In the same battery capacity, why is the laptop battery much larger than the phone?

The physical meaning of battery capacity means – how much charge the battery can hold or release, we usually use Ah (Ah) or mAh (mAh). According to the definition of current: I=Q/t, we can know that Q=It, the unit of current I is mA (milliampere), and t represents time, the unit is h (hour), so our battery capacity unit is mAh.

That is to say, if a battery capacity indicates 1000 mAh, if it is 100 mA when operating, it can theoretically be used for 10 hours. However, from the formula we can see that Q=It does not involve voltage, only the number of coulombs that can be accommodated inside the battery.

mAh does not accurately describe how much work the battery can do, or how much energy it has, because the operating voltages of different types of products are different. So today we have to mention a new unit – Wh, in fact, we are no stranger to this word, there will be a number in Wh next to the mobile phone battery, laptop battery mAh, but everyone usually causes special note.

The work that the battery can do is W=UIt=UQ, that is, when the voltage is *mA, the unit of voltage U*current I is W (Watt), so W in the battery is represented by Wh, which indicates how much work the battery can do. .

Notebook Adapter for Microsoft Surface Pro 10.6inch

For example, the voltage of the 5200mAh battery of the camera battery is 14.4V, W=UQ=14.4V×6600mAh=74.88Wh, and the power can be directly converted into energy, W=U*Q (unit mAh)=14.4V*5200mA* 1h=14.4V*5.2A*3600s=269568J (Joules).

The voltage of the general charging treasure or mobile phone is 3.7V, so the theoretical 5500mAh mobile power supply can theoretically do 3.7*5200=19.24Wh, 3.7v×5.2A×3600s=69264 joules.

Clevo D900CBAT-12 6600mah 14.4V
Wh is the amount proportional to voltage, current, and time. And mAh is only an indicator of battery charge and discharge. The actual battery capacity (or the energy contained) between different devices is comparable to Wh, which means that the battery voltage must be known. Finally, please remember this formula: Wh = mAh / 1000 × voltage.