Finding out cell chemistry

Hi All,

I have now collected a couple of cells and want to see which ones I can use for a Powerwall.
I have now read that LiNiMnCoO2 (NMC) cells are the best choice.
However, there are sometimes contradictory statements about the cell chemistry of the same cell type.
As an example, I would mention the US18650VTC6, of which I have more than 100^^
The safety data sheet says Lithium Nickel Cobalt Oxides so it should be a --> LiNiCoO2 --> NCO?
Datasheet attached.

On many websites and databases, however, it is described as NMC with LiNiMnCoO2.
Example: https://voltaplex.com/sony-vtc6-18650-battery-us18650vtc6

Which is true now?

Thanx for helping out!
Peff

The producer's datasheet should be correct. A powerwall with VTC6 cells is able to power big loads, are you sure you need such cells, considering they are also more expensive?

For example a 20P powerwall (that is quite a small powerwall) could give 200A in continuos current. That means using at least a 50mm2 wire to connect series. And looking at the datasheet it could even give double that current (400A).

If your requirements are for such current then VTC6 is the right cell! Higher costs for cells, wires and everything but higher power.

My power needs are very small, my flat uses on a monthly basis an average of 250KWh (0.35KWh or 1.6A all day all month). With VTC6 cells I could power the whole building of 10 flats!

no no, I don't wanna create a powerwall with such big current.
I got these cells from the recycling, I tested them and they are still in good condition.
I plant to create a 40p or 60p powerwall depending on the cells I got.
We need around 3-4 kWh per day. I plan only to get max. load of 20A from the hole powerwall, so around 800W with a 48V system.

But back to my question, is LiNiCoO2 (NCO) save as LiNiMnCoO2 (NMC) ?
It's not easy to find reliable informations about that.
Of course I'll use a BMS.

peff said:

But back to my question, is LiNiCoO2 (NCO) save as LiNiMnCoO2 (NMC) ?

Click to expand...

italianuser said:

The producer's datasheet should be correct

Click to expand...

https://www.murata.com/-/media/webr...6-sds.ashx?la=ja-jp&cvid=20210215080000000000

[ EDIT: to select cells to be put in parallel I look at capacity, IR, SOH and C/D curves, if they are similar I will put them in parallel obtaining a more-or-less balanced pack; if these parameters are different I'll get an unbalanced pack, which I avoid! ]

Hi,

Thanx for your replay, but I think you misunderstood.
I understand your message. The data sheets are the best way to find out the chemistry.
What you have posted is the same as what is attached to my first post.
Accordingly, the VCT6 is a LiNiCoO2 (NCO), but should this be seen as problematic?

Because many people tell that NMC are much saver.
And of course, I'll have a look on IR, SOH and the curves.
Each cell is carefully documented and analysed ;-)

br
peff

Ah, I see what you mean, sorry I read "saver" and I thought you were talking about "price" and not "safety"!

I must say, to my knowledge (I could be wrong) all 18650 are equally dangerous, I treat them all with the same important safety measures. To reduce risks you should leave 18650 cells and go for other kind of batteries, LFP for example.

I liked this video by GWL, overcharging, short circuit, mechanical damage, ignition, LiPo vs LFP vs LTO.