Battery a Fire Hazard only when Charging and Discharging?

[justin_le]

As best I can recall, all the reported lipo fires have occurred in multi cell packs, not in single cell units.

That's not what I've seen. Every reported instance of a cell phone battery fire or other small consumer electronics gadget lithium fire (like the recent incident from a portable credit card reader on alaska air flight) is from a single cell LiPo, not a multi cell pack. In EV's you ever only see massive series packs so this fact of them being in packs rather than cells isn't very telling as you say, and for sure the wiring/circuitry can sometimes be to blame.

Some of the time? Most of the time? It's a good question, but single cell LiPo's have certainly been known to go up exactly the same way in all the industries that use single cell LiPo.

 

[Hillhater]

I have not seen those cell phone battery fire reports, and certainly not seen any reliable investigation as to the causes..
...but I would sure like to see some....there are just so many possible external causes, but without a reliable detailed investigation it's pointless speculating
Remember, even with all the resources thrown into the Beoing APS fires, the final report did not cite any hard evidence as to the root cause of the primary fault....only throwing suspicion on YUASA's manufacturing quality control.

 

[999zip999]

Want a new phone battery go to Verizon and tell them your phone gets hot.

 

[TypeThree]

The quality of the BMS circuit balancing and the LVC threshold could also be behind unseen cell damage. In an effort to squeeze as much performance out of the battery as possible they might be setting LVC too low from the factory. I looked into buying BMS circuits from OEM suppliers in China and was not too impressed with sub 3v cutoffs on most of the ones I encountered. On a couple I could define up to 3v be set from factory upon my order but I've always set 3.3v for lipos or even higher when using higher currents whenever possible as a safety margin. Death by a thousand cuts as they say. Discharging to the lowest threshold of a poorly defined BMS could be the cumulative damage a battery needs to spontaneously combust for no 'apparent' reason.

 

[4LivesPerGallon]

My Surefire flashlight batteries will go up if they get wet.
http://www.surefire.com/batteries.html

Have dunked many CR123A's in water -- nothing happened at all.

 

[4LivesPerGallon]

LIFEPO4 -- completely safe. See bullets shot into them on YouTube.

 

[riba2233]

LIFEPO4 -- completely safe. See bullets shot into them on YouTube.

They are not. You can find few fires on diyelectriccars, they burned properly. They are pretty safe, but not 100%.

 

[justin_le]

LIFEPO4 -- completely safe. See bullets shot into them on YouTube.

They are not. You can find few fires on diyelectriccars, they burned properly. They are pretty safe, but not 100%.

Indeed. We had a customer with a PING LiFePO4 pack here in Vancouver have a cell go bezonkers and release billowing clouds of smoke in his apartment. No flames and fireballs fortunately, but certainly not benign either.

The abuse videos on youtube are unfortunately quite misleading. Remember LFP doing all kinds of destructive tests on hobby LiPo packs, dunking in nitric acid, stabbing with knifes etc. all to minimal effect? You kindof think wow, these things are pretty safe. And yet in other far more benign scenarios the exact same cells been known to burst into flames, even with all "proper handling" precautions. There are elements of long term instability and unpredictability that you'll never see from shooting a bullet through a cell... or stabbing it with a knife... or dunking it in acid.

 

[999zip999]

But did Luke pull their wings off ?
All bike batteries with all the stored energy are fire hazards. With or without wings.

 

[major]

LIFEPO4 -- completely safe. See bullets shot into them on YouTube.

Here is a DeWalt A123 26650 cell which was not completely safe. It happened during discharge on the dyno right in front of me. Looked like a road flare in there. Lucky nothing else caught fire. No evidence of wiring problem or short. Did have a BMS. My post of 15Oct2013, https://endless-sphere.com/forums/viewtopic.php?t=47012&p=810881#p810881

I have witnessed maybe about 4 or 5 "events" on the race track (motorcycles and karts) where cells lose the smoke. Not that I able to do postmortems, but to my knowledge among the racers and crews and officials in the paddock, none were due to bad wiring, short circuits, or punctures. Most if not all had BMS. Never had a battery problem with a crashed racer, just ones running a normal race. I always worried about charging fires in the paddock and pits, but never saw one. This was TTXGP, LSR and university competitions.

Be careful,

major

 

[Syonyk]

https://endless-sphere.com/forums/viewtopic.php?f=14&t=73599&view=unread#unread

Perfectly safe my ass.

 

[999zip999]

Ping told me be careful lifepo4 can still make fire. Stored energy.

 

[4LivesPerGallon]

LIFEPO4 -- completely safe. See bullets shot into them on YouTube.

Here is a DeWalt A123 26650 cell which was not completely safe. It happened during discharge on the dyno right in front of me. Looked like a road flare in there. Lucky nothing else caught fire. No evidence of wiring problem or short. Did have a BMS. My post of 15Oct2013, https://endless-sphere.com/forums/viewtopic.php?t=47012&p=810881#p810881

I have witnessed maybe about 4 or 5 "events" on the race track (motorcycles and karts) where cells lose the smoke. Not that I able to do postmortems, but to my knowledge among the racers and crews and officials in the paddock, none were due to bad wiring, short circuits, or punctures. Most if not all had BMS. Never had a battery problem with a crashed racer, just ones running a normal race. I always worried about charging fires in the paddock and pits, but never saw one. This was TTXGP, LSR and university competitions.

Be careful,

major

To be clear, these incidents were LIFEPO4 fires?

 

[blisspacket]

Makita-lookalikes BEWARE: one went into my bonafide Makita charger, next thing I knew there was popping then banging and finally fire shooting out the battery on the charger, and 18650 shells propelled out of the battery. Yes the fire extinguisher was handy. Lots of smoke, fire. These were 3amp batteries for the XLT tools.

 

[4LivesPerGallon]

My Surefire flashlight batteries will go up if they get wet.
http://www.surefire.com/batteries.html

Did my own mythbusters teston this circa 2007 by submerging some CR123a's and CR2's in water outdoors. Absolutely nothing happened.

 

[dogman dan]

All types of batteries dangerous as hell if you short them. The cell may do nothing, while a short causes heat, even flames. I had a truck burn in 1976, because the main 12v to the battery chafed and shorted out.

That was a nice safe 12v lead car battery.

My belief is that a great number of battery fires are just from shorts. it can be an internal short,( which typically means fireworks when you charge) but more likely external. The hoverboards for example, I wouldn't say any bms equipped pack is safe from shorts, after you throw the thing into the wall a few times learning to ride it.

 

[4LivesPerGallon]

As best I can recall, all the reported lipo fires have occurred in multi cell packs, not in single cell units.
Now obviously, single cell use is not common for our aplications , so that in itself proves nothing......except that all packs have by definition multiple interconnects, wires, joins, etc etc, and a lot of human interference !
Even the A123 20Ahr pouches which were known to be made with internal defects, did not prove to be fire bombs !
I just suspect that the weight of evidence suggests that lipo pack fires are not initiated by internal cell faults, but by external "pack related" issues like poor assembly, bad connections, wiring shorts, BMS failures, physical damage, over charging, etc etc.
Many of these factors will be agrivated during charge/discharge, so to that extent I agree with the thread title, and also still accept that lipo packs should be respected and treated in a similar way to having a potentially leaky gas can in your house !...IE:, store them outside the house !

If true, then the obvious answer, for safety, is to run use single-cell power, albeit a very large one, lol.

 

[Hillhater]

Well, no!,
I stand corrected by Justin who says that reports of single cell lipo fires are not uncommon (phones, portable devices, etc) , so i would not be relying on that fat ass single cell for safety !