# Why does this mobile phone battery have 4 terminals? [duplicate]

Why do some mobile phone batteries have 4 terminals? I want to use a mobile phone battery for my project.

• i think one is for temperature sensing – BASIL VARGHESE Feb 27 '14 at 4:35
• The circle in your image covers up the labels for the terminals. Assuming that the missing label is -, the other two could be for Temperature, Data, or something else. – jpaugh Dec 3 '16 at 18:49