Counterfeit batteries

Some days ago I was given a dual SIM chinese Android phone. The LCD screen was broken and the battery was noticeably swollen, so nothing could be usable. I noticed the battery was a Nokia-like battery, even with the same prints on it, but obviously a counterfeit battery.

 I noticed the cover adhesive was easy to remove, so I peeled it off, and this is what I got:

It is not a surprise. A theoretically 650mAh battery trying to pass as a 890 mAh Nokia battery. Now I understand why the user complaints about the really poor autonomy of the phone: No more than 4 hours in stand-by.