Turnigy nano-tech round cells.

[x88x]

So I was on HobbyKing's site today, checking to see if they had restocked their US warehouse yet, and I ran across these interesting things.

Apparently now they are making the nano-tech's in small cylindrical format. I took the largest capacity one they have listed (1.2Ah), and ran the numbers on it. Came out in cost between their 25C and 40C nano-tech pouch cells, but a higher density both by volume and weight than any of their other cells. Not anywhere near the Panasonic 18650's in density, but a hell of a lot higher C rate than those too. They're using an interesting, non-standard size. Converting to standard naming convention would be a 15580 format I guess.

Capacity: 1.2Ah
Constant C-rate: 15C
Length: 58mm
Diameter: 15mm
Weight: 23g
Cost: $2.80
USD/Wh: $0.63
Wh/kg: 193.04
Wh/L: 433.41

Also found this video introducing them.

http://www.youtube.com/watch?v=D_PsILc1h8E

Judging from the post date, it looks like they only launched them 6 days ago, so I guess that answers the question I was going to ask, which is has anyone gotten any of these to play with.

I can't quite tell from the picture they have what the terminals are like or how rigid the casing is, but these look interesting, imo.

[Ypedal]

I think the 5ah cell we commonly use is about perfect, 5ah is as small as an ebike pack can be to get any distance, and if you are going to build a 5ah+ pack it makes no sense to do it using multiple smaller cells when you can get the bigger one's..

I did notice them last time ordering, almost for a few for headlight and various other uses, but not as a main pack power

[x88x]

Fair point. What caught my interest was the 50% greater volumetric density when compared to the 5Ah 20C's. Even compared to the big 12.8Ah 40C pouches (best volumetric density I've seen in a non-cylindrical cell of any type) they edge them out by a good 33%. How much of that would get swallowed up in packaging, idk, but I'm considering picking up a few just to see what the terminations are like.

[maydaverave]

If they made modules that you could just pop these into and then connect in serial or parallel that could be interesting. Maybe little 12v boxes that the cells could be put in with simple tools then you could bolt them to other modules, bolt one way for a serial connection and another way for parallel. Got a bad cell just pop out and replace.

[x88x]

Well, I went ahead and picked up 10 of them to see what I can see. Will report back when they come in.

[x88x]

Will report back when they come in.

When it going to be?

Don't know. According to the shipping tracker, they're somewhere between Singapore and the US right now. Last update was them leaving the country.

[NeilP]

Have you compared volume/density when you have multiple of them made up to a same Ah pack as the flat pack types? They maybe better per cell, but I am wondering once you pack them and the gaps between the cylinders how they compare
So the smallest pack you could make for easy comparison would be 30Ah pack so 25 of these to 6 x 5Ah singles

[x88x]

Have you compared volume/density when you have multiple of them made up to a same Ah pack as the flat pack types? They maybe better per cell, but I am wondering once you pack them and the gaps between the cylinders how they compare
So the smallest pack you could make for easy comparison would be 30Ah pack so 25 of these to 6 x 5Ah singles

That would vary too much depending on how you package them to be of any real use. That's part of why I got some; to play around with some ideas for packaging.

[NeilP]

Well not really, without getting involved in spacers etc like the headway cells there is only two basic arrangements that you are likely to use; parallel rows in both directions , or staggered rows, where each new layer is offset by half a cell so a layer of 8, then. 7 then 8, so a pack 8 rows high

Yes, of course you could have some end to end , but you need to start with some basic building blocks.
Still I reckon they will be too small for bike packs, unless the energy density is a substantial improvement, cylinders are never going to stack as well as flat packs, and you are going to need a lot more of them as they are only 1.2ah per cell, instead of 5 or so per pouch


For stuff like lights etc, they are great, but I think for a pack too small. I'll try and work out some exact pack equivalents, probably going to have to work on 12Ah pack for comaparasion as that is going to be the closest exact Ah match to current pouch cells 3ah
I think the smallest pack you could make to give an exact voltage and capacity equivalent ( although not C rate) would be
6s10p = Nominal 22.2 volt 12 Ah
this would match with 3 three 6s 4Ah packs
http://www.hobbyking.com/hobbyking/stor ... FPack.html

60 1.2Ah Cells at 23g =1380g
or
3 x 6s packs as above 3x 630 = 1890g
looks good so far

Even if we do them just as one flat pack to start with, none end to end.

Umm 15mm diameter..60 cells...so between centres on each row...15mm one in the middle on top, next row up..that will be 15mm to its centre too

[NeilP]

Think I got that about right..anyone see any total errors in that arrangement? and calcs?

Untitled.jpg (43.03 KiB) Viewed 800 times

15mm diameter cells
58mm long...plus a bit for the wiring..so say 65mm

so round figures 120 x100 x 65 = 826800 or 827 cubic cm

The other packs are 163 x 49 x 39 = 311493 x 3 packs = 934479 or near enough 935 cubic cm

So just on a quick calc like that it does seem more energy dense, at the tightest possible packing..but you are looking at 15C not 25 C, but that is largely irrelevant at 10Ah I think

Lot of soldering and a lot of work to make a big pack though...Cell level monitoring is going to be out.
But small cells, if you were trying to stash a lot of cells in small spaces within a frame


60 of them would be $156 USD
3 of the flat packs as linked above $148.80

So not a lot in it in price.

So maybe for special build and packing lots of small cells in tight spaces it could be worth it....but trying to find a duff cell in a big pack made up to something like a 50 volt 12 ah pack.... 120 cells...
but for a small pack these could be great.

Now if they started selling cells that were bigger Ah capacity than 5 or 6 per cell, not smaller, then they would have something

[Hillhater]

...I can't quite tell from the picture they have what the terminals are like

They are supplied with tabs ready for soldering.
I will wait for the 26650 , 5Ahr version

[neptronix]

Hm, looks like a prismatic cell in a round wrapper.

The turducken of batteries!

[x88x]

And all this ^^^ is why I just gave in to my curiosity and ordered a few. So we can skip the speculation stage where we all sit around and talk about how we think something would work based on one picture that doesn't exactly show anything about it very well. Besides, they're pretty cheap. Worst case I'm out $60.

[NeilP]

well you will not loose out, they can always be used for other things, torch, bike lights etc

[x88x]

So...yeah...if you're ever ordering stuff from HobbyKing's Hong Kong warehouse, I cannot recommend Swiss Post. I bought 5 5S 20C Turnigy packs the day after I placed this order, shipped them with Singapore 'Speedpost', and figured I'd see which was faster (this order was with Swiss Post btw).

Both shipped on 2012-05-23.

Speedpost package was delivered on 2012-06-08.

Swiss Post package still has not been delivered, even after arriving as US border on 2012-05-31 and arriving at "sorting" (supposedly in my zip code) on 2012-06-05.

[x88x]

Well, today I finally got the "you weren't home so we'll try again later" note. So that's 14 days from arrival at "sorting" at my zip code to delivery. I can only assume that the majority of that time was spent in customs.

Unfortunately, I won't be able to pick it up from the post office until Thursday, but once I do I'll post pics/measurements/etc.

[Trackman417]

Strange, I always thought shipping battery's from Hongkong to US would be a couple month wait time. I guess not!

[x88x]

Got the cells in today. Not quite thrilled with them, I have to say.

Images (camera can't seem to focus well):



Construction:
Appears to be standard cylindrical wrapped cathode/anode layers, encased in the same sort of foil material as the pouch cells. Ok, I'm guessing on the wrapped layers, but that's what it feels like, based on how solid it is.
Because of the foil material used for the shell, there is a small ridge along each side of the cell, where the foil is joined together.
About the same diameter as a AA, but about 5mm longer.

Termination:
One tIny 2mm wide tab at each end, each about the thickness of the tabs on the pouch cells.

Actual density:
I laid them out, comparing against a 5S 5Ah 20C pouch cell pack. It looks like I could fit 18 of these in about 1.2 times the space of the 5S 5Ah pack. With termination bars/etc, I would say optimistically about 1.5x.
That brings us to 115.44Wh for these, vs 138.75Wh for 1.5x the 5S5Ah pack. Of course, you would also have extra space taken up by whatever termination system you use for the pouch packs...I'm gonna say optimistically you would probably end up breaking even.

So to sum up, I think that for building a large pack these are out of the question. If they had a more solid termination, maybe they could be feasible, but like with 18650 cells, it would still probably require a large amount of engineering work to get them into a usable module. Interesting, and they seemed like a good prospect, but let's just say I'm glad I only got 10. I'm sure I'll find some use for them, but it looks like my original thought of combining the energy density of 18650 cells with a fairly high discharge capability is a bust.

If anyone has any questions or anything they would like me to try with these cells, let me know and I'll see what I can do.

First on the list is some discharge tests.

[neptronix]

Aaaahhhh.. i figured that was the case..

BTW, how are you getting the 138whr/KG figure? Did you know that this RC Lipo is actually 3.8v nominal? were you using 3.6 or 3.7v as the nominal voltage in your calculations?

[cwah]

Are lipo 3.8V nominal? Because on HK they use 3.7V nominal and the WH you can get out of it should rather be calculated at 3.7 rather than 3.8V

[x88x]

BTW, how are you getting the 138whr/KG figure? Did you know that this RC Lipo is actually 3.8v nominal? were you using 3.6 or 3.7v as the nominal voltage in your calculations?

I used 3.7V. I've never really seen a good justification for any of the quoted 'nominal' voltages for lipo. LiFePO4 makes sense, as the voltage curve levels off at 3.2V for the majority of discharge, but with lipo not really having a level discharge at all, there's no clear point to draw the line.

[neptronix]

Are lipo 3.8V nominal? Because on HK they use 3.7V nominal and the WH you can get out of it should rather be calculated at 3.7 rather than 3.8V

They are if you put a moderate load on them, like 1/4th their rated C, and charge them up to 4.15-4.2v/cell, then yes.



( this image does not fully demonstrate that, since this pack is only charged up to 4.15v/cell. )

I'm not sure why hobbyking rates it at 3.7v nominal. That's probably if you are pushing them really hard, like at their C rate, constant..

[neptronix]

BTW, how are you getting the 138whr/KG figure? Did you know that this RC Lipo is actually 3.8v nominal? were you using 3.6 or 3.7v as the nominal voltage in your calculations?

I used 3.7V. I've never really seen a good justification for any of the quoted 'nominal' voltages for lipo. LiFePO4 makes sense, as the voltage curve levels off at 3.2V for the majority of discharge, but with lipo not really having a level discharge at all, there's no clear point to draw the line.

It's difficult to calculate, but i've noted that about 20% of the rated amp hours are usually left at 3.7v/cell average, and there is a miniscule amount of energy after 3.6v.

Without voltage sag being a factor, the 50% mark for these batteries is actually 3.85v/cell average.

[cwah]

With my 4 pack of 5s8AH 30C zippy, when I charge them to 4,15V and use then up to 3.7V I have around 400wh of power usable at 4C. At 3.7V nominal I should consider that my pack has 592WH of power and I'd use around 2/3 of the battery power with 400wh which is normal.

I wouldn't consider that I could have more energy than that so if I count the lipo at 3.7V nominal that would be more representative of the energy stored. However, it's true that most of the time I'm around 3.8V and I don't like to go lower than that