My original Nokia battery swelled up quite a bit and became unusable. The replacement generic didn't and lasted twice as long and is still going. "Approved" is just a way for manufacturers to make more money.
This must have come from the East of London (UK) near Bow where there are of course locks, locally known as Bow Locks!
In over twenty years in the cellular trade I have never seen or heard of a battery so much as make more than a little gas! Hence the 'pregnant' look of some batteries - Oddly enough, especially Samsung!
In many cases, the generic comes from the same factory as the original in any case!!