A123 26650 FIRE

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Jolfstn74   1 mW

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A123 26650 FIRE

Post by Jolfstn74 » May 30 2020 7:45am

from BatteryHookup.com I got 2 of the A123 48 cell packs and was breaking them into 6s4p modular packs for my e bike, had some balance wires on some hanging loose and stripped when I tripped on it, causing a short, causing a thermal runaway. I managed to get it off the wood floor inside the house and brought it to the yard, where in rapid succession lost 4 cells as they burst like firecrackers, tons of funky smoke and battery bits and fire. Never had that occur before. Pay attention when building battery packs to the risk of accidentally causing a short, when wiring a battery there really isn't a way to isolate the battery, once the main contact positive and negative bus and balance wires are on, it's hot. knock into it before you're done and anyone who saw the NASA robot fire knows these can be incendiary devices. Be aware and be careful. I was not burned carrying it outside but easily could have been, and I only lost 4 cells! considering what could have happened to my house, it's warped that the cells being lost occured to me at all, but if I'm being honest, yes it did. I got very lucky. Not hurt, house structure fully intact. I've heard it said to think of lithium batteries basically as 2 oz cylinders of gasoline. I had a first hand lesson as to why.

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pwd   10 kW

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Re: A123 26650 FIRE

Post by pwd » May 30 2020 7:57am

Damn, must have scared the crap out of you. Glad to hear you and your house are OK. Definitely a good reminder to take the time to insulate things as you go.
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jonyjoe303   100 W

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Re: A123 26650 FIRE

Post by jonyjoe303 » May 30 2020 11:45am

same thing happen to me, the A123 cells packs a punch, I only lost one. Thats why I always tell everyone that lifepo4 is not any safer then 18650 li-ion, they both will catch on fire extremely well if mistreated. It goes off like a blowtorch and it keeps reflashing until all the internal pressure is vented. After my experience I treat all lithium the same, and take extreme care taking packs apart, which is when the cells might be shorted out.

I still use the A123, I got about 200 of them, as long as you don't short them out or punch holes in them they are as safe as 18650. I use them in jump packs and also on my portable solder iron.
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john61ct   100 GW

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Re: A123 26650 FIRE

Post by john61ct » May 30 2020 11:51am

Yes LFP is much SAFER for thermal risks than most other LI.

But **any** high-discharge battery getting SHORTED!!!!

can basically explode, melt steel etc

not to mention just electrocute you (factors)

Be careful out there!

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Re: A123 26650 FIRE

Post by 999zip999 » May 30 2020 4:42pm

Taking apart and chopping up batteries can be a dangerous hobby. Maybe cut the tabs with ceramic scissors.

Hillhater   100 GW

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Re: A123 26650 FIRE

Post by Hillhater » May 30 2020 8:20pm

Maybe try to fully discharge all the cells (min safe voltage ). before you attempt assembly or disassembly of packs
Working on charged cells increases the risks dramatically.
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Rassy   10 MW

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Re: A123 26650 FIRE

Post by Rassy » May 30 2020 8:56pm

I would like the opinion of some of you concerning relative safety of LiFePO4 batteries versus other Li-Ion batteries.

My preferred and often recommended battery is a Ping LiFePO4 battery that is constructed using a prismatic type of cell. I have been under the impression that these cells would not self ignite even if abused by over or under discharge, shorting, or physical damage.

Is this true, because the chemistry is not incased in a steel cylinder?

I am well aware that a short will create intense heat that can burn you or ignite wire insulation or other combustibles around the battery because of the large amount of energy within the battery, but my concern is would the battery then proceed to self ignite into a huge ball of fire. I have read about tests that indicate the battery will not proceed to the common Li-Ion type of uncontrollable burning.
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Re: A123 26650 FIRE

Post by amberwolf » May 30 2020 10:02pm

There was a Ping battery fire on ES some years ago, but I can't find the thread now, and don't recall the circumstances. AFAICR it happened while someone was riding thru a park, and they had to throw the battery out of a basket?

:(



A google search on "Ping battery fire" finds this
https://visforvoltage.org/forum/9360-my ... aught-fire
but given the circumstances, there's no way to know what actually caused it.
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Hillhater   100 GW

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Re: A123 26650 FIRE

Post by Hillhater » May 30 2020 10:04pm

Fire risk all depend on the individual cell chemistry.
The burning/ explosive nature is dictated by the choice of electrolyte used by different manufacturers.
There is a video posted here somewhere of serious overchargeing tests on various cells.
Most ignited at some stage of overcharge and in varing degrees of violence, but some had minimal reaction,,even some of the different brands of RC lipo pouches, which just puffed and smoked...no flames at all.
LiFEpo4 is considered safer than LiPo, but as above, those A123 cells are LiFepo4 .....and they were not safe.?
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john61ct   100 GW

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Re: A123 26650 FIRE

Post by john61ct » May 31 2020 8:13am

Yes LFP can burn.

As above, not from normal usage just getting worn out

which is the case with other LI chemistries.

And not from being punctured etc afaik.

But definitely from a charger allowed to go rogue, and it seems possible from dead shorting bypassing your fuse protection.

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Re: A123 26650 FIRE

Post by john61ct » May 31 2020 8:15am

Good old lead banks can explode too.

There is no absolute meaning of "safe" wrt high power electricity, only relative safety.

999zip999   100 GW

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Re: A123 26650 FIRE

Post by 999zip999 » May 31 2020 9:50am

Safe is battery LTO big heavy and low voltage. Still can make fire. Best for heart battery.

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Rassy   10 MW

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Re: A123 26650 FIRE

Post by Rassy » May 31 2020 10:08am

AW wrote:
There was a Ping battery fire on ES some years ago, but I can't find the thread now, and don't recall the circumstances. AFAICR it happened while someone was riding thru a park, and they had to throw the battery out of a basket?
AW, good memory, except I don't think it was a Ping battery, or even a LiFePO4 battery. Here is the thread you were probably referring to:

viewtopic.php?f=14&t=31849&hilit=fire

The battery in this fire was a Battery Space Lipo 48V 10AH with BMS.

I have read that Green Machine (Eric) and Luna owner (Eric Hicks) are one and the same.
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Jolfstn74   1 mW

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Re: A123 26650 FIRE

Post by Jolfstn74 » Jun 01 2020 5:39am

I have seen firsthand deliberate shorting of 18650 cells and the reaction was more violent and occurred faster than my own accident. I believe all high current cells have the capacity to conflagrate, albeit some more forcefully and faster than others, I hadn't considered this and am now grateful that I was working with A123 vs 18650 at the time, possibly would not have had time to carry the pack outside or would have been injured in the attempt.

Jolfstn74   1 mW

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Re: A123 26650 FIRE

Post by Jolfstn74 » Jun 01 2020 5:43am

also, my mention of the source of the batteries was not intended to suggest they were in any way responsible, I mentioned them because they specialize in reselling repurposed batteries, and in this case there is a lot of cutting through pcb bms electrical board in order to harvest the cells, for which I was/am fully responsible for having decided to do, as was I responsible for leaving partially installed balance wires, as was I for clumsily tripping over the object. BatteryHookup.com is a great source for inexpensive cells and have many safety recommendations should one care to read them.

Hummina Shadeeba   10 MW

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Re: A123 26650 FIRE

Post by Hummina Shadeeba » Jan 07 2022 2:27pm

I’ve done a lot of intentional shorting of A123 26650s and haven’t been able to start a fire. Strangely the cells will greatly reduce current when shorted for a short time yet still show a decent voltage. It’s misleading and u can have a cell showing 3.6v but will barely put out current after being shorted for a bit of time.


My concern is this battery pack that i can’t balance and made with these cells. (Id planned to balance externally but for some reason now that the cells are built into a battery and potted and I drill through I can’t get a stable voltage from any of the groups and very weird. and I’ve now had two that have outgassed. I’ve done a lot of abusive testing on these cells including way overcharging and trying to charge cells that have outgassed and nothing dangerous has happened, making me feel safer, but I feel I’m pushing it now with this second out gassing bubble What u think?


It’s always said lifepo4 isn’t combustible even if u puncture it. That isn’t true and my friend drilled through one snd it ended in flames. It was a relatively minor fire that didn’t ignite the cells around but still. (he didn’t mean to drill it).
Attachments
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A bubble in the potting.
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Drill holes to the cell to try to balance but doesn’t give a stable voltage.
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john61ct   100 GW

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Re: A123 26650 FIRE

Post by john61ct » Jan 07 2022 6:23pm

Yes voltage alone says nothing about State of Health.

Cap test benchmarking is canonical and before/after ESIR refines that.

Testing to destruction can be useful, but abused cells of any chemistry are no longer suitable for production use.

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Re: A123 26650 FIRE

Post by Hummina Shadeeba » Jan 07 2022 9:36pm

john61ct wrote:
Jan 07 2022 6:23pm
Yes voltage alone says nothing about State of Health.

dont know if youre responding to me or about what specifically here. When charging i can see how the pack is losing capacity. and for some weird reason i cant get a decent solid voltage reading off each group of 7 cells. i dont know why. i have no idea whats going on with my battery. i cant even get the probes to give a solid reading and so weird. Another weird thing about these cells I held a couple in a short, and they would stop putting out the power. they would stop getting hot. they wouldnt spark. but they show 3.6 volts.
Cap test benchmarking is canonical and before/after ESIR refines that.


i dont know anything about that.

Testing to destruction can be useful, but abused cells of any chemistry are no longer suitable for production use.


i dont know what youre talking about.
two cells or maybe more have degassed and im running the battery anyway. i lanced it before and the resin is soft enough it does this bubbling. I'll guess i'll lance it again. cant believe im doing this. i cant get a solid voltage for some unknown reason on the 14s7p. i think i feel a drop in torque with the same esc settings and the battery is dying. i can see it with the amphours in as i charge. (i should get data logging). i cant get a voltage reading off the groups of 7 cells for some weird reason, which is super weird. i drilled holes to through to the copper foil to balance. I stuck in bare multistrand and the multimeter wont stay on a stable voltage.

searching the web i cant find these cells going into flame from being abused electrically but im worried about using this battery.

jonyjoe303   100 W

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Re: A123 26650 FIRE

Post by jonyjoe303 » Jan 08 2022 8:30pm

I dont understand how drilling holes in the copper will help with balancing. But that is dangerous in risking puncturing the cell. If you cannot get the pack to balance you might have a weak cell somewhere or loose balance connections. On my A123 packs I used an IR tester on all the cells to make sure they were good, I found some high IR cells when testing and didnt use those cells or would have had balancing issues. Your cells that have outgassed are no longer usable, they will cause the balancing issues and might even drain your pack and ruin all the rest of the cells.
My advice would be to take your pack apart and find the bad cells and replace them, also do an IR test on all the cells. The IR should be about the same on all the cells, any reading too high or low shouldnt be used. The packs I build have kept perfect balancing the entire time and they are about 3 years old since I built them.
The A123 cells are safe as long as you don't puncture them, I still use mine everyday.

Hummina Shadeeba   10 MW

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Re: A123 26650 FIRE

Post by Hummina Shadeeba » Jan 15 2022 10:31am

charging a cell to as high a voltage as possible I couldn't get an A123 cell to go to "fire" but at 6 volts the vent popped and at 8 volts it put out a lot of nasty smoke and heat. I think this is the scenario im looking at if continuing to run this battery i cant seem to balance, if not worse since it's potted.

I held many of these in a short and could not get them to ignite and somehow it seems some safety was triggered and they would stop putting out current but still show a voltage. drilling through a cell would put out a flame but not nearly as violently as an ion cell.

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Re: A123 26650 FIRE

Post by jonyjoe303 » Jan 15 2022 1:45pm

how bad is the balancing problem? I have a 220ah lifepo4 battery pack that was giving me balancing problems and have been using active balancers on them for the past 3 years because I didnt want to take the pack apart (160 cells). It didnt fix the balancing problems but it allows me to continue to use the pack without any issues.
As long as you don't puncture the A123 cells, just get some active balancers and that will keep the cells from reaching too high of a voltage which would be more of a problem for your pack.
I also use the chargery bms8t as the bms on my pack, that shutsoff charging if any cell voltage gets too high (above 3.65 volts) and it has an lcd screen so I can see cell voltage as its charging in realtime. Thats how I can tell the active balancers are doing there job since the cells are always close to each other in voltage.
Myself I would try my best to keep the cells withing its minimum and max limits to prevent any mishaps.

active balancers I been using, without the balancers 1 cell would be reading 3.65 volts shutting down the charging too early.
active balancers qnnbm.jpg
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Hummina Shadeeba   10 MW

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Re: A123 26650 FIRE

Post by Hummina Shadeeba » Jan 15 2022 2:08pm

I can’t get a stable voltage reading for some weird reason. I have active balancers and had planned to use them

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batteryGOLD   100 W

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Re: A123 26650 FIRE

Post by batteryGOLD » Jan 15 2022 3:57pm

Only a shortcircuit contact/bad battery design could destroy this A123 cells
This cells are very safe even overcharged. (do not try overcharge cells)

Here is the situation:

At company we have a drift Etricycle. I converted it from Pb to 8S LiFePO4 A123
8S system 1P
but at datasheet it says A123 supporting super fast charge @ 12min
Sooo I start charging @10A this 8S battery no BMS, than I went to repair a electric scooter and forgot time..
Than I came back to see charge status and found a 8S LiFePO4 @ 32V !!! this means each LiFePO4 went to 4V!
max should be 28,8V for 8S system.. sooo battery went to maybe +130% capacity with no heat, stable and same performance after discharge.

This could gone very wrong with 18650 cells overcharged will go on fire!!

LiFePO4 very safe at overcharge. No fire OK (do not overcharge any kind of cells)

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batteryGOLD   100 W

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Re: A123 26650 FIRE

Post by batteryGOLD » Jan 15 2022 4:07pm

Sir, is this real? are U using solid resin to pack battery?
Or is flexible silicone resin flexible with thermal conductivity?

Remember cells expand/reduce with temperature and need air flow to breath..
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Hummina Shadeeba wrote:
Jan 07 2022 2:27pm
I’ve done a lot of intentional shorting of A123 26650s and haven’t been able to start a fire. Strangely the cells will greatly reduce current when shorted for a short time yet still show a decent voltage. It’s misleading and u can have a cell showing 3.6v but will barely put out current after being shorted for a bit of time.


My concern is this battery pack that i can’t balance and made with these cells. (Id planned to balance externally but for some reason now that the cells are built into a battery and potted and I drill through I can’t get a stable voltage from any of the groups and very weird. and I’ve now had two that have outgassed. I’ve done a lot of abusive testing on these cells including way overcharging and trying to charge cells that have outgassed and nothing dangerous has happened, making me feel safer, but I feel I’m pushing it now with this second out gassing bubble What u think?


It’s always said lifepo4 isn’t combustible even if u puncture it. That isn’t true and my friend drilled through one snd it ended in flames. It was a relatively minor fire that didn’t ignite the cells around but still. (he didn’t mean to drill it).

Hummina Shadeeba   10 MW

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Re: A123 26650 FIRE

Post by Hummina Shadeeba » Jan 15 2022 5:34pm

It’s a semi-hard polyurethane often used for potting cells. Cells don’t need air to breathe though and just some room to expand

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