Why is a laptop battery much bigger than a mobile phone with the same battery capacity?

For a long time, the battery technology is one of the biggest bottlenecks of the development of smart phones. In the past 24 years, there is little progress in mobile phone batteries. Mobile phone hardware performance is upgraded, but the battery life is always not synchronously improved.

Because of this, so the mobile power supply market is so hot. But for the purchase of mobile power supply, a lot of people don't even know battery capacity of the unit, even mistaken for 6000 mAh battery is bigger than 5000 mAh notebook.

1, the different types of batteries do not compare mAh

One day, a friend to his camera battery, puts forward an interesting question, my camera battery (very heavy) so much larger than my mobile power supply, how capacity was a little big. The following figure, figure to the right of the mobile power supply is 5200 mAh, on the left side of the big camera battery 5200 mAh.

Theory of volume, the camera on the left the lithium battery at least is on the left side of the two times, the battery is empty inside? Ii is really heavy. Bricks are put inside? It is certainly not. For example, below the laptop batteries, only 4910 mAh, nominal Numbers less than two pieces of mobile phone batteries, but the volume is greater than 10 pieces of mobile phone batteries.

Why the volume and capacity will have so much difference? Careful friends may have noticed that although these batteries are lithium battery, but the voltage is not the same, that is because of voltage, so the size of the pure than mAh digital is not comparable.

Actually, if the battery is also a mobile phone battery, that their size or can be compared with mAh.But if they are not of the same type products, in direct contrast so would be wrong.

2, small science: more accurate than the mAh Wh

Since then the problem comes, mAh is not accurate, so how is the accurate? Don't try so hard, the first to catch up with the high school physics knowledge, the high-energy ahead, be prepared.

Battery capacity of the physical meaning is - how much charge the battery can hold or release, we often use Ah (Ann) or mAh (mAh).According to the current definition of type: I = Q/t, is Q = It, when the unit of electric current I mA (mA), t represents the time, and the unit h (), so we can for mAh battery capacity of the unit.

That is to say, if a battery capacity is 1000 mAh, if he works at the time of the current 100 ma, the theory can use 10 hours of power supply. But we can see from the formula of Q = It, voltage is involved, can only show how much the coulomb of charge inside the battery can accommodate.

MAh cannot accurately describe the battery can do much work, or how many energy, because the working voltage of different types of products are different. So today we are going to mention a new unit, Wh, actually we are not unfamiliar, this word beside the mAh of mobile phone batteries, laptop batteries will also have a the number of units for Wh, just everyone special attention at ordinary times.

Battery to do the work W = UIt = UQ, namely voltage * mAh, the unit of voltage U * current I to W (W), so the battery in the W by Wh, it indicates how much battery can do the work.

For example, the camera battery 5200 mAh battery voltage of 14.4 V, W = UQ = 14.4 V x 6600 mAh = 74.88 Wh, work also can be directly converted to energy, W = U (mAh) = 14.4 V * * Q 5200 ma * 1 h = 14.4 V * 5.2 A * 3600 s = 269568 j (joules).

While charging voltage of 3.7 V treasure or mobile phone, so the above 5200 mAh mobile power theory to do the work for 3.7 * 5200 = 19.24 Wh, 3.7 V * 5.2 A * 3600 = 69264 joule s work.

So whatever unit is Wh or J (joules), camera battery energy are much more than charging treasure, the article mentioned that confusion is solved. It also shows that does not indicate the voltage of the battery, are all play rascal.

Summary:

Wh is proportional to the voltage, current and time. And the index of mAh is just the index of battery charge and discharge. The real battery capacity between different devices (or contain energy) only become comparable to convert to Wh, namely as the voltage of the battery. Finally, please remember this formula: Wh = mAh / 1000 x voltage.

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