Evolution and limit of battery energy density

[Andres125sx]

This last point means the "no maintenance" part goes out the window. You will need to do a lot of pre-flight checks and rely on complicated software with LOTS of sensors (redundancy, agreement management, etc) and each time before flight there will need to be a strict checking to ensure those are really functioning as needed. Fixing problems will be complex as any flying aircraft, not just replacing an arm. The consumer and prosumer grade electronics are not nearly redundant enough for transportation level flight and risk management IMHO.

Agree, didn´t pretend to use prosumer grade electronics to carry people. My point was that even for hobby use, there´re fully redundant systems, all parts are duplicated at any current drone over 1k$, controller, sensors, motor speed controllers, motors and props, so there´s no one single part of the system wich can fail without a redundant one assuming control to prevent the accident. If this is plausible today for hobby use, obviously for aeronautic use it is too, but with much much higher quality standards.

Maintenance will always be necessary, but at a much much lower scale. Pre-flight checks will consist on checking motors spinning smooth with no play and no free screws, all the rest is electronics wich will self-check before taking off. Mechanical simplicity of multirotors is unbelieveble when compared to any other flying aircraft

[hollus]

Focus, gentlemen. This is a battery thread.

[Edax]

I think the obsession with energy densities in comparison with liquid fuel is overrated. Energy density nor weight has never really been a factor in car development so why should it be a breaking issue for electric vehicles. If you could pump gas in every parking spot we wouldn’t be driving around with 60 liter fuel tanks anyway.

Since we were talking about aircraft it's of cardinal importance.

Besides it also matters a lot in cars. More weight makes it less efficient and poorly handling. And more dangerous in an accident.

If you read the rest of that post that is exactly the statement I make. Energy density matters for airplanes but not for cars. Since this tread addresses both cars and flying things, I think that is OK to say. Main point is that the value proposition for an electrical vehicle does not necessarily has to be the same as for a conventional equivalent.

That is an error made often with new concepts. People discarded the Ipad am writing this on because it couldn’t do the same as a desktop. True but it can do other things like discussing this with you while I am sitting on my couch. Electrification is a disruptive concept, and with these you should always look for the opportunities they open, not benchmark them against the things they replace.

I think that is the flaw in just looking at energy density as a benchmark for battery development. I bet that for many usecases charging times are much more important than energy density.

As for the car statement. On the surface this might seem true. But having worked in automotive, I find it a penny business more than anything else. Goal is to create as much “perceived value” as possible for as little costs as possible. They would quite comfortably market a car made of cast iron with lightweight alloy wheels as an environmentally conscious sporty concept.

Truth is weight doesn't sell. I bet that if you ask a number of people, they will not be able to tell you the weight of their car. (But they probably can tell you it has a magnesium gearbox). My first car was 660kg. I bet that with all the weight saving technologies you cannot buy a car today that comes close to that. Comfort sells, gadgets sell, safety sells, weight doesn’t.

The fact that the F150 is still the best selling car in north america for the past 30so years proves that consumers are not overly concerned with weight ( nor handling ).

[aterren]

looking back 2015 is it interesting to note that some 4+ years later the Tesla Model 3 (arguably the most advanced battery in a production car) comes in at about 207 wh/kg and the stream of 'battery breakthroughs' has not abated one bit.

It's going on for far longer than four years. Most of these "breakthroughs" are based on wishful thinking or outright dishonesty to solicit funding. But some of them have actual potential. Sooner or later some substantial improvement will hit the market. To me solid electrolyte ("solid state") batteries look the most promising. Many separate groups are working on it with different approaches, including big corporations.

I agree. It is amazing how many people are drawn into the hype cycle of battery technology (or Theranos, the 'Energy Catalyzer, or ZeoSync). It is devilishly hard to make a battery that has the right energy density, peak current capabilities, performance at temperature and can be charged at a reasonable rate and a reasonable number of times for an acceptable cost. A 2x increase in battery performance for high current applications is vanishingly unlikely in the next 10 years. This is not like building faster computers.

[Just_a_fan]

The fact that the F150 is still the best selling car in north america for the past 30so years proves that consumers are not overly concerned with weight ( nor handling ).

The key point is that it isn't a car at all. It's a light truck, so far as the US system is concerned, and so doesn't have to meet all of the expensive requirements cars do. So it can be cheap. And that's why it's popular.

[theblackangus]

I think the obsession with energy densities in comparison with liquid fuel is overrated. Energy density nor weight has never really been a factor in car development so why should it be a breaking issue for electric vehicles. If you could pump gas in every parking spot we wouldn’t be driving around with 60 liter fuel tanks anyway.

Since we were talking about aircraft it's of cardinal importance.

Besides it also matters a lot in cars. More weight makes it less efficient and poorly handling. And more dangerous in an accident.

If you read the rest of that post that is exactly the statement I make. Energy density matters for airplanes but not for cars. Since this tread addresses both cars and flying things, I think that is OK to say. Main point is that the value proposition for an electrical vehicle does not necessarily has to be the same as for a conventional equivalent.

Energy density per KG of weigh matters for transportation in general. Just more to air vehicles than ground vehicles.

For ground vehicles safety and range are the metrics this affects most, with another important one, handling/ride, for us folks who like agile cars with a good ride.

The heavier vehicles get the more dangerous accidents become at lower speed, because of the energy involved.
I would much rather be hit by a Fiat 500 at 20 mph than a model 3. (let alone an F150 =)

[ispano6]

Honda Fluoride Ion Batttery. 10x battery density of Lithium Ion.

https://www.batterypoweronline.com/news ... lly-means/

[hollus]

That's more of a battery concept than a practical battery at this point, but cool.

Very nice quote from that article, highlighting the realities of reasearch and economic development versus hype and expectations:

...the development of Li-ion batteries: “Whittingham described the first prototype in 1975 [using lithium metal] with a liquid electrolyte, Goodenough demonstrated the lithium-cobalt oxide cathode in 1980, Basu and Yazami the graphite anode in 1977-1982, and Yoshino the first full cell in 1985 leading to Sony releasing the first commercial battery in 1991. So it’s a slow process, and we are currently at the electrolyte/cathode/anode development stages for fluoride ion batteries [e.g., around 1980 in the Li-ion timeline]...

[Andres125sx]

True Hollus, but you didn´t quote next phrase in that same paragraph, wich is also important

However, many more people are working on battery technology worldwide compared to the early days of Li-ion.”

Also

“There are many electrochemical researchers out there with an abundance of good ideas, and we want to make them aware of another part of the electrochemical toolbox they can work with,” says Jones. “Given the intensive worldwide studies on lithium-sulfur, lithium-oxygen, magnesium and other ‘next-generation’ battery chemistries, here’s something quite different and potentially high-energy that should be worth their research efforts.”

Anycase it´s obvious it will take some years yet, but things will change so dramatically when any of these succed we must be eager to see it as soon as posible. I am

[AJI]

Not sure if this has been covered?

Father-of-eight invents an electric car battery https://www.dailymail.co.uk/news/articl ... e-masthead

[rscsr]

Not sure if this has been covered?

Father-of-eight invents an electric car battery https://www.dailymail.co.uk/news/articl ... e-masthead

That whole article just to say in a single sentence that this is not rechargeable. And that this is an Al/air battery. And there have been road tests in 1990.
And that whole article seems to be either promotional and includes remarks like that hasn't been developed before because the industry suppressed it.
And it is claimed that it would cost 5000£ and would be good for 1500miles. That's 3.33£/mile (2.03£/km).
That is quite expensive.

[Andres125sx]

Indeed, quite expensive


But it open up the possibility for electric planes, which is not possible with current LiIon batteries as they're too heavy

[rscsr]

Indeed, quite expensive


But it open up the possibility for electric planes, which is not possible with current LiIon batteries as they're too heavy

That is certainly true, and something I didn't even consider. afaik about 200Wh/kg for LiPo vs 1300Wh/kg for AlAir.

[rscsr]

Indeed, quite expensive


But it open up the possibility for electric planes, which is not possible with current LiIon batteries as they're too heavy

That is certainly true, and something I didn't even consider. afaik about 200Wh/kg for LiPo vs 1300Wh/kg for AlAir.

If we assume that those AlAir batteries consist 100% of Aluminium weight wise, and we can use it fully, and Aluminium costs about 2.2USD/kg (which I would assume will increase in the short term because the productioncosts, even from scrap, are mainly due to the used energy). Then even theoretical 2000Wh/kg would mean 1.1USD/kWh. And the electrolytes and packaging would only increase the costs. Probably to 3USD/kWh most likely to more.
The lowest priced LiPo seem to cost about 70USD/kWh.
So I pretty much doubt that AlAir has any place in the automotive space. Maybe as a spare charge it would be feasible.
And of course as you said, for flying operations.

[AJI]

AlAir could be a good solution for formula E?