I have a Kindle Keyboard with no battery. A replacement is not for sale where I live. But I can find different kinds of 3.7V Li-ion batteries with 4 pins.
This is an original battery:
And this in an example of a battery I can buy:
+ and - are straightforward, but I don't know if the other pins serve the same function or have the same position in all batteries.
I want to know if anybody has any information on this matter.