Question – Can you mount LiFePo4 batteries on the side or inverted?
Article By DD @ Solar Power Edge
Hi folks, this is to start a new series of posts (and videos) about Lithium Iron Phosphate batteries. It’s my favorite battery chemistry of all time, so far. I first started researching and using LiFePo4 batteries before about 2012. At that time there was a lot of resistance to their adoption, mostly due to bad information and rumours of volatility (LiFePo4 is one of the safest and least volatile Lithium-Ion chemistries available).
I do not claim to be off the electrical grid, but do maintain a system fully capable of running my house off the electrical grid indefinitely.
Some of the information posted may not match conventional wisdom and established dogmas. It is up to the end user to do his own research and hands on testing. Relying on a so called popular figures or YT channels to educate you without due diligence and critical thinking, is a recipe for disaster.
The first article is going to address a common question about LiFePo4 prismatic cells.
Does it matter which orientation LiFePo4 prismatic cells are stored or used in?
Can I mount them upside down, for example?
Absolutely not recommended.
LiFePo4 prismatics – basic internal structure
First of all, there are many layers inside the cell case (to build up capacity) and they are pressed together and attached at the top to the terminals at the factory.
So it’s best to keep them in the orientation they were built in – right side up. It’s important not to risk straining or placing any undue forces on junctions where all the layers connect to the terminals of the cells at the top.
Limited electrolyte in the cells
And here is another problem. There is a limited amount of electrolyte inside each battery cell case. Little, if any, would be free. But if there is any free electrolyte, naturally it is more dense than the air inside the cell case, and would sit at the lowest part of the interior of the cell case. And it needs to be available to whichever layer needs it, in other words, able to contact any of the layers that might need it. Put the cell on the flat side, only the lower layers in the stack can potentially contact the electrolyte.
The electrolyte is pretty expensive, and the manufacturer doesn’t want to use any more than necessary to make the battery cell functional. Otherwise, perhaps there would be more.
If you lay the batteries on their LONG flat side, it is absolutely possible for some higher layers inside the case to become Electrolyte Starved over time. It’s simply not worth the risk. We cannot monitor inside of the cell casing to determine what is happening.
Anyone who claims otherwise is welcome to take a risk, but with a $10,000+ battery bank – I don’t gamble.
Electrolyte starvation could in fact potentially happen, and it would affect the capacity and performance of the cells.
The correct orientations are:
RIGHT SIDE UP (always use this if you can)
LAYING ON THE NARROW side 90 degrees to the orientation of the internal layered structure, ONLY IF YOU ABSOLUTELY HAVE NO OTHER OPTION.
As tempting as it is, one should not store or install the cell laying on the widest side, as this places the internal layers in a vertical stack, and so if they need to wick up electrolyte only the layers on the bottom would have access to do so.
Keep in mind not all LiFePo4 prismatics may have the same internal structure, confirmation from the manufacturer might be necessary.
Potential venting of toxic electrolyte
Furthermore, the safety vents on the batteries should be in a vertical orientation at all times. LFP cells are very safe when properly handled and operated, but those vents are there for extreme cases and and any pressure relief needed. You don’t want to have anything interfering with their operation. Also if the cells vent sideways there is a risk of the electrolyte spraying out – since it is toxic, this is to be avoided at all costs.
I hope this article helps someone. If you’d like to see any particular topic addressed by video or posts, please email me or reply to the article. Any feedback is appreciated. Thanks for reading!
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