18650 vs other cells?

Jaraya

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Jan 9, 2021
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A buddy of mine that I work with Vapes. *sigh* Anyway, when I mentioned the whole 18650 power wall thing he actually knew a lot about the batteries from his vaping. I had no idea. It kinda clicked with me at that point that the 18650 is really prolific and in every darn thing..

He asked about the 26650 battery or the 20700 battery which I guess are used a lot in vaping? (I dunno) ...and if they would also work or be more appropriate due to being more powerful https://trackeasy.fun/usps/ https://showbox.tools/ than the 18650.. He kinda implied the 18650 was old crap technology and not worth the investment.

I disagreed because unless my basic search was wrong, 18650's are in every darn thing and easy to come by. 26650's and 20700's seem to be about $10 each!!

So now to my question; Are there other cells that would be just as good and are just as readily available?

I mean if we could get bulk 10440's by the truck load cheaply they would work and be just as viable..etc..

Thoughts?
 

ajw22

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18650 just denotes the size of the cell (18mm diameter, 65mm long), and have been in production for decades. So you could get everything from shitty cells produced with decade old technology in a shady factory in China, all the way up to top spec Korean/Japanese cells produced using the latest machines and technologies.
So certainly wrong to say that _all_ 18650 cells are crap.
Cost and availability are very good due to strong competition and large production numbers.

20700 (20mm diameter, 70mm long) on the other hand has been introduced just a couple of years ago - mainly driven by Tesla? My guess is that all these cells would therefore have been produced using machines and technologies no more than a couple of years old.
But I suspect 20700 will slowly die out over the next couple of years, as Tesla seems very eager to move to the much larger 4680 cells.
 

DiggsUt

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18650s are fading away also. The big driver was laptops and they no longer use them having switched to prismatic or pouch cells as they are more economical to produce. I used to be able to walk into a computer repair shop and walk out with boxes of 18650s but not any more. Even medical equipment that provided quite a few higher quality cells in the past are/have switched to prismatics. Coupled with new chemistries (Iron Phosphate, etc.) that don't even come in the 18650 form factor, I believe the days of the 18650s are rapidly declining.
 

ajw22

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18650s are fading away also. The big driver was laptops and they no longer use them having switched to prismatic or pouch cells as they are more economical to produce. I used to be able to walk into a computer repair shop and walk out with boxes of 18650s but not any more. Even medical equipment that provided quite a few higher quality cells in the past are/have switched to prismatics. Coupled with new chemistries (Iron Phosphate, etc.) that don't even come in the 18650 form factor, I believe the days of the 18650s are rapidly declining.

Very true that use in laptops have declined massively. But they are still used in so many devices, I think demand and therefore supply will remain for years to come.
I think the big users will be:
Powertools. Pro's eat through packs, and they really don't like switching systems. And ever more tools are going battery nowadays, even chainsaws!
E-Bikes. Super popular in Asia, with dozens of cells inside each pack.
 

DiggsUt

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And ever more tools are going battery nowadays, even chainsaws!
It seems every tool pack I've investigated has been beat to crap. The cells just aren't worth reusing. But, that may have just been my luck of the draw so to speak.
 

ajw22

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It seems every tool pack I've investigated has been beat to crap. The cells just aren't worth reusing. But, that may have just been my luck of the draw so to speak.

Same experience here. Epoxied together, high charging rate, even higher discharge, overheated, dropped, covered in dust, dipped in various liquids.
Using commuter E-Bike packs almost exclusively now.
 

OffGridInTheCity

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I just processed 2500 cells from RING battery rejects - and 99+% were full power, newish. I don't think (at least I hope not) using 18650 for powerwalls will disappear overnight.

The volume of 18650s was mentioned above - and its hard to overstate compared to other cell types. I don't know the numbers.. but something really really large AND they work OK even after sitting around 10yrs. 1,000(s) of cells I've processed at 85%+ capacity - working fine in my powerwall show date codes 8yrs old.

I do think a big change will occur if Tesla get's these off the ground -
This would change the landscape if billions and billions get produced - but it will take a while - to reach the ubiquity of 18650 adoption so that it leads to a second hand market.
 
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Dr. Dickie

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20700 (20mm diameter, 70mm long) on the other hand has been introduced just a couple of years ago - mainly driven by Tesla? My guess is that all these cells would therefore have been produced using machines and technologies no more than a couple of years old.
But I suspect 20700 will slowly die out over the next couple of years, as Tesla seems very eager to move to the much larger 4680 cells.
Not be a stickler (but I am), aren't those 2170 cells?
 

LithiumSolar

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"20700 was meant to be the next standard driven by Tesla, but Tesla changed their minds and added another 1 mm to the diameter."

Interesting. I wonder if that's why they exist but are rarely used and hard to find holders/etc for them. A few manufacturers jumped on thinking it would be the "next big thing" to 18650s maybe.
 

Dr. Dickie

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Yeah, my understanding is, the 2170 cells were developed by Panasonic in cooperation with Tesla to replace the 18650 in their early model cars. They have used the 2170 in their cars over the last few years, but it seems as if they are the only (or at least the super-majority) of the users for that cell configuration. Tesla is transitioning to 4680 cell--seems as if this cell will likely be proprietary.
Even so, I doubt there will be a lot of 2170 cells around. The reason there are so many 18650 cells are they are used in dang near everything Li ion.
 

Ebikeforlife

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Yeah, my understanding is, the 2170 cells were developed by Panasonic in cooperation with Tesla to replace the 18650 in their early model cars. They have used the 2170 in their cars over the last few years, but it seems as if they are the only (or at least the super-majority) of the users for that cell configuration. Tesla is transitioning to 4680 cell--seems as if this cell will likely be proprietary.
Even so, I doubt there will be a lot of 2170 cells around. The reason there are so many 18650 cells are they are used in dang near everything Li ion.
The ebike world seems to be transitioning to the 21700 cells although i find that most of the cases readily available and the frames(stealth Bomber) are made for the 18650 sizes with internal diameter of 142mm which allows for a folded pack to fit in perfectly with protection fitted around them.
 

Crimp Daddy

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Your friend has limited insight. Their application requires high drain cells and often times the performance of the device is highly dependent on the quality and discharge potential of the cell. The wrong cells can actually be a dangerous proposition in the world of “mechanical mods” where you are actually short circuiting the cell across a low resistance coil.

I used to test cells for a local vape shop because they source crap batteries from a lot of Chinese sources, and before a customer blew their face off, I figured I help out.

18650 cells are still made, in abundance, and of high quality… if you buy the right stuff. It really just depends on the project and your needs. The larger the project, the easier it is to justify large physical cells like prismatic cells or EV modules.

It just comes down to the cost per kWh and the complexity of making cells into a pack.

Regardless of the type of battery, you want to get quality batteries.
 

Overmind

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18650s are fading away also. The big driver was laptops and they no longer use them having switched to prismatic or pouch cells as they are more economical to produce. I used to be able to walk into a computer repair shop and walk out with boxes of 18650s but not any more. Even medical equipment that provided quite a few higher quality cells in the past are/have switched to prismatics. Coupled with new chemistries (Iron Phosphate, etc.) that don't even come in the 18650 form factor, I believe the days of the 18650s are rapidly declining.
I disagree.
Both the demand and supply are still growing significantly.
There will be significantly more 21700s produced, maybe even a good growth in 26XX0; 21700s will gradually take over some market segments of the 18650. but 18650 is still the main and will remain so for most applications for many years.
 

anton_voltx

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The market for 18650 branded cells like LG, Samsung, and so on is more in-demand now than in any other previous year I can remember. There are serious cell shortages for all the most popular models right now even the Panasonic B. Big companies like Tesla have booked out production lines. Once you multiply the number of cells in an electric vehicle by the amount of vehicles sold you realize we are overdue some battery gigafactories.

Right now China is racing to fill that demand, nearly all new li-ion factories are opening in the mainland including from the big brands.

Larger cell formats than 18650 will eventually get more popular. Management of the cell system is just much easier with fewer cells and also you can achieve better energy densities because there is less steel in the equation. But I believe Tesla and others quickly moved on from 21700 to favor even larger sizes and I think fundamentally that probably become more common. Managing 20 giant LTO cells vs. 500 18650 cells -- which one is more prone to error and engineering costs?
 
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