Solid state battery tech

begreen Posted By begreen, Mar 8, 2017 at 11:06 AM

  1. begreen

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  2. Lake Girl

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    At 94 years old, excellent to see Dr. Goodenough and his research fellow come up with a safe, durable energy source alternative. Wonder how long before it is in production?

    Extreme cold weather capable is a huge bonus and likely a lower cost for production from the description!
     
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  3. begreen

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    The use of glass electrolytes is intriguing. Noncombustible and has a long cycle life (battery life) with a high volumetric energy density and fast rates of charge and discharge and works well at cold temps. Sounds like a winner though the development time probably will be several years. Unknown are the size and cost of a production battery based on this technology. The LiIon battery took about 10 yrs to develop.
     
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  4. Lake Girl

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    From the article, it seems they are optimistic on reduced cost due to more common materials used. Time will tell.
     
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  5. Lake Girl

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  6. begreen

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    Goodenough for me.
     
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  7. woodgeek

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    With a metallic sodium or lithium electrode, I suspect non-flammable is a relative measure. :p

    One of the great things about EVs is the ability to innovate on the energy storage side, which would be like changing fuel chemistry or combustion cycle for an ICE, while keeping most of the drivetrain and car design fixed. I think lithium will have a good run for the next decade, but on longer horizons who knows.

    Once these solid-state batteries are at scale, we will be seriously talking about Jetson's style flying cars. Like the 'personal quad copter taxi' service just launched in Dubai. :cool:

    http://www.designboom.com/technology/ehang-184-dubai-passenger-drones-02-15-2017/

    I think the range on these things will be poor (compared to typical US commuter range) with lithium, but with solid state batteries...let's fly. Where's Craig when you need him?

    The economics are obvious...while flying takes more energy than driving, the electric drivetrain and low-massing of the vehicle means that a drone commute might use less primary energy than one person driving a big ICE SUV. And automating flight (and in air avoidance) is MUCH easier than automated driving on crowded, poorly repaired streets. Less material to build the vehicle, no emissions, reduced need for asphalt and concrete infrastructure...sounds GREEN to me.
     
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  8. pdf27

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    <choosing my words carefully here because I actually work in a Tier-1 aerospace supplier working on electric aircraft>
    1. A conventional helicopter-style or quadcopter drone is always going to use more energy to travel a given distance than even a huge SUV, unless the SUV is stuck in a pretty hideous traffic jam. Rotary-wing aircraft use most of their power simply to keep themselves from falling, while in a fixed-wing aircraft the power is used to move places.
    2. Weight reduction could be done to both an aircraft and a ground vehicle - in fact it's substantially easier in a ground vehicle since the fail-safe (i.e. the opposite of fail-dangerous) requirements are vastly more stringent. For instance, aircraft engine generators are typically designed to be twice the power output required - a typical commercial aircraft will have four fitted, and must be able to take off with one not working and lose another in flight without affecting any systems. For a ground vehicle you'd fit a single generator and the vehicle would safely coast to a stop if it failed.
    3. Automated avoidance under the same conditions as on the roads is actually substantially harder in the air, because you have to keep track of movement in three dimensions rather than two, and at significantly higher speeds. The reason it works well in controlled airspace at the moment is because access to the airspace is controlled and everybody has transponders on board which talk to one another. This makes it a restricted access system - but this doesn't apply to the overwhelming majority of airspace, which is where the "flying cars" would be.
     
  9. woodgeek

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    Sure. Let's do the maths...

    The existing 1 person quadcopter (e.g. the Ehang 184) has a 15 kWh battery and a 23 minute air time. We could extrapolate that it would require 15*(60/20) = 45 kW in normal forward flight at 30 mph, or 45 kWh to carry one person 30 miles.

    As you asserted, motor peak output is more than 2X this figure, 106 kW.

    The existing model, of course doesn't have 30 mile range, it would only get 10 miles and then need to be charged for 2 hours, but I was supposing a future superior, lower specific mass battery.

    A proper US SUV might have 15 mpg, and use 2 gallons of gasoline to carry one driver 30 miles in normal road traffic.

    Primary energy content of 2 US gals of gasoline = 228,000 BTU. The Ehang's 45 kWh = 153,000 BTU.

    It appears that the Ehang 184 electric helicopter uses less primary energy to move 1 person than some SUVs in current use, as asserted.

    What am I missing?

    ------------------------------------------

    While fixed wing aircraft can obviously glide, they don't always have a place to land in a dense urban area. The Ehang can neither glide nor even gyro, it would need a low-mass parachute in case of power failure. Multiple motors do provide some redundancy.

    As for avoidance...three dimensions makes it easier rather than harder compared to two dimensions (or in a single lane, one dimension), especially with vehicles that can hover and execute sharp turns.
     
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  10. peakbagger

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    Development is the b**ch.

    I would be curious how modular the Tesla factories are to allow switching over the production to completely different technology. Curious if Tesla owns the building and lets Panasonic eat the obsolescent equipment inside if new tech comes out. At some point we may hear about the lithium battery cartel suppressing sodium glass battery development ;).
     
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  11. pdf27

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    Main one is mass - as a rough figure of merit each of these 110kW motors would have a mass of 40kg plus say 20kg for power electronics, and improving this is hard work. That's 250kg for propulsion, even before you start adding in structural mass and batteries.

    Ah - I assumed you were doing a direct comparison of an electric SUV available in a few years to an electric quadcopter available in a few years. Current hybrid SUVs are typically 20 kWh for 30 miles of driving (although most are pretty tepid hybrids incapable of this) - if you go all-electric (permitted for the quadcopter) you can cut out a shedload of mass such as the entire IC drivetrain to get it down to maybe 15kWh without much of a drama - a third of the power consumption of the quadcopter.

    More than you'd think, if done properly. The quadcopter example we're talking about, for instance, might well have two motors per rotor with each being powered and controlled independently to ensure that there is no single point of failure (well, it certainly would if certified under FAA or JAA rules - given that they're talking about flying it in Dubai but not under either set of rules rather suggest that some short-cuts might have been taken here). Unfortunately there's a lot I know here about current projects that I can't really talk about, but there is some serious money being put into electric aircraft of all types - mostly hybrid rather than pure battery. The battery type tend to be either tech demonstrators or possible trainer aircraft like the Airbus E-Fan.
    68100631_an_airbus_3370568b.jpg
    The range and size of electric aircraft like this is actually quite impressive, but most of the big money is going into commercial airliners which of necessity will be hybrid systems. The 787 for instance has about 1.5MW of installed generating capacity on board, all for non-propulsive power at present. You can imagine the size of battery needed for that on an 8 hour flight!

    The physical avoidance is easier, but that really isn't the problem with self driving cars. Instead the problem is spotting and interpreting a hazard, then deciding what it will do. Controlled airspace gets over this problem by only permitting aircraft with transponders to enter, and insisting that they are under positive control from the ground at all times. To get "flying car" type functionality you need to get rid of this - which either means that everything needs to have transponders/TCAS on board (cue massive revolt from other airspace users - balloonists, glider pilots, GA pilots, hang gliders, etc.) or you have to use optical systems as per current self-driving car systems. With aviation that's much harder however - the threat can come in three dimensions rather than two, and given the very much higher average speeds you need to spot potential threats at a far greater distance than on the ground. It's also worth noting that the maximum rate of deceleration/turning is significantly higher on the ground than can be achieved by anything but an aerobatic aircraft - tyres help an awful lot because they give you positive contact to something that isn't moving, compared to shifting a lot of air to apply a force.
     
  12. woodgeek

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    Always nice to hear from you again @pdf27.

    I think with existing or near-future Li-battery tech helicopters are going to be a bit of a stretch...I'll defer to you on fixed wing.

    Just saying that solid-state batteries with significantly higher performance (including very fast charging) will enable a lot of things besides long-range EVs, that may be hard to predict.

    I personally think that autonomous driving will have a difficult rollout, not b/c it is intrinsically difficult, but because we are imaging a **mixed** environment with both human and autonomous controlled vehicles on the same roads. Way harder than an all autonomous system...predicting human behavior is harder than figuring out a fixed obstacle in your path. As long as humans are in control, lightweighting land vehicles is probably out as well.

    In the air it will likely be easier...define controlled airspace corridors that no human operated aircraft are allowed to enter.

    I also think that in a future renewable powered world, there will be plenty of primary energy for those that can afford it. While probably not enough that we can all vacation on the moon once a year, a system of electrically powered, lightweight autonomous aircraft for commuting is no crazier from a primary energy point of view than the asphalt/concrete/steel/ICE/fossil system that we seem to have now.
     
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  13. pdf27

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    With batteries as the only power source, yes. All I'm comfortable saying is that there is some serious money going into electric helicopters right now, coming from people who know what they're doing.

    Getting that airspace will be very painful - no way would "flying car" type aircraft be permitted into existing controlled airspace, and kicking existing users out of airspace that is currently not controlled will also be very difficult. Controlled access highways may actually be easier, since the restricted access interstate/motorway/autobahn system already exists.

    Have a think about the cost of inter-seasonal storage of energy - the only plausible way I've yet seen proposed is to use it to generate synthetic hydrocarbons, probably methane. Once you've done that, synthesising jet fuel is pretty easy using standard processes: the assumption that future aircraft will be all-electric is actually quite an implausible one, although they will certainly have a very significant electric component and probably a very large battery capacity (peak power demand >> cruise power demand, but cruise energy consumption >> energy consumption during peaks).
     
  14. woodgeek

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    The issue in the US is the built environment, with these very spread out cities and core-suburb sprawls. Currently Americans spend 40+ hours a year sitting in traffic. I take light rail, but its 60 mins door to door for a 13 mile one way trip. And driving is often even slower.

    I think we can live with jet airliners for the rest of the century, with fossil, bio or syn hydrocarbons as fuel.

    I just want to get to work and back in a way that makes more sense than what we do now. :rolleyes:
     
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  15. pdf27

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    Yeah, I'm actually quite aware of that (my wife is originally from New York, and her parents are now on the NJ/PA border). Unfortunately I don't think personal aircraft will fit that niche - the public are far less accepting of aircraft crashing than of cars crashing, rightly or wrongly, so they will always be exposed to a vastly more stringent regulatory requirement. The best we can hope for is that technology encourages ride sharing services to reduce the required road area, and that self-driving cars allow better use of the time spent in a car than staring at the car in front and waiting for it to move.
     
  16. woodgeek

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    I think that when the technology allows (i.e. solid state batteries) and a new generation is used to autonomous transport, there will be no barrier to ultralight, autonomous aircraft as one commuting solution.

    As will all things, it will start with the rich. If my wealthy neighbors could get a 10 minute autonomous ride from their back yards to the roof of their office building, pay $100k for the personal vehicle (or $500/mo lease/share) and the ride used $10 worth of electricity instead of $6 of gasoline...many would jump on it.

    And all I'm saying is that such a solution needn't break the climate, or even use more primary energy that what they are doing now.

    I get what you are saying about current regs of airspace...but that can change as soon as the tech comes along.
     
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