Usually the voltage is indicated on the battery case as 3.7 V. In actual measurement (MF47 multimeter, several measurements were taken by several people to take the average) it is 4.2 V (when fully charged). Lithium battery bulge, its voltage at that time was 4.8V (the internal circuit board of the battery was removed during measurement).
It is normal that the cell phone battery voltage is between 3.7 -4.2v.
Cell phone batteries are energy storage tools that power cell phones. Mobile phone batteries generally use lithium batteries and nickel metal hydride batteries. Cell phone batteries generally consist of three parts: the battery core, the protection circuit, and the case. “mAh” is the unit of battery capacity and the Chinese name ismilliampere-hour.
Mobile phone batteries are composed of three parts: the battery core, the protection circuit and the case. Currently, mobile phone batteries are all lithium-ion batteries (often called lithium batteries in non-standard situations), and the cathode material is lithium cobalt oxide. The standard discharge voltage is 3.7 V, the charging cut-off voltage is 4.2 V, and the discharge cut-off voltage is 2.75 V. The unit of power is Wh (watt hour). Since the standard discharge voltage of cell phone batteries is uniformly 3.7 V, mAh (milliamp hour) can also be used instead. The conversion relationship between these two types of units on cell phone batteries is: Watt-hour = Ampere-hour × 3.7.