When we say a phone is charging, what actually is filling the battery? is it electric charge? q

Question

anonymous · Answer

Charge is accumulating on one electrode of the battery.  The battery's electric field is also increasing as its potential difference (voltage).  The primary driver though is the accumulation of a charge on one electrode of the batter--or more specifically a charge difference between the electrodes of the battery.

isaiah.feynman · Answer

Okay. So the percentage you see on your screen is how much charge has accumulated on the battery electrodes?

anonymous · Answer

No.  Every battery has a maximum storage capacity.  The percentage you see is the percent of the current amount of charge/voltage compared to the total charge/voltage possible.

isaiah.feynman · Answer

Make sense now. My battery has a maximum of 3.7 V. Thanks.