New 21700 Battery From Samsung SDI

SubLGT

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"...Samsung SDI also unveiled a battery pack product equipped with 21700-type batteries, noted for their upgraded energy capacity compared to previous cylindrical types. The 18650 battery, or rather the small cylindrical battery of 18mm diameter and 65mm length, has been in dominant use until recently. However, the creation of new battery applications has boosted the demand for high capacity batteries. In response, Samsung SDI has come up with a battery that has upgraded a maximum of 35% of energy volume, now known as the 21700 battery, and has successfully applied it onto e-bikes for the first in the world.
The 21700 model can have various applications other than e-bike, such as in electric tools, laptops, and more. It is expected to become the new standard in small cylindrical battery usage…"

http://www.greencarcongress.com/2015/08/20150826-samsung.html
 

StorminMatt

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I've always thought the 18650 was just too small, and that increasing cell size would both improve capacity and decrease the proportion of the cell volume dedicated to the can itself. This looks like a good step in that direction. And with laptops switching over to LiPos, there is no longer any need to stick with 18650s in order to minimize thickness. Of course, 26650s with higher energy density would be nice as well. But given that 26650s tend to be rated more conservatively than 18650s, they're not as far off as many people think.
 

SubLGT

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No doubt Samsung scientists and engineers have done their computations, and have determined that 21700 is a more efficient/optimal size than 18650 or 26650.

Approx volume of 18650 = 16,540 cubic mm
Approx volume of 21700 = 24,245 cubic mm
Approx volume of 26650 = 35,510 cubic mm

I am guessing that 26650 is not optimal for an e-bike battery pack because there is too much void volume when they are stacked in a pack.
 

ChrisGarrett

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I've got lights that work on all sizes of li-ions, from the lowly 10440 up to the 26650, so I like variation, but I don't find anything inherently wrong, or lacking, with the 18650s that I have. If I need more runtime, I just carry a spare cell in one of those silicon stretchy things that I bought a while back.

I have the DQG Tiny Triple and have two Efest 3500mAh 26650s and while I can carry it easily enough in a pocket, it is fatter than most of my other 18650 lights.

For people who aren't able to carry a spare, but need maximum runtime...at any cost, sure.

If it happens, fine, but I'm not itching to get another cell size, regardless of energy density.

Chris
 

StorminMatt

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I am guessing that 26650 is not optimal for an e-bike battery pack because there is too much void volume when they are stacked in a pack.

When cells are placed in a pack, the void ratio is independent of the cell size.
 

KeepingItLight

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No doubt Samsung scientists and engineers have done their computations, and have determined that 21700 is a more efficient/optimal size than 18650 or 26650.

Approx volume of 18650 = 16,540 cubic mm
Approx volume of 21700 = 24,245 cubic mm
Approx volume of 26650 = 35,510 cubic mm

I am guessing that 26650 is not optimal for an e-bike battery pack because there is too much void volume when they are stacked in a pack.

Do these volume ratios translate into similar capacity ratios? If so, then a new 21700 would store approximately 50% more energy than a similar 18560. 3400 mAh would become 5100 mAh, and so on.

That sounds good to me!

Although the larger capacity will be welcome, the larger size will probably have a negative impact on EDC. A small 18650 flashlight such as the Zebralight SC62w goes almost unnoticed in the bottom of a pants pocket. I say "almost" because for me it is already a bit too large to EDC there. For a jeans pocket, I prefer the smaller diameter of an AA or AAA. There are many people, however, for whom the Zebralight is fine. Would an increase of 3mm in diameter and 5mm in length push that to the tipping point? For a lot of folks, I am sure it would. For those people, the 21700 will not be an attractive replacement for the 18650. In a light that is carried in a coat pocket, however, or in a pack, the increased capacity of a 21700 should be a boon.

For hand holding, I think the wider diameter of a 21700 will also be a plus.
 
Last edited:

chuckhov

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"I am guessing that 26650 is not optimal for an e-bike battery pack because there is too much void volume when they are stacked in a pack."


This is irrelevant, as All dimensions will scale accordingly. - The 'void volume' increases in proportion to the cell volume.

Thank you,
-Chuck
 

SubLGT

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Samsung SDI also displayed cells and modules based on the new 21700 standard of cylindrical battery. A '21700' battery is 21 millimeters in diameter and 70 millimeters in height. Its capacity is 50 percent bigger than the existing 18650 battery. Its size is optimal for maximizing capacity, life and output simultaneously. The new battery beats batteries of any other size in light of cost competitiveness. A 21700 battery draws attention from major global manufacturers as the next-generation standard which can be applied to all sorts of products including electric vehicles, ESS and electric tools.

http://www.samsungsdi.com/sdi-news/1682.html?idx=1682

http://www.businesswire.com/news/ho...acnnViVjtb72bOP4-4nHK5idAXrgr_e1ZUbxvK6BY66Xm

What is missing from this recent announcement is capacity and current specifications, and model names.
 
Last edited:

carl

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Brand: Samsung
Model: 48G
Size: 21700
Chemistry: INR
Nominal Capacity: 4800mAh
Nominal Voltage: 3.6V
Discharge: 9.6A Max Continuous, 4.8A Max Continuous for optimum cycle life
Positive: Flat
Protected: NO, UNPROTECTED
Rechargeable: Yes
Dimensions: 21mm x 70.5mm
Weight: 67.4g
 
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