Is 21700 actually behind???

Cree XHP 70 LED

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I just ran across this video and I think these cells Elon is using probably are about 10,000 mAh each possibly, but would make a pretty fat flashlight body.
 

Cree XHP 70 LED

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After looking it up they are about 9,000 mAh per cell but super fat. D cells are 31 mm x 61 mm so we're talking fatter than a Maglite probably not a use case for flashlights. Sorry I slept late and didn't research before posting could replace soda can lights though just 2 in series.😆
 
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Lynx_Arc

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I think 21700s may stick around for awhile in tool and electric lawn power battery formats as we already see all the main brands of battery tools using them and the slightly larger size of them are not inconvenient when you need extra power and run time. What is probably the up and coming cylindrical battery competitor is flat stacked battery packs like Dewalt's Power Stack battery. It is interesting tech that shows great promise but it is too early to know if it will overtake the 21700s because the batteries can be made smaller, have more power on demand and likely more overall power density per battery pack due to the air gaps in cylindrical cell packs adding more volume but overally lowering power density of the entire pack.

It may well be that larger and larger cylindrical batteries may find themselves a home in very heavy power hungry tools like saws and mowers and jackhammers that eat up batteries even the largest available batteries don't last long enough.
What will be the driving force on more acceptance is cost vs other batteries IMO. The second consideration is safety. Unless there is technology in batteries to protect from fires and explosions that goes beyond protection circuitry to physical damage larger batteries can pose a greater risk and with it liabiility that could preclude them from some uses. The new flat stacked batteries are said to be a lot safer from physical damage causing fires etc I believe which if the cost is about the same along with a supposed battery cycle life of about twice that of 18650s etc that may in itself be enough to compete well with any cylindrical cells if the price can be held down to reasonable levels.

I wouldn't count 21700s out..... nor 18650s either but I wish they would help 14500s and other smaller cell sizes catch up with the power density and cost per watt hours so we could see less of a need for jumping to 18650 and larger. I think that as long as power density is about the same then what it comes down to is just plain size consideration and power needed. It is likely that the makers of electric vehicles etc will constantly try and get the most power at the cheapest cost which means as long as they can figure out how to save considerable money they will abandon sizes and types and even chemistries as it is such a huge industry up and coming that such changes are more and more possible. The electric car industry will likely fuel research into battery technology the next 20-50 years or more along with power grids that have solar and wind feeds needing to store energy efficiently. What will this mean for flashlights? It is possible that the only thing we will soon see from electric cars to help with flashlights is chemistry and types of batteries it may be the batteries they start using become less useful to us. If one remembers lead acid batteries in flashlights and lanterns they were ok back then because we were used to large lights and batteries to get more output and run times but today we are used to small lights doing what an incan bulbs and small lead acid battery was needed for.

Personally I think that somewhere down the line electric car batteries as a source for flashaholics will be replaced by tool battery makers. I think the tool battery market will be a driving force themselves to better batteries suited for their application and what I'm really hoping is some sort of universal tool battery design in the future that aleviates the endless amounts of different packs driving up costs (and profits) for consumers (and companies) like the proprietary cell phone charger market did that was finally brought down by the EU and micro USB connectors long ago
 

idleprocess

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Last time I ran the math, if the 4680 is going to approximate the 18650 and 21700 on Wh/cm³ it's going to need to clock in at around 25 Ah. This number aligns with ballpark cell count comparisons between known 18650 and 21700 packs Tesla already produces and how many 4680 cells could fit into a similar volume.
 

orbital

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+

Higher recharge* rate on the bigger 46800 cells.
Range (distance) & speed of recharge, are the two biggies w/ EVs'

*and discharge

One of the very first articles I read on the 46800 last year, it was all about the higher discharge rate, that equates to performance

====================

Anyway, someone has to make a 2x46800 light!!! !
 

vicv

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I just ran across this video and I think these cells Elon is using probably are about 10,000 mAh each possibly, but would make a pretty fat flashlight body.

I wouldn’t call it “behind.” I mean his battery would be behind a 67850 by that logic. Bigger will always have a higher capacity. A car battery is ahead of the 21700?
 

electromage

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I wouldn’t call it “behind.” I mean his battery would be behind a 67850 by that logic. Bigger will always have a higher capacity. A car battery is ahead of the 21700?
Well, 21700 is technically a car battery, right?

I did the math at some point and for a custom pack for my car I could fit more kWh with 21700s than 4680s, but maybe after figuring out the cooling it would be different.
 

idleprocess

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Higher recharge* rate on the bigger 46800 cells.
Range (distance) & speed of recharge, are the two biggies w/ EVs'

*and discharge

One of the very first articles I read on the 46800 last year, it was all about the higher discharge rate, that equates to performance
Historically, Tesla has wrung industry-leading range and impressive performance out of high-density cells, massively paralleled. The ~3C rates that high-density 18650s (~3.5Ah) and 21700s (~5Ah) manage have proven sufficient to the point that the Model S Plaid can lay some claim to being the fastest production car in the world.

I've seen a few sources mentioning 960x 4680 cells for a Model 3/Y pack, which at 9Ah would imply a capacity of only about 31kWH as opposed to the 54kWH that the original base-level Model 3 achieved with 2976x 21700 cells. Whatever efficiencies are to be gained through less capacity loss to heat doesn't seem like it begin to will make up for a loss of ~43% overall capacity - especially since normal driving isn't running up against discharge limits.

Anyway, someone has to make a 2x46800 light!!! !
I would like to see this myself - even if it does indeed just end up being 9Ah per cell.
 

fuyume

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Li-ion battery technology has not seen any fundamentally new technology breakthroughs in a long time, and many people believe that Li-ion has reached its limits. The fact that technology has improved rapidly in the past is no evidence that it will continue to advance.

Yes, incremental improvements have been made, but no leaps in many years.
 
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