Let us agree, that there are rumours about TWO different to-be-standard sizes. The 20700 and 21700.
Unsure to me if this is caused by erroneous calculations, or there will come a divine battle to settle this once and for all.
Yes and no. Articles were written about Samsung and about Panasonic.
So I have done some digging of my own and found: NCR20700B
If this is a fake than it has cost him/her a few hours of solid work.
All of the later stories I have seen, such as this one at Fortune, say 21-70. Initially, I was reading 20700.
I know your Internet research capabilities are top notch. What is the tenor of the articles your are now seeing?
The future of the 21700? I haven’t got a clue. But there was a recent industry conference on advanced batteries for the automotive industry.
A very interesting peek at what is going on:
https://www.advancedautobat.com/uploadedFiles/AAB/Content/Conferences/AABC/Agenda/AABC-2016-Brochure.pdf
Top notch or bonkers? The jury is still out on that one. I seems that Tesla from 2013 on has hinted on the abandonment of the 18650 standard. And in 2014 more and more rumours indicated the introduction of a 20700. But Elon Musk apparently has done some last minute math and has announced that 21-70 would become the standard (not only introducing a new standard size, but also a new standard description). This was last july at the Tesla Gigafactory tour.
Which makes more sense of the 21700 Samsung is developing for E-bikes.
Any idea what they are trying to push 21700 to? 4000mah minimum I would think. Maybe up to 4500 with the right technology. Panasonic expected to have the 18650 4000mah released by now
Thanks, Henk.
21-70 it is. With initial production due to begin by year's end, I doubt Tesla will back away from that size.
For carry in a pants pocket, 1x18650 is a tad larger than I typically prefer. Even the diameter of the ZebraLight SC62w is a tiny bit bigger than I like. In a coat pocket, of course, 1x18650 is fine.
In the hand, I think I would like 1x21-70 better than 1x18650. In a jacket pocket, the difference does not matter.
I say, bring on the 21-70. Even if it were to dominate the flashlight world, it should still be possible to get 18650 batteries for a long time to come. There should be no hurry, therefore, to sell the 18650 flashlights I currently own.
OK, looks like the info is out and the batteries soon to follow. Great article titled “‘Quantum Leap’ in Battery Innovations Presented at Eurobike”, full link: http://www.bike-eu.com/home/nieuws/2016/9/quantum-leap-in-battery-innovations-presented-at-eurobike-10127504
And the article also discussed the new 20700 Panasonic cell.
I was reading the other day some where the highest a 18650 can go is 4200 from Panasonic at around $40 a piece used with nano technology to make the sheets thinner. But can’t take the stress of today’s 2+ amp charging. And kept within industry use. With the slow charge and high cost no real market niche for it until technology improves It needs a low charge rate. These new Tesla celks will be 4200mah but can do rapid charging. It seems technology wasn’t advancing fast or cheap enough for Tesla to make cars go further without recharging
Panasonic is hold their cards close to the vest, but these guys published that in addition to a 68% output, a battery which is exhausted after 3 years will now last 12 years. Those are huge things. One has to assume that Tesla and Panasonic, with the resources they have working on this issue, have achieved something similar.
Nope- the 18650 is too well entrenched, too widely-used, too highly-developed, and too well-loved to be knocked off the throne by a newcomer. Perhaps in 10 years that will be different but I think my prediction is safe for at least 5 years.
Phil
I sure hope the 21700 (aka 21-70) becomes the next oversized battery to take the place of the 26650. It’s only 3mm larger in diameter and 5mm longer than the 18650, yet has a lot more potential for future development whereas the 18650 has already topped out, development wise.
Presently, many protected and hi-cap 18650’s are close to 70mm long and 19mm in diameter so we were headed in that direction anyway.
I’m hoping for a BLF-SE model using a slightly enlarged version of the Eagle Eye X6R as the general format, including the latest version of the BLF backlit tailcap as our next big group-buy!
Article: Huge leaps in e-bike battery capacity coming to e-bikes soon by Elliot Johnston Nov 4 2016.
http://ebiketips.co.uk/content/news/…bikes-soon-428
“New, larger 21700 cell e-bike batteries from Samsung and German battery supplier BMZ, and a 20700 cell from Panasonic have pushed the envelope for e-bike power standards forward.”
“Energy density is higher for the new cells, meaning that 700Wh batteries are likely to be commonplace by 2018.”
“A 21700 cell can have a capacity of 4.8Ah, as opposed to 3.5Ah for an 18650 cell. ”
“The unit also comes with high quality materials including stronger conductors and a greater proportion of active cell material which allows for a claimed 50% increase in energy supply and a 68% increase in output.”
“…the development possibilities of the 18650 cell format are exhausted.”
Also, the newest LG HG6 (20-65) 3000mAh 3.7V 30A discharge current 20650 battery is being advertised for use in power tools.
If they want a bigger FF (and volume) vs the 18650, why not just use the already entrenched 26650? Stick a protection circuit on it and it’ll be a 26700.
Nahhhhhhhhhh…the 18650 is here to stay. Sure, any battery size may exceed it in production numbers, BUT, they will never exceed the number of 18650 sized battery tubes and hands that contain them.
No, the only thing even close the popularity of 18650 is the 26650.
Highly doubt people will want to go with a lower capacity battery than a 26650 anyway, and if they do then 18650 is perfect.
Tesla will make batteries in house and use them for their EVs and Powerwalls. Basically a closed system, no one else is making for Tesla.
So unlikely to have an effect
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.
Not sure that’s true. I’d scribe a unit circle in a unit square (L = D = 1), and the box scales up and scales down equally. With twice the diameter, you’d have 4 unit-squares instead of 1, but the ratio of space-to-stuff should stay identical. A cylinder would just stretch that in a 3rd dimension.
Packed in a zigzag fashion, you’d only have something different for edge-cases around the periphery.
Anyway…
I think more important would be the rather fixed thickness of the walls of the cells (ie, an AAAA won’t have a foil-thin wall), there’d be more active material in the bigger cells. Ie, by analogy, a jumbo box of cereal would be much more “efficient” vs a trial-size, considering the cardboard of the box is the same thickness in each, so the cereal:cardboard ratio is much higher in the jumbo box. Pretty much, the same goes for any packing material.
Plus, fewer connections total for fewer-but-larger cells, fewer protection circuits, less overhead in tops (even flattop caps), and so on. Otherwise, a nest of 10440s would be most efficient. 
And things like laptops if anything would go to a thinner profile, else use prismatic cells in nice rectangular packages.
Pretty sure that packing circles in a 2 dimensional space works in the exact same way.
The height of the cylinders is completely irrelevant.
You are so right.
I was confused because I actually posted that from the 5th dimension. :weary: