Exploration: Opening the can on LiFePO4 cells Part 1

Exploration.

We posted the below picture of some cells on Facebook to see if anyone could guess what had happened to them.

And several people who commented on pregnant / middle aged cells  were on the money.

Both cells were brand new - one an EVE LF280K V3 cell, and the other was one of the new REPT CB84 345AH cells, Both premium cells direct from the manufacturer.

The two cells pictured were forcefully discharged to 0v..

I use the term forcefully, as it was literally that, the voltage rebound after reaching 0V went on for hours, to the point in which the load current was reduced to 0.5A and it just continued until I was sick of monitoring it.

The cells sat unloaded overnight and by morning both had rebounded to around 2V, but dead and gone in reality, Incredible.

The reason for doing this was simple, it was preparation for the real task, exploration of the internal construction of different cells we use, to gain a better understanding of the mechanical and electrical limits, how cell manufacturers are optimizing their production tech to accumulate more capacity in the same form, aswell as debunking whether or not these cells can be used in any orientation.

Most LFP cell manufacturers when questioned about operating cells in any position other than upright, will claim that this is not optimal, and the reason claimed is electrolyte distribution.

I will go through several post examining what I have found, this kind of information is not publicly available from cell manufacturers, they are very tight lipped and prefer to provide fairly bland explanations.

For most of you, none of this matters, but I know there are some people out there that are likely intrigued.

If anything can be taken from these this posts, its to take care of your battery and it will take care of what you need it to - If it is flat, make it a priority to charge it, If the cells fall below 1.5v - 1.8v at any point in there lifespan, Discard it, it is not worth the potential safety issue that could arise.