Rapid discharging batteries enable electric passenger planes

Mixing magnetic nanoparticles into battery electrode materials and applying a light magnetic field doubles the discharge rate of batteries.

24M is making prototype batteries using this magnetic approach.

Zunum will use the batteries for electric planes.

The batteries must be able to deliver a massive amount of power at takeoff. They must have energy density to cruise for at least hundreds of miles. They need to be as long-lasting and light as possible. They must be rapid charging or easily swapped for a fully charged battery between flights.

In 2022, Zunum will have a hybrid plane with a gas turbine and two battery packs. It will be able to fly around 700 miles (1,127 kilometers). They will have an all-electric version with three battery packs and a range of less than 200 miles. The plane will hold 12 passengers.

66 thoughts on “Rapid discharging batteries enable electric passenger planes”

  1. A range of 200 miles seems very short, considering the possible need to divert if there is bad weather at destination, or even to stay in a holding pattern.

  2. Okay, If I ever decide to invent anything with a closed loop battery system, I’m hiring Goatguy. Period. Hands down. That’s it…

  3. How much energy is used on takeoff compared to cruising? Would it make much of a difference to use EM launchers in airports like on carriers?

  4. The “double discharge rate” is a bit of a ruse. Truth is, that commonplace LiPO type batteries have marvelous discharge rates. And, truth be told, for a plane to take off, it definitely uses its maximum power plant output, but not much outside what a bunch of LiPO batteries can easily produce. More telling for airplanes-using-batteries is the specific energy of the battery packs. For instance, for the Tesla Model S, the main battery pack weighs in at about 600 kg, and has an useful-energy of about 85 kWh. 300+ miles of range, on that. I used to disdain (kWh/kg) specific energy measures, and preferred (MJ/kg) which is a more “SI” science based value, but you know, kWh/kg is just fine too. 3.6 MJ = 1.0 kWh. Conversions are easy.Still… (85 kWh ÷ 600 kg) → 0.142 kWh/kg. almost exactly ⅐ kWh/kg. Compare that to (44 MJ/kg × 0.30 efficiency) ÷ 3.6 MJ/kWh → 3.7 kWh/kg for jet fuel. That means that jet fuel is about 26 times more contained-useful-energy potent than Tesla batteries. ________________________________________But Tesla batteries are optimized for ground-based vehicular use, you shout! Yes, true. They were designed to be nearly indestructible in accidents, while being bathed in salty winter road grime, and so forth. They used materials that’d SURVIVE for 10+ years of abuse. Stainless steel. thick multiple silicone seals, structural reinforcements, copper busbars, all that. What would be done for electric aircraft?Aluminum electrical busbars. Way lighter for the current carrying capacity needed. Probably cheaper too, with the spot-market cost of copper being what it is these days. The little battery cells — thousands of 18650 type lithium-ion rechargeable pods — could be encased in tough plastic shells instead of heavy metal ones. Not much is lost, either. Except “containment” if they catch fire. Indeed — if I were designing an electric plane, I’d have the battery packs be EJECTABLE in case of fire. You got 5 of them? Just jettison the one that catches on fire. Who cares. Better than burning up before you emergency land. (Jets do this all the time with their fuel. If they have to “turn back” and land… they dump most of their jet fuel outboard in flight. The EPA hates it, but the passengers have a different view.)________________________________________I think telling though is the above ranges. 200 miles all electric, with 3 batteries. 700 miles, hybrid, with 2 batteries, 1 turbine generator, 1 tank of jet fuel. ⅔ of 200 miles = 133 miles (on 2 batteries).700 – 133 = 566 miles on jet fuel. Pretty potent, that jet fuel. Especially considering that the turbine has an irreducible mass.Its not a weak idea, hybrid. Get the peak power at take-off and initial flight plan climb. Then when cruising, the turbogenerator does all the work. At whatever RPM its most efficient at. Win, win, win.Just saying,GoatGuy

  5. 24M? Who kept promising flow batteries that have better energy density than li-ion batteries…This vaporware company still exists?

  6. Any article that says “double the discharge rate” and “airplane” in the same sentence is scary. I prefer to land at airports on time and not “before scheduled arrival”.

  7. As I always point out the specific power of lithium ion batteries of (charitably) 0.2 kwhr/kg is quite bad for air travel.Batteries, jet fuel, hydrogen, (lol flywheels) are just stores of energy. The plane must get the store of energy up to speed and up to cruising altitude. This means transferring energy from the energy store to the kinetic and potential energy of the aircraft.So how much energy per kg of energy store (specific power) really matters. Specific power is the MPG of flying things, in particular for VTOL planes (which seem to be the fancy of many PPT jockeys).Comparing batteries with even fuel cells you find that fuel cells are 4-5x more efficient in terms of specific power. This means that every 5 kg of battery could be replaced with 1kg of fuel cell most of which is the tankage. This adds up quickly.Stick to the liquid fuels. If you must go electric then go fuel cell.

  8. Guys, there is a new technology that will eliminate batteries all together for awhile. I don’t like the approach I am talking about because it is mechanical. Imagine a battery you can recharge millions of times with a energy density much greater than 50 times the best battery we have today. What I am talking about is supposedly a company in China just found a way to make carbon nanotubes in quantity cheaply. By encasing a flywheel in carbon nanotubes and spinning it at 750,000 rpms a car could store enough power to go 10,000 miles. If this is true flywheels will replace a lot of batteries. For example the gigawatt installation in australia could have been build with just flywheels.Of course there are problems with using flywheels but it is a old technology, so no real surprises.

  9. With the 2 hour safety dance stuff at airports these days, combined with it taking 20 minutes to park at the airport (or 20 minutes to wait for a taxi, your choice), and then 20 minutes to get your luggage at the other end and another 20 minutes waiting to get a taxi and then drive to your destination…Cheaper AND faster to drive for under 320 km (200 miles) and if you drive you can then have a car at your destination.

  10. 200 miles is pointless.. considering that airports are usualy 10-20 miles from where you are and want to go .. theres a chance it would be slower to go somewhere then to just drive it.. all other things equal

  11. With the 2 hour safety dance stuff at airports these days, combined with it taking 20 minutes to park at the airport (or 20 minutes to wait for a taxi, your choice), and then 20 minutes to get your luggage at the other end and another 20 minutes waiting to get a taxi and then drive to your destination…

    Cheaper AND faster to drive for under 320 km (200 miles) and if you drive you can then have a car at your destination.

  12. 200 miles is pointless.. considering that airports are usualy 10-20 miles from where you are and want to go .. theres a chance it would be slower to go somewhere then to just drive it.. all other things equal

  13. if I were designing an electric plane, I’d have the battery packs be EJECTABLE in case of fire.”And what about the forbidding extra weight/volume/complexity of an ejection system? It’s better to just not use flammable electrolytes as tesla does. Maybe fire retardants in the casing(s). (I don’t see why cell should be in discrete cylinders, they could be manufactured in bulk in a honeycomb like or similar structure)

  14. I didn’t say V flow batteries, nor did they. They claimed some sort of semi-solid lithium flow batteries. However that was supposed to turn out. I have these NBF articles bookmarked:”MIT has new semi-solid flow batteries that have ten times the energy density of liquid flow batteries””24M Could Reduce Cost of Batteries for Electric Cars by 85% by 2015″”Startup 24M hopes to commercialize battery with liquid electrolyte

  15. Strangely enough, the more recent Zenum renders show a mid wing battery pod, apparently for build/accessibility reasons. Not currently ejectable though…

  16. ” if I were designing an electric plane, I’d have the battery packs be EJECTABLE in case of fire.”

    And what about the forbidding extra weight/volume/complexity of an ejection system? It’s better to just not use flammable electrolytes as tesla does. Maybe fire retardants in the casing(s). (I don’t see why cell should be in discrete cylinders, they could be manufactured in bulk in a honeycomb like or similar structure)

  17. The “Flight of the Century” guys proposed UAV battery pods that can link up with a flying aircraft to provide effectively unlimited range. They are apparently doing work for the US navy on midair electric recharge (which looks suspiciously like readapting probe-and-drogue refueling equipment and doing the equivalent of an electric toothbrush recharger).An interesting argument could be made for a flying battery pod with a fast discharge profile that is mated on the ground to a departing aircraft, then released after a reasonable climbout to return to the originating airport. If possible, have it be vertical landing capable to not occupy the runway/landing pattern.Chargepoint was showing off megawatt class connectors for cable charging electric semi’s and electric aircraft, and it’s roughly firehose sized, for a sense of how big the connectors need to be.

  18. I didn’t say V flow batteries, nor did they. They claimed some sort of semi-solid lithium flow batteries. However that was supposed to turn out. I have these NBF articles bookmarked:

    “MIT has new semi-solid flow batteries that have ten times the energy density of liquid flow batteries”

    “24M Could Reduce Cost of Batteries for Electric Cars by 85% by 2015”

    “Startup 24M hopes to commercialize battery with liquid electrolyte”

  19. I don’t dislike mechanical things, I just like solid state things without friction and the fewer moving parts the better.

  20. Many of the proposed electric planes have multiple distributed propellers instead of just one or two the way normal aircraft do. The idea being that moving more air at a lower velocity gives the same thrust for less energy, and hence greater efficiency. This approach would also be significantly quieter.Of course the illustration in this particular article doesn’t show that, but that’s just “an artist’s impression” and doesn’t intend to convey technical information.

  21. I was on a plane that had the hatch “not close right” as we were about to take off. So an “engineer” was called, who solved the problem by wrapping wire around the catch and telling us to keep away from that particular door during flight.Needless to say, this was not a major airline.

  22. We discuss the nanotube flywheels extensively in the article about nanotube flywheels a bit below this article.Also, why do you not like mechanical things?

  23. The only way you are getting ejectable batteries is if they are on wing mounted pods. Which sounds pretty cool.The history of air disasters is filled with “the hatch didn’t quite close right when we closed it the thousandth time”.

  24. Vanadium flow certainly not. Look down on the periodic table to find Vanadium to see why it will never beat lithium ion for specific power. Plenty of other grid uses of course for 1,000 m^3 Vanadium tanks.

  25. You missed the largest aspect of energy used. 1: takeoff2: climbing to cruising altitude3: cruisingEM launchers don’t really help unless your runway is too short. Most all commuter flights spend the majority of their energy climbing to cruising altitude where you then slowly trade altitude for efficient flight as you travel to the runway.

  26. As I always point out the specific power of lithium ion batteries of (charitably) 0.2 kwhr/kg is quite bad for air travel.Batteries, jet fuel, hydrogen, (lol flywheels) are just stores of energy. The plane must get the store of energy up to speed and up to cruising altitude. This means transferring energy from the energy store to the kinetic and potential energy of the aircraft.So how much energy per kg of energy store (specific power) really matters. Specific power is the MPG of flying things, in particular for VTOL planes (which seem to be the fancy of many PPT jockeys).Comparing batteries with even fuel cells you find that fuel cells are 4-5x more efficient in terms of specific power. This means that every 5 kg of battery could be replaced with 1kg of fuel cell most of which is the tankage. This adds up quickly.Stick to the liquid fuels. If you must go electric then go fuel cell.

  27. Guys, there is a new technology that will eliminate batteries all together for awhile. I don’t like the approach I am talking about because it is mechanical. Imagine a battery you can recharge millions of times with a energy density much greater than 50 times the best battery we have today. What I am talking about is supposedly a company in China just found a way to make carbon nanotubes in quantity cheaply. By encasing a flywheel in carbon nanotubes and spinning it at 750,000 rpms a car could store enough power to go 10,000 miles. If this is true flywheels will replace a lot of batteries. For example the gigawatt installation in australia could have been build with just flywheels.Of course there are problems with using flywheels but it is a old technology, so no real surprises.

  28. Strangely enough, the more recent Zenum renders show a mid wing battery pod, apparently for build/accessibility reasons. Not currently ejectable though…

  29. The “Flight of the Century” guys proposed UAV battery pods that can link up with a flying aircraft to provide effectively unlimited range. They are apparently doing work for the US navy on midair electric recharge (which looks suspiciously like readapting probe-and-drogue refueling equipment and doing the equivalent of an electric toothbrush recharger).

    An interesting argument could be made for a flying battery pod with a fast discharge profile that is mated on the ground to a departing aircraft, then released after a reasonable climbout to return to the originating airport. If possible, have it be vertical landing capable to not occupy the runway/landing pattern.

    Chargepoint was showing off megawatt class connectors for cable charging electric semi’s and electric aircraft, and it’s roughly firehose sized, for a sense of how big the connectors need to be.

  30. As many here will no doubt know, hybrid aircraft are an active area of development using light weight high energy and power density superconducting flywheels. See particularly last para for a bit about this.

  31. A range of 200 miles seems very short, considering the possible need to divert if there is bad weather at destination, or even to stay in a holding pattern.

  32. Many of the proposed electric planes have multiple distributed propellers instead of just one or two the way normal aircraft do. The idea being that moving more air at a lower velocity gives the same thrust for less energy, and hence greater efficiency. This approach would also be significantly quieter.

    Of course the illustration in this particular article doesn’t show that, but that’s just “an artist’s impression” and doesn’t intend to convey technical information.

  33. I was on a plane that had the hatch “not close right” as we were about to take off. So an “engineer” was called, who solved the problem by wrapping wire around the catch and telling us to keep away from that particular door during flight.

    Needless to say, this was not a major airline.

  34. We discuss the nanotube flywheels extensively in the article about nanotube flywheels a bit below this article.

    Also, why do you not like mechanical things?

  35. Okay, If I ever decide to invent anything with a closed loop battery system, I’m hiring Goatguy. Period. Hands down. That’s it…

  36. It would be interesting to know what the decibel level for a propeller or a ducted fan is…much as most of the noise on a freeway is from tires these days (minus the semis) and not motors.

  37. The only way you are getting ejectable batteries is if they are on wing mounted pods. Which sounds pretty cool.

    The history of air disasters is filled with “the hatch didn’t quite close right when we closed it the thousandth time”.

  38. Vanadium flow certainly not. Look down on the periodic table to find Vanadium to see why it will never beat lithium ion for specific power. Plenty of other grid uses of course for 1,000 m^3 Vanadium tanks.

  39. You missed the largest aspect of energy used.

    1: takeoff
    2: climbing to cruising altitude
    3: cruising

    EM launchers don’t really help unless your runway is too short. Most all commuter flights spend the majority of their energy climbing to cruising altitude where you then slowly trade altitude for efficient flight as you travel to the runway.

  40. As I always point out the specific power of lithium ion batteries of (charitably) 0.2 kwhr/kg is quite bad for air travel.

    Batteries, jet fuel, hydrogen, (lol flywheels) are just stores of energy. The plane must get the store of energy up to speed and up to cruising altitude. This means transferring energy from the energy store to the kinetic and potential energy of the aircraft.

    So how much energy per kg of energy store (specific power) really matters. Specific power is the MPG of flying things, in particular for VTOL planes (which seem to be the fancy of many PPT jockeys).

    Comparing batteries with even fuel cells you find that fuel cells are 4-5x more efficient in terms of specific power. This means that every 5 kg of battery could be replaced with 1kg of fuel cell most of which is the tankage. This adds up quickly.

    Stick to the liquid fuels. If you must go electric then go fuel cell.

  41. Guys, there is a new technology that will eliminate batteries all together for awhile. I don’t like the approach I am talking about because it is mechanical. Imagine a battery you can recharge millions of times with a energy density much greater than 50 times the best battery we have today. What I am talking about is supposedly a company in China just found a way to make carbon nanotubes in quantity cheaply. By encasing a flywheel in carbon nanotubes and spinning it at 750,000 rpms a car could store enough power to go 10,000 miles. If this is true flywheels will replace a lot of batteries. For example the gigawatt installation in australia could have been build with just flywheels.
    Of course there are problems with using flywheels but it is a old technology, so no real surprises.

  42. How much energy is used on takeoff compared to cruising? Would it make much of a difference to use EM launchers in airports like on carriers?

  43. One more advantage for the hybrid: The ability to take off and land “all electric” will probably open up more landing slots. Both for noise reasons (or at least the ability to convince activist groups that an electric plane will be quiet, regardless of the actual dB) and because as soon as it becomes possible, at least some cities will start having pollution charges or pollution free landing slots or some such thing. The way London has a “congestion charge” that is waived for electric cars, even though electric cars use just as many square meters of road space.

  44. The “double discharge rate” is a bit of a ruse. Truth is, that commonplace LiPO type batteries have marvelous discharge rates. And, truth be told, for a plane to take off, it definitely uses its maximum power plant output, but not much outside what a bunch of LiPO batteries can easily produce. More telling for airplanes-using-batteries is the specific energy of the battery packs. For instance, for the Tesla Model S, the main battery pack weighs in at about 600 kg, and has an useful-energy of about 85 kWh. 300+ miles of range, on that. I used to disdain (kWh/kg) specific energy measures, and preferred (MJ/kg) which is a more “SI” science based value, but you know, kWh/kg is just fine too. 3.6 MJ = 1.0 kWh. Conversions are easy.Still… (85 kWh ÷ 600 kg) → 0.142 kWh/kg. almost exactly ⅐ kWh/kg. Compare that to (44 MJ/kg × 0.30 efficiency) ÷ 3.6 MJ/kWh → 3.7 kWh/kg for jet fuel. That means that jet fuel is about 26 times more contained-useful-energy potent than Tesla batteries. ________________________________________But Tesla batteries are optimized for ground-based vehicular use, you shout! Yes, true. They were designed to be nearly indestructible in accidents, while being bathed in salty winter road grime, and so forth. They used materials that’d SURVIVE for 10+ years of abuse. Stainless steel. thick multiple silicone seals, structural reinforcements, copper busbars, all that. What would be done for electric aircraft?Aluminum electrical busbars. Way lighter for the current carrying capacity needed. Probably cheaper too, with the spot-market cost of copper being what it is these days. The little battery cells — thousands of 18650 type lithium-ion rechargeable pods — could be encased in tough plastic shells instead of heavy metal ones. Not much is lost, either. Except “containment” if they catch fire. Indeed — if I were designing an electric plane, I’d have the battery packs be EJECTABLE in case of fire. You got 5 of them? Just jettison the one that catches on fire. Who cares. Better than burning up before you emergency land. (Jets do this all the time with their fuel. If they have to “turn back” and land… they dump most of their jet fuel outboard in flight. The EPA hates it, but the passengers have a different view.)________________________________________I think telling though is the above ranges. 200 miles all electric, with 3 batteries. 700 miles, hybrid, with 2 batteries, 1 turbine generator, 1 tank of jet fuel. ⅔ of 200 miles = 133 miles (on 2 batteries).700 – 133 = 566 miles on jet fuel. Pretty potent, that jet fuel. Especially considering that the turbine has an irreducible mass.Its not a weak idea, hybrid. Get the peak power at take-off and initial flight plan climb. Then when cruising, the turbogenerator does all the work. At whatever RPM its most efficient at. Win, win, win.Just saying,GoatGuy

  45. 24M? Who kept promising flow batteries that have better energy density than li-ion batteries…This vaporware company still exists?

  46. Any article that says “double the discharge rate” and “airplane” in the same sentence is scary. I prefer to land at airports on time and not “before scheduled arrival”.

  47. It would be interesting to know what the decibel level for a propeller or a ducted fan is…much as most of the noise on a freeway is from tires these days (minus the semis) and not motors.

  48. One more advantage for the hybrid: The ability to take off and land “all electric” will probably open up more landing slots. Both for noise reasons (or at least the ability to convince activist groups that an electric plane will be quiet, regardless of the actual dB) and because as soon as it becomes possible, at least some cities will start having pollution charges or pollution free landing slots or some such thing. The way London has a “congestion charge” that is waived for electric cars, even though electric cars use just as many square meters of road space.

  49. The “double discharge rate” is a bit of a ruse. Truth is, that commonplace LiPO type batteries have marvelous discharge rates. And, truth be told, for a plane to take off, it definitely uses its maximum power plant output, but not much outside what a bunch of LiPO batteries can easily produce.

    More telling for airplanes-using-batteries is the specific energy of the battery packs.

    For instance, for the Tesla Model S, the main battery pack weighs in at about 600 kg, and has an useful-energy of about 85 kWh. 300+ miles of range, on that.

    I used to disdain (kWh/kg) specific energy measures, and preferred (MJ/kg) which is a more “SI” science based value, but you know, kWh/kg is just fine too. 3.6 MJ = 1.0 kWh. Conversions are easy.

    Still… (85 kWh ÷ 600 kg) → 0.142 kWh/kg. almost exactly ⅐ kWh/kg.

    Compare that to (44 MJ/kg × 0.30 efficiency) ÷ 3.6 MJ/kWh → 3.7 kWh/kg for jet fuel. That means that jet fuel is about 26 times more contained-useful-energy potent than Tesla batteries.
    ________________________________________

    But Tesla batteries are optimized for ground-based vehicular use, you shout! Yes, true. They were designed to be nearly indestructible in accidents, while being bathed in salty winter road grime, and so forth. They used materials that’d SURVIVE for 10+ years of abuse. Stainless steel. thick multiple silicone seals, structural reinforcements, copper busbars, all that.

    What would be done for electric aircraft?

    Aluminum electrical busbars. Way lighter for the current carrying capacity needed. Probably cheaper too, with the spot-market cost of copper being what it is these days. The little battery cells — thousands of 18650 type lithium-ion rechargeable pods — could be encased in tough plastic shells instead of heavy metal ones. Not much is lost, either. Except “containment” if they catch fire.

    Indeed — if I were designing an electric plane, I’d have the battery packs be EJECTABLE in case of fire. You got 5 of them? Just jettison the one that catches on fire. Who cares. Better than burning up before you emergency land. (Jets do this all the time with their fuel. If they have to “turn back” and land… they dump most of their jet fuel outboard in flight. The EPA hates it, but the passengers have a different view.)
    ________________________________________

    I think telling though is the above ranges.

    200 miles all electric, with 3 batteries.
    700 miles, hybrid, with 2 batteries, 1 turbine generator, 1 tank of jet fuel.

    ⅔ of 200 miles = 133 miles (on 2 batteries).
    700 – 133 = 566 miles on jet fuel.
    Pretty potent, that jet fuel. Especially considering that the turbine has an irreducible mass.

    Its not a weak idea, hybrid.
    Get the peak power at take-off and initial flight plan climb.
    Then when cruising, the turbogenerator does all the work.
    At whatever RPM its most efficient at.

    Win, win, win.
    Just saying,
    GoatGuy

  50. Any article that says “double the discharge rate” and “airplane” in the same sentence is scary. I prefer to land at airports on time and not “before scheduled arrival”.

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