Oils4AsphaultOnly
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Re: Toyota Mirai Fuel Cell

Tue Jan 28, 2020 1:56 pm

mux wrote:
Tue Jan 28, 2020 12:38 am
To be fair that's just anecdotal, it'd be much more informative to gauge the experience of, say, 100 FCEV drivers and see what they do and don't like about it and what their upgrade plans would be, if they had to choose today.

There are a LOT of municipal Mirais around, like, I'd wager it is at least a plurality if not a majority. Those are driven on and off by multiple people with often just one person generally responsible for fueling or even aware of how the process works. The rest just drive them. I'd imagine, it being an EV, that the experience of most of those people has to be pretty positive. If there's a hydrogen shortage, they'll just switch over to other vehicles so no harm done.
True it's anecdotal, but two out of a small total population is the beginning of a statistically significant sample size. Removing the municipal Mirais would simply make these two anecdotes more representative of the consumer population.

Anyway, I was only contributing my aunt's experience.
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GRA
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Re: Toyota Mirai Fuel Cell

Tue Jan 28, 2020 6:28 pm

There's no question whatever that the explosion at the Air Products facility in the Bay Area last year caused a lot of H2 supply problems here, and AFAIA they aren't yet completely solved. As it is, current spacing of H2 stations in much of the Bay Area (outside the South Bay) is about 15 miles, so if your local station is out you have that far to go to another.

That being said, I see a fair number of Mirais being driven around here (that I'm two miles from a station, and am often traveling along a major arterial that connects to it probably boosts the frequency I see them) - I've even seen two at the same intersection at the same time on a couple of occasions (including yesterday), and talking with some of the owners, while they report occasional problems with supply, they also recognize that this isn't a mature infrastructure yet, and (at least the ones I talked to) are willing to put up with the occasional problems. One of the steps being taken is to refuel more frequently than they otherwise would need to, to give themselves a cushion. This is apparently a fairly common practice statewide, judging by the average fill quantity reported by the state in their annual reports.

Re fill speed, some of the first gen. equipment did have problems, but as was to be expected the 2nd gen stuff is a lot better (and required to be). Unfortunately, at the moment the 1st gen equipment still dominates, and will until they get the supply stabilized (and diversified) and can start building new sites again at previous rates.
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WetEV
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Re: Toyota Mirai Fuel Cell

Wed Jan 29, 2020 5:22 pm

Or until Toyota gives up on fuel cells.
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coleafrado
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Re: Toyota Mirai Fuel Cell

Sun Mar 08, 2020 9:29 am

Is Toyota still using platinum fuel cells?

mux
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Re: Toyota Mirai Fuel Cell

Sun Mar 08, 2020 12:49 pm

Yes, there is still platinum group metal (PGM) loading in their PEM fuel cells. There is no way around that for the time being. Not sure if it's platinum in particular, they may also be using palladium or rhodium. There's something like 30g of Pt/Pd/Rh in a MIrai.

coleafrado
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Re: Toyota Mirai Fuel Cell

Mon Mar 09, 2020 5:20 am

One ounce (28.5g) per car is the figure I've been hearing, thanks for the check mux.

From the perspective of a physicist: getting 100 kW worth of proton exchange from that quantity of catalyst is insanely impressive.

GRA
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Re: Toyota Mirai Fuel Cell

Mon Mar 09, 2020 5:18 pm

All the companies making fuel cells have reduced the amount of Pt required for each succeeding generation, to the point where the next gen is apparently down to the same level as is in a diesel catalytic converter now. See: viewtopic.php?f=7&t=14744&p=557335&hili ... um#p557335
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

mux
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Re: Toyota Mirai Fuel Cell

Tue Mar 10, 2020 5:41 am

The platinum problem in PEMFCs isn't just centered around the amount necessary for each PEMFC stack, it's really a cumulative problem tied into a particularly nasty speculative market:
- Each PEMFC has its counterpart in platinum used for electrolyzers
- PGMs in fuel cells are inherently a lot harder to recoup, as it's much more sparsely distributed and in the form of nanoparticles that tend to erode much more easily
- Platinum is a largely speculative market with centralized, tightly controlled supply that is hard to expand

We've seen in the early '00s that even the vague promise of future FC cars sent the platinum price up to ridiculous levels. That in turn actually made the platinum so expensive that fuel cell stacks became intrinsically uncompetitive in the long run, it was that bad - it went to over $2000/oz, which is about the total materials cost of a 100kWh battery - back then. It's gone down substantially now, to the point that you can theoretically make a ~100kW PEM fuel cell for less than the cost of a 100kWh battery, but imagine what the markets would do if some large automaker would decide to go 100% with fuel cells for the future.

Diesel cat converter platinum can be recouped 98%+, PEMFCs have much lower recovery rates, I think the best rates are still well below 50%. This is not completely intrinsic (i.e. this can be improved with better technology), but until we're at parity with other catalytic uses of platinum, we're going to need to supply the rest of the platinum with mined, new platinum. That's really what the speculation is all about. There's still a large technology gap enabling good platinum recovery AND low platinum usage at the same time. Keep in mind - Diesel cat converters may have the same total amount of platinum in them, but the total platinum demand from the catalytic converter industry is just 2% of their production capacity - the part they can't recover. That makes it a completely different ball game, for now at least.

TL;DR: the platinum discussion is more complex than raw materials amount, it's a quite unique combination of materials usage, recovery and speculative precious metal markets.

Oilpan4
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Re: Toyota Mirai Fuel Cell

Tue Mar 10, 2020 11:51 am

Saying platinum is speculative is putting it mildly. It's a market that booms and busts on speculations and disruptions.
I read about it almost daily as I hold approximately 342 grams of it.

In 2000s platinum prices went to $2,000 an ounce also because of the demand for platinum crucibles that are used to melt silicon for solar cells. I read one article that said the crucibles use around 10 ounces of platinum each, but everyone that sold them was out and at one point the used crucibles were going for as much as $40,000.
Last edited by Oilpan4 on Tue Mar 10, 2020 11:58 am, edited 1 time in total.
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Oilpan4
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Re: Toyota Mirai Fuel Cell

Tue Mar 10, 2020 11:52 am

coleafrado wrote:
Mon Mar 09, 2020 5:20 am
One ounce (28.5g) per car is the figure I've been hearing, thanks for the check mux.

From the perspective of a physicist: getting 100 kW worth of proton exchange from that quantity of catalyst is insanely impressive.
Precious metals such as gold and platinum are traded in Troy ounces, approximately 31.1 grams.
trumpvirus
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