Lithium Battery Catastrophic Events - Summary Thread

[izeman]

... You cant be serious. smack it with a hammer? I imagine you wouldn't get an explosion but more so a really hot fire that was burning like one of those old model rocket engines....

sure. why not. you should just try it yourself. youtube videos are nice and intersting to watch, but you have no idea what it's really all about if you haven't tried yourself.
as drbass already said: an empty or near empty battery will do ABSOLUTELY nothing if you nail it, hammer it, burn it ... i tried that. nothing did happen. i also tried with one of those little 1000mah batteries. fully bloated. charged. nailed it. cut one edge with an axe. NOTHING. it got warm. maybe hot. i bit of white smoke came out of it. that was all.
what i didn't do was OVERCHARGING a battery. and in my opinion this is the really dangerous thing.
empty broken cells on the floor? no problem at all. storage charged batteries on the shelf? minimal risk.

 

[izeman]

... I realised I had forgotten to drill a hole for the BMS thermistor. Unthinking, I picked up the dremmel with a 3 mm drill bit and started drilling. At about 90% of the way through I realised I should put something underneath the PCB to stop the trill from sucking through and piercing the cells below. Too late

LOL. EXACTLY the same thing happened to me. lucky me it was a storage charged a123 lifepo4 battery. but my heart was almost beating at 200+/min. in the end it was totally non spectacular. i drilled into the cell. smoke came out. i could watch inside and see it glowing. i pressed the cell and some fluid came out of the hole making more smoke. then the fire went out. of course at that time i already had the cell removed from the pack and was ready to throw it out of the open window on the concrete floor of my driveway.

 

[dnmun]

i wonder if chris could have stopped his fire if he had a large metal wire to use as a conductor to short out the cell that was pierced immediately after it started overheating from the shorted electrodes.

if you had a conductor capable of carrying all the current and just used it to short the terminal on top of the cell, would that have stopped the heating inside the pouch and lowered the temperature the electrolyte is subjected to.

i am of the opinion that the electrode potential is primary in these thermal runaway events also and if the cell is overcharged and goes into thermal runaway, i feel that shorting the cell out on an external conductor would drop the cell potential dramatically and stall or extinguish the self heating and thermal runaway.

i have not tried it but i do have it in the back of my mind so if i ever get to the point where i have a cell going to thermal runaway, i wanna test that theory.

 

[izeman]

wouldn't shorting the cell heat it even more? i thought a cell with a load way higher than it's c-rating would cause extreme heating leading to possible thermal runaway as well?

 

[dnmun]

no, i think you miss the idea. you need to reduce the cell potential and shorting the battery through a low resistance load will drop the cell voltage rapidly imo. i think of the thermal runaway being driven by the reaction of the electrolyte with the newly exposed carbon surface. this reaction would be driven by the electrical potential between the electrolyte and the carbon.

 

[fechter]

Test. With video.

My experience is if you short a cell, the electrochemical energy is still there and wants to take the path of least resistance. If the shorting wire is heavy, little energy will be dissipated on it and the remainder heats the cell through it's internal resistance. The cell will get very hot. The total energy in the cell will need to be dissipated as heat. The slower you can discharge the cell, the lower the temperatures will be. I don't think you can reduce the amount of energy in the cell by shorting it.

 

[friendly1uk]

no, shorts are inevitable when there are so many cycles of handling the JST plugs to plug the charger in and out each time so the sense wires are gonna be damaged by the user and not the charger.

the charger has internal controls that prevent it from overcharging so we know it is not caused by overcharging so it is because of shorted sense wires.

Everytime I use the ballance wires, which I guess are JST, I feel like I'm really straining when I unplug them. Is that just part of the design?

JST connectors are not meant for constant connection and disconnection. They are a one shot item, though you can get a removal tool for servicing. It's like a pair of tweesers, that get over what tiny lip there is. However JST plugs are cheap and light. If you flew model planes you wouldn't want anything else.

There is a good chance of pulling a wire out the plug if your not very careful. If you pull out two, then hope they don't touch. If one comes loose and you don't notice, you can't expect the precision measurements to be accurate. It could even fall out as you walk away if your not vigilant.

I have had a wire come out on a jst extension lead, and I really didn't pull that hard at all.

If you have a pack that you call 'done' then it should really have a bms in all but the most extreme cases. That is where a typical one bike newbie should be heading. It's how consumer goods work.

What's a bms again?
If you understand balance charging, you know you have a mains psu, the charger and batteries. Picture them on the bench. Batteries to your left, charger ahead of you and psu to the right. When you want to go out, you disconnect the batteries, scoop them up and take them with you. Though it's a little more involved than it sounds. Now back to the table. It's all there charging away. Time for the bms version of events. disconnect the charger from the psu. Scoop up the batteries and the charger and run off with it. Which sounds just as messy, but picture your charger was actually the size of a 20 block and actually wrapped with the cells. The connection between it and the psu that must be broken, a 2 pin plug. The price of this extra convenience? Generally cheaper!

 

[chessir]

FILE - In this Jan. 24, 2013 file photo National Transportation Safety Board's (NTSB) Joseph Kolly, holds an fire-damaged battery casing from the Japan Airlines Boeing 787 Dreamliner that caught fire at Logan International Airport in Boston, at the NTSB laboratory in Washington. A report by federal accident investigators points to a manufacturing defect as the likely cause of an internal short circuit that led to a battery fire in a Boeing 787 airliner parked at Boston's airport last year. The National Transportation Safety Board (NTSB) report released Monday says an inspection of the manufacturing plant in Japan where the battery was made found that flaws and debris in lithium-ion aircraft batteries were going undetected. (AP Photo/Manuel Balce Ceneta, File)

Eye Opening !! Amazing how sloppy mfg almost crashed an airliner.What are the chances now for all our batteries having these kind of defects. Can we isolate these defects in our batteries by examination and analysis?

 

[dnmun]

Early in the investigation, the NTSB said that the fire began after one of the battery's eight cells experienced an internal short circuit leading to thermal runaway of the cell, which propagated to the remaining cells causing full battery thermal runaway. This condition caused smoke and flammable materials to be ejected outside the battery's case and resulted in excessive heat and a small fire.

"The investigation identified deficiencies in the design and certification processes that should have prevented an outcome like this," said NTSB Acting Chairman Christopher A. Hart. "Fortunately, this incident occurred while the airplane was on the ground and with firefighters immediately available."

Because the APU and main lithium-ion batteries installed on the 787 represented new technology not adequately addressed by existing regulations, the Federal Aviation Administration required that Boeing demonstrate compliance with special conditions to ensure that the battery was safe for use on a transport category aircraft.

Investigators said that Boeing's safety assessment of the battery, which was part of the data used to demonstrate compliance with these special conditions, was insufficient because Boeing had considered, but ruled out, cell-to-cell propagation of thermal runaway (which occurred in this incident) but did not provide the corresponding analysis and justification in the safety assessment. As a result, the potential for cell-to-cell propagation of thermal runaway was not thoroughly scrutinized by Boeing and FAA engineers, ultimately allowing this safety hazard to go undetected by the certification process.

As a result of its findings, the NTSB is recommending that the FAA improve the guidance and training provided to industry and FAA certification engineers on safety assessments and methods of compliance for designs involving new technology.

"Through comprehensive incident investigations like this one, safety deficiencies can be uncovered and addressed before they lead to more serious consequences in less benign circumstances," said Hart."

NTSB investigators also identified a number of design and manufacturing concerns that could have led to internal short circuiting within a cell.

As a result of the investigation, the NTSB made 15 safety recommendations to the FAA, two to Boeing, and one to GS Yuasa.

 

[chessir]

Can we profit from this by purchasing Yuasa batteries with augmented QC? Both the lithium cobalt oxide for aircraft and the lithium manganese oxide for ev's were implicated in fires.

 

[crea2k]

This is what happens if you overcharge lipo, then hit it with I presume a stick with a nail in it https://www.youtube.com/watch?v=gz3hCqjk4yc

 

[chessir]

This is what happens if you overcharge lipo, then hit it with I presume a stick with a nail in it https://www.youtube.com/watch?v=gz3hCqjk4yc

Wow. Could have occurred with the Boing 787 or did it?. Lucky Lucky !!

 

[windtrader]

Not only scary but plain stupid! Not sure what sort of goo goes flying but it seems like ignited goo could easily have caught this dude on fire. Also explains the extra caution required to ship these batteries around.

 

[dnmun]

none of this has anything to do with the 787 fire.

in that case and the JAL flight it appears that metal particles were introduced into the electrode separator sandwich during fabrication of the cell which caused one of the cells to short out and i assume the charger began trying to charge it as it drained down but then that led to enuff heat generated in the shorted cell to allow it to go into thermal runaway.

boeing was faulted for not testing the presumption that thermal runaway in one can would not lead to thermal runaway in adjacent cans inside the battery case. a really big engineering error of judgement.

one can only assume this was because of the way the plane was assembled by a number of different contractors and supervised by boeing engineers, who in this case did not have the ability to see this fallacious presumption or have the time and budget to investigate it because of the time schedule established by management to get the plane released on schedule.

Challenger suffered from a similar management forced override of engineering decisions.

 

[amberwolf]

http://www.endless-sphere.com/forums/viewtopic.php?uid=13812&f=14&t=66159&start=0#p994979

 

[spinningmagnets]

Sept 2016

"52V 14Ah Dolphin battery on fire (Shenzhen BatteryBuilding)"
https://endless-sphere.com/forums/viewtopic.php?f=4&t=83208

 

[Merlin]

and if it starts, let the frame closed and dont give it air to breeze.................

 

[izeman]

WTF!!

 

[ziltoid81]

Holy crap your girlfriends new raptor.....

 

[liveforphysics]

and if it starts, let the frame closed and dont give it air to breeze.................

That is an awesome photo!

 

[izeman]

that's the problem i see with these big frames. if you cram them with lipos, there's no way to stop them from moving and one they do they will dent a corner or some other physical damage may happen.
the good thing i see is, that the frame can withstand the pressure, the flames and the heat. my bike is made of 3mm thick 7020 alloy and should hold back flames as well, once something like that happens. sure you don't want to happen it indoors, but still better to have a house full of smoke, than a burned down house. if this would happen outside in my garden shed i wouldn't worry too much (of course the loss of batteries etc is hard)

 

[Merlin]

some more "content"

it was:
- 8x 10s Zippy 5800
- Adaptto MIDI
- Adaptto BMS
- DC/DC shit
(Yes ...Controller was INSIDE)
It was a short, yes. But after everything is totally fried i cant find where it starts. a Day before one Part of the BMS stopped working and we switched to another module.
Next day this happend. You cant prevent to think this happens in context. No Matter, shit happens. No one was harmed, just the Air and a bit my neighbours nose.
It was one of her first rides. she was only learning some ride technics on a bit bumpy meadow. It starts to smoke, but i was to far away for a try to open it... to much "actions" inside and it was clear to me if i open the frame a big 1,6Kwh Fireball will show me whos your daddy....
you can hear that one cell after the next fart his life out and this video is only the short version. 20 minutes of "fun" is the complete version.
At the End we just cutted the phase wires to roll home.
half an hour later i opend the frame...woshhh. flames come out in a second.
closed the pot for another hour and tried again.
now i saw the complete fried stuff 1st time. that hurts....
measured with ir thermo cuddly 380°c / 716°f
started to cool down that BBQ with a water-spray-bottle.
worked so far.
Rest you can se on the pics.
disassambled same day. sandblast from a friend.
new black powdercoat and frame looks like new.
this happend one month ago and my gf was really sad. alot of tears for her.
alot of work burned down. we build, wired and soldered as good as we can without any compromiss.
so we dont blame our self that we probably did something wrong or dabble/botch.
cells were fully charged on this day, all cells in a row on the bms screen.
nothing to worry....but it happend. i wish i could tell: this was the problem.
but i cant. (except of ---m a y b e--- more cushion for the lipos)


[youtube]tRUC_05KmkU[/youtube]

[youtube]L9DE-EZ_Mfk[/youtube]

 

[Green Machine]

wow amazing.... the bike frame contained the lipo fire.....really great.

can you tell us which frame that was?

 

[sansander.ebike]

oooh no a nice Raptor, my condolences....
I'm sure the more beautiful is the new raptor. Important is that the frame is not distorted

 

[drew12345]

Wow! I thought it would have exploded or blew the cover off. Sorry to see. And glad no one got hurt. That was an awesome video though!