Battery Balls, fast way to fill your electric vechicle?

[firepower]

another solar road way type technology.

http://tanktwo.com/

https://youtu.be/8BAk4l98GtY


I think its a Gimick, low energy density (casing and air gaps and electronics) and low current path  due to point contacts and random connections will mean random voltage ranges.
Not all  cells will be used as only those that meet the algorithm.
This is basically a box of dry joints, any vibration would cause intermittent open circuits and arching.

with most energy density you want the most chemical in the smallest volume, thats why you use liquids or powders or gels/pastes
hell of a lot easier to just transfer electrons at high current and voltage then transfer battery balls.

Is there any spec on the cell? Ah capacity? dimensions? volume?

I smell BullSh!T

"On the other hand, Tanktwo battery packs offers more kWh and more peak kWs for the same cell capacity, compared to traditional battery packs. For this reason, the price per kWh for a Tanktwo battery pack will always be lower than the price per kWh of traditional battery packs made with the same battery chemistry and capacity."

[BlueBill]

Slick site with very little actual data. IMHO It's an interesting but impractical idea, I'll go as far as saying it's a bad idea. 

I could name a handful of issues of the top of my head but instead I'll speculate the project will never go into production.

[free_electron]

nope. the thing exists. I know the guy who invented it.

[BlueBill]

nope. the thing exists. I know the guy who invented it.

As a prototype? All the "photos" on the site appear to be CGI renders. Seems TankTwo is at the get investors stage so slick presentations and press releases are top priority. But I couldn't find any actual data or independent test info at all.

I simply don't see any practical use for it, who's going to dedicate a big old hole to fill with balls in their car? Who's going to finance, build and maintain the ball stations? I'm amazed this got off the drawing board.

[electr_peter]

A well-maintained Tanktwo battery-equipped EV can have more capacity at resale than when it was new, allowing for unseen resale values.

I guess statement refers to increased capacity of a single cell in the future so tank of the same size new batteries could be better in the future.

Sounds like a EV solution with changeable batteries made from small modules. I have doubts about tank construction and bigger capacity claims, but it may work. I have not seen real thing besides the site, it would be interesting to see it action.

EDIT: looking through the claims it seems that such technology (small replaceable battery modules) may have some strong advantages over more conventional battery types only and only if it proliferates and dominates the market (meaning significant local/global infrastructure upgrade, big market share of vehicles). Claim

Chicken or egg?
No avian dilemma here: A Tanktwo battery beats the alternatives even if you just charge it the old fashioned way, without new infrastructure.

seems to be unfounded. Small battery modules may have advantages (gradual replacement/upgrade of battery cells, quick refill) only if they are treated as such. If they are treated as a single battery pack, many advantages vanish (this would be the case if little or no infrastructure is built) in comparison to single battery pack unit.

[DanielS]

If you wanted to recharge an electric-drive car's battery pack in 1h, you would need an electrical circuit rated for 400A/240V and a battery able to absorb that much energy that fast. Easier said than done and some people may have trouble handling cables that thick.

The dry joint issue can be mostly solved by simply adding an air bladder at the top to compress the balls after they have been loaded so cells won't shift or break contact so easily.

I agree that energy density, both by volume and mass, would be questionable at best - stacked lithium cells are already at the limits of being practical without the extra weight and volume of fully enclosing individual cells, along with the routing MOSFETs' losses.

As for some cells not getting used, that is not necessarily a significant issue as long as you only get billed for the difference between the charge in the cells you dumped and the cells you picked up.

Sounds like a EV solution with changeable batteries made from small modules. I have doubts about tank construction and bigger capacity claims, but it may work. I have not seen real thing besides the site, it would be interesting to see it action.

It would be much simpler to simply come up with standard EV battery pack sizes, capacities and locations so they can be quickly swapped out when fast-charging is either not possible or still not fast enough. If swappable batteries become part of the energy delivery infrastructure rather than individual property, battery packs would get progressively upgraded over time to deliver more billable capacity at lower labor and material costs.

[Marco]

Ionic liquid aluminium air batteries seem more practical for quick refueling.

[helius]

Seems very much like the strategy of swapping battery packs for range extension. Except for the differences:
1. Since there are many small batteries, they can be derated/replaced at a finer granularity
2. Dynamic mesh power reduces impact of single failed cells, and can keep using marginal cells

those seem to be the only real advantages. Disadvantages compared to single swappable packs:
1. Less energy and power density because of spherical packing arrangement
2. Higher cost per Wh capacity because of the construction of the balls and contacts
3. Cooling the cells efficiently is impossible
4. Contradictory requirements for materials: to make contact reliably, the patches on the outside of each ball must be compliant. But that means they have to be thin, reducing their power handling ability and making wear and tear a problem
5. Requirement for a large storage tank inside the vehicle, which you can calculate must be larger than either a liquid fuel tank or an EV battery pack. The tank needs to be large in each dimension so it is nearly cubic
6. Multiple unproven technologies required: mesh power, randomly oriented contacts, air delivery (easily the wildest proposal if you understand how pneumatic tubes work), and on and on.

[BlueBill]

Don't forget a delivery system that can exchange hundreds or thousands of those balls through forced air tubes without jamming in less than three minutes. That I'd like to see.

[tszaboo]

I think it is a great idea, with a lot of problems, some of them are breaking it totally. Namely the contact resistance of these batteries. If you put a lot/all of them in series, you basically have a system, where you have a lot of batteries connected to each other by only a small surface, and small forces. The real EV batteries (not these tesla notebook ones) all have screw terminals and all use busbars and thick metal plates to make the connections. Replace it with two rounded surface touching each other randomly and you are asking for trouble.
Probably all the cells have to be in series to reach a voltage level to decrease the current, such the contact resistance doesnt matter anymore, but at around 500-600V you start having trouble with the electronics, MOSFETs stop behaving and IGBTs are pain.
So far I would have prefered the Renault-Nissan battery swap, but that went down the drain.

[Ian.M]

Does anyone care to offer odds on the transfer system jamming badly enough that one or more charged spheres suffer sufficient shock damage to cause them to catch fire?

How many catastrophically failing spheres can the charging system hopper contain without the whole lot going up?

If the spheres have enough impact absorbing and fire protection material round their batteries to make these concerns dismissible, the energy density will be even lower . . . .

[macboy]

This technology seems ahead of its time. Like maybe about 2 days ahead.

[BlueBill]

Seems like a bunch of mobile phone guys got together with a bunch of marketing guys.
http://tanktwo.com/team/

Here's the patents.
http://worldwide.espacenet.com/searchResults?DB=EPODOC&submitted=true&locale=en_EP&ST=singleline&compact=false&DB=EPODOC&query=tanktwo
https://tanktwo.com/tanktwo-blog-post/
They're tiny!

[PA0PBZ]

Bumpy roads could be a problem: <bump>*rerouting*........<bump>*rerouting....  *rerouting*

[691175002]

Even in some magical universe where spherically packing a bajillion separately packaged batteries was somehow not a spectacular waste of time, space, and weight; how do they expect this to gain critical mass among car manufacturers and charging stations?

I'm pretty sure that no engineer would ever want to be associated with such an awful project, I just can't tell if the whole idea is a result of incompetence or a deliberate scam.

I suppose the algorithms for routing paths through the spheres could have some niche uses, but nothing like what they are advertising.

[voja]

200A current thru those contacts? Yeah, sure... 

[helius]

At least we know who's going to do their marketing...

[Chipmunk]

The very front page asks a question: why not make the batteries smartphone smart: Anyone who's seen the latest EEVblog mailbag where Dave's phone craps itself randomly will know why not.

And the front page looks like it has marketing smeared all over it. 

[firepower]

Can't believe they the size of ping pong or squash balls, bugger all capacity. By the time you add up all the tech it meant to have and the construction of the casing for strength and shock. You be filling up more often than current EV.
Tesla are designed for fast charging, fastest possible as well as battery swap. EV are topped up every night at home, always full tank every morning.

[taylor12]

just think about the sound of exchanging them i would sound like you won a slot machine  ding ding ding

[ajb]

The ideal solution would be replacing a complete battery pack, but the trick is designing a car where such a large, heavy component can be quickly and easily removed without unduly compromising safety or performance.  And of course, coming up with a standardized pack that can be fit into a wide range of vehicles.  Probably the best way to do it is to have the pack slung under the car, but then you need to have access to the bottom of the car at every battery swap station--probably means a lift or a pit unless it's an SUV. 

I wonder if a better solution than battery balls would be to use a standardized cylindrical cell.  You could still have a large 'tank' of arbitrary size/shape that only needed a small outlet and inlet opening for getting spent and charged cells out and in, but cylinders will rest and pack more densely and predictably than balls, and can have larger contact surfaces on their ends.  You could have the two contact-bearing sides of the walls press in to provide high contact force once the cells are in place.  Contacts can be arranged to give whatever series/parallel arrangement is required.

The big challenge is feeding them in and out reliably; without a proper set of guides the cylinders will be even more prone to jamming then balls.  Maybe having them snap together into a belt would be beneficial, with internal sprockets to help feed them into place.

[helius]

The big challenge is feeding them in and out reliably; without a proper set of guides the cylinders will be even more prone to jamming then balls.  Maybe having them snap together into a belt would be beneficial, with internal sprockets to help feed them into place.

Mechanisms for feeding cylinders in and out are already highly evolved in automatic firearms. Look for a design called the HK73.

[miguelvp]

Aluminum, Gallium and water to power Hydrogen fuel cells, the byproduct is aluminum oxide (alumina) and the Gallium is reused. At the "pump" you can recover the alumina that can be converted back to aluminium using solar or wind energy so that new aluminum pellets are available for the next customer.

http://www.purdue.edu/uns/x/2007a/070515WoodallHydrogen.html

Not sure where this research is at, there are several companies trying to bring it to market with their own versions of the reactor to produce hydrogen on demand, to be used directly or via fuel cells to produce electricity.

[eneuro]

The real EV batteries (not these tesla notebook ones) all have screw terminals and all use busbars and thick metal plates to make the connections. Replace it with two rounded surface touching each other randomly and you are asking for trouble.

Not such a big deal-those surfaces will be.... spot welded in rush current and they will have useless EV wehicle full of soldered metal balls and sparks will destroy NASA mission to Mars while jamming their radio equipment 

[amyk]

I wonder if a better solution than battery balls would be to use a standardized cylindrical cell.

...like an 18650?