# LiFePO4 Battery Orientation?



## www.3xE.pl (Nov 22, 2008)

Some time ago we asked manufacturers directly and they said that it is fine to lay cells on the side. Of course it is not preferred (safety valve supposed to be on top).


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## dougingraham (Jul 26, 2011)

PZigouras said:


> If the electrolyte gets up to the terminal connections, will it cause a short/drain?


No. The electrolyte itself is not conductive.


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## samwichse (Jan 28, 2012)

Isn't part of the definition of an electrolyte that it conducts electricity?

Just checked Wikipedia:



> When*electrodes*are placed in an electrolyte and a*voltage*is applied, the electrolyte will conduct electricity.


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## www.3xE.pl (Nov 22, 2008)

The only danger in my opinion could be bubble of air that could reduce the working surface of the battery... but as far as I know batteries are filled to the top.
Besides if you have seen the cell inside - you know how impossible is it


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## dougingraham (Jul 26, 2011)

samwichse said:


> Isn't part of the definition of an electrolyte that it conducts electricity?
> 
> Just checked Wikipedia:


And this is why you can't cite Wikipedia as a reference in a professional paper.

If the electrolyte conducts it will be a direct short between the anode and cathode which will cause the battery to self discharge. In the case of lithium batteries the electrolyte promotes the migration of lithium ions between the plates.


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## dladd (Jun 1, 2011)

my kid just did a 6th grade report on volcano's. Her only source was Wikipedia. I told her that would never fly with her teacher, you gotta go to the library and get some real books. She disagreed and said wiki was good enough to cite as her source. 

She got an A. sigh. Is this what research has become now?


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## PZigouras (Jun 5, 2010)

I just found a PDF that Jack Rickard of EVTV wrote for the Calb cells (it's available at http://media3.ev-tv.me/cellcare.pdf)

On page 16, he writes:

*CELL
POSITION​*The manufacturer advises us that the ideal mounting of the cells is vertical with the vents
pointing UP.
Mounting the cells upside down is absolutely forbidden as this causes electrolytes to pool in
the pressure vent, disabling it.
Horizontal mounting is somewhat more controversial. The manufacturer advises this
shortens cell life, with mounting on edge preferable to mounting flat side down horizontally.
We have yet to receive a cogent explanation of why horizontal mounting would cause any
decrease in battery life or capacity. All such explanations we have found on the Internet are
demonstrably nonsense.​But this remains the manufacturers recommendation and we pass it on.


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## nimblemotors (Oct 1, 2010)

I opened up a 20ah pouch cell. They have no 'fluid' in them.
If there was fluid that could migrate then keeping them upright would also not work, as the fluid would settle to the bottom. Looks to me they vacuum out the air before sealing them. If you've seen the video of a winston cell abused to vent and explode, the venting just blows out the electrolyte anyway even when upright. Note the pouch cells have no vent.

The manufacturer advice is good, but they also have CYA motivation too.


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## samwichse (Jan 28, 2012)

dougingraham said:


> And this is why you can't cite Wikipedia as a reference in a professional paper.
> 
> If the electrolyte conducts it will be a direct short between the anode and cathode which will cause the battery to self discharge. In the case of lithium batteries the electrolyte promotes the migration of lithium ions between the plates.


Snark aside, I only cited Wikipedia as the quickest appeal to authority.

An electrolyte is an aqueous solution of dissolve salts, and as such, it IS conductive.

I will instead quote my old chem text :



> ...aqueous solutions with ions conduct electricity to some degree. Pure water, having a very low concenration of ions, cannot conduct electricity. When a solute dissoctiates in water to form ions, it is called an electrolyte, due to the solution being a good electrical conductor. When no ions are produced, or the ion content is low, the solute is a non-electrolyte. Non-electrolytes do not conduct electricity or conduct it to a very small degree. In an aqueous solution a strong electrolyte is considered to be completely ionized, or dissociated, in water, meaning it is soluble.


Quoting Wikipedia does not make something wrong and an electrolyte is defined by the fact that it is conductive.


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## EVfun (Mar 14, 2010)

dougingraham said:


> No. The electrolyte itself is not conductive.


Wait a minute... an electrolyte is an acid, base, or salt. It is generally conductive, though its purpose in a battery is to pass ions, not electrons. The potential difference within the cell prevents it from being a short. The actual electrolyte in a Lithium battery is Lithium ions, within the organic solvent base. In a Lead acid battery (for comparison) the electrolyte is sulfuric acid, in a water base.


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## onegreenev (May 18, 2012)

Cells can be on their sides. The Nissan Leaf has half of the cells on their sides. There is so little electrolyte that capillary action keeps what little there is between the cells. Yes, pouch cells are vacuum packed. But that is not a requirement. Just holds things tight if they are vacuum packed.


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## grip911 (Dec 14, 2011)

I have noticed some anomalies in laying down batteries on their ends.
It could be coincidence but in bottom balancing ,near the very end of discharging ,the cells would bounce back up dramatically more that the cells that were upright, making it a little more difficult to achieve the desired voltage.

It didn`t seem to affect the performance in any way. Maybe ,there are some long term effects of laying some cells on their sides .
This is just an observation, not a conclusion, but merits saying because it`s not the first time the subject has arisen.


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