Yesterday I decided to open up this Mottcell 39 Ah LiFePO4 cell that reads almost 0V and has had problems in the past (the postive terminal was a bit swollen and disformed, and I heard some strange noises from the inside, so I put it away for good)
Like all the other cells in my Battery Energy Storage System, it comes from a Prius PHEV kit that can be found at Enginer.us
This cell is made of 3 13Ah cylindrical cells hooked up in parallel, let's see how:
Removing terminals
0.08V => not a lot :-(
There is a top glued to the rest of the cell container
Scew driver to open
Looking good ...
Some white stuff... insultion foam or something like this maybe
Top off
Terminal bars lifted, showing the insulation plate
Plate removed, now we can see the top cylindrical cell, taken all the width
Bad news, the white mastic is blocking everthing, and I can not lift the cells out of the shell
Cutting and cracking the plastic shell with saw & pliers
One side is gone giving me easier access and showing the way the cylindrical cells are connected to each other (reminds me my RC models battery, their cells were connected like this)
That's what I thought, once diconnected the cells show different individual voltages
It looks like the last one, at the bottom shows more damage than the other with this brown smelly electrolyte liquid/paste
The top cell: I thought it was damaged at first, but removing this cartborad cover I could discover it is not so much; The positive terminal and negative outer shell are insulated from each other by a one millimeter plastic ring (at the junstion of the cynlinder and the the top plate)
The bootom cell is really messy ...
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