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Question for the cleverclogs engineers.


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There's this promising-sounding new battery technology being put into an electric plane.

But if you read the article carefully, the cycle life of this battery is currently approx 250 cycles and they only "hope" to double that in the next 2 years.

How is that remotely helpful or economic? A plane that can only be charged up 250 times before it needs another (presumably very expensive) battery. :S

Surely this would only be useful if the battery can be swapped easily and can easily be recycled into a new one. Or have I misunderstood something? 

https://newatlas.com/aircraft/oxis-lithium-sulfur-battery-electric-aircraft/

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Battery breakthroughs, cancer cures, baldness cures..  file alongside Amazon drones ie bullshit PR lapped up by idiots.

From the article it sounds like it is just some PR news on the development cycle. Perhaps they are aiming to raise money for more development. They have to start somewhere. Much more exciting to say t

Shame women don't...   XYY

18 minutes ago, swiss_democracy_for_all said:

There's this promising-sounding new battery technology being put into an electric plane.

But if you read the article carefully, the cycle life of this battery is currently approx 250 cycles and they only "hope" to double that in the next 2 years.

How is that remotely helpful or economic? A plane that can only be charged up 250 times before it needs another (presumably very expensive) battery. :S

Surely this would only be useful if the battery can be swapped easily and can easily be recycled into a new one. Or have I misunderstood something? 

https://newatlas.com/aircraft/oxis-lithium-sulfur-battery-electric-aircraft/

 

From the article it sounds like it is just some PR news on the development cycle. Perhaps they are aiming to raise money for more development. They have to start somewhere. Much more exciting to say that you have developed super new batteries that can power a sexy aircraft rather than the boring carpet cleaner.

Then again there probably is a big chunk of US Defense spending money going for research in this area. Battery powered drones, helicopters, etc, will be super-quiet.

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I now yawn when I read about battery breakthroughs; they are always oversold by some publicity-seeking researchers. The real-world capacity is usually a small percentage of the theoretical.

With a car, the IC engine weighs a substantial fraction of the total car weight so moving to electric motor saves weight, and the on-board fuel is a smaller portion. With an aircraft, the engines are a trivial weight, and the fuel might weigh more than the aircraft. Couple that with the fact fuel weight diminishes during flight, but batteries stay the same, or even increase in weight, then full electric long-distance flight is not on the horizon. Everyone seems to be looking at hybrids where a battery can keep the thermal engines away from inefficient operating points.

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24 minutes ago, The Masked Tulip said:

 

From the article it sounds like it is just some PR news on the development cycle. Perhaps they are aiming to raise money for more development. They have to start somewhere. Much more exciting to say that you have developed super new batteries that can power a sexy aircraft rather than the boring carpet cleaner.

Then again there probably is a big chunk of US Defense spending money going for research in this area. Battery powered drones, helicopters, etc, will be super-quiet.

Won't really be that much quieter as most of the noise will come from rotors or props. Ignoring 2 stroke autogyros and TPE731 turboprops.

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2 minutes ago, spunko said:

Battery breakthroughs, cancer cures, baldness cures..  file alongside Amazon drones ie bullshit PR lapped up by idiots.

Yeah, they nearly all disappear into the ether.

I'm intrigued to see what the tosser Musk is going to announce on 15th September though, as although he doesn't always deliver on time, his stuff usually shows up eventually.

 

3 minutes ago, Rare Bear said:

Won't really be that much quieter as most of the noise will come from rotors or props. Ignoring 2 stroke autogyros and TPE731 turboprops.

You sure about that? There's a small plane where they designed it to be very quiet, including putting the engine entirely on the inside, that was coveted by an ex-colleague of mine who flew gliders. I saw one flying about in the Malverns years back, it really was remarkably silent. Sorry don't know it's name.

 

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2 minutes ago, Rare Bear said:

Won't really be that much quieter as most of the noise will come from rotors or props. Ignoring 2 stroke autogyros and TPE731 turboprops.

 

I knew someone would raise that when I wrote it. Yep, the rotors make a lot of noise. In the future they might not have either though. Yep, there will still be turbo blades but they will be enclosed. All fun stuff and long-term development.

We just won't be flying from Stansted to the Med in a battery powered aircraft for a long time to come. Might not even be doing that in a petrol or diesel powered one.

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55 minutes ago, swiss_democracy_for_all said:

There's this promising-sounding new battery technology being put into an electric plane.

But if you read the article carefully, the cycle life of this battery is currently approx 250 cycles and they only "hope" to double that in the next 2 years.

How is that remotely helpful or economic? A plane that can only be charged up 250 times before it needs another (presumably very expensive) battery. :S

Surely this would only be useful if the battery can be swapped easily and can easily be recycled into a new one. Or have I misunderstood something? 

https://newatlas.com/aircraft/oxis-lithium-sulfur-battery-electric-aircraft/

Trade offs and compromises, look at it from the aircraft manufacturers's point of view, they want to establish an electric power aircraft, once of the big issues is energy density and the size of the battery compromising the whole design.Short term solution, go with a battery with twice the enegery density for a few years to get established rather than having a plane with a compromised flight time / distance or one where youv've pretty much designed the plane around current battery inadequacies. 

Batteries are on a  long running improving streak of a good few percent per year.  Lots at power tools - weak, hardly usable NiCD'snow you can run gardening equipment as well as most power tools very effectively from them.

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56 minutes ago, swiss_democracy_for_all said:

There's this promising-sounding new battery technology being put into an electric plane.

But if you read the article carefully, the cycle life of this battery is currently approx 250 cycles and they only "hope" to double that in the next 2 years.

How is that remotely helpful or economic? A plane that can only be charged up 250 times before it needs another (presumably very expensive) battery. :S

Surely this would only be useful if the battery can be swapped easily and can easily be recycled into a new one. Or have I misunderstood something? 

https://newatlas.com/aircraft/oxis-lithium-sulfur-battery-electric-aircraft/

Planes need the batteries to be ultra-light weight.  A heavy battery will lead to more battery required to carry it (about 20% of an aircraft's fuel is required just to fly the fuel).

It could actually make sense to have single use batteries for aircraft, so long as the batteries were light enough and that there was an efficient/streamlined recycling system*.  At the very least, this approach would allow for each flight to have exactly the right amount of battery loaded for the flight, as opposed to a 'more complex to replace' battery where the plane might be flying with excess battery (weight) for a fair bit of the time.

[* and aircraft would use so much of the things that a streamlined recycling system would be guaranteed.]

I'd also say that a specifically about-250 cycle battery would be a poor compromise -- not good enough to leave to the general maintenance cycles, but too good to have as a routine part of the aircraft turn-around.

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1 minute ago, swiss_democracy_for_all said:

Yeah, they nearly all disappear into the ether.

I'm intrigued to see what the tosser Musk is going to announce on 15th September though, as although he doesn't always deliver on time, his stuff usually shows up eventually.

 

You sure about that? There's a small plane where they designed it to be very quiet, including putting the engine entirely on the inside, that was coveted by an ex-colleague of mine who flew gliders. I saw one flying about in the Malverns years back, it really was remarkably silent. Sorry don't know it's name.

 

You could build a pretty quiet propeller if you keep down the tip speed. Make it really slow turning but you would presumably run into other problems for a practical aircraft. 

I wonder if the aircraft you are thinking off is a really fancy motor glider which has the engine buried in the fuselage and the prop folds and is covered by part of the nose section when gliding. Really elegant, complicated and expensive.

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Tesla are having their battery day in a few weeks time. Everybody is expecting the announcement of a breakthrough. Speculation that it will be a million mile battery, cheaper and longer lasting battery which could bring the cost of EVs to parity with ICE cars. 

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11 minutes ago, Popuplights said:

Tesla are having their battery day in a few weeks time. Everybody is expecting the announcement of a breakthrough. Speculation that it will be a million mile battery, cheaper and longer lasting battery which could bring the cost of EVs to parity with ICE cars. 

Impressive if true.

I was surprised to see that Nissan Leaf batteries have no cooling system meaning that the inevitable over-heating kills individual cells off one by one so that by seven years you need a new battery.

That's terrible.

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2 minutes ago, Frank Hovis said:

Impressive if true.

I was surprised to see that Nissan Leaf batteries have no cooling system meaning that the inevitable over-heating kills individual cells off one by one so that by seven years you need a new battery.

That's terrible.

Bit of an anecdote. My mate has a Leaf, and took it to Northumbria from the South coast recently. Every time he stopped to do a rapid charge, the car would charge a bit less, so first stop, 85%, then 70%, then 60% etc. This was directly due to the lack of active battery cooling. It took him ages to get there. 

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Theres a huge investment in replacing fossil fuels, some of them:

Solid state batteries look like the way forward, give it 5 years to and it should be commercially available
https://youtu.be/TAFk-CebHWA

Lithium Ion Titanate (LTO battery), good for 20k charge cycles but has low energy density. Ideal for fit-and-forget systems?
https://youtu.be/p1xildSl4Hk

sodium-ion, similar performance to li-ion but raw materials are more common (ie cheaper) https://www.theregister.com/2020/06/02/sodium_batteries_improve/

Gel batteries https://www.theregister.com/2020/07/31/battery_boffin_john_goodenough_to/

The flip side showing the environment cost of "green" vehicles
https://autovistagroup.com/news-and-insights/swedish-study-calls-smaller-ev-batteries-finds-tesla-more-polluting-8-year-old
Many modern ic cars are scrapped due to electrical faults (mot fail due to abs light etc) rather than the rust that used to kill old cars. EV cars won't have a long life due to failing batteries and electrical faults.

https://www.autocarindia.com/car-news/un-study-highlights-environmental-impact-of-ev-battery-production-418198

Lots more https://duckduckgo.com/?q=ev+battery+damage+environment&t=h_

Edited by Andersen
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43 minutes ago, Popuplights said:

Bit of an anecdote. My mate has a Leaf, and took it to Northumbria from the South coast recently. Every time he stopped to do a rapid charge, the car would charge a bit less, so first stop, 85%, then 70%, then 60% etc. This was directly due to the lack of active battery cooling. It took him ages to get there. 

Lithium battery degradation rate is a function of temperature so seems like these are going to get fucked pretty quick.

Edited by goldbug9999
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1 hour ago, Rare Bear said:

You could build a pretty quiet propeller if you keep down the tip speed. Make it really slow turning but you would presumably run into other problems for a practical aircraft. 

I wonder if the aircraft you are thinking off is a really fancy motor glider which has the engine buried in the fuselage and the prop folds and is covered by part of the nose section when gliding. Really elegant, complicated and expensive.

Rubber bands are the future

 

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1 hour ago, Frank Hovis said:

I was surprised to see that Nissan Leaf batteries have no cooling system meaning that the inevitable over-heating kills individual cells off one by one so that by seven years you need a new battery.

 

53 minutes ago, Popuplights said:

Bit of an anecdote. My mate has a Leaf, and took it to Northumbria from the South coast recently. Every time he stopped to do a rapid charge, the car would charge a bit less, so first stop, 85%, then 70%, then 60% etc. This was directly due to the lack of active battery cooling. It took him ages to get there. 

There are lots of early Leafs around (2012) still fine on the original battery but reliable range does come down to 70 or so miles in many cases.

The newer - 40kWh - models have caught out owners who imagined the increased range and one or two fast charges would mean 300-400 miles in a day would be easy. Anecdotally, many of these have found the same as @Popuplights friend: repeated fast-charging takes longer and longer as in the absence of a cooling system, the battery software throttles down current rate to keep temperatures down. All in all, if you're in the market for a £35k + EV then Leaf is now not the way to go as other manufacturers can offer better range and more useful re-charging rates.

As ever, it's a case of determining exactly what you need. My wife's 30kWh Leaf cost around £10k, seldom does more than 60 miles every day or two and will recharge during daylight hours off our PV panels. Today, she's using it for a 110 mile journey, which the car will happily do without recharging and if it's needed in the morning then we'll recharge overnight.

 

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1 minute ago, Duck said:

As ever, it's a case of determining exactly what you need. My wife's 30kWh Leaf cost around £10k, seldom does more than 60 miles every day or two and will recharge during daylight hours off our PV panels. Today, she's using it for a 110 mile journey, which the car will happily do without recharging and if it's needed in the morning then we'll recharge overnight.

If I didn't want a Berlingo so it could double as a camper that would be exactly my usage and with that reasonably cheap starting price costs will be tiny.

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57 minutes ago, whitevanman said:

Rubber bands are the future

That's not a totally ridiculous statement It's surprising how much elastic energy can be stored per kg. A colleague put 1MJ into 60m of thin Dyneema line by stretching it. If we ever get carbon nanotube filaments, then they could have a very high specific elastic energy. Perhaps the structural beams to react the pull might be a bit weighty!

Edited by Nippy
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28 minutes ago, Duck said:

repeated fast-charging takes longer and longer as in the absence of a cooling system, the battery software throttles down current rate to keep temperatures down.

Does rapid charging also reduce battery capacity over the long term?

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1 minute ago, Nippy said:

Does rapid charging also reduce battery capacity over the long term?

Yes in most cases, possibly no if really careful. Most batteries like being in the range  20-80% charge, kept in that range and battery life is maximised - you might use rapid charging to do that and specifically target that range.However all cells ave internal resistance, faster charging equals faster increase in pack temperature and high (and very low) temperatures fasten battery degradation. Battery management systems ad chargers are pretty smart but they make all sorts of compromises. Nissan got it wrong with the latest  Leaf and "rapidgate", without active cooling the car was not able to take advantage of rapid charging the the way users thought they could - i.e. drive, rapid charge, drive, rapid charge. 

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