Why Is 18650 So Popular?

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Mithion   10 W

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Why Is 18650 So Popular?

Post by Mithion » Jul 04 2018 1:50pm

https://goo.gl/images/SBep9p

Why is the 18650 so popular say over the 26650 or any other size?

Is it a perfect size for the power thing?

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spinningmagnets   100 GW

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Re: Why Is 18650 So Popular?

Post by spinningmagnets » Jul 04 2018 1:56pm

Price and availability. Both are the result of mass production. I think it's useful to understand that electric bikes are a very tiny part of battery cell production. The biggest users of 18650 cells are laptops and cordless tools. Laptops use low-amp cells that have a medium capacity, and they are sold based on the lowest price.

The 18650 cells that are the most useful to ebikes are from cordless tools, which have the dual needs of high amps and long range. A typical laptop cell might be 2,000-mAh, and can produce 2A without getting hot. Compare that to a 30Q cordless tool cell which has 3,000-mAh and easily provides peaks of 15A.

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st35326   100 W

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Re: Why Is 18650 So Popular?

Post by st35326 » Jul 04 2018 4:06pm

Actually, the laptop thing used to be true but not anymore, 18650s are actually too thick for many of the new laptops. Like the MacBook Air Im typing this on, most are using flat battery packs. I believe the number one consumers of 18650 batteries right now, are electric cars, specifically Tesla. With 8,256 18650 batteries in a single 100kwh models S pack.

dustNbone   10 kW

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Re: Why Is 18650 So Popular?

Post by dustNbone » Jul 04 2018 5:18pm

I'd say they still sell 1000+ tool packs for every Tesla that gets sold.

Most of the tool packs aren't sold to average consumers for occasional use, they're sold to trades people that burn through these packs at a rate of several per year.

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Dauntless   100 GW

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Re: Why Is 18650 So Popular?

Post by Dauntless » Jul 04 2018 9:54pm

So I go looking for LED flashlights that'll take the 18650 to use as portable lighting when I'm shooting. A 'D' Orr even 'C' cell size should be better but that is not yet pervasive. These lights get hot when you keep them on, good question if a larger cell at the same draw would be so hot. But I can get the flashlight and the cell in that size, though most flashlights aren't that size yet. It's the basic snowball effect. See
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thepronghorn   100 W

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Re: Why Is 18650 So Popular?

Post by thepronghorn » Jul 05 2018 7:03pm

dustNbone wrote:
Jul 04 2018 5:18pm
I'd say they still sell 1000+ tool packs for every Tesla that gets sold.

Most of the tool packs aren't sold to average consumers for occasional use, they're sold to trades people that burn through these packs at a rate of several per year.
Not sure about that... 2000 Model S and X last week = 16 million cells a week = 832 million cells a year. Most tool packs are 10 cells, so that means 83.2 million tool packs a year. Maybe... Seems unlikely to me...

Going by your number of 1000+ tool packs per Tesla, each Tesla is almost equivalent to the number of cells in 1000 tool packs lol.

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Re: Why Is 18650 So Popular?

Post by Hillhater » Jul 05 2018 11:42pm

Mithion wrote:
Jul 04 2018 1:50pm
https://goo.gl/images/SBep9p

Why is the 18650 so popular say over the 26650 or any other size?

Is it a perfect size for the power thing?
Many reasons, but primarily its a price thing together with choice of supply.
18650s were so widely used in laptops from the '90s through to the last few years, that a hugh manufacturing capacity was established by all the big suppliers as well as other minor players.
As the laptops slimmed down and subsequently moved to custom made batteries, much of that 18650 production capacity went begging for an outlet, driving down prices and pushing up availability.
Power tools helped move the chemistry to the higher power and capacities , whilst retaining the proven 18650 manufacturing quality and leveraging volume costs.
Other formats ..26650, 32500, 38120, etc etc, have existed for many years, but they have never had the volume of production to reduce the cost of manufacturing in the scale of 18650s.
The cream topping was probably Tesla adopting the 18650 as its prefered format for several reasons (thermal dispersion, safety, cost, quality, availability etc) ..and then pushing development to new levels with Panasonic.
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cwah   10 GW

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Re: Why Is 18650 So Popular?

Post by cwah » Jul 06 2018 2:45am

Safer is a key differentiator as well.

Not that they are safe inherently, because they are not. But compared to lipo pack it's way safer and easier to maintain
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dapkcuf   100 µW

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Re: Why Is 18650 So Popular?

Post by dapkcuf » Jul 06 2018 8:26am

21700 seems to be the new 18650 pushed by the ecigarette market

Hillhater   100 GW

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Re: Why Is 18650 So Popular?

Post by Hillhater » Jul 06 2018 11:21pm

dapkcuf wrote:
Jul 06 2018 8:26am
21700 seems to be the new 18650 pushed by the ecigarette market
Early days, but currently there is not much choice , and the cost per Ah is much greater.
This forum owes its existence to Justin of ebikes.ca

John in CR   100 GW

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Re: Why Is 18650 So Popular?

Post by John in CR » Jul 07 2018 10:15pm

Popular in what sense? For retailing to individuals or for use in the lowest priced packs sure, but for traction batteries no way. Other than Tesla who else has gone that route?...Probably a poor decision by Tesla simply because cylindrical of any size waste 22% of the space available simply due to the shape, not to mention the materials and volume waste of structural integrity to each cell . Manufacturers of the higher quality pouch cells don't sell retail or to any company without providing proper engineering pack design. The proof of the effectiveness of this approach is the almost complete lack of battery fires in the news for other electric car manufacturers.

Our issue as ebike builders is that the narrower cell width we need for ebikes isn't in demand for the large volume customers. The sooner the Chinese market for 2 wheel EVs demands longer range and higher power the better it will be for us in terms of better batteries. In the meantime, if you want to build safe and powerful packs you have to figure out how to fit cells designed for a different purpose. Don't copy the bicycle manufacturers at this point, because they're still noobs when it comes to electric drives.

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