Disassembly of some UltraFire batteries



I wanted to check the construction of some more cheap batteries, this time it is 3 UltraFire batteries.



UltraFire 6000mAh



The specified capacity is not possible, but what does the battery contain?



It looks real enough, this is the way a LiIon battery is made.



Lets look a bit closer on the top of the battery.



The plastic around the top is to isolate it from the can of the battery.



The metal foil below the button top is the pressure vent, but it does not contain any mechanishm to break the connection when the battery vents.
The button top is part of the top, not added later, this makes me suspect that this cell is special made for consumer useage and it is made very cheap without PTC and CID.



But on the battery it says it has protection and that the circuit board (PCB) will last for 10 years (Not the cell).



This type of protection is usual placed at the bottom of the cell, but there is no protection present here and as we saw above the top is also without protection.



UltraFire 3000mAh B



During my battery test this cell failed completely, why?



It looks like this cell is better filled than the above cell.



It looks like there is some more build into the top of this cell.



On this cell the button top is added, i.e. it is probably a regular LiIon cell. The washer around the button top hides the real vent holes, but I expect that it will easily blow away if the cell vents.



The pressure vent looks more complex.




Here are the parts from the top, from left: Top with extra button top, PTC, CID, washer.
There is an X in the CID, this is where it breaks if the cell vents and when the X opens it will break the connection.



Between the two surfaces of the CID is a plastic washer (The white part).



Here it say the battery has over current and short circuit protection, that is partely correct when it has a PTC



And here it says it has a protection circuit, lets check the bottom.



No trace of a protection circuit, but it looks like there is a metal plate on the bottom. Using a knife it can be removed.



Looks like there is some corrosion on the bottom and 4 marks in a square. These marks shows that the cell is from a battery pack and with the corresion and a not working cell, it is probably from a used battery pack.



UltraFire 3000mAh C



I decided to do one more of the 3000mAh cells, it is from the same order as the one above.



This cell looks like the above 3000mAh, but not completely, the washer has a different color and the wire from the cell roll also has a different color. I would expect this to be a completely different cell.



The cell does not look new.



It is again with a added button top.



Here is a PTC and probably also a CID, but with another construction than the above cell.



There is also the extra metal plate on the bottom, hiding the marks from usage in a battery pack.
The battery do also looks corroded.



Conclusion

Both types of UltraFires are bad cells. The 6000mAh is made to be a cheap/fake cell for consumer usage with minimal protection, the 3000mAh cell is made from old battery pack cells and when you buy multiple cell they may be different, even if they have the same wrapper.



Notes

I bought the 3000mAh cells as a 4 pack from ebay dealer ezb4u
I bought the 6000mAh cells as a 4 pack from ebay dealer yuancong2016

Disassembly of cheap 18650 battery
How is a protected LiIon battery constructed
Is my battery protected

Review of UltraFire BRC18650 3000mAh (Red-silver) 2015
UltraFire SJ18650 6000mAh (Black) 2015,