I had two notebooks, but the batteries almost come to an end,soIhad to buy a new one,It's hard tosearchfor therelevant knowledge.So I go to read some books about laptop battery andinquiry some engineers.And belows are whatI have learned, hope it help the ones who also want to learn some laptop battery knowledge or want to buy a new laptop battery as me.
First, the composition of laptop battery:
A laptop batteryincludes battery cells, control loop, charge and discharge circuit and other components (as shown), while the quality of the battery cellis the biggest overall impact to the laptop battery. Battery consists of battery cells,People said 4Cell, 6Cell refers to the number of battery cellswithin the battery.
Most current laptop batteries use battery cells which are based on industry standard. Thecellsare generally divided into two kinds: cylindrical and square. Cylindricalcells are a little bigger than AA battery (see first picture above), while the size of the the squarecells is roughly equivalent to the size of a Zippo lighter (shown below).
How to estimate the number of the laptop battery cells by its parameter?
The Capacity of current mainstream batteries: cylindricalis 3.6 ~ 3.7V/2000 ~ 2200mAh, square is 3.6 ~ 3.7V/1800 ~ 2000mAh, so number of cells can be inferred according to the above figures, such as the IBM ThinkPad T40/T41 standard battery: 10.8V/4400mAh, then ithas six cells, using two-parallel and three-series connection, that is:every threecells connect in seriesresult in3 X 3.6V = 10.8V, and the twogroup ofthree series connected cellsconnect inparallel.Afterthat the capacity of the laptop batteryis 2 x 2200mAh = 4400mAh.
And thehigher capacitybattery of IBM ThinkPad T40/T41 is 10.8/6600mAh, then the cells' number is 9, with threeseries and three parallel,that is:every threecells connect inseriesget 3 X 3.6V = 10.8V, then thethree groupsconnect inparallelresult in3 x 2200mAh = 6600mAh.
Generally speaking, the difference of the higher capacity batteryandthe standard battery is that the higher capacity battery increase the number of parallel batteries to increase capacity.
In general, the principle of notebook battery is almost the same as digital camera rechargeable batteries. The larger capacity of a single cell, the battery last longer.
