Yet another battery discussion

[steve454]

Why is almost everything powered by tiny 18650 batteries, and the only way to get more power is add more tiny batteries?  Maybe in the future batteries can be one cell with any shape and the bigger the cell the more the voltage.  I guess that they can only go up to about 4.2 volts, and the only way to increase voltage is adding more cells.

[meepmeepmayer]

1. If the tiny batteries have no technical downside... (or do they?)

2. Standardized things are cheaper... much cheaper

[US69]

5 minutes ago, steve454 said:

Why is almost everything powered by tiny 18650 batteries, and the only way to get more power is add more tiny batteries?  Maybe in the future batteries can be one cell with any shape and the bigger the cell the more the voltage.  I guess that they can only go up to about 4.2 volts, and the only way to increase voltage is adding more cells.

These are the best and most powerful available industrial cells! there are bigger cells...26650 for example..but they dont have that much energy....

the new tesla is not even on the market...and noone knows its pricepoint 

[esaj]

11 minutes ago, steve454 said:

Why is almost everything powered by tiny 18650 batteries, and the only way to get more power is add more tiny batteries?

It's an economics thing, the 18650 is, or at least was, most used (think laptops etc), so the mass manufacturing concentrated on those, bringing the prices down compared to other types.

 

Quote

 Maybe in the future batteries can be one cell with any shape and the bigger the cell the more the voltage.  I guess that they can only go up to about 4.2 volts, and the only way to increase voltage is adding more cells.

Lithium-polymers (Li-po, Lipo) is the current technology where the cells can be shaped more freely. The voltage comes from the galvanic pair (or something like that, forgot the actual term), so making bigger galvanic pair won't make the voltage larger, only the capacity. The voltage comes from the potential difference between the dissimilar materials, and needs an electrolyte (and with "real" commercial cells, all sorts of additives to make it rechargeable and otherwise make the attributes better).

 

That chart is nowhere near complete, lithium is something like -3.xx   I've actually got a bunch of graphite bars and rods somewhere, as I was building some galvanic cells for testing purposes earlier...

 

[US69]

3 minutes ago, esaj said:

Lithium-polymers (Li-po, Lipo) is the current technology where the cells can be shaped more freely. The voltage comes from the galvanic pair (or something like that, forgot the actual term), so making bigger galvanic pair won't make the voltage larger, only the capacity.

yip, and even there the used standard industrial  "size" is 3,6 Volt (4,2 full)...and higher voltage is got by serialising... :-(

[steve454]

2 minutes ago, esaj said:

It's an economics thing, the 18650 is, or at least was, most used (think laptops etc), so the mass manufacturing concentrated on those, bringing the prices down compared to other types.

That's what I instinctively knew, but what about the cost ratio for higher capacity cells?  I imagine it climbs very rapidly.  I guess the technology will be here eventually, but by that time we will be driving the cars from the Jetsons.

[US69]

2 minutes ago, steve454 said:

That's what I instinctively knew, but what about the cost ratio for higher capacity cells?  I imagine it climbs very rapidly.  I guess the technology will be here eventually, but by that time we will be driving the cars from the Jetsons.

When even tesla and some other car companies are using the  18650 it must have an advantage:-)

price and energywise....and i dont think EUC's are the driver of a new batterie tech  :-(

 

i take a bet that we wont see the new tesla cells...anywhere in the next 3 years elsewhere as in a tesla!

@esaj good you are here...perhaps split our off-thread away ;-)

[steve454]

Cell phone batteries are flat, very thin, and square.  I know they are low drain, but the life cycle is long like other lithium batteries.  I wonder if cell phone batteries could be linked in series to provide the voltage for an EUC?

[esaj]

14 minutes ago, KingSong69 said:

yip, and even there the used standard industrial  "size" is 3,6 Volt (4,2 full)...and higher voltage is got by serialising... :-(

It's not the size of the cell, it's the galvanic pair used (+ additives, I think), here's a table showing potentials for more metals/materials:

Standard Electrode Potential

• The potential difference measured between a metal M and the Standard Hydrogen Electrode - SHE

The electro-chemical series (electro-motive series) is a list of metals arranged in order of their standard potentials to the hydrogen electrode:

Element	Electrode Potential  (volts)
Lithium	-3.04
Rubidium	-2.92
Potassium	-2.92
Calcium	-2.87
Barium	-2.80
Sodium	-2.71
Magnesium	-2.37
Beryllium	-1.85
Aluminum	-1.67
Manganese	-1.19
Zinc	-0.76
Chromium	-0.74
Tungsten	-0.58
Iron	-0.44
Cadmium	-0.40
Cobalt	-0.28
Nickel	-0.24
Tin	-0.14
Lead	-0.13
Hydrogen	+0.00
Antimony	+0.10
Copper	+0.34
Iodine	+0.54
Silver	+0.80
Mercury	+0.85
Bromine	+1.07
Platinum	+1.20
Chlorine	+1.36
Gold	+1.50
Fluorine	+2.87

 

So basically, if you take, say, a piece of silver and a piece aluminum, place them in a jar with some salt water (without the metals touching), you can measure about 2.4V of voltage between the pieces. Depending on the electrolyte (salt water in the example), you can for example light a led with it (assuming there's enough voltage). The passing current will actually start plating the smaller potential piece with the metal of the higher potential (or was it the other way around, I forgot ).

There's a lot more to it when it comes to battery cells that can actually give out more "meaningful" (useful) currents, as well as being rechargeable, but the basic idea is the potential difference between the metals. I never really learned chemistry, so the finer details escape me  

[US69]

@esaj yeah, i understand and know that...

i just mean that even on Li-pos the currently available cells, whatsoever electrode potential they have, are mostly available in 3,6 Volt....

 

 

[steve454]

1 minute ago, KingSong69 said:

currently available cells, whatsoever electrode potential they have, are mostly available in 3,6 Volt....

 

That is what I am wanting to know also.  I guess I will have to go to the eight vault.

[US69]

20 minutes ago, steve454 said:

That is what I am wanting to know also.  I guess I will have to go to the eight vault.

want an lipo example? here:

 

note that each of the green packs is 4 x 3,6 voltage cell(4.2 full) = 16,8 volt...(called 4S=4 seriell flat cells)

4 packs (2 each wheel side) with each 16,8 = 67,2 volt....(means 16 times x 4.2 volt)

 

note also that this used lipo gets to a 592wh.....if you use best 18650 you fit !820wh! in there!!!

[esaj]

27 minutes ago, KingSong69 said:

@esaj yeah, i understand and know that...

i just mean that even on Li-pos the currently available cells, whatsoever electrode potential they have, are mostly available in 3,6 Volt....

Going higher on the voltage per cell would require using more exotic metals, and the price would go up... think something like gold + lithium, the price of the cells would be very high, so it's much cheaper to use more commonly available materials and just to put more cells in series to achieve higher voltages. But the potential difference is not "everything" when it comes to cells/batteries, look for example here: 

 

[US69]

@esaj yeah, thats all fine, and i think since i am limping around here on that forum i seen about a dozen "new technologies" :-)

Unfortunatly until they come over the "standard" and are payable and available to all kind of electric driven products, its nothing more than a good story :-)

i also thought about making one of my wheels a lipo driven one, as the amp rates and so voltage sag are phantastic...

but price point, charge abilities and so on, had stopped me from doing!

dont get me wrong...i would love to have that futuristic batterie tech and progress! but unfortunately i do not find someone who pays for it :-)

Even my next wheel gets me in discussion with my government:-)

[esaj]

1 minute ago, KingSong69 said:

@esaj yeah, thats all fine, and i think since i am limping around here on that forum i seen about a dozen "new technologies" :-)

Unfortunatly until they come over the "standard" and are payable and available to all kind of electric driven products, its nothing more than a good story :-)

i also thought about making one of my wheels a lipo driven one, as the amp rates and so voltage sag are phantastic...

but price point, charge abilities and so on, had stopped me from doing!

dont get me wrong...i would love to have that futuristic batterie tech and progress! but unfortunately i do not find someone who pays for it :-)

Even my next wheel gets me in discussion with my government:-)

Yup, it's not the first (and probably not the last) time we hear of new "ground breaking" battery technology. Even when viable, it can easily take a decade before it can actually enter mass production. The more or less only difference to most of those stories in this case is that Dr. Goodenough (yeah, I know, what a name ) at least has some reputation, so it's likely not just some marketing gimmick of a new company trying to get government funding or something  On the other hand, universities probably do get government funding... we'll see

[OliverH]

7 hours ago, KingSong69 said:

When even tesla and some other car companies are using the  18650 it must have an advantage:-)

price and energywise....and i dont think EUC's are the driver of a new batterie tech  :-(

 

i take a bet that we wont see the new tesla cells...anywhere in the next 3 years elsewhere as in a tesla!

@esaj good you are here...perhaps split our off-thread away ;-)

The Giga-Factory of Tesla started to produce a new type of battery cell called 2170:

21 mm diameter
70 mm hight

The production partner is Panasonic if I remember right.

[Chris Westland]

Scale economies.  There is a huge amount of production capacity for 18650s, since they are standard for laptops and Teslas ... both heavy consumers of 18650s. 18650 cells are made in a "jelly roll" process, with a single long sandwich of positive electrode, separator, negative electrode and separator rolled into a single spool.  Once you switch production on, you can continuously turn out standardized "jelly rolls".  The main disadvantage of this method of construction is that the cell will have a relatively high series inductance.   LiPo's remove the case and use a polymer (the Po) pouch to reduce weight by about 20%.  They were invented as a way for Sony to use its old cassette tape assembly lines after the rise of CDs, and their applications grew because of their light weight.  LiPo cells have the highest gravimetric energy density, but they change size when charged, and they can be punctured, catching fire. So for EUC's, Teslas, laptops, etc. which need to keep the batteries corralled, LiPo won't do.  

[16bitSprite]

11 hours ago, KingSong69 said:

When even tesla and some other car companies are using the  18650 it must have an advantage:-)

price and energywise....and i dont think EUC's are the driver of a new batterie tech  :-(

i take a bet that we wont see the new tesla cells...anywhere in the next 3 years elsewhere as in a tesla!

@esaj good you are here...perhaps split our off-thread away ;-)

Tesla have been fairly liberal with their patents in the past. Maybe they will share their new cell technology with everyone for the greater good. If they take his approach again, we might see these new cells sooner than 3 years. One can hope so anyway. 

[US69]

1 hour ago, Chris Westland said:

18650 cells are generally LiFePO4 cells producing 3.2 volts

Sorry, this is just wrong....perhaps you can say 18650 are generally/most often Li-ion...with some different kind of chemistry.

LiFepo4 is a total different cell type.....

if a 18650 cell is LiFEPo4, then it is just a small mah rate (max about 1100mah) and hell expensive for this mah rate...

LiFepo4 is only good for amp rates, but has a totally low energie capability, so this kind of cell type is not used in cars, EUCs, laptops...

 

Also the LiPo's that are currently on the market, do not have a higher energy density, placewise you can better fill a Euc with 18650 liIon than with Lipo's(speaking about payable options and not science tech).....See link above, is a good example....

 

Energiedensity:

lifePo4 90wh/kg

li-po 100-130wh/kg

li-ion 110-160wh/kg

[Chris Westland]

You are right ... you can put any number of chemistries inside the 18650 package, but I agree the  LiFePO4 chemistry would be very limited and not particularly useful for EUCs

[Jason McNeil]

While at CES I visited the Panasonic/Tesla booth, who were exhibiting the new 2170 cell that's used in the upcoming model 3. I tried prying information from the Panasonic engineers about cell's properties. They said that Tesla not only has sole & exclusive rights to the new cell, but all information about it's characteristics are, for the moment, a confidential trade secret. What he was prepared to say, was that the cell's capacity is higher than Samsung's 5.7Ah of the same format.

• They have no plans to offer this cell to other sectors, such as Consumer Electronics
• Was told that the primary forces driving production to the 2170 format are 1) $/Wh cost reduction, 2) Increased lifespan by up to 3-5x (critical for their grid storage ambitions), 3) Improved fast-charging capabilities
• If it's true that 6Ah/cell, at 75g, then = 22.2Wh/cell =  296Wh/kg, which is a quite a leap over the current best 3.5Ah, 12.6Wh in the 18650 (50g) = 252Wh/kg

On 3/11/2017 at 6:12 AM, KingSong69 said:

Energiedensity:

lifePo4 90wh/kg

li-po 100-130wh/kg

li-ion 110-160wh/kg

At the cell level, current Li-ion 18650 energy density is 252Wh/kg. 

[Chris Westland]

9 hours ago, Jason McNeil said:

While at CES I visited the Panasonic/Tesla booth, who were exhibiting the new 2170 cell that's used in the upcoming model 3. I tried prying information from the Panasonic engineers about cell's properties. They said that Tesla not only has sole & exclusive rights to the new cell, but all information about it's characteristics are, for the moment, a confidential trade secret.

So much for Tesla open sourcing their battery tech ... Samsung, LG Chem, etc. apparently also have their own 2170 cells that will compete with the Panasonic/Tesla 2170 ...https://electrek.co/2017/01/09/samsung-2170-battery-cell-tesla-panasonic/  ... and Tesla started up their line in early January ...

 

[Chris Westland]

... and further out ... https://phys.org/news/2017-03-nanofiber-important-battery.html