Battery breakthroughs

That's a very open-ended question, so I'm going to give a second reply to it.

While the type of lead-acid batteries found in nearly all cars today (even most plug-in EVs use a 12v starter battery to maintain trickle power for the auxiliary systems) is a very mature technology, with no significant changes seen in many decades, this doesn't necessarily mean more advanced types of lead-acid batteries are impossible.

Those interested might want to read the "Advancements in Lead Acid" summary at the Battery University website.

However, caveat lector! (reader beware). Claims for breakthrough battery tech are notorious for being at least exaggerated, and often utterly without foundation. Case in point: The linked page has an entry for EEStor, whose claims have been thoroughly and completely discredited. I think it has been some time since that page was updated.

I'm not suggesting here that we'll ever see more advanced lead-acid batteries put into production. I'm just pointing out the dangers of assuming that the tech we're using today can't ever be improved. There are places where the laws of physics or thermodynamics places severe limits what can be achieved, such as using hydrogen fuel in fuel-cell cars. But with batteries, we are very far away -- orders of magnitude away -- from theoretical limits to energy storage. In theory at least, batteries should be able to attain the energy density of gasoline or diesel.

 

I think the reason ICE manufacturers have stuck with lead acid batteries is that they remain the best engineering solution for that particular application. They are inexpensive, rugged, safe, and tolerate a wide range of temperatures. For the relatively small amount of energy they need to contain, energy density is not important. Another advantage is that they are very easily recycled - 99% of lead in them is reused.

One interesting possible replacement is supercapacitors. A number of people have experimented with them in cars - you'll find them easily by googling - and I use them on my narrowboat to start the engine. By doing so, I can save having a dedicated battery to start the engine and use it instead as an additional 'leisure' battery.

The problems encountered by Boeing in their Dreamliner when they attempted to use Lithium instead of the more widely used lead-acid batteries were very interesting too. As I understand it, their 'solution' to the propensity of these batteries to auto-ignite was to stick them in a stainless steel fireproof box equipped with a chimney (aka a 'vent') to the atmosphere. Practical, but hardly an endorsement of the safety of the batteries.

I suspect that Lithium may already have been pushed as far as possible in terms of battery chemistry, and big improvements are rather unlikely. The 'breakthroughs' that don't actually ever appear is evidence of this. It is up to the individual as to whether they are sufficiently good in energy density for EVs of course, but my personal opinion is that they are only marginally adequate.

 

That's what I thought. Do you know the significance of the 48V technology that seems to be appearing in some cars? Obviously reduction in current draw and therefore wiring & other componentry can be lighter? Probably off-topic now...

 

We all hope for the miracle breakthrough, don't we? Problem- we have already had it with the improvement from Lead Acid to L-ion. Let's hope the next 'giant leap' happens in far less than a century!

 

Knowing you are totally anti hydrogen fuel cells in cars but do you see a future in aircraft? I mean, batteries as currently understood will never power airliners, will they?

 

Unfortunately, the most effective way of packing energy into a small space is to use fossil fuel. Diesel and gasoline both have energy densities of around 46 MegaJoules/kg - about 100 times that of a practical Lithium battery.

It took 150 years to get an order of magnitude improvement over lead acid, and we need TWO orders of magnitude to get to that of petrochemicals. I can't see battery powered A380s coming anytime soon!

I wonder whether we are looking at the problem in the wrong way. Perhaps we should be looking at synthesising a chemical fuel as good as diesel in energy density that burns more cleanly and is manufactured from atmospheric carbon dioxide.

In other words look at chemical fuels as energy stores rather than as energy sources.

 

I'm just as negative on hydrogen for cars as Pushmi-Pullyu is, but I see no good alternatives for fossil fuel on the horizon for commercial aviation. Maybe, eventually, hydrogen, but I expect synfuels to be tried first.

 

Commercial aviation has a place for small, limited range electric aircraft; Norway has/intends replacing its fossil planes on local routes with such planes. As air taxis the current crop of electrics is close to that sort of role, eg http://sunflyer.com/ has secured 105 deposits for its [battery swap?] 2 seat trainer & has developed a 4 seat version.
But synfuels sounds a great intermediate step for larger craft. Electric air is taking off [sorry!] faster than the surface EV market. Quite exciting.

 

One consideration with electric airliners (assuming batteries with good energy density appear) is that charging time is an important factor in making them economical. Time spent sitting on the ground waiting for charging to complete involves very expensive machinery doing nothing. You need to keep them in the air earning money. Conventional aircraft are turned around in minutes for that reason. Unfortunately, if you could charge in a short time, the power levels would be astronomical so I think electric aircraft will be limited to small short hop applications.

Hydrogen sounds attractive, but I'm not sure about the size and number of high pressure tanks you'd need to hold it.

A company called Joule Inc. had a nice idea of using genetically modified bacteria to produce a range of fuels including ethyl alcohol, diesel and jet fuel. The 'fuel' for these bugs was sunlight. They built a pilot plant in New Mexico which was working and were attempting to license their technology in collaboration with a motor manufacturer. Audi I think, but I believe they went bust. I don't think it was because the GM bugs didn't work though. Perhaps someone else will buy the IP and try it.

 

As far as I know it was simply to save copper. Four times the voltage means a quarter of the current and you only need a sixteenth of the copper. I don't believe there were any other reasons for it.

 

Oh, that's an easy one. Higher voltage allows use of smaller/thinner wires, and copper wiring is expensive, so higher voltage (up to a point) saves money. It also saves a small amount of weight. But based on your comments, you already knew that.

The problem with switching from the current 12v system for auxiliary power in cars is that you can't just switch over one thing, you have to switch everything over, or run part of it thru a transformer or voltage regulator (I never can remember which is used where), which rather defeats the purpose of making it cheaper. But for everything to run on 48v, that means you have to have such things as headlights, tail lights, the instrument panel, the infotainment screen, interior lights, the stereo system... pretty much everything in the car which uses electricity except the motor, run on 48v current. That limits choice of vendors, and since you've got fewer choices, that means your overall costs will likely be higher, plus it will be harder to get exactly what you need in off-the-shelf parts.

So with all that, it's easy to see why 12v systems have remained the standard even when everybody would probably be better off with 48v systems.

 

There are several serious players [Boeing, Airbus, Easy Jet etc] aiming to develop up to 100-seat planes presumably with limited range & I reckon battery swapping will be the go, for the reason you said. Charging infrastructure would be relatively easy at airports that already need high power supplies. There's a lot of short- haul routes that are ideal for electrics, or maybe hybrids?

 

Yeah, I would expect synthetic fuels to replace petroleum for aviation fuel. There doesn't seem to be much point in trying to use either electric power or H2 as a fuel for aircraft. Electric power would limit the planes to lower speeds, around .7 Mach instead of the .9 Mach speed at which commercial aviation travels. For short "puddle jumper" flights, battery-powered planes may make sense, altho the longer turnaround time noted by Martin Williams certainly is a negative factor. At best, electric drive airliners would be a niche market. If you want to get into science fiction scenarios, we can imagine a future in which room temperature superconductors allow MHD (magenetohydrodynamics) drive, so-called "electric jets", powered by ultra advanced batteries capable of being charged in just a few minutes, perhaps with the ground power source being a compact nuclear reactor to generate that much power. (Or even a compact onboard nuclear reactor directly converting nuclear power to electricity, using the tech touted here.)

But I'm over 60, so I don't think I'll ever see such advanced tech in my lifetime.

Using hydrogen -- for the sake of argument, since Martin doesn't believe it's true, let's set aside the fact that H2 will never be able to compete on cost. Another unsolvable problem with H2 is that it takes a great deal of volume to store. That makes it great for the fuel for the booster stage of a rocket, where weight is very important but volume isn't. Contrariwise, volume is very important for an airliner, so H2 is a non-starter.

 

Altho battery swapping is of course possible in the engineering sense, I'm not sure we're ever going to see it deployed. (Project) Better Place tried it and failed, which was (at least to me) entirely predictable due to up-front costs of setting up battery swap stations being much too high to be supported by the inevitably small initial number of customers. Tesla also abandoned its plans for battery swapping, not only due to a change in government regulations but also due to the negative reaction from Tesla customers. I think I read that nobody who used the one prototype Tesla battery swap station ever used it again?

I note that Tesla also didn't mention the possibility of battery swapping for its Tesla Semi Truck, despite much speculation before the Reveal event for that vehicle.

At best, battery swapping will only be useful until battery tech improves by lowering the internal resistance of the cells to the point that they won't overheat with ultra-fast charging. That tech will almost certainly be coming within the next decade or two. In fact, some are claiming that solid state batteries in development are already capable of that. Once we have batteries that can be ultra-fast-charged without prematurely aging them, nobody is gonna be interested in developing the tech for swapping battery packs.
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Please tell us more! I learned a lot about supercapacitors on The EEStory forum, but that was all on the theoretical side. I know very little about their practical use. I presume you have electrical power at the dock where your narrowboat resides?

And just the term "narrowboat"; that means you live in the UK and you use this boat for pleasure cruises on the British canal system, is that right? Sounds very romantic, but then I am an Anglophile! Yeah, I know that's off-topic for an EV forum, but who cares?

It astonishes me that Boeing had such problems with its battery pack. It astonishes me even more that the FAA approved the Dreamliner to fly with Boeing basically saying "Well, it doesn't matter if they catch on fire, since we put a fireproof box around them." If ever there was a case for EV haters to make about the dangers of using li-ion batteries, it's the Dreamliner story!

I can't figure out why Boeing didn't just resort to battery swapping until they designed and built a battery pack with proper cooling system, such as Tesla and GM and other auto makers use in their BEVs. Or why Boeing didn't switch to using NiMH batteries, or some other chemistry without the fire hazard of li-ion batteries. I do understand that Boeing was very constrained by available space, but this is not how you engineer a vehicle intended to carry people safely!

I also think the FAA was under political pressure to approve the use of those battery packs despite the clear and present danger of fire hazard, because the Dreamliner was already delayed multiple times, and U.S. politicians (and lobbyists) didn't want to lose potential Dreamliner sales to Airbus.

Anyway... the fact that I'm a big advocate of BEVs doesn't mean I think we should make excuses for what Boeing did with the Dreamliner. IMHO that's going to go down in history as one of the worst examples of engineering in airplanes, ever.

I'd be interested to know if your opinion changes after watching this:

 

(Or even a compact onboard nuclear reactor directly converting nuclear power to electricity, using the tech touted here.)
LOVED it! You no doubt know that the original design brief for the LFTR built by ORNL's Alvin Weinberg was to develop a miniaturised thorium fission reactor to power the US Air Force heavy bomber fleet. Which of course proved impossible but led on to the first successful LFTR.

 

I use double-layer capacitors. Six of them in series at 500F per cell(they are limited to 2.7v per cell, and each one has a PCB with a bypass circuit to protect them when being charged) Each one is a little bigger than a 'D'cell. The whole pack is about 9" by 3" by 4" and very light. I have a microprocessor system which - when I press the 'Start' button charges the capacitors, and heats up the glow plugs. after 30 seconds, the capacitor bank is connected to the starter motor, and off she goes, running on diesel.

Charging supercapacitors is a bit tricky. They look like short circuits, so you need a constant current circuit to do that. I use the microprocessor to run switch-mode control of this.

Boeing, I think, evidently designed themselves into a corner with their dreamliner. The solution is a kludge!

I am sceptical of this 'breakthrough' in teh video. What has been sacrificed to achieve it? Energy density? Number of charging cycles? Speed of charge? You can't assess its importance without knowing how it impacts on every other requirement.

Yes I live in the UK, and in the summer drift around the canal network eating and drinking at the canalside pubs and restaurants, and yes the marina has mains power. I should install solar panels on the boat, but somehow haven't got round to it yet.

 

No, I had no idea what the origins of that were. Thank you!

Was that the U.S. Air Force project which used a crazy prototype where they actually built a small -- but not really that small -- nuclear reactor into a heavy bomber, with shielding only between the reactor and the cockpit, and the rest of the reactor unshielded, so that everything around the plane (hanger, maintenance equipment, ground crew, tarmac, etc.) was exposed continuously to ionizing radiation? Of course, that was back in the days when they didn't fully understand the dangers of long-term exposure to moderate or even relatively low levels of ionizing radiation. Wikipedia says the flights of the Convair NB-36H were from 1955-57.

Anyway, if that is the project where the tech originated, then I'm amazed that it developed into a truly miniature nuclear reactor which could -- at least according to claims in the article I linked above -- be effectively shielded by nothing more than aluminum foil.

Now more nukes!
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You're certainly right to be skeptical. We have no idea how well the tech would stand up to repeated cycling, nor have we any idea of the cost. You're also correct to question the energy density. If I recall, Ionic Materials is claiming lower resistance in its cells, so the speed of charge should be an improvement, assuming that's true. The company claims to be working to achieve mass production, but so are many other companies, and I think we all know that nobody has put solid state batteries into industrial-scale mass production yet.

Anyway, I was quite impressed that the principal of the company was willing to allow a reporter to handle and test prototypes to destruction, with cameras rolling. I think Ionic Materials must be pretty confident its tech actually does work, or they wouldn't have allowed that kind of access! It doesn't prove that a true breakthru in li-ion batteries can be commercialized, but it does at least appear to prove it's possible -- which IMHO pretty sharply contradicts your claim that the tech is approaching its limits. Those are li-ion batteries demonstrated in the video; but very different li-ion batteries than the ones found in today's plug-in EVs.

 

Didn't see the link but had a look at the Convair experiment, about which I had not heard. 3 megawatt air cooled [uranium, presumably] reactor, carried solely to measure radiation exposure of crew. It was only partially shielded by 12 tons of lead but back, top & bottom had *no shielding due to weight limitations. Program was cancelled in 1961 as unfeasible; maybe the Liquid Fluoride Thorium Reactor I referred was built because the radiation levels are orders of magnitude lower than uranium reactors & it could be made far smaller.
* radiation products were vented to the atmosphere as the plane flew, reportedly 14 times the total emitted by the Three Mile Island meltdown!