TankTwo Still Wants To Stuff Your String Battery Full Of Nuggets

1 day ago by Sebastian Blanco 18

TankTwo Demo Battery

TankTwo Demo Battery

When you introduce a completely new idea in battery technology, expect to get laughed a bit. That was some of the Internet’s reaction to TankTwo when we learned about the unusual string cell battery concept earlier this year. Well, TankTwo didn’t take the derision as a sign to quit, and is displaying its wares here at The Battery Show in Novi, MI this week. We got to talk with founder and CEO Bert Holtappels to see what’s new with the battery that looks like an aquarium full of glowing rocks.

Tanktwo’s prototype refillable battery cell

Holtappels was busy showing the TankTwo to a gathered crowd, and from that presentation and our own discussion, here’s what we learned about what’s coming and the answers to some of your questions from the first go-round:

  • TankTwo is indeed moving forward, and will have some sort of announcement with “one of the major players” about how its batteries are being used in some sort fo four-wheeled vehicle next year. Holtappels was not willing to share any more details than that, but at least we now know to keep an eye out when the calendar turns.
  • As for what happens when the little egg-shaped nugget cells get “scrambled,” the system not only has electronics that will reroute the power before the electricity can arc, its actually designed to prevent any movement of the eggs in the first place. First, the rounded cell shape means that once they’re packed in the container, they have a hard time moving. Second, there are arms that push upward from the bottom to compress the space that the eggs are in, minimizing movement. Third, one of the container designs has a silicon “balloon” that expands from the top to shrink the space the pellets are in even further. Last, there is an ultracapacitor built in to cover the energy output should a big enough shake happen and disturb the nuggets for a second.
  • The cells are made by a factory that used to make cells for Nokia, so it has excess capacity right now. Holtappels said that this gives TankTwo “pretty much unlimited capacity” to get cells now, enough to make 100 million cells with two or three months of lead time.
  • Energy density is about the same as other batteries on the market – a little bit under 200 watt-hour per liter, volumetricly – but that can be adjusted based on the demands of the customer.
  • Holtappels believes that, while most EVs will still be sold with one battery capacity and charged normally like we know today, there are some applications where buying the energy capacity separate from the battery itself makes sense. Think electric bus fleets, where some buses will go 50 miles today and others will go 100. If you have a fleet of 30 buses, you don’t need to buy the battery capacity for all of them to go 100 miles, and you can save money if you buy a total of, say, 2,000 miles of capacity, and then can share it between the buses as needed. Personal EVs, too, can benefit, if you could have a cheap 60-mile EV most days , but go fill it with more nugget cells on Friday to go on a 300-mile road trip on the weekend.

For your viewing pleasure, here’s a video of Holtappels talking about these topics from the show floor:

Source: TankTwo

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18 responses to "TankTwo Still Wants To Stuff Your String Battery Full Of Nuggets"

  1. protomech says:

    “About the same”
    “a little bit under 200 watt-hour per liter, volumetricly”

    Zero’s battery monolith is about 41L, so 270 Wh/L.

    Tesla’s 2012 “85” module is 15.8L, so around 330 Wh/L. Their newest “100” module is north of 400 Wh/L.

    http://www.evwest.com/catalog/product_info.php?products_id=463

  2. L'amata says:

    To me, this is a ridiculous idea. Before you know it Batteries will charge in 10 minutes anyway…Instead of swapping the entire battery Here you swap the individual cells themselves. How many times can you Bounce those around before they malfunction???BTW, Any ambulance Business that has to stop to “GasUp” on it’s to an emergency call , SHOULD BE SHUT DOWN!

    1. theflew says:

      The ability to charge your car in ten minutes requires a small neighborhood amount of power. Having charge stations like that everywhere especially in rural areas (read as areas between cities) just isn’t as feasible.

      This idea isn’t the worst idea and it’s this type of thinking we need. Just because Tesla and others have went the fixed capacity route doesn’t mean it’s the best option. Maybe this idea goes no where. But at it’s root this is just a simple battery swap idea with “smart” cells.

      Imagine buying a car and buying your “default” capacity as two separate things. The arguments about city cars and cross country become mute.

      1. krona2k says:

        You don’t need a small neighbourhood amount of power, at least not from the grid.

        You need on-site storage using re-purposed end of life EV batteries. The batteries constantly slow charge from the grid until they’re full.

        When someone wants to charge the battery bank can provide the necessary power for very fast charging.

        Obviously if the charging station gets heavily used it’s possible that the onsite storage could run out, but this would be the exception rather than the norm.

      2. Pushmi-Pullyu says:

        “The ability to charge your car in ten minutes requires a small neighborhood amount of power. Having charge stations like that everywhere especially in rural areas (read as areas between cities) just isn’t as feasible.”

        This comment shows the same attitude people had early in the motorcar revolution, when they used to yell “GET A HORSE!” The idea that paved roads would lead everywhere you’d want to drive, and that cities would be rebuilt to cater to motorcars, was something they couldn’t imagine.

        Similarly, the idea that, within a human generation or two, high power lines will run almost everywhere people drive, feeding ultrafast EV charging stations in even the smallest towns, is something you can’t imagine. You can’t imagine that even though the change to our infrastructure will be far less than what the original motorcar revolution brought.

        You need to feed your imagination. It’s too small.

  3. Pinewold says:

    This is a viral marketing campaign, spoof product or just a gag joke Simons is playing!

    1. Pushmi-Pullyu says:

      Yeah, it’s hard to take such a ridiculous and obviously impractical scheme seriously.

      At best it’s an elaborate joke; a hoax. At worst, it’s a scam. Sadly, given the high frequency of B.S. claims in the field of high-tech batteries, I suspect it’s the latter.

      “The storage battery is, in my opinion, a catchpenny, a sensation, a mechanism for swindling the public by stock companies. The storage battery is one of those peculiar things which appeals to the imagination, and no more perfect thing could be desired by stock swindlers than that very selfsame thing. … Just as soon as a man gets working on the secondary battery it brings out his latent capacity for lying.” — Thomas Edison, 1883

  4. Rad says:

    Would that four wheel vehicle be Power Wheels?

    1. ClarksonCote says:

      Yup, they were spied doing some dyno testing on them too…

  5. Spoonman. says:

    It would be nice to see this powering an actual device, getting refilled, and going back to powering a device – just as a proof of concept.

  6. Francis L says:

    I don’t see how this is much different from battery swapping, which already prove to be hardly viable.

    1. theflew says:

      Battery swapping wasn’t viable because you had 1000 pound batteries that needed to be stored and lifted into vehicles. Here you could have 3000 4oz batteries that are easily added or removed. Given the design you could easily have a hopper where charged batteries are at the bottom and dead batteries at the top being charged a filling station.

      It will be interesting to see if this idea goes anywhere.

    2. Pushmi-Pullyu says:

      Francis L said:

      “I don’t see how this is much different from battery swapping, which already prove to be hardly viable.”

      Battery swapping for a PEV is certainly practical from an engineering perspective. It’s only the economics for battery swapping that fails.

      Contrariwise, the scheme shown here appears to be entirely impractical in the engineering sense, for any application needing much power. For example, it has been pointed out that the very small surface area where the “egg” cells contact each other would severely limit the power put out by an array of such cells. It might be able to power a small toy, or the pretty-but-useless blinking LED lights used in the display, but certainly not anything needing as much power as a real BEV automobile.

      1. Amperaguy says:

        Well, the contact surface not as problematic as one might think. If eggs are small enough, there are many parallel cells which reduces current of each cell.

        There are three issues that I see as bigger fundamental problems of this idea:

        1) Balancing. I just don’t get it how they could balance cells in battery like this.

        2) Cost. Every cell has it’s own electronics and enclosure. Lot of extra cost.

        3) Volumetric density. With enclosure and air around each cell, this can never be as dencely packed as traditional battery pack.

        1. Pushmi-Pullyu says:

          Your numbered points are good points, thanks.

          On the other hand…

          “Well, the contact surface not as problematic as one might think. If eggs are small enough…”

          …then the surface area of each contact will be even smaller.

          I think you’re wrong here. Tesla solders a wire onto every single one of the thousands of cells in its battery packs, for a good solid connection. No doubt other EV makers do something similar.

          Just letting egg-shaped cells touch each other, so they have only a tiny point of physical contact with the next… that’s very far from a good solid connection, and the curved surfaces ensure the actual area of contact is very, very small. That’s definitely going to limit maximum power, and limit it a lot. It’s also going to raise the electrical resistance, which means lower energy efficiency and more waste heat.

  7. trololo says:

    @InsideEVs: please, just tweet a link to the video of that alien thing to Mr Musk. His reaction should be funny.

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