18650 fire!

RVD

1 kW
Joined
Apr 26, 2011
Messages
418
Location
Seoul, Korea
Hi everyone, it's been a long time since I've been back here. Quick summary...I was active in here way back in the day when I was building electric bikes, playing with various battery technology (lipos, etc.), etc. A few years ago I moved overseas to Korea and brought some of my bikes with me. I got rid of all of my lipos and harnesses and chargers, etc. when I moved and only kept the 18650 packs, etc. I was messing with building my own packs back in the day but never actually got into it and sold off all of my naked cells and gave away my spot welder, etc.

Anyway, on one of the bikes (BBS02 mid drive), I changed out the battery (small capacity 52v 8ah 18650 pack purchased from luna) to a larger capacity 52v 12ah chinese made aliexpress hard pack 18650 2+ years ago. I connected everything and it worked fine and had a few nice rides with it, etc. The ad (and pricing iirc) reflected samsung cells so I thought they were high quality, etc. i.e., I didn't cheap out.

But this weekend I decided to take the bike out so last night I charged up the battery for the first time in about a year. Battery was dead but after plugging it into the charger for awhile, it seemed to come back to life and charge. There are small led indicators that show charge and it slowly went up.

This morning it was fully charged. Battery felt slightly warm to the touch but I think that's relatively normal...it wasn't super hot or anything. I unplugged the battery charger and went to work.

About an hour or so after I left I get a frantic call from my wife saying that the battery is on fire! Being in Korea, we live in an apartment in a high rise so obviously that's not good. She tried to pour water on it but obviously smoke everywhere, water won't help much, fire department called, etc. I think they took care of it but I don't know how much damage there is in the apartment right now.

So where did I screw up? Or did I? Battery was unplugged so I guess there was thermal runaway? I didn't take the battery apart but I'm pretty sure it had a BMS in it, etc. My only guess is that the cells were pretty dead after about a year or sitting there?
 
RVD said:
...
I changed out the battery (small capacity 52v 8ah 18650 pack purchased from luna) to a larger capacity 52v 12ah chinese made aliexpress hard pack 18650 2+ years ago
...
So where did I screw up? Or did I?
...

I think you already know. Or at least that is what I wish I could say, but I think the vast majority of people outside of the DIY forums are ignorant to just how critical material selection + reliable cell monitoring/balancing + safe battery construction is with these increasingly popular PEVs that are finding their way inside of residential and high density living complexes.

Frankly your fire scenario is most likely going to be increasingly more common in the future and could eventually result in some serious/heavy-handed regulation in the future IMHO. I may be getting ahead of myself here, but it is possible governments may even require a license in order to purchase individual cells at some point down the road. If apartment and elevator fires become more commonplace from PEV battery packs immolating spontaneously, then this possibility or other high-energy-density battery regulation may come to pass.

A random aliexpress/ebay battery assembler is not sufficient for ensuring the long-term safety of these high-energy products. A vendor can make whatever claims they like online, but an overseas assembler is not really legally liable and doesn't necessarily have to stand behind their products the same way a domestic assembler would. The likelihood of shorts or disconnects in between cell groups if QC and manufacturing processes aren't robust, especially as the battery packs used in PEVs are subject to a huge amount of vibrations with regular use over time, can result in dangerous imbalances that leads overcharging cells and then thermal runaway/fire. They could have used poor quality or non genuine cells as well. I have no way of knowing what exactly caused your fire, but it's easy to speculate.

Sorry for your (financial) losses, but I think the best outcome here is for more people to recognize they are potentially putting others at risk by using/storing these questionable quality high-energy battery packs in places with other people live and sleep. The lesson is to stick with battery pack vendors who are vetted and demonstrate high quality/attention to detail if you are going to purchase a retail battery pack, even if the costs are higher.
 
The lesson is to stick with battery pack vendors who are vetted and demonstrate high quality/attention to detail if you are going to purchase a retail battery pack, even if the costs are higher...
Sound advice ...on the surface anyway !
The reality is that even the best pack manufacturers (Tesla, GM, LG, Sony, Apple, Luna, etc) have suffered pack fires from unforeseen, non abuse, circumstances.
So the absolute best advice is ...be prepared for the worst case. !
 
RVD said:
So where did I screw up?
Seriously?

RVD said:
I changed out the battery.. to a larger capacity 52v 12ah chinese made aliexpress hard pack 18650 2+ years ago...

Battery was dead but after plugging it into the charger for awhile, it seemed to come back to life and charge.
-Aliexpress pack is invariably salvage or knockoff cells (or both :lol: ) and thus suspect
-Pack was overdischarged, thus unbalanced -- both conditions are unsafe
--Bulk charger did not properly detect/prevent unsafe charging of overdischarged pack
---Unbalanced cells would have been overcharged
 
ok, i think i get it. i basically got one of those hailong hardpack batteries on aliexpress but the fact of the matter is that in korea (where i live), i can't go down to a local ebike store and buy a battery. they all end up ordering from china.

should i just buy from one of the usa guys like luna, bolton, etc.? i bought from them in the past. i have bought lifepo4 batteries from china in the past as well (from ping, etc. back in the day) with luck. i'm not sure if they can ship to korea though.
 
Shit happens. From my point of view, you were just very unlucky. The market is flooded with tons of batteries of dubious quality and yet the frequency of battery fires is still negligible.
 
Safest is buy the cells - top quality, recent date, brand new Grade A, from a trusted vendor

and build your own pack, or have someone local do it

You need to educate yourself, so you know exactly where the battery is in its lifespan

and never leave such a risky chemistry battery charging unattended.

Ideally never charge anywhere near an inhabited building.

Temperature sensor triggering charge termination.

If "cannot" avoid bringing inside a home, sacrifice energy density and use LFP.

Lives are at stake!!!

 
RVD said:
But this weekend I decided to take the bike out so last night I charged up the battery for the first time in about a year. Battery was dead...
You presumed the battery was "dead" by what means? By measuring the voltage? What was the voltage? Do you know that once cells are drained beyond a certain level they cannot be trusted as "safe" anymore?

RVD said:
So where did I screw up?
Possibly by leaving a battery after recharging it after it was drained to a dangerous level.
 
I didn't actually know if it was dead. I pushed the button with the leds and it was just down at the bottom light. Since it had been so long since I had last charged it, I guess I was thinking (hoping) that it had been sitting at 3.7v. I was just being lazy...I have multimeters somewhere but didn't bother looking for them and measuring.

With those old pouch lipos I was really vigilant on this stuff but with a more professionally (supposedly) assembled 18650 pack I thought the risk was much lower and more or less treated it like I do the other batteries in the house...laptop, cell phone, portable usb, electric scooter, drones, etc.
 
Sorry hear about your unfortunate event, while on the subject what is the best way put out a lithium fire? , obviously is best to leave to professionals ,but if a wet blanket works then would be tempted to try before exiting building asap to avoid fumes ,any fire fighters on here had battery fire training ? :bolt:
 
I think about the best you can do is to try to keep the stuff nearby from catching fire. Sand/dirt is the best and maybe only way to put out Li fires. I keep a thick fire blanket around and keep the batteries covered with it when charging and in storage.

Never keep your batteries near highly flammable materials. (just Ask Dogman)

The smoke damage will be bad. :(
 
in the end, the fire was put out simply with water. i was not home so my wife ran over with water and it put most of it out almost immediately but there was a lot of smoke. she then took a wet towel and placed it over the battery. she was freaking out because there was so much smoke and she could hear clicking noises from the batteries as the fire was being put out from the water that she dumped on it. we do have a fire extinguisher in the house and i knew where i was and she did too but since it's been a few years she didn't even realize we had one let alone know where it is. i have a small thin fire blanket that i keep in the kitchen in case there is a kitchen fire but i suspect that would not have been able to do much in this case.

she called the fire department so they came quickly and they used the water hose in the hallway to put it out for good.

of course since the fire department's primary goal is to put out the fire at all costs, they immediately turned on the water to full blast, ran into the house with the hose running water, ended up flooding much of the carpet, hardwood floors, bedding, clothing, desk/electronics, and anything and everything along the way from the front door to the master bedroom.

i'm not necessarily complaining since they had a job to do and that was to put out the fire but it's been around 5 solid days of cleanup, throwing away most of the electronics (laptops, cameras, etc.), batteries, drones, etc. (i tend to have expensive hobbies i guess) that were drenched in water.
 
Safe charge and storage facility....with auto extinguisher ! :D :D
I have posted this a few times previously, so apologies to those who remember, ..but a useful reminder..!
lipostore.jpg

Packs in a plastic bag ....(with a long charge lead attached if charging )
Include a cheap battery powered smoke detector in the bag.
Suspend the entire bag over a large water container..bath, dustbin, pool . !....
If the packs overheat for any reason they will set off the smoke alarm, and melt the bag such that they fall into the water container ( or pool !)
:bigthumb: :bigthumb:
 
Hillhater said:
If the packs overheat for any reason they will set off the smoke alarm, and melt the bag such that they fall into the water container ( or pool !)

Also, if a local squirrel takes a fancy to the cord you are using... :)
 
Battery packs need an absolute way to monitor cell voltages and check them regularly. A simple cell checker will do and of course you'll need a JST-xh balance lead.

I just do not trust those cheap BMS units, especially the ones that automatically balance cells by burning off the highest state of charge cells thru resistors. Likewise trusting those BMS units to top balance by burning off extra current thru resistors seems dodgy to me. What if the charger provides too much current and the BMS cannot keep up? You end up with some cells being overcharged and that quickly becomes dangerous.

I've owned and used a 5a active balancer for several months and this will do a far better job than most BMS at keeping cells balanced. The newer versions have JST-xh plugs already installed. Had to fab a wiring harness for mine since its the older version, lol.

I've charged packs with up to 5a of current while the active balancer was connected with no issues.

https://www.aliexpress.com/i/4000181271387.html

These things are also sold on feebay, scamazon and places like Goodluckbuy and Banggood. Dont listen to any youtubers that say they are not needed, especially on those gigantic at home LifePO4 packs where they are definitely needed and will keep 320ah cells balanced.

https://www.youtube.com/watch?v=Wlr6IIYBFJo
 
GREAT ADVICE , ONE AND ALL

Lithium batteries are firebombs that store electricity.
If Sony and Samsung engineers are having issues, you should know what you are up against.

Charge in a place where you will be safe if the unforeseen happens. Trust nothing.

Watch the youtubes on battery fires and fire safety.

You got off easy, tough as it was. Somebody could have been hurt.

TIP: if you can't charge outside, do the charging in the oven.
Have a plan at all times ,should a fire start.
Know what you would do if a fire started AT ALL TIMES.
Goofy as the swimming pool picture was, having a smoke detector nearby is a great suggestion.
https://www.airseacontainers.com/blog/how-to-put-out-lithium-battery-fire/

Most of the industry is not done by experienced folks, so always pay attention to risk.


Thanks for sharing. Stay safe.
 
onemorejoltwarden said:
GREAT ADVICE , ONE AND ALL
Goofy as the swimming pool picture was, having a smoke detector nearby is a great suggestion....
Yes , and exaggeration to make the point that you need a LOT of water to suppress a Li pack fire.
But the principle is the same, instead of the pool you could have a large bin ( dustbin etc) in the garage, or even a similar suspended system above a filled bath in an apartment building ( but i would not take lipo into an apartment ).
Play safe !
 
Reflecting on my usual "what can go wrong"
Li ion fires have the issue with Thermal Run Away, where the heat creates more fuel,
so one needs to cool as well as suffocate the fire.
Dousing is good, but ABC/BC dry chemical extinguisher is best first move.

@ hillhater, If you have a plastic pail or a fiberglass bathtub I could see a potential problem.
Add: Charging where an uncontrolled fire has proximity to any combustible ( gas, paint , paper,plastic, wood....),
no clear path to noncombustible spot outside, or tool for portaging the problem out the door.
Apartments are tough to find good spots to charge in
and are full of folks who can be quite chagrined afterwards if things get messy.

Just part of a quick "what if..." checklist
to avoid having a hassle turn into a bummer,
should your karma also be running low.

It's not real common, but it sure can happen.
As ebikes proliferate,especially in urban locations, I would expect to hear more on this.

The lucky think they are smart.
The smart know they are lucky.
 
onemorejoltwarden said:
....Dousing is good, but ABC/BC dry chemical extinguisher is best first move.
@ hillhater, If you have a plastic pail or a fiberglass bathtub I could see a potential problem.
Dry chemical does little if anything on a Lipo fire....plenty of Youtubes show that
..Sand may be a better smothering option, but still wont prevent heat build up, and not easy to store or use.
Water will soak the heat away, especially if submerged...and certainly stop a secondary fire starting.
And yes, use a metal container..outside or in an area with plenty of ventilation.
Apartment living with an Ebike is not a good mix. ! :shock:
 
On the subject of Lithium fires, this happened last week..
One of the latest, a 450 MWh Tesla Utility installation is just being commissioned in Victoria.
Unfortunately, during testing, one of the (100+) “Megapacks” caught fire and rapidly spread to another nearby unit.
So this is 6 MW of Tesla cells going thermal...
cCGIqJ.jpg

https://www.smh.com.au/business/the-eco ... 58eh4.html
The Professional Fire responders , and Tesla, seem to accept there is no way to stop the fire, and plan to let it burn out !
I would have assumed that these units were designed with automatic fire suppression etc built in ( as with any new industrial facility ?)...but if it did, either it did not work or it was totally ineffective ?
 
Hillhater said:
Still burning apparently.... 5 days after it started !

Bummer. Just think about how many bike batteries that could have made.

But it's better than having a nuclear reactor melt down.
 
WAPO Today
While they were asleep, their Teslas burned in the garage. It’s a risk many automakers are taking seriously.
https://www.washingtonpost.com/technology/2021/08/04/tesla-fire/
Prolly pay-walled

Maybe we need a fire safety and fire fighting sticky?
 
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