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LiFePO4 what they leak and why they should be installed upright

michael d

off-grid solar pilgrim
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I just watched a youtube video a couple of days ago of will Prowse with a leaking LiFePO4 battery. just starting this thread as an informational warning to system installers using LiFePO4 battery cells. feel free to add information. I will add information as I get it organized a bit better.
the electrolyte inside is quite hazardous to your health.?



 
ethylene carbonate–dimethyl carbonate (EC–DMC) 1–1 lithium perchlorate (LiClO 4) 1M.....and it's nasty stuff


the electrolyte inside the lifepo4 cells
hydrogen fluoride --- be extremely careful leaking --- do not breathe it or get any skin contact with it
 
LiFePO4 cells do not need to be fused when they are in parallel packs. UL listed packs in hospitals and grid back up have these cells in parallel with no issue. Check out some of my older videos where we tear them apart. I actually covered this misconception in previous videos a lot. They will get hot, but each cell has a burst cap and will relieve pressure if necessary. Then temp would drop. But the reaction is not self-sustaining, so even if this did occur without safety protection, it is not that big of a deal.
this was a Will Prowse comment in the above video
 
good information for the 2P8S setup I use with the 272Ah Lishen cells. I was not going to put fuses in between cells anyways. the class t catastrophe fuse I use between the inverter and the 13926.4 watt-hour potential capacity 2P8S battery build with 16 Lishen 272Ah cells.
 
The orientation is important for the cell to work properly but is likely not the cause of the leak. My guess as stated in original comment is that cell that leaked was overcharged that created gas inside the cell that in turn created pressure allowing the valve to open and due to unfortunate orientation instead of the gas escaping it was the electrolyte. LiFePO4 is very safe and something like a NMC or LiCoO2 may have resulted in a fire if overcharged. The reason for overcharging is an improper or defective BMS. None of this type of batteries can work correctly (I'm referring to 12V and 24V direct lead Acid replacements). When any cell gets to 3.6 or 3.65V the charging should stop but this sort of BMS with no separate path for charge and discharge can not just stop the charging as that means disconnecting the battery from the circuit so they prefer to allow significant overcharge up to 3.9V or even more in some cases. There will always be a cell with just slightly lower capacity to get first to full charge say 3.6V while all other cells will be very close at around 3.4V so with a 12V 4s battery that will be 13.8V or so but most chargers are set to 14.4V thus that one cell will get to 4.2V if you do not want to disconnect the battery from the system. With 24V 8s that becomes even worse. Many charge sources like some solar chargers do not like the battery to be removed while PV panels are still connected and also removing the battery and leaving some chargers directly connected to some loads may also be a problem.
Dacian the electrical engineer comment above: same video
 
only one video i am referring this safety hazzard to:

no,,, maybe I need to clarify all comments i directly copied and pasted from the same video. there is no second video. sorry for any confusion. all comments I utilized are under the comments part of Will Prowse's video. Dacian made his comments in the comment section under Will Prowse's video.
my writing is often rapid and my mind is a lot faster than my keyboard skills. never will be a good secretary. I hired a typist to type all my college/university papers. I hunt and peck at the keyboard and still look at the keys.? thanks, I will add that to my post so hopefully less confusion for others.
it is good to read other people's information and glean from their expertise.
 
My mind is faster than typing as well..........and my mind is slow.
Should there be any electrolyte in the case, should it not be contained in the pouch? Is this a part of the grading of these cells (and the price we wish to pay) along with power leakage to the case?
Perhaps we are getting what we pay for.....
 
My mind is faster than typing as well..........and my mind is slow.
Should there be any electrolyte in the case, should it not be contained in the pouch? Is this a part of the grading of these cells (and the price we wish to pay) along with power leakage to the case?
Perhaps we are getting what we pay for.....
As for electrolyte in the pouch, I think it’s a different type of cell with that configuration. I don’t believe it is supposed to be the case with these prismatic pouch cells.
 
My mind is faster than typing as well..........and my mind is slow.
Should there be any electrolyte in the case, should it not be contained in the pouch? Is this a part of the grading of these cells (and the price we wish to pay) along with power leakage to the case?
Perhaps we are getting what we pay for.....
I am not sure of this answer but I think the electrolyte surrounds the pouches.
I have not seen the inside of these cells
not sure I want to.
i have mine in an outside insulated solar power shed.
hopefully, someone who knows the correct answer to your question can provide more expertise here.
there was a video on youtube where some guy tore apart an aluminum-cased prismatic cell.
the best bet is to be careful. put the cells upright when assembling them.
i am glad none of mine are in the living quarters.
install in a plastic box -possibly? or a drip pan arrangement.
i never thought installing them on their side was a good idea. I think that is a bad idea.
experts - please feel free to add to this thread.
thanks in advance
 
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the reported very small mA and microA power leakage to the case was shown to be a minor issue essentially a non-issue.
I would not let that bother me.
but I do believe the cells should be put in a fixture to prevent friction between cells.
they are claimed to increase the number of cycles. possibly? buy putting them in a clamping type fixture.
the problem I foresee and the advantage to clamping them is the stress on the tiny studs when using busbars.
they will expand and contract when charged.
the important part is not to overcharge them. or to too deeply discharge them.
an extra layer of slick non-conducting material between cells is a very inexpensive upgrade.

i have worked around many chemicals in labs and we used ventilation hoods etc.
so why would one mount them on their side as they were done in big battery?
lack of knowledge!
China is never going to pay anyone any more than they did with the chemicals in the pet food killing off the pets as a fake protein replacer
be safe is the best course of action.
sorry for the soapbox. ??
leaking chemical from these cells will be dangerous ---
 
...the important part is not to overcharge them. or to too deeply discharge them.
an extra layer of slick non-conducting material between cells is a very inexpensive upgrade.
...
Would 1/32” thick neoprene rubber be a suitable material? (Apologies if this is off topic)
 
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Would 1/32” thick neoprene rubber be a suitable material? (Apologies if this is off topic)
neoprene is non-conductive? is it slick?
1/32 inch would be fine for the thickness.

Mechanical Properties
  • Compression Set: Good.
  • Rebound Rating: Fair to Very Good.
  • Flex Cracking Resistance: Good to Very Good.
  • Abrasion Resistance: Very Good to Excellent.
  • Tear Resistance: Good.
  • Impact Resistance: Good to Excellent.
  • Flame Resistance: Very Good to Excellent.

I bought chopping mats 11 inches by 14 inches in a package for 2 for one dollar at the dollar store.
this makes 4 spacers for the Lishen 272Ah cells inexpensively.
plastic is nonconductive. I really wanted the harder cutting board (white stuff) in a solid sheet but did not find it.

the above does not mention conductivity about neoprene rubber.
one needs an expert opinion or data or find it in a conductivity table somewhere? not a total answer for you - sorry. ?
need a little more research on it (neoprene rubber). I can picture its use in pond liners and roof applications as a replacement for rubber.
 

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I see a new youtube video from Will Prowse and he said the leaking defective cell was not too common but it gave him enough respect to want to orient the battery so the terminals are mounted upright. I agree.
mounting the prismatic aluminum cased cells on their sides is a bad idea.

 
the datasheet for a 272ah Lishen cell has a line about that in there. "c)During the course of storage or usage, keep the cells upright ."

keep them upright, just for no other factor than having the vent at the top.

they were reported to be Lishen cells in that pack.
Will Prowse prefers the Lishen 272Ah over the Eve 280Ah,
but I believe keeping them upright no matter what brand would be the safer way to go.
 
but I believe keeping them upright no matter what brand would be the safer way to go.
I feel the same way. There is just no reason compelling enough to NEED to orient them any way other than upright. Anything else is just asking for trouble (or grossly negligent, take your pick).
 
they were reported to be Lishen cells in that pack.
To be clear the Lishen cells in that pack are 170ah cells. And Big Battery claims Lishen told them mounting the cells on their side was ok.

but I believe keeping them upright no matter what brand would be the safer way to go.
No doubt about it. However there are some with tight spaces that can't keep them upright and so they mount them to fit the space they have. They should be checking with the manufacturer to find out if that's ok. But even though the 272ah Lishen spec sheet says to keep the cells upright it has been ignored by another forum member.

I am not sure if the recommendation is to keep the electrolyte even around the jelly roll. Or if it's concern about leakage from the cell. But whatever the reason, not following the spec sheet is asking for trouble.
 
The Headways that leaked smelled like Ether. I thought the flouride compound only came from combustion. I did not see it it the list above.
 
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