Impressive battery in the Tesla Model 3

To excoriate means to peel away layers as you might do with an onion. This is generally considered a good technique for getting at the truth by stripping away layers of nonsense.

I am not anti EV. I am anti-battery powered ones for the simple reason that batteries are unsuitable for the application and the result is the cars are more trouble than they are worth. I am strongly in favour of electric drive. It is simply that batteries bring so many problems that the vehicle requires far more attention than it should. A hydrogen car would be something I'd be quite enthusiastic about, were it to be reasonably priced and as easy to fill as an ICE. They seem to have solved the problems of making them now, and I expect them to displace batteries as quickly as flat screens replaced CRT displays.

 

I am not sure what you mean by 'volumetric efficiency'. If you have cylindrical items, the same percentage of space is wasted irrespective of their diameter and length. For a square array of cylinders, the volume wasted is (1 - Pi/4)*100% - about 21.5% - irrespective of the diameter of the cells. A hexagonal array is more efficient than a square one - I can't be bothered to work out by how much unless someone really wants it - but the percentage of waste space is again independent of the diameter of the cylinders.

It is possible that a smaller percentage of the volume is taken up by things like connections and insulators inside a big cell than in a small one, but I can't really see that making a lot of difference.

I think I detect some 'specmanship' here. A 50% increase in energy density would make a HUGE difference to range and be celebrated by battery car enthusiasts here ad nauseam!

P.S. Arranged in a hexagonal array, the percentage of waste space is about 16.125% - again independent of the cylinder's diameter.

 

The actual costs are

Model 3 - $4.78
Mirai - $0.00 (You get free hydrogen for three years.)

I imagine hydrogen prices will fall as the amount sold rises and economies of scale kick in, and in three years one can expect a significant drop in price. But I think anyone buying either is deluding themselves if they imagine they can recover the greater capital cost of these vehicles by savings on running costs.

Of course, you also get 100% availability from your Mirai, and freedom from having to fiddle about with cables and chargers and worry about the battery or whether putting the heater on will cost you more miles than the distance home.

 

No. You can go ten times (or a hundred times) further and pay nothing.

 

Yes, real-world, non-subsidized prices for H2 dispensed into a fool cell car are around $14-16 per kg. One kg of H2 is roughly equivalent to 2 gallons of gas, insofar as how much you need to push the car down the road.

To make a "Captain Obvious" statement, if the sales of FCEVs ever really took off, then Toyota (and other makers of fool cell cars) would have to stop offering free fuel for them. So I find it amusing when fool cell fanboys argue in favor of fool cell cars because Toyota offers free fuel for three years. Well, I guess when you're a fool cell fanboy you have to use any argument you can find, no matter how weak!

* * * * *

We don't need to "imagine" anything. We only need to observe that fool cell fanboys have been promising for years that the price of H2 would drop dramatically as more H2 fueling stations are built; yet over the past three years since Toyota started selling the Mirai, with more H2 fueling stations built every year, no such drop in price has occurred.

This is merely one of many examples of how fool cell fanboys' claims and hopes are based on wishful thinking, rather than reality or facts or science or economics.
-

 

Further demonstration that running costs do not figure very highly in deciding what cars people buy. Not that any further evidence is needed. The fact that the overwhelming majority of cars sold burn oil with glorious inefficiency rather than buying EVs establishes this as an indisputable fact. Banging on about running costs the way you do is about as pointless as complaining that hydrogen has only one proton in its nucleus. Nobody cares about it !

I admire the degree of cognitive dissonance that you are able to maintain in convincing yourself that 'batteries will improve and become much less expensive' whilst the evidence suggests any improvements will be marginal at best, whilst being equally convinced that hydrogen will stay at its current price forever, despite economies of scale and even when home production of hydrogen from solar power is a distinct possibility.

 

One only needs to look at real-world data to see improvements in energy density, and reduction in prices, keep happening every year. No "convincing" is necessary; one only needs to be able to read a graph. It's amusing that you are in such denial of that reality. Sadly for you, denying reality does not actually change reality!

We're still waiting for fool cell fanboys to explain what magic is going to be used to change the physical properties of the hydrogen molecule, to turn it into a practical or affordable fuel. Oddly enough, none of you is ever willing to address that question. I wonder why?
-

 

The real-world graph of energy density in car batteries is very easy to read. It is a straight line, rising very slowly at around 150Wh/kg Plus or minus 10 or 20 Wh/kg.

As to the cost of hydrogen, it's been explained many times, but strangely it seems to be ungraspable by you. I will try again:

The cost of producing hydrogen comes down to the cost of the equipment needed to collect the energy needed to make it. The bulk of this involves windmills and solar panels. These together have fallen dramatically and will continue to do so for the foreseeable future. Apart from that, it comes down to an electrolyser and storage tanks. Both are conceptually very simple, and a high differential pressure electrolyser makes the process even simpler by eliminating the need for a compressor.

The cost of energy collection is covered largely by the people wanting the power, but the demand varies widely meaning that meeting the peak demand leaves one with plenty of cheap electricity at times when it is not in demand. In other words the energy is cheap enough for efficiency to become rather less important than is vulgarly supposed.

Finally, if householders can make their own hydrogen then this will set a limit on what commercial operators can charge. The recent announcement that the research group ar Rice has found a way of meeting the DOE's target for low-pressure storage of hydrogen in boron nitride sheets is a further boost to the establishment of this sort of system, and if it comes off may well reduce the cost of all of this enormously.

Finally, I would point out that the energy density of hydrogen is about 33kWh/kg. This is about three times the energy density of petrol or diesel, and, embarrassingly for battery advocates, over 200 times the energy density of the best battery packs for cars. Nobody in their right mind is going to be very worried about efficiency unless it costs hundreds of dollars a kg. It is already cheap enough for people to accept and clearly it is going to fall in price without any changes needed to the hydrogen molecule whatsoever as you appear to imagine.

I respectfully suggest you read the above carefully, and several times until you fully understand it and then hopefully you will not repeat the same question quite as often as you have in the past.

 

Thank you for once again proving one of my points: That fool cell fanboys only want to talk about the cost of generating hydrogen, and completely ignore all the other -- cumulatively much greater -- costs in the supply chain.

Sadly for your wishful thinking, reducing the cost of merely generating H2 will have little impact on the actual at-the-pump cost.

/economics
-

 

May I suggest we move this discussion to an appropriate thread. This is supposed to be about one of Tesla's assemblies of torch batteries. Perhaps you could list some of the costs I've allegedly ignored - probably because they are fictional or trivial.

 

All li-ion battery packs need a BMS (Battery Management System), and I think you've given one example of why that is.

 

Or maybe you could just quit beating this dead horse.

Well, I'm "embarrassed", or rather annoyed, that you waste space on this forum with increasingly silly arguments like this one.

The wonderfully high gravimetric energy density doesn't help much, when the volumetric energy density would require you to tow a gas bag the size of the Hindenberg behind the fool cell car, if the H2 wasn't highly compressed! And even with high compression, the volumetric energy density is -- for you fool cell fanboys -- embarrassingly low.

It's pretty insulting that you seem to think your Gentle Readers are so clueless that they won't see the obvious fallacies in your fool cell fanboy arguments.

No need to repeat myself yet again. I created the thread linked below in the hope that I could just point to it when appropriate, but you simply reject facts and figures you find inconvenient to your wishful thinking, and keep repeating the same thoroughly refuted arguments.

"How to Promote the Hydrogen Economy Hoax"
-

 

In theory, yes. In practice, there is a slight advantage to larger cylindrical cells because the "can" (cell casing) isn't made thicker when increasing the size from 18650 to 2170 cells. And I'm not sure about this, but there may be a bit of wasted interior space due to the geometry of the "jelly roll" which is improved with a larger cell. That is, the amount of wasted space isn't increased in a larger diameter cell, so it's a smaller fraction of the whole, and as a result, overall energy density goes up.

Again, though, there is only a slight improvement due to geometry.

Whether or not the 2170 cells actually have an energy density significantly better than the 18650 Tesla currently used in the Model S and Model X, is unclear to me. Epic battles have been waged over that question on the Tesla Motors Club, with some Usual Suspects there stating one position or the other as proven fact -- altho there is obviously a lack of consensus -- and I certainly don't pretend to know more than they do on that subject!
-

 

Older transcripts of Tesla earnings call have Elon and JB Straubel clearly stating that the 2170 cells would have improved chemistry, and therefore improved energy density. So I don't think there is any doubt that the 2170 cells have better energy density than older 18650 cells. What is not clear to me is whether or not Panasonic has made those same changes to the 18650 cells that Tesla is currently using.

Is that the total for the cell, or the figure per liter? If it's the total milliamp hours per cell, then of course the larger 2170 cells would hold significantly more energy. That doesn't mean the energy density would be significantly better.
-