# Swollen LiFePO4 battery



## flyinginnet (Apr 19, 2013)

Has anyone experienced a LiFePO4 battery become swollen when self-discharge slowly for a long time?


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## jeremyjs (Sep 22, 2010)

flyinginnet said:


> Has anyone experienced a LiFePO4 battery become swollen when self-discharge slowly for a long time?


You either over charged it or over discharged/reversed the cell.

Edit: It could also be a defective cell.


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## onegreenev (May 18, 2012)

flyinginnet said:


> Has anyone experienced a LiFePO4 battery become swollen when self-discharge slowly for a long time?


Good pictures help.


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## alvin (Jul 26, 2008)

I had one that was slightly swollen still in the crate. I had never charged or discharged it. The old one was at the same voltage as the others. 

I e-mailed Balqon and they sent a new cell and picked up the old one. 


Alvin


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## mora (Nov 11, 2009)

I have 9 bad cells laying around. Few of those are swollen. I got to measure one that was still in use (trolling motor battery) and it had less than 80% of capacity left then. I overdischarged it once down to 2.0V at about 1/3C and it bulged at the same time. Now it won't hold charge anymore. Just keeps warming up if I try to charge it. Other swollen cells came out of my car traction pack as I noticed them sagging way more than others.

But over half of my current traction pack consists of cells that were really slowly discharged down to 0.01V resting voltage. They still hold charge and perform nicely. None of them have swollen. Those that ballooned up a bit were even lower than 0.01V resting voltage.


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## jddcircuit (Mar 18, 2010)

flyinginnet said:


> Has anyone experienced a LiFePO4 battery become swollen when self-discharge slowly for a long time?


Yes, but sorry I don't have root cause.

I have a couple 40ah CALB cells that swelled up a lot just sitting on the shelf.
I posted pictures but the only response I got was they must have been over charged/discharged. Not helpful.

I did handle them while building a battery rack but that is all.

Jeff


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## flyinginnet (Apr 19, 2013)

alvin said:


> I had one that was slightly swollen still in the crate. I had never charged or discharged it. The old one was at the same voltage as the others.
> 
> I e-mailed Balqon and they sent a new cell and picked up the old one.
> 
> ...


The cell will self-discharge slowly.


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## onegreenev (May 18, 2012)

flyinginnet said:


> The cell will self-discharge slowly.


Not unless its been damaged. Yes, cells can be defective from the factory.


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## Ziggythewiz (May 16, 2010)

Can also be damaged (overcharged/discharged) in the factory. You shouldn't be the first to charge and discharge the cell, though at least Winston has given instructions to imply that may be the case.


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