Are NMC-based LG or Samsung 18650 batteries safer than others?

[cwoods400]

I have a question hopefully someone can answer: How safe are 18650 NMC-based batteries? Particularly, more "brand name" batteries such as LG or Samsung? Are they subject to issues like thermal runaway? In other words, if I am charging these in my home at night, would they be a major fire hazard? Or should I forego charging any Lithium battery at night, and only charge when I am awake and aware of what is happening?

I have charged Pb (lead acid / AGM) batteries for decades with ZERO worries. I'm still rather skeptical about the true safety of any Lithium chemistry, to include LiFePO4. Should I be concerned?

Best,

Colin

 

[snoobler]

NCM is safer than NCA (Tesla). LFP is the safest. LFP is comparable to AGM in terms of safety.

 

[cwoods400]

Thank you. I appreciate the comment.

 

[Substrate]

LG and Samsung are good cells.

Knowledge is safety. That is, when the batteries are operated within their design parameters, there is not much to fear. But since you asked, maybe some of the following will help in your research:

A battery such as an LiNMC (lithium nickel-metal cobalt) has an inherent problem when used outside it's design parameters. You mentioned thermal runaway, and when one of these goes out of bounds, they "vent with flame".

LiFeP04 (lithium IRON Phosphate). Still in the lithium family, but much safer. IRON is a very greedy molecule. So much so, that it won't allow for oxygen - one of the principle parts of needing fire - to escape, and as such if operated waaay beyond their design parameters, will not catch fire, but can "boil off the electrolyte". Vent-with-a-stench, rather than flame. It is not good to breathe that however.

LiFePo4's inherent safety is one reason that motorcycle riders that put LFP batteries in their motorocycles as starter batteries, are mere inches away from their butt cheeks. Shorai is a well known brand. Seriously.

Thing is with ALL battery setups, including AGM, (especially like my high-powered Odyssey and Optima pure-lead types), the surrounding infrastructure if not designed properly, can be the one at fault when not designed, operated, or maintained properly.

A good example is this very historical one:

Did you know that the very first AGM introduced was the D-sized "Cyclon" ? (Which you can still get!)
And that one of the tricks a salesman would pull when he whipped out this D-sized cell was to put a paperclip across it to short it, and have the paperclip evaporate?

Can't do that with an alkaline cell, but the point is that some battery issues are due not to the chemistry but the surrounding infrastructure and lack of knowledge.

Me - I personally have no problem leaving LFP charging overnight, but that is with good equipment that I have personally vetted for proper operation. But no, not in the living room or bedroom. In the garage, next to the AGM's, just in case they decide to blow their top with the way I charge them.

 

[Roqm]

All are safe untill used out of spec...none like over/under charging or to high/low temperature but he mindfull there can always be a manufacturers defect so test for heaters or self draining cells.