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Can LiFePO4 Batteries Combust in Thermal Runaway Event?

Yessir. It's the reason that an LFP starter battery can be 3 inches under your butt when using them in motorcycle applications, like Shorai, Antigravity, Earth-X and a whole host of others.

Extenuating circumstances, like wrong charging voltages and poor wiring infrastructure, bms failure etc can cause them to cook off the electrolyte and melt poor wiring becoming the primary source of trouble - not the cells themselves.

But at the end of the day, the greedy little iron-phosphate molecules in the active material simply won't release oxygen. So yes, you are absolutely right. It's the other things that if handled casually, are the instigators.

Probably the reason that these companies have been in operation for many years, and not sue-balled out of existence.
 
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This happened to me a few days ago after a year of zero issues in my van. It literally exploded with audible explosion. No open flames but it was bad. Only one cell was damaged and BMS measured ~3.4v when it happened.
First of all I am glad you and your van are ok and there wasn't more damage.

The cell is severely bloated and I have seen worse bloating and the vent did not pop. But the vent on your cell did. It appears the cell got hot because the PVC wrap is deformed on that cell. So the BMS reported 3.4 volts for that cell?

These cells can be used in a mobile environment if properly compressed to reduce terminal stress. Tape alone isn't going to work.

Cells should be insulated from each other and anything conductive that can come in contact with the cells. The PVC wrap can't be relied on especially in mobile environments.

The bolt/screw torque of the cells terminals should be checked on a regular basis to make sure nothing is coming loose and all connections are good. Do you know how much torque you used on the bolts when you assembled the pack?

If possible I would like to know what happened. Is there any more information you can provide? I would also like to know the AH rating of the cells and the manufacturer. Thanks.
 
Any idea what happened? It has been said the prismatics are not suitable for mobile use.. also, the cells needing a physical separator between each cell, compression…
So… I honestly have no idea what happened. This is a 120ah build of cheap aliexpress cells and a overkill BMS. I use a red arc 1225 charge controller to manage the 100w solar panel and alternator/starting battery To keep the cells charged. They have worked flawlessly for a year with delta between cells typically 0.02-0.05 and I think 3 recorded overvoltages, all of which I witnessed via the BMS Bluetooth app. My van has been sitting for 2 weeks with hardly any use and a 12v fridge consuming power so the batteries were discharged around 40% of the 120ah rating The day before. When I got in the van and checked the state of charge it read overvoltage disconnect and a fully charged system. This was odd as there is no way my little solar panel charged up those cells to 100% in a day and overcast skies. Ambient temp outside around 92F so it was a hot day bit the overkill temp sensors were showing 37-38C in the battery box. I drove to the store and watched the BMS to see if it would kick on charging again and it never did. Driving back home I heard a hiss and smoke immediately released into the vehicle. I pulled over and looked under the seat quick where the battery is and the smoke stopped. I checked the BMS and saw the voltage in cell 4 rapidly dropping while the other 3 remained stable. I used the BMS to disconnect the cells and drive home (3min drive). I got home and looked under the seat and saw the cell was significantly deformed and swelling and closee the box and immediately a loud bang and a ridiculous amount of “smoke” (fumes really)…. I ran for a fire extinguisher and was overcome by the fumes and the heat n the battery box and just called 911. Fire department came, put on respirators, and used a yellow powder fire extinguisher to stop the reaction or “put it out” and pulled the cells from the vehicle and that is essentially it. I have a number of fuses setup in the system and none were blown. Zero damage to the other cells and any of the components of the system. Just this one cell failed, cell #4.

In another forum, people are saying the casing on these cells is charged and say the cell was shorted out on the metal battery box Which I find ridiculous. Even if the cell was negatively charged, it’s already grounded to the car so contact with the metal box should not do anything in my estimation. If they are positively charged, I would assume this would be happening a LOT and all 4 cells, being connected by the bus bars, would have been damaged.

The cells were separated with very sticky foam tape and taped together… I believe I saw this done in one of Will’s videos?

I am all ears as to what you guys think happened or I need to do differently to prevent this again. I hope to replace the system as it was working awesome and way better than the lead acid i used to use.
 
When I got in the van and checked the state of charge it read overvoltage disconnect and a fully charged system.
Do you know what the voltages were on all the cells then? It sounds like from what you describe cell 4 was seriously over voltage which would explain why the pack read fully charged even though you thought it shouldn't be. Can you pull cell 4 out carefully and fully examine it?
 
So… I honestly have no idea what happened. This is a 120ah build of cheap aliexpress cells and a overkill BMS. I use a red arc 1225 charge controller to manage the 100w solar panel and alternator/starting battery To keep the cells charged. They have worked flawlessly for a year with delta between cells typically 0.02-0.05 and I think 3 recorded overvoltages, all of which I witnessed via the BMS Bluetooth app. My van has been sitting for 2 weeks with hardly any use and a 12v fridge consuming power so the batteries were discharged around 40% of the 120ah rating The day before. When I got in the van and checked the state of charge it read overvoltage disconnect and a fully charged system. This was odd as there is no way my little solar panel charged up those cells to 100% in a day and overcast skies. Ambient temp outside around 92F so it was a hot day bit the overkill temp sensors were showing 37-38C in the battery box. I drove to the store and watched the BMS to see if it would kick on charging again and it never did. Driving back home I heard a hiss and smoke immediately released into the vehicle. I pulled over and looked under the seat quick where the battery is and the smoke stopped. I checked the BMS and saw the voltage in cell 4 rapidly dropping while the other 3 remained stable. I used the BMS to disconnect the cells and drive home (3min drive). I got home and looked under the seat and saw the cell was significantly deformed and swelling and closee the box and immediately a loud bang and a ridiculous amount of “smoke” (fumes really)…. I ran for a fire extinguisher and was overcome by the fumes and the heat n the battery box and just called 911. Fire department came, put on respirators, and used a yellow powder fire extinguisher to stop the reaction or “put it out” and pulled the cells from the vehicle and that is essentially it. I have a number of fuses setup in the system and none were blown. Zero damage to the other cells and any of the components of the system. Just this one cell failed, cell #4.

In another forum, people are saying the casing on these cells is charged and say the cell was shorted out on the metal battery box Which I find ridiculous. Even if the cell was negatively charged, it’s already grounded to the car so contact with the metal box should not do anything in my estimation. If they are positively charged, I would assume this would be happening a LOT and all 4 cells, being connected by the bus bars, would have been damaged.

The cells were separated with very sticky foam tape and taped together… I believe I saw this done in one of Will’s videos?

I am all ears as to what you guys think happened or I need to do differently to prevent this again. I hope to replace the system as it was working awesome and way better than the lead acid i used to use.
The issue isn’t that negative shorting to case or vehicle ground… remember you have FOUR differing polarities, if ground on one shorts, unless it is the main negative cell, there will be a short circuit. So, yes… a cell casing shorting to ground would be an issue, because in a series build of cells, negative on one cell is connected to the positive of the other cell… thus a series.
 
The issue isn’t that negative shorting to case or vehicle ground… remember you have FOUR differing polarities, if ground on one shorts, unless it is the main negative cell, there will be a short circuit. So, yes… a cell casing shorting to ground would be an issue, because in a series build of cells, negative on one cell is connected to the positive of the other cell… thus a series.
And can anyone confirm the casing on these cells is in fact this dangerous and any contact with metal can cause a short circuit?
 
And can anyone confirm the casing on these cells is in fact this dangerous and any contact with metal can cause a short circuit?

I can only say for sure that the EVE 280 cells (version E I think, the ones that were available originally last year) can only supply a small leakage current through the case (case is positive). I noted that here:

Other cells may very well be different.
 
And if this was the case, wouldn’t all 4 cells be damaged instead of one single cell catastrophic failure ?
 
I was in the van in my driveway!
glad you're OK and glad you shared. Maybe you should start your own thread about this. I bet you'll have a lot of interested forensic (shadetree) analysts to help diagnose.
 
How hot are the gasses when LFP vents? Can this ignite wood? Melt aluminum plate? It was hard to t
Feel free to read through this thread and draw your own conclusions.
I’m guessing this is a possibility, thst the blue film wore through somewhere and short circuited… maybe? Cell voltage was 3.4 when it happened and dropped from there. I never blew a single fuse anywhere in the system and none of the wires had any wear or melting exc
 
I’m guessing this is a possibility, thst the blue film wore through somewhere and short circuited… maybe? Cell voltage was 3.4 when it happened and dropped from there. I never blew a single fuse anywhere in the system and none of the wires had any wear or melting exc
It is a possibility. Either that or something happened to the cell's terminal due to the lack of proper compression, and that in turn caused an internal short in the cell. Of course it's still possible the cell shorted internally by itself. But I find it odd a cell would short internally by itself after being in service for a year.

I think you have a good understanding of what should be done when you do your next build. Eliminating possibilities for a failure is the best anyone can do.
 
From what I've read and what Will and the other solar gurus say, the technology is safe from self combusting but I I still put my LiFePO4's and associated equipment in and on non flammable enclosures and surfaces. Oorah.
 

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I just had a "fb expert" telling me that any lithium can catch fire from thermal runaway. He gave this example but they literally used an external device to overheat the batteries so I don't think that counts. I linked this thread under his comment and told him to come share his genius since he thinks he's such an expert lol.
 
From the abstract:

"The cells are over heated using a heating plate. The heating plate is utilized to simulate the abuse process triggered by TR of the adjacent battery in modules." (note: TR = Thermal Runaway).

Yeah, this makes no sense. Let's heat one cell to induce thermal runaway, and pretend this heat is from another cell that went into thermal runaway. Don't matter how that cell got there...
 
Please don't get news or technical information from FB on anything.
I don't mate. I just corrected some people who were saying lifepo4 explode into flames and vent toxic gas then this tool decided to try and flex his "expertise" lol. I get all my info from Will's YouTube/blog or industry professionals
 

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