'Li-ion' battery nomenclature

T

The Madmadscientist

10 W
Joined
May 29, 2022
Messages
93
Hello all,
I'm trying to spec a battery for my goofy project bike but am becoming increasingly more frustrated.
No choice (i think) but to use chinese battery pack producers (not resellers) and their lack of specificity is driving me bonkers.
When an ad says 'LI-Ion' it doesn't tell you a thing about the actual battery chemistry.
The LiFePo batteries are clearly labeled but the rest....arrrgh...

What chemistry is being used on these packs?
Is it the scary Li-Po? The original death dealer?
Is it a NMC or NCM I've seen it both ways.
Or a different chemistry altogether?

I believe I need a 72V NMC 21700 20ah 60A cont 20S4P battery.
Trying to get actual spec's is like pulling teeth.

What chemistry are the Chinese producers primarily use?

Any insight would be greatly appreciated.
Thanks,
 
If they don't give you a specific cell model and brand with a datasheet you can look up at the cell manufacturer level, that has all the specs on it, you can't know what they actually use.

In too many cases they use literal recycled garbage cells. (mostly on the super-cheap packs that look "too good to be true")

In other cases they use random (mixed) cells that might be new, but unknown characteristics or even chemistry.

In other cases they use single type of cells, but again, unknown characteristics / chemistry.

Any place that doesn't give the cell model and brand (that you can verify!), or looks too good to be true, is unlikley to be what you want to use.

If you want a pack that you actually know what's in it, you'll either need to buy from a place that specifies everything about the packs that you need to know, *and* actually uses what they say they use, or you'll have to build it yourself from cells sourced from a place that actually sells real new cells of the kind you want to use, *and* actually sends what they say they will.

Neither one is likely to be inexpensive. (building a battery well is likely to cost significantly more than buying one, becuase of the testing and building tools you'll need).

I don't have a current list of places that are likely to have what you want; others may be able to help with that. (there are also quite a few threads over the years in various subforums where people ask where to buy batteries or cells that may have useful info).


Becuase it's so hard to find such places for good budget prices, I'm using used large-format EV cells. They're harder to build into packs that fit on bicycle-shaped bikes, but they work fine for my cargo bike / trike applications, as big rectangular blocks. The ones I'm using (EIG C020, 20Ah NMC) haven't been made in years (maybe a decade) but they still work fine for my application, even if they might not perform as they're rated anymore. :)

If you want to go that route, it's easy enough to find used Leaf modules, and there are places that recycle batteries (batteryhookup is one most people have had good luck with here on ES so far) that have other similar cells available.

There are also EV starter batteries and other types of packs made of many small cylindrical cells but these have more chances for interconnect failures, which can cause problems even when all the cells are fine (or were before the IF). So I prefer packs made of a series of single large-capacity cells.


The Madmadscientist said:
Hello all,
I'm trying to spec a battery for my goofy project bike but am becoming increasingly more frustrated.
No choice (i think) but to use chinese battery pack producers (not resellers) and their lack of specificity is driving me bonkers.
When an ad says 'LI-Ion' it doesn't tell you a thing about the actual battery chemistry.
The LiFePo batteries are clearly labeled but the rest....arrrgh...

What chemistry is being used on these packs?
Is it the scary Li-Po? The original death dealer?
Is it a NMC or NCM I've seen it both ways.
Or a different chemistry altogether?

I believe I need a 72V NMC 21700 20ah 60A cont 20S4P battery.
Trying to get actual spec's is like pulling teeth.

What chemistry are the Chinese producers primarily use?

Any insight would be greatly appreciated.
Thanks,
Click to expand...
 
amberwolf said:
If they don't give you a specific cell model and brand with a datasheet you can look up at the cell manufacturer level, that has all the specs on it, you can't know what they actually use.

In too many cases they use literal recycled garbage cells. (mostly on the super-cheap packs that look "too good to be true")

In other cases they use random (mixed) cells that might be new, but unknown characteristics or even chemistry.

In other cases they use single type of cells, but again, unknown characteristics / chemistry.

Any place that doesn't give the cell model and brand (that you can verify!), or looks too good to be true, is unlikley to be what you want to use.

If you want a pack that you actually know what's in it, you'll either need to buy from a place that specifies everything about the packs that you need to know, *and* actually uses what they say they use, or you'll have to build it yourself from cells sourced from a place that actually sells real new cells of the kind you want to use, *and* actually sends what they say they will.

Neither one is likely to be inexpensive. (building a battery well is likely to cost significantly more than buying one, becuase of the testing and building tools you'll need).

I don't have a current list of places that are likely to have what you want; others may be able to help with that. (there are also quite a few threads over the years in various subforums where people ask where to buy batteries or cells that may have useful info).


Becuase it's so hard to find such places for good budget prices, I'm using used large-format EV cells. They're harder to build into packs that fit on bicycle-shaped bikes, but they work fine for my cargo bike / trike applications, as big rectangular blocks. The ones I'm using (EIG C020, 20Ah NMC) haven't been made in years (maybe a decade) but they still work fine for my application, even if they might not perform as they're rated anymore. :)

If you want to go that route, it's easy enough to find used Leaf modules, and there are places that recycle batteries (batteryhookup is one most people have had good luck with here on ES so far) that have other similar cells available.

There are also EV starter batteries and other types of packs made of many small cylindrical cells but these have more chances for interconnect failures, which can cause problems even when all the cells are fine (or were before the IF). So I prefer packs made of a series of single large-capacity cells.


The Madmadscientist said:
Hello all,
I'm trying to spec a battery for my goofy project bike but am becoming increasingly more frustrated.
No choice (i think) but to use chinese battery pack producers (not resellers) and their lack of specificity is driving me bonkers.
When an ad says 'LI-Ion' it doesn't tell you a thing about the actual battery chemistry.
The LiFePo batteries are clearly labeled but the rest....arrrgh...

What chemistry is being used on these packs?
Is it the scary Li-Po? The original death dealer?
Is it a NMC or NCM I've seen it both ways.
Or a different chemistry altogether?

I believe I need a 72V NMC 21700 20ah 60A cont 20S4P battery.
Trying to get actual spec's is like pulling teeth.

What chemistry are the Chinese producers primarily use?

Any insight would be greatly appreciated.
Thanks,
Click to expand...
Click to expand...

Do you happen to know what chemistries these places are using?
No one would use Li-Po now-a-days would they?
I'll have to squeeze the data-sheets out of these folks....
I wasn't originally looking for where to buy advice but I'll take it.
It's all communications on WhatsApp and 'will you buy it now, pushiness'
I have to be real about building my own battery...a task I don't think that I could do.
 
The Madmadscientist said:
Do you happen to know what chemistries these places are using?
Click to expand...
I guess I didn't say it clearly enough, but no one but they know what they are using, unless they specify it.

I expect some of them don't even know what they are using (almost certainly the sales people you'll probably be talking to have no idea, and don't care, and will say whatever it takes to get you to buy something--they will usually either parrot whatever you asked or copy/paste what the website says, or make something up).

Sorry to sound so pessimistic, but plenty of people have come here with their aliexpress/ebay/amazon/etc battery problems, or questions about something they want to buy, and troubleshooting finds some incredibly bad stuff in some of them (rarely do they contain what they said they did, or were built like they should be, etc). Analyzing their sales pages when they have a link to where it was bought often shows serious inconsistencies (not typos) even within the specs posted for just a single item, much less between various different ones on the site.

I only provided advice (and suggested getting more/better) on where to buy because if you're looking at the batteries that don't specify the stuff you need to know, you're almost certainly looking at the cheap stuff that is too often something you will be wasting your money on. (some of them will actually power up and work for a while...some won't even operate at all when you get them....some can even be a fire risk).

There are a lot of things I wouldn't worry about buying cheap and maybe losing a few bucks on...but anything to do with a battery isn't one of them, partly because of fire risk for badly built ones, partly because the battery is the heart of the whole EV and if it doesn't work as needed, neither will anything else.
 
amberwolf said:
The Madmadscientist said:
Do you happen to know what chemistries these places are using?
Click to expand...
I guess I didn't say it clearly enough, but no one but they know what they are using, unless they specify it.

I expect some of them don't even know what they are using (almost certainly the sales people you'll probably be talking to have no idea, and don't care, and will say whatever it takes to get you to buy something--they will usually either parrot whatever you asked or copy/paste what the website says, or make something up).

Sorry to sound so pessimistic, but plenty of people have come here with their aliexpress/ebay/amazon/etc battery problems, or questions about something they want to buy, and troubleshooting finds some incredibly bad stuff in some of them (rarely do they contain what they said they did, or were built like they should be, etc). Analyzing their sales pages when they have a link to where it was bought often shows serious inconsistencies (not typos) even within the specs posted for just a single item, much less between various different ones on the site.

I only provided advice (and suggested getting more/better) on where to buy because if you're looking at the batteries that don't specify the stuff you need to know, you're almost certainly looking at the cheap stuff that is too often something you will be wasting your money on. (some of them will actually power up and work for a while...some won't even operate at all when you get them....some can even be a fire risk).

There are a lot of things I wouldn't worry about buying cheap and maybe losing a few bucks on...but anything to do with a battery isn't one of them, partly because of fire risk for badly built ones, partly because the battery is the heart of the whole EV and if it doesn't work as needed, neither will anything else.
Click to expand...

Thanks, now I understand. Please forgive me sometmes I'm a little slow on the uptake.
 
The Madmadscientist said:
[Do you happen to know what chemistries these places are using?
Click to expand...
Amberwolf made it clear in the first answer, NO, they likely don't know themselves.

> No one would use Li-Po now-a-days would they?

LiPo is just lightweight packaging tech, can have just as much chemistry variation as other types.

And is fantastic for use cases that need top power density.

Choose the cell model you want, never mind generalising about chemistry. Assemble the pack yourself or pay someone to do it.

All the 3.6-3.7Vnom cells are fire-risky if you don't know what you're doing.

 
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