LiNiCoMnO2 Battery Question

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Aug 21, 2014
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Oakville
Forgive my ignorance. I don't know much about battery chemistry.

I've heard that Lithium Cobalt batteries turn into little fire-bombs if they're discharged too much and then one attempts to charge them up again (boom). But I've seen a number of LiNiCoMnO2 (Lithium Nickel Manganese Cobalt Oxide) batteries for sale lately - I'm reticent to consider them as an alternative to LifePo4 because I'm unsure whether they would have the same full-discharge+charge=fireball safety issue?
 
There's a potential for fire with any battery.The more power in them, the greater the potential, and you don't get more powerful than rc lipo. Still the likelyhood for a fire is very small used and charged properly. In 3.5 years of use, I've never had a problem and I wouldn't use anything else. See this thread if you're concerned.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=27241
 
Thanks. I read the thread, but to be honest, some of it does go over my head a bit.

Basically what I want to know is - if a LiNiCoMnO2 battery is discharged by mistake (who knows what might happen, hypothetically), and I plugged the bike in to charge it (not knowing the battery was discharged) - would it catch fire? That's what I was warned about, and I was advised that LifePo4 did not have that issue.
 
It doesn't matter what chemistry it is. If it's made right, and has zero defects in it, then it probably won't catch fire even if it's discharged all the way and hten recharged (albeit more slowly than normal, just to be sure). But it could, and there are some chemistries more likely to have such problems than others becuase of the way the chemistry works.

But if it's not made right, as is too frequently the likely case with cheap batteries like the RC LiPo and whatnot, or cheap ebay packs that may well be made from rejected cells from other places (no way to know for sure), then the risk of fire is greater.


What it comes down to is that it is more likely to be a risk under even normal conditions with a cheap pack made of unknown-quality and probably untested cells, than it is to be a risk under adverse conditions for a properly-made pack out of well-made and tested cells.


It is unfortunatley not possible in most cases ot know *exactly* what caused a pack fire, either because of the lack of remaining evidence to sift thru, or because of unknown conditions leading to it, etc.


Keep in mind that if you have some sort of cell-level monitoring system that prevents overdischarge of cells, you should be less likely to have such an event in the first place, and less likely to be at risk of a fire because of it. But it doesn't mean that some other defect or design flaw in the BMS or pack or wiring would not cause a problem.




That said, I have personally had some EIG brand NMC cells in my lighting pack brought down to 0V, and recovered them successfully (with trepidation at the time) to normal use. I sitll use those cells as part of my lighting pack, and they are at this moment powering my laptop via it's wall-adapter port. :) I have never tested them (before or after) at high discharge rates, but they do give their full capacity as they did before, at the low rates I use them at. (1/4C or less) And they charge normally at similar rates.

I have never tried to recover RC LiPo cells in the same way simply because the QC on those is unknown and probably non-existent, unlike the EIG cells (which are used in larger EVs). I *have* deliberately overcharged such cells to see what they would do, and they can indeed vent and burst into flame under the more-than-extreme conditions I put them thru. ;) I have not tested EIG NMC cells the same way.

I have also accidentally tested NiMH, NiCd, and SLA under charge and discharge conditions that caused dramatic failures of the cells. :(

I'd intended to test a number of other types but I no longer have them to be able to do that.


There are some videos here on ES in one of member Liveforphysics' threads of various types of cells being THOROUGHLY abused with physical damage, overcharge, shorts, heat, and open flame, showing how they may fail under such unlikely-to-occur-under-normal-use situations. :)
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=17354

Under the right (wrong) conditions, any chemistry can fail dramatically. ;)
 
Amberwolfs answer was exceptionally written, and covered it perfectly.

I will give you the brief technical knowledge on the matter.
The copper foil of the anode current collector is the safety critical component that becomes damaged in over discharge. This means all types are equally venerable.

The exception is LTO. No damage with 0v discharge for LTO.
 
Nelson37 said:
What battery chemistries are chosen by the major e-bike makers as suitable for the average idiot? Or absent-minded old fart?
Also, are rigid cells inherently safer than pouch-type? They seem much less vulnerable to me, with some weight penalty. The pouch thing just seems like carrying rocket fuel in a ziploc.
Some still use sla, but the one thing most commercial ebikes have in common are they use a bms with their lithium battery packs. The standard 18650 type cells are probably safer, but you lose a lot of power with them. Most will only do 1C at best, but some can do 5C. They have become popular for some reason I can't seem to figure out. Personally, I don't think they're good for anything except flashlights,
 
wesnewell said:
Nelson37 said:
What battery chemistries are chosen by the major e-bike makers as suitable for the average idiot? Or absent-minded old fart?
Also, are rigid cells inherently safer than pouch-type? They seem much less vulnerable to me, with some weight penalty. The pouch thing just seems like carrying rocket fuel in a ziploc.
Some still use sla, but the one thing most commercial ebikes have in common are they use a bms with their lithium battery packs. The standard 18650 type cells are probably safer, but you lose a lot of power with them. Most will only do 1C at best, but some can do 5C. They have become popular for some reason I can't seem to figure out. Personally, I don't think they're good for anything except flashlights,


That's quite ignorant opinion! Luckily, it's just an opinion.

18650 cells come in various power and capacity ranger, you can get a 10A 3.2 Ah cell, but also a 2.5 Ah 35 A cell. So, you don't have to lose power, just find the suitable cell. They are also smaller than lipo, and infinitely safer.

For Nelson37, safe chemistry are lifepo4, li-nmc, li-nca, li-mn, also some li-co, but it depends. You can check the datasheet of some 18650 cell, you will see that it has report form safety tests, eg. for samsung 25R which is 10C high current cell:

LQGi3en.png
 
It's certainly an opinion, but I can assure you it's not an ignorant one. I've looked at test of hundreds of 18650 cells. They are all pretty weak compared to the weakest rc lipo. And to get acceptable power from a pack using them, you have to use a lot of cells in parallel, which makes them difficult to assemble and gives them hundreds of possible failure points. As for your chart, it doesn't even show discharge amps, just charge amps. It's true you can find a few newer cells rated for up to maybe 10C, you will be hard pressed to afford a pack made up of them since it will cost multiple times more than rc lipo an still not have half th power. A 10A 3.2ah cell is under 5C. I've not seen any 2.5ah cells rated for 35A, but that's still only 14C. I use 20C rc lipo, but you can get rc lipo rated for 100C or more. So there's not really a comparison when it comes to power. Now who's ignorant? :p Might want to check this out.
http://lygte-info.dk/review/batteries2012/Common18650comparator.php
 
Honestly, who needs 100C? 14C is more then enough for our usage. You can have lg he2, samsung 25r and 20r, sony vtc5 and vtc4.

But I agree, if you really need more than 10C, then fine, use lipo, but if you don't, 18650 is,the way to go, also it's not that expensive. But yes, assembly is somewhat complicated.

My chart only shows safety tests, not performance ones. Take a look at this topic, you can find complete discharge graphs.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=57291
 
I've got 12 5ah 20C packs that cost $275. I actually took longer to unpack them than it took to configure them into a 10ah 88.8V pack, which was only a few minutes. No tools required. Rated for 200A discharge. Now tell me how much it's going to cost you for the 10C cells for 10ah 88.8V pack, tools, welders, and time to assembly it? That's the difference. I can reconfigure my pack into a 20ah 44.4V pack in a few seconds. If I have a cell failure, which has never happened yet in over 3.5 years, all I have to do is unplug a $25 pack and replace it in seconds. What or you going to have to do to that pack made up of 96 18650 cells all tab welded together. :lol:
 
You folks are ALL insanely brill on this subject, THANK YOU all for taking the time to share your wisdom.

So for this gal, who is neither granny nor the kind of person who can assemble a 10ah 88.8V pack out of 12 x 5ah packs either :lol: - I'm going to ask for your suggestions.

I'm shopping for lithium, I want about 30ah capacity for distance on my Motorino, and I need a 72V pack. I'd need to to do 6oA continuous and handle 120A on burst for the bike's controller (It could probably do 40A continuous, but I'd prefer 60). And I want to charge at about 10A (I can buy a decent quality 10A lithium charger from kelly if I give them the battery configuration in advance).

I talked to PING and he's a great guy, but he can only make 2 x 36V packs that I have to plug in separately (not ideal), I've exchanged emails with numerous "vendors" on Aliexpress and Alibaba, and they can ALL do it, most for under $1000, but what quality cells and components the packs are made of - I'd never ever know for sure.

Here in Canada, I realize I'm looking at double that cost and more. I wouldn't mind doing that, but so far can't find a place that'll do it locally, either. SO...

Can anyone recommend where I could go to get a pack like this assembled? I know there are legit, trustworthy places overseas like PING, I just don't know who they are - anyone want to share your good experiences?

As for me, I've had one bad one already - ordered from CODD Power / "www.lifepo4.in" and I just got my money back from Paypal today ("Eddie" stopped talking to me immediately after I paid him last month, and never provided tracking so Paypal refunded me the money - ouch) - I even know another guy here in Toronto who got a pack from him, though I found out today it apparently took 70 days to arrive. So I'm guessing something went wrong and "Eddie" just didn't want to bother telling me .. and decided kept the money in his account as long as he could. Anyway, that's over.

Good leads? :)
 
There are a couple threads dedicated to opinions of vendors and manufacturers and sellers. I don't have a link to them ATM but they should be easy to find.
 
starlightkayak said:
Forgive my ignorance. I don't know much about battery chemistry.

I've heard that Lithium Cobalt batteries turn into little fire-bombs if they're discharged too much and then one attempts to charge them up again (boom). But I've seen a number of LiNiCoMnO2 (Lithium Nickel Manganese Cobalt Oxide) batteries for sale lately - I'm reticent to consider them as an alternative to LifePo4 because I'm unsure whether they would have the same full-discharge+charge=fireball safety issue?

we have not had a fire caused by overcharging reported here on the sphere. the most serious fire resulted in the loss of floont's house and garage which i think was caused by bulk charging 35S of lipo with a series of meanwell power supplies but he has never documented it.

the only other charging fire of lipo was caused by the BC168 balancing charger overheating the sense wire leads and catching the pack on fire from shorts but not from overcharging.

there is no evidence on the sphere to support the conjecture that over discharging the pack and then recharging it will cause a fire. many of us have recharged lipo pouches that were discharged to very low voltages and had some fail to charge up and hold charge and others went back to full charge and held the charge without high rates of self discharge. YMMV.

if you avoid bulk charging without a BMS for protection and avoid the BC168 as a balance charger you should have little to no risk of creating a fire from charging. in fact all battery fires are from shorts reported here. including chroot's headway pack fire.
 
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