Tesla's gigafactory dropping 18650's and going with 20700 - per Elon Musk

[StorminMatt]

The only savings I can see is they can use less cells to get the same amount of power but the less cells may not take up any less size perhaps even more size when they are grouped together as the holes between cells I believe will be larger and the cells are taller too.

When it comes to hexagonal packing of cylinders, the void ratio is independent of the diameter. It is always .0931. So there is neither a gain nor a loss here. On the other hand, the battery casing itself can take up a lower percentage of the total real estate on a larger cell, allowing more of the cell to be active material. This can increase the energy density if larger cells are used.

 

[JB007Rules]

Most of the dollars in laptop batteries is not 18650 any more.

Maybe for the consumer market this is true since they are all thin and light... This isn't true AT ALL for the commercial and military market though.... I'm a managing partner at one of the largest Toughbook re-sellers in the country (Rugged Depot) and coming from 12+ years in the Panasonic Toughbook world, Panasonic OWNS the rugged laptop market and they are mostly 18650's but they are slowly going towards either 14500's or something similar to make the laptops skinnier.

Seeing as ALL the cells are Panasonic (They invented the 18650) it's an IN for them to sell their laptops with their cells in them too

I'd be interested to see what Panasonic can offer for these consumer grade laptops as you said they don't have 18650's in them. They are probably losing the business to Samsung or LG on those cells

Thanks!

 

[Gauss163]

When it comes to hexagonal packing of cylinders, the void ratio is independent of the diameter. It is always .0931

But that packing density is for packings in the infinite plane. For packings into some finite region you also need to account for the voids left at the boundaries of the region, which smaller cells will generally fill better. For example, see this page on circle packings in a square.

 

[CuriousOne]

Modern laptops mostly use 16650 cells. UR16650ZT generally.

 

[PH1]

I don't think that other battery makers are going to copy this size if they don't get a contract making batteries for them as larger cells will only make laptop and drill battery packs larger as they are built around certain voltages and eliminating batteries to make a taller wider but not necessarily longer pack isn't going to be worth it.

Some power tool manufactures has already switched from 18650 cells to 20700 cells.
So Telsa isn't inventing a new cell format for the Giga Factory / Model 3. They just use the 20700 cell format that's already sold by power tool manufactures.

Metabo 18V LiHD packs use 20700 cells, they were introduced to the market already a year ago in May 2015.
Metabo LiHD: https://www.metabo.com/com/en/info/news/highlights/lihd-battery-pack-technology/
Metabo LiHD battery pack capacities:
Slim pack (5s1p): 3100 mAh
Fat pack (5s2p): 5500 mAh and 6200 mAh.
Accroding to http://www.werkzeug-news.de/Forum/v...&sid=f9a4c70cc4bbc14e0a40d9ec6280a742#p324039 Metabo LiHD is based on Panasonic/Sanyo NCR20700A cells.

Bosch is also coming out with an EneRacer GBA 18V 6.3 Ah fat pack battery based on 20700 cells this fall.
Press release - Bosch Power Tools relies on connectivity:
http://www.bosch-presse.de/presseforum/details.htm?txtID=7664&tk_id=112&locale=en

The latest example of innovative cordless technology from Bosch is the high-performance battery GBA 18V 6,3 Ah EneRacer Professional, which will be available from autumn 2016. An improved power connector within the cells ensures lower internal resistance, which means that higher currents can be drawn from the cells over a longer time. The result is an increase in available power in a compact battery.

It also looks like Bosch has switched to from nickel to copper connections between the cells to lower the internal resistance of the battery pack.

Pictures of the new Bosch 6.3 Ah EnerPower battery pack and 20700 cells:
Picture sources:
Pic 1-6: https://www.bosch-professional.com/de/de/community/category/eneracer-die-neue-akkutechnologie/10603405-t
Pic 7-9: http://www.sg-toolbox.com/bosch-eneracer/

 

[Kurt_Woloch]

As far as I know, self-balancing boards still use 18650 batteries. And currently their sales vastly outnumber sales of electric cars with millions of boards having been shipped to the USA so far. ;-)

 

[JB007Rules]

Speaking of power tools.

I have taken apart almost all of my DeWalt packs (I have a quite an extensive collection ) the larger 20V's have 10 high drain 18650's in them (pancake/smaller ones only have 5 of course) (5.0AH's have the blue 2500MAh's in them and the 3.0's have 1.5MAh's in them and they are red in colr)

5 * 3.7V nominal = 18.5V... 4V*5 = 20V "MAX"... They are 18V batteries but in the US they are marketed as 20V... the EXACT same batteries in Europe are 18V! ( http://toolguyd.com/blog/wp-content/uploads/2012/07/Dewalt-18V-XR-4-0Ah-Battery-Gauge.jpg ) - Since they can't get away with stretching the truth there...

The 8V gyro screwdriver has TWO 14500's . The 12V ones have 3 x 18650's in them.

Thanks!

 

[snakebite]

If they are not 18650 anymore, what are they?

lipoly pouch cells.
apple has been using them a long time.
most high end slim notebooks now use them.

 

[Kurt_Woloch]

Well, I have seen laptop batteries having a unusually high voltage... Dell laptops, specifically. I think those are 3S batteries, but they charge up to about 13.12 V (which is 4.37 V per cell), having a nominal voltage of 12 volts (4 volts per cell). However, the voltage doesn't seem THAT high to me... it's maybe 0.2 V per cell higher than the voltage of the cells Lenovo uses in T60/T61 batteries.

 

[Gauss163]

Well, I have seen laptop batteries having a unusually high voltage... Dell laptops, specifically. I think those are 3S batteries, but they charge up to about 13.12 V (which is 4.37 V per cell)...

Those are cells that charge to 4.35 volts, and they have been in use for many years in laptops.

 

[parametrek]

the Tesla battery packs are liquid cooled.

This also put an upper limit on the size of cell Tesla can use. Smaller cells are easier to cool than larger cells since they have more surface area for a given amount of watt-hours. But as battery technology improves they can use larger cells. Specifically a lower internal resistance means less heat generated inside the battery.

Regarding the research that has gone into 18650 cells, all of that directly carries over to any size cell. Every li-ion cell is basically rolls of metalic foil and moist paper in a vented metal tube. But 18650 cells get the latest and greatest manufacturing processes before other sizes because that is where the demand is.

 

[PH1]

Speaking of power tools.

I have taken apart almost all of my DeWalt packs (I have a quite an extensive collection ) the larger 20V's have 10 high drain 18650's in them (pancake/smaller ones only have 5 of course) (5.0AH's have the blue 2500MAh's in them and the 3.0's have 1.5MAh's in them and they are red in colr)

5 * 3.7V nominal = 18.5V... 4V*5 = 20V "MAX"... They are 18V batteries but in the US they are marketed as 20V... the EXACT same batteries in Europe are 18V! ( http://toolguyd.com/blog/wp-content/uploads/2012/07/Dewalt-18V-XR-4-0Ah-Battery-Gauge.jpg ) - Since they can't get away with stretching the truth there...

The 8V gyro screwdriver has TWO 14500's . The 12V ones have 3 x 18650's in them.

Yes it a well known fact that power and garden tool manufacturers lie about the voltage, especially in North America, by stating a made up marketing/max voltage of 4 V per li-ion cell instead of the nominal 3.6 V per cell. To convert from Vmax to Vnominal, simply multiply Vmax by 0.9.

4 Vmax = 3.6 Vnominal
8 Vmax = 7.2 Vnominal
12 Vmax = 10.8 Vnominal
16 Vmax = 14.4 Vnominal
20 Vmax = 18 Vnominal
24 Vmax = 21.6 Vnominal
28 Vmax = 25.2 Vnominal
...
40 Vmax = 36 Vnominal
56 Vmax = 50.4 Vnominal [EGO garden tools for example use 50.4 Vnominal batteries but market them as 56 V].
... and so forth.

Actually all li-ion cells used in power and garden tools has a nominal voltage of 3.6 V, not the 3.7 V used in you calculations, you can confirm this by looking of the nominal voltage of these cells in the datasheets. The cells used in power tools are has a very low internal resistance / very high max. continuous discharge rate and all these cells only has a nominal voltage of 3.6 V.
Lower discharge rate li-ion cells like the ones use in laptops has a nominal voltage between 3.7 and 3.8 V and can store more energy [Wh], partly due to the higher nominal voltage, as energy storage is calculated as nominal voltage [V] * capacity [Ah].
You can't have both very high max. continuous discharge rate and the highest capacity in the same type of cell. That's why you should never use laptop cells for power tools as they can't handle the high current draws and has too high internal resistance. Laptop cells are instead designed to have the highest possible energy storage.
You can however use power tool cells in laptops, but they will have lower capacity.
Some of thee most common cells used in power tools by several brands are the Samsung SDI INR18650 cells listed here: http://www.samsungsdi.com/lithium-ion-battery/power-devices/power-tool.html
As you can see they all have a nominal voltage of 3.6 V, but very high max. continuous discharge rate.
Their Samsung ICR18650 laptop cells on the other hand has nominal voltages up to 3.78: http://www.samsungsdi.com/lithium-ion-battery/it-devices/laptop.html

 

[JB007Rules]

Thank you for clarifying the 3.6 VS 3.7 on the voltage. I think I know where I went wrong on this. See below:

I have also taken apart my mini-dyson battery pack as it shows 22.2V on the casing.... it has 6 x 18650's inside of it (Of course right lol).

3.7*6 = 22.2...

In closing I think that TOOL manufacturers in SPECIFIC use 3.6V and other companies (Such as Dyson in this case) use 3.7V.

Not sure on why that it as Panny says that it IS certainly measured as 3.6 nominal per their datasheet.

Thanks!

 

[Gauss163]

...Yes it a well known fact that power and garden tool manufacturers lie about the voltage, especially in North America, by stating a made up marketing/max voltage of 4 V per li-ion cell instead of the nominal 3.6 V per cell....

That would be "lying" only if they used such voltage "labels" to falsely deduce inflated energy ratings (Wh). But I doubt that is true. To compare packs you should compare the energy (Wh) they deliver under typical load conditions

 

[Lynx_Arc]

That would be "lying" only if they used such voltage "labels" to falsely deduce inflated energy ratings (Wh). But I doubt that is true. To compare packs you should compare the energy (Wh) they deliver under typical load conditions

That and Alkaline batteries are labeled at 1.5v and rarely have more than 1.55v in them while nimh charged fully are rated at 1.2v and if you measure them it is only under a load or depleted that they measure that low off the charger it is more like 1.4v. A 20v pack would measure 20v with no load on it and perhaps under 18v under a very heavy load even. Off the charger an 18v pack would measure about 4.2v x 5 or 21v. I think battery makers just chose 20v so as to differentiate them from the 18v nicad packs out there which also measure about 20v off the charger I think.

Simply speaking what is the selling point is more the Ahr ratings on packs of similar range with 3Ah 4Ah 5Ah etc. If a 20700 battery were sold as cheap as a similar 18650 battery with the additional mah extra due to physical cell size difference I think it would be a selling point indeed but if you are going to pay more per Ah for 20700 batteries then they won't make a huge splash right away but for those who really are willing to pay considerably extra for the extra capacity they offer. What I wonder is why they don't make large diameter very short cells like a 60200 which could have 2.5 the capacity of a 20700 but I guess that would make it harder to put them in packs with that size of a battery.

 

[IamMatt]

Tesla is just trying to catch up with Mercedes' new battery technology.

 

[CuriousOne]

Earlier DeWalt lithium batteries, which are compatible with older instruments, use A123s LiFePO4 18650 cells.

 

[KeepingItLight]

Tesla is just trying to catch up with Mercedes' new battery technology.

ROTFLMAO!

 

[Overclocker]

larger format is good. saves me from having to weld so many of them

 

[MAD777]

Tesla is just trying to catch up with Mercedes' new battery technology.

That saleswoman almost sold me a Mercedes! 😄😄😄