Disassembly of UltraFire 9900mAh 18650 battery

Disassembly of UltraFire 9900mAh 18650 battery

I recently reviewed this battery, it did not live up to its specifications, capacity was significantly below rated capacity, but how do manufacturers make this type of very cheap battery? One solution I have seen is to rewrap old batteries, but this cell was too consistent in capacity for that.

The final look at the cell. The PCB mentioned on the cell was nowhere to be found.

And it is open, without any heat, smoke or flames (If the cutter short the battery it will get hot).

The roll do not fill the battery, that is some of the explanation for the low capacity. I included another cell for comparison.

This do also explain the low weight of the cell.

Wrapper, can, roll, and top.

Lets take a closer look at the top, below the white washer is the vent holes. The button top is not welded on, it is part of the top, this means this battery is produced with button top.

The plus pole is isolated from the can with a soft plastic spacer.

Remaining part of can removed.

Top removed from plastic spacer.

The underside of the plus pole has a metal foil that works as an over pressure vent, i.e. it is supposed to break if the pressure in the cell gets to high.

I did have some problems breaking it with a screwdriver and needed pliers to fold it out. I wonder what will break first on high pressure, the can or the seal? Below the seal the vents and the backside of the button top can be seen.

There is no trace of a PTC (Over temperature protection and indirectly over current protection), it is supposed to be placed between the pressure vent foil and the external positive connection.

lets take a closer look at the battery roll.

I rolled it up and placed it down for photos and then it started smoking. The paper (My photo background) sheet behind the copper foil was brown/black due to heat.

Here is one more look at the layers:

Positive electrode (Cathode) is Lithium Cobalt Dioxide coating on aluminium

Negative electrode (Anode) is Lithium Carbon (graphite) on copper

The two layers of separator is a plastic foil with microscopic holes in it, when in the battery there was also some organic solvent.

The length of the anode was around 32 to 33cm.


This cell is manufacturer to be a cheap low capacity cell, to make it as cheap as possible the safety is not very good.

I have a suspicion that they use the old Lithium Cobalt construction (This is the most dangerous LiIon type).


Review of UltraFire SZ18650 9900mAh (Yellow)

Disassembly of cheap 18650 battery

Disassembly of some UltraFire batteries

Is my battery protected

How is a protected LiIon battery constructed

Grade A

My God! these are criminals…

Thanks for this
How dangerous is it to do this with the smoke?
How one disposes of the remains?
That is some exposed chemicals there.

I do not know dangerous it is, but I stay out of the fumes and in this case smoke from the battery when disassembling it (That is one of the reasons I do it outdoor).
We have a small container for used batteries, this makes it easy to get rid of it.

Just read this latest “UltraFake” review. You just confirmed a theory I had formulated once with regards to these batteries:

For UltraFake batteries, the higher the battery rating, the lower the true capacity and performance. :–5

Quite long ago, I once bought a couple of cheap unprotected 2000mAh blue UltraFire 18650 units, and they performed more or less acceptably.
Man, if I were you, I’d be waay more expeditiously gross with regards to expressing what I think off these PoS batteries. LOL.


Thanks for the nice pictures - i will point some newbees to this thread :wink:

Very interesting…I really wonder why there is so little capacity.
The hole in the middle is <50, but even when it would be full the capacity would have been super small….how is the lengths of the innards compared to a good cell, on the picture next to the tube it looks like if it is considerably smaller than the 60mm tube…
Is it the chemistry which makes these cells so low capacity or the poor build?

The reason I guess on a Cobalt chemistry is the low capacity, it could also be manganese (It is cheaper than cobalt) . The different layers may be thicker than more modern cells.
My guess is that the cell is made on old LiIon factories that cannot make modern cells, but instead of closing them, they are making these cells.

Even that seems total nonsense.
My theory is that the Chinese government, in an undercovered industrial operation, is rewrapping all kind of batteries from wasted and recycled appliances on filthy warehouses which, apparently, manufacture the cells. They are really amassing all that (supposedly spent on the cells) lithium for manufacturing nuclear weapons on secret facilities, and making money with these UltraFake rip-offs and scams. :smiley:
Time to call on James Bond. :wink: LOL!!!


*Contrary to rumors, there is no definitive ‘smoking gun’ proof of discarded PU-238 cells being rewrapped and sold as CrudFire batteries by vendors on AE…yet!

That looks like one thick “pressure vent”. Everything else is bad enough but then they can’t even give a real safety vent.

OMG!! I’d say that this sort of construction is criminally negligent.

Thanks HKJ. Ever so informative.

Just opened dead Panasonic 2250mAh. Lenght of copper electrode is 66cm…

It certainly is. But the chinese government couldn’t care less.

I thought we where going to see a mouse running on a wheel inside! that would also explain the capacity :smiley:

And people wonder why transporting these things on an airliner is getting strict. If Samsung, LG, Sony, & Panasonic/Sanyo were the only cells available, and no chinese junk cells, there probably wouldn’t be restrictions.

^ Exactly. There is always someone who must who ruin things.

How these dangerous toxic bombs are even allowed to enter North America for sale is beyond me…