Toyota Fuel Cell Hybrid Vehicle advanced (FCHV-adv)

Among the things I've learned about the Nissan FCHV project is that one of the reasons Nissan was able to go from zero to Leaf in such a short amount of time is that they borrowed much of the running gear and other technology from the FCHV vehicle.

In fact, the current iteration Nissan fuel cell is almost exactly the same dimensions as the Nissan Leaf battery pack.

 

Does the pack also include the battery, or would a hypothetical fuel cell Leaf lose space to make room for the battery?

FCVs are just EVs which have a fuel cell in addition to the battery. I'm sure a successful production model will also be a plug in to extend the fuel cell's usable life.

 

Then there's the "flash point" thing. Hydrogen has the easiest explosive/ignition mix range with air of all the gases except acetylene. Hydrogen-air mixtures can ignite with very low energy input, 1/10 that required igniting a gasoline-air mixture. You think auto/gas fires are bad? Nope. You think Hindenburg was bad? Nope:



Hindenburg wasn't pressurized. FCV's carry 5,000 pound pressure cylinders. Sure, hydrogen floats up ... but if it's in the cab of a car, that's not going to help much. Think back to 2007 when the coal plant/hydrogen explosion took place:
1 killed and 9 injured by explosion at Ohio coal-burning power plant, utility says - 7NEWS Boston News WHDH-TV 7NEWS WHDH.COM

Think back to just last year - Japan's Nuke facililty ... those were hydrogen explosions that blew it to smithereens:

Then there's Hydrogen embrittlement ... the thing that happens to those 5,000lb high pressure metal fuel lines, trying to keep the explosive element contained.. (sigh) ... it just goes on and on and on and on. But I digress. Ok, I'm goina try and leave it alone ... again.

[ame=http://en.wikipedia.org/wiki/Hydrogen_safety]Hydrogen safety - Wikipedia, the free encyclopedia[/ame]

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CNG HEV (P or not) just isn't practical for most cars. You're combining a relatively low density fuel that needs a large, reinforced fuel tank, with a lower density battery and hybrid system that takes up even more space. It could work for larger vehicles with excess space, such as buses.

 

I agree here, which along with cost is why phevs use gasoline not cng. There are over 10 million cng cars running around the world. IIRC cng has over three times the energy per mole, which is why fuel tanks are more of a problem for hydrogen fcv than cng. There is also an infrastructure for cng in the US, that would cost billions of dollars to create for hydrogen. DOE goal for a fc cost is to have it drop in price to around that of an entire cng civic by 2015, $30/kw. Its currently $42/kw ($31/hp).

 

And you are doing the same with the battery, fuel cell stack, and hydrogen tank on a FCV.

The Honda Clarity has a range of around 240 miles. About the same has their non hybrid Civic NGV. They will beat a battery in refueling times for quite awhile, but liquid fuel PHVs have them beat on range. Yes, those Hondas have the Audi A1 Etron beat with it's 155 mile range, but that's only because the designers priortized cabin space over range. The tank is only a little over 3 gallons, as compared to an average ICE, HV, or PHV's 9 to 16 gallons. How far would those Hondas get on the equivalent fuel gas volume?

As battery energy densities and prices improve, using less efficient and/or costilier liquid fuels in an ICE of a PHV become more practicable. Ethanol, butanol, biobased diesel, and gasoline can already be produced. Some of which don't require changing exisiting vehicles and distribution networks.

Some of those fuels can actually be 'burned' in a fuel stack. So research doesn't have to be halted into fuel cells, but their use in a consumer vehicle likely will always be bested by another system.