Hi, I have an older Nokia cell phone and the battery has 4 terminals, the outer two are the actual + and _ and the inner one is split in two parts (almost touching each other, no plastic insulation). The cell phone has 4 contacts to the battery.
I have another not-so-old cell phone (Nokia 6030) and I notice the battery has 3 terminals, the outer two are + and - according to the label on the battery, but then there is this middle contact. The phone has 3 clamps (contacts).
So, why this one or two additional contacts on cell phone batteries?