Will the 21-70 Battery (a.k.a. 21700) Replace 18650?

Unlike with car batteries, there is no coolant running between the 18650 cells in a 5 year old laptop.
Standing air does not provide any cooling.
All modern laptops use Lipo packs instead of cylindrical cells for space savings and more capacity.

This is not the reason why macbooks have such long battery life, since there are other laptops with short battery life that also use lipo cells, so in that sense he is wrong.

Not in a tube. :smiley:

True :stuck_out_tongue: the guy was talking about laptops tho.

I know.

Sux, though, that I can’t get any decent pax to scrounge for more 18650s anymore.

So Now what? All these 18650 flashlights I’ve collected will become obsolete? I sure hope the 18650 stays around for a long time.

That does not refute my point. There are low end thin computers, and low end thick laptops. There are also high end thin computers, and high end thick computers. If you want to refute my point properly, show me proof that most high end thick workstation and gaming laptops have switched to lipos.

The cell phone makes no sense. Aside from early car phones, I only know of one cell phone since 2002 that has had a cylindrical battery, and it used a AA.

Laptops or cell phones, it’s about form factor.

I’ll oppose my stance. I searched for best gaming laptop, and the most expensive laptop in the first search result was the Razer Blade Pro at $4000. The 5th search result for this laptop shows that it apparently it has a lipo. You can tell because of the swelling.

I’m not a laptop designer, but I think it’s safe to say the lipo needed cooling or protection, or both.

Don’t think it needed cooling, they would have added if needed.
Most if not every laptop (and smartphone and every other consumer device that uses a lipo battery) already has electronic protection.
Pretty sure this is just a problem with the battery itself. Just like the problems with the Samsung batteries.

In that case electronic protection doesn’t do anything, it needs mechanical protection like we see on the cylindrical liion cells. If it would have a venting option the battery wouldn’t swell.
But don’t know if that’s possible with the design of a lipo battery.


Found some interesting reading (at least to me) on the state of the battery industry. I will note that nowhere is battery use in flashlights mentioned in this report.
Annual Update on Li ion battery technology 2018

The 21700 format is gaining traction with automakers and power tool manufacturers.

A SEP 2017 news story:

At another Korean news site I read a report that Samsung has converted some of it’s 18650 production lines to 21700, to keep up with demand.

A FEB 2018 news story:

Has anyone noticed a shortage, or price increase, for Panasonic or Sanyo 18650 cells?

A DEC 2017 news story:

It sounds like Panasonic has converted many (or all?) of their Japan cell production lines over to 21700 from 18650, to make up for the shortfall at the Gigafactory in Nevada.

I think its happening now. I now own four 21700 flashlights and four 21700 batteries. They said that 26650 format was a dead end but lots of flashlights use em now. I suspect that the 21700 format will catch up fast.

I haven't been keeping up with the flashlight world for almost a year and a half. The appearance of 21700 cells that rival 26650s in terms of both capacity and output current makes me excited, I have to admit. Not sure how pocketable tube 21700 light will handle heat management with all that power, since they'll only be a fraction larger?

(edit: larger than 18650 lights)