LIFEPO4 cell opened-up, with pictorial

[recumbent]

This was a cell from a group if 15 i bought from Ebike.ca over a year ago that died, so i decided to rip it open, Which is the custom of Endless Sphere 8)

Before and after pictures:

 

[recumbent]

I started to pull the insides out but the bundle stuck fast and started to puff smoke, so decided to let it cool & rest outside before i cut the side and unroll the bundle.

 

[Ypedal]

Cool !

Thanks ! I"ve been meaning to do the same thing, i've got 3 of those exact cells.. dead.. :|

 

[dogman dan]

So that's a long foil packet, folded up many times in there? I had assumed for a long time that you'd see a paralell group of foil pop tarts in there. I love to see the innards of this stuff! Looking again, I guess there are seveal packets in there after all? It looks like I see a bunch of tabs that connect to the terminals?

 

[recumbent]

I guess there are seveal packets in there after all? It looks like I see a bunch of tabs that connect to the terminals?

Two bundles, and the copper and aluminum leaves are connections that go into the folds of the rolled-up bundle.

There was a strong iso-alcohol smell (as Ypedal mentioned different times) covering the bundles inside so i had to leave it outside to discharge and evaporate the mysterious smelly stuff.

I'll pull apart or unroll the bundles and expose the secret that makes lithium cells work, and in this case not work very long.

I live in a condo so I have to wait till the folks here are awake before the side grinder goes into action again.

 

[recumbent]

Here are the rolled-up bundles opened.

They are layers of what seems like plastic, then a thin (.001") copper leaf covered with black powder on bothsides then the palstic, over and over about 30 or 50 times. The other bunmdle looks to be made of aluminum looking substance, but have'nt got there yet.
Here are some pictures for ya.

 

[monster]

how many electrode pairs are in the cell?

 

[recumbent]

how many electrode pairs are in the cell?

About 50 pairs.

Each bundle is made up of one layer aluminum colored metal coated with black paint (lithium?) then plastic, then copper, also coated with this black paint substance. rolled 25 times approx.

The smelly alcohol is either a coating or a byproduct of the chemical reaction, because it does'nt appear to be flamable, nor is the canister filled with it either.

Edit: corrected the layering sequence.

 

[Alex Lar]

No any folded $100 dollars bills inside ?? :lol:

 

[dnmun]

so there was no slushy paste inside when you opened it? the aroma is an organic electrolyte used to transport the lithium ions. the black paint could be a carbon coating on which the lithium is plated, with the lithium iron phosphate coating the other side, with the separator in between, all bathed in electroyte. that disappeared when your pack shorted out when you cut it open, and just the baked residue remains. it could have leaked electrolyte out already and that coulda been why it was deAD.

 

[Deepkimchi]

Could you take a close picture of the terminal bottoms with the foil layed back. Wanted to see what holds them in place.

DK

 

[monster]

whats the capacity of the cell and the demensions of the electrodes?

 

[recumbent]

so there was no slushy paste inside when you opened it? the aroma is an organic electrolyte used to transport the lithium ions. the black paint could be a carbon coating on which the lithium is plated, with the separator in between, all bathed in electroyte. that disappeared when your pack shorted out when you cut it open it could have leaked electrolyte out already and that coulda been why it was deAD.

a) no slushi paste for sure, just few drops of clear liquid.
b) I only had the pack for a year, and never shorted it out, but would not hold a charge for long.
c) I made a misprint up top, the cell was not dead, still held a charge, and would smoke when i stuck the plyers inside to pull the bundles out, pinched the plates together a PUFF-a-smoke rose up, it was fun, almost mad scientist like.

I'll take closer and clearer shots for "Deepkimchi" tomorrow set to macro on my camera settings.

Capacity of the cell was 12 amp/hrs

 

[paultrafalgar]

Please assume that the fumes from those cells are toxic and that the cells are an ongoing fire hazard! (Don't go to sleep in any building in which these cells reside)! Lithium is the most reactive of elements. I have no idea in what exact form it exists in those cells, but assume the worst. When you've finished playing with those cells, I suggest that you dispose of them safely. Without knowing what your dealing with I can't say how that would be, but the words OUTSIDE UNDER-WATER AND BURN might be relevant. :wink:

 

[dogman dan]

Heh Heh, couldn't be any worse than the balls of mercury we played with as kids. :lol: But I wouldn't leave it laying around on a flamable place, like the coffee table either.

 

[monster]

have you got anymore of those dead cells? i'll buy them off you.

 

[recumbent]

Here are some more pictures

 

[recumbent]

The layers of copper, then silver covered in plastic insulator does not show-up in the pictures. But the plastic is stuck onto the silver layer and looks black because the painted lithium stuck to the plastic is seethru, like wet linen.

Oh, the battery was stored outside only for safety of course, and it still reeked of that solvent smell after three days.

 

[recumbent]

have you got anymore of those dead cells? i'll buy them off you.

Yeah, 15 cells left but none are dead, nor was the one i opened-up. The pack just started to hold less and less amp hrs of energy because one cell was pulling down the LVC too early. Then i changed the cell and upgraded the BMS and now the batteries only hold half of the amp hours and want to sell the pack to someone who can fix it, maybe for $200 with the charger?

I bought 16 new PSI cells from Andy, and he soldered a Gary/Fetcher BMS board also, can't wait to post pictures of finished battery box.

Here's a picture of the pack i took the cell from originally.