correctly anticipate all conditions and everyone takes appropriate precautions, we can make it safe - if anything happens that's not expected or someone gets careless enough, bad things happen.

So why would we want to take the risk when it's not any cheaper and not any more efficient or cleaner?

With the current levels of the various technologies, it only makes sense if for some reason EREVs and BEVs are politically unacceptable - like if you had the world under your thumb and folks being able to refuel at home from any sort of fuel they have lying around or none at all (solar and wind) might get them out from under your thumb.

 

[bjrosen]

There is absolutely no reason to expend any time, effort or money on fuel cell passenger cars, they have no significant advantages over batteries and the cost of building a hydrogen infrastructure to fuel them is insurmountable. The only advantage that fuel cells have today is longer range, but that's a very temporary advantage that will be overcome years before a hydrogen distribution system could be built. Even if the state of the art in batteries were to freeze today, BEVs would still be better than FCEVs. The battery pack in a Bolt costs $9K, if GM wanted to build a 350 mile Bolt all they have to do is put in a $15K battery pack. If they wanted to compensate for the extra weight they could just substitute aluminum for steel (Ford is doing it in their pickup trucks so it's not an exotic material), or use carbon fiber (the Alfa Romeo 4C has a carbon fiber body, it's a pricey car but not ridiculously so). Of course the state of the art in batteries hasn't frozen, even today Tesla is claiming the Gigafactory batteries are already down to $120/KW, by 2020 the cost of batteries should be down to $100/KW.

Battery cars are useful even without an fast charging network because the cost of installing a Level 2 at home is already less than $1K. FCEVs are useless without a fueling network unless someone builds a home hydrogen generator, doable but certainly much more expensive than an EVSE. For long range travel BEVs do require a network of fast chargers but building out a DC Fast charger network is trivial as compared to a hydrogen fueling station network. All you need for a charger is a spot to stick a pole in the ground and a wire, no complex permitting is required, no expensive tanks, just a simple charger. If you look at where existing DC Fast chargers are located you'll find many of them in places like supermarket parking lots, that's because the cost is so low and the installation is so simple, and the space requirements are so minimal that a supermarket can do it for no other reason than it makes them look environmentally friendly (all of the DC Fast chargers in the Portland ME area are at Hannaford markets, that's a down market chain it's not a high priced chain like Whole Foods). Hydrogen fueling stations are much more complex and expensive so no one is going to invest in them on a whim, they will have to be able to justify their large investment on their own.

 

[DrMiguelitoLoveless]

Fatigue life issues should affect the entire high pressure side, not just the tanks - the pressure regulator and everything upstream of it, although of course different parts have different safe lives.

To my mind, it's kinda like Nuclear Power. If the engineers correctly anticipate all conditions and everyone takes appropriate precautions, we can make it safe - if anything happens that's not expected or someone gets careless enough, bad things happen.

Exactly. Plus, you have to look at maintaining not just the cars, but the fueling stations as well. And while engineers might design a perfectly safe system, they inevitably turn such systems over to people who will neglect them out of ignorance or for profit.And when something bad happens, the failure will not be pretty.

 

[Jmaj]

I had a chance to chat with a NASA engineer recently. He's working on fuel cell powered aircraft in a joint program with Boeing. When I told him my opinion based on electric vehicle ownership (electric motors great, batteries still suck) he agreed with a chuckle. Which is why they are using NG fuel cells. I have a lot of background in solid state chemistry so I understood the concepts but he couldn't say much about the fuel cells (oxygen rich oxides) in detail because of non-disclosure agreements with Boeing.

I think I am unique in this forum by actually leasing and using high pressure (200 cu ft at 2000 psi) hydrogen cylinders. Nothing bad has happened so far, it's no big deal. I consider it far safer than say acetylene. But, a large scale transportation system will have to be based on NATGAS.