Autonomous Battery Exchange

That may look like a Ferris wheel but it acts a battery replacement station for small robots. The marXbot heads to the battery station when it gets low on juice. Once in the cradle, arms on each side hold the bot in place while the low battery is sucked out and a fresh one from the 15-slot carousel is inserted. The robot doesn’t power down but relies on stored electricity from some large capacitors during the changeover. See it happen after the break.

A while ago we saw a robot that could plug itself into a wall outlet. That’s great because the robot doesn’t have to return to a charging station, but it still has to wait for its battery to top off. With a few strategically placed battery stations it’s easy to keep a robot up and running with almost no down time for a battery swap.


[via BotJunkie]

24 thoughts on “Autonomous Battery Exchange

  1. maybe this kind of idea could be used to improve electric cars. swap out an entire bank of cells would take minutes as opposed to hours to charge then the cells could be charged quicker (presumably) as they could be processed in a more effecient environment.

  2. @steaky: electric car batteries are too expensive for that right now, aren’t they? it would be a great idea if it could be made practical, though. having a machine do it could be pretty costly too, unless you made it part of stations instead of the owners’ garages. but then you have to wonder if you’re getting a nicer battery than you started with… or something :P

  3. kristian – a quicker charge time would be one of the hurdles that people see tho. plus, i am assuming that the batteries would be graded etc, and you get what you pay for with the charge. And this would be the kind of solution that would be in a “petrol station” as otherwise you’d need 2 or 3 extra batteries

  4. @ steaky
    I agree with that, and is has seemed an obvious way to go for me for a few years now. Unfortunately, it requires standardization of the battery units across manufacturers to be useful, which isn’t likely (it’s an entire industry full of Microsofts)

    It would eliminate all problems with battery powered cars though, including end-of-lifed batteries (which would automatically be rotated out of the usable population, and be disposed of centrally, while keeping cars running fine).

    Time for the governments to mandate something.

  5. @nebulous
    the US government already bailed out(forgot number of auto makers) so i kinda see it as Mr Obama & co kinda own (forgot automakers) and should have a leg up on this kind of mandate. something like “super pay cut those fat cat CEOs of yours and start making and synchronizing battery tech or else we take our money and put it into Aptera or something”

  6. This is something they should use in space while on the moon or mars. That way their bots don’t rely in heavy solar panels. They could have a solar powered battery station close at hand and easily maintain power.

  7. If being able to plug itself into the wall is great, and this is great, why not both? It could plug itself in but if no outlets swap the batteries out at spread out bases.

  8. @Raged,

    Perhaps they use a capacitor because the motion of the battery changing mechanism makes it difficult to maintain a jitter-free steady flow of current through contact springs. Perhaps contact springs wear out or corrode too easily. Or maybe it’s a safety factor not having exposed power terminals. The supercap might also help the robot survive hard shocks that could momentarily jar the battery pack.

    Supercaps are also fairly small, light, and very reliable for this kind of app. Motorized contact springs (or a motorized plug and socket) would be complex, possibly heavy, and certainly more difficult to engineer.

    I think there could be a lot of valid reasons.

  9. “Better World” Israel is pushing battery swap stations for EV’s in Australia, under a contractual system much like cell phones, where you do not own the battery in your car, just subscribe to the system and buy kwh’s or km’s.

  10. @matthew,
    surely you would want that the other way round, swap that batteries out first, and if the carousel has no fresh batteries then hunt out an outlet.

    better yet, if you have multiple carousels then they can update the robot with their current battery status so that the robot doesnt make the journey in vain – plus if you know the distances etc you could make informed decisions on which base to go to.

  11. Very well executed. I’m sure this shouldn’t impress me so much, but it does.

    I think the capacitor idea is better than contacts. You have a few other advantages such as power maintained when manually swapping batteries, and most likely more stable voltage the rest of the time.

  12. @zacdee316
    Fantastic idea. Just have a bunch of parent base stations landed at separate locations, dot the robots in between, explore the whole area.
    Better yet if they build the base stations with wheels for movement, or allowed the robots to grab on to them and drag them to new locations.

    Doubt it will happen. Never any good ideas up there these days, always crappy crap and “WE NEED TO SEND HUMANS TO MARS!”, yeah, to see those amazing vistas, something that totally can’t be done by an awesome, cheaper, fleet of robots… no wonder NASA lost funding.

  13. SO

    When I build my homebrew wheeled ROV years back I wanted some thing like this but had no way to make it happen.

    Q: Are those individual charging circuits on each battery cradle?
    If so it’s an awesome idea, as if you can build sensing into it it could detect and automatically cycle past a defective battery until it can be changed out.

    Really great work!

  14. Wonderful build, i would love to see this employed in common day life situations, everything from cellphones to space machines.
    there would be an issue that might occur, the waste from the batteries once they are dead..

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