Why are all cell phone lithium batteries 3.6V or 3.7V?

Lithium batteries are all 3.6V. So-called 3.7V is actually just a different way of marking. Since the lithium battery is 2.8V when fully discharged and 4.2V when fully charged, so it is correct to mark it as 3.7V.

< p>The voltage of each battery is determined by the characteristics of the electrode plates that make up the battery. The type of electrodes naturally determines the type of voltage, unless you connect several single-cell batteries in series. So as long as it's a lithium battery, it should be 3.6V.