How Does a Laptop Battery Work?
By Anmol Taneja
There is little difference in how a laptop battery works and how other device batteries
work. The batteries that power your portable CD players, radios, camcorders etc. are more
or less the same except that a laptop battery is more intelligent if you can call it that.
Just like the rest of the batteries, laptop batteries too come in different shapes and
sizes with the addition to a complex electronic circuit that works in conjunction with the
laptop hardware. This electronic circuit manages the power that flows into the battery
while recharging and the power that flows out of each cell of the battery while
discharging, a feature that is not included in ordinary rechargeable batteries for other
Just like any other battery there are cells inside a laptop battery. Each cell is
typically 1.5 volts and a number of cells are arranged in series and connected in parallel
to deliver optimum power to the laptop or device. A number of cells are connected together
to form a battery. Connecting a number of cells in parallel means to connect all the
negative terminals to each other and positive terminals likewise this increases the power
delivering capacity of the battery but not the voltage. Then a number of these batteries
are connected in series (negative to positive terminals to raise the voltage). This is
done to optimize the voltage level of the battery. These cells are controlled by an
internal electronic circuit in the battery.
The internal electronic regulator is the unique property of a laptop battery. This
circuit regulates the flow of charge into and out of each internal cell in the battery
thus ensuring that each cell has an equal charge at all time in turn ensuring the optimum
use and long life of each cell. It also ensures that the cells do not over charge.
The plates of each cell react with the electrolyte (chemical/acid) in the battery
causing a flow of electrons from the negative to positive terminals and a flow of ions
from the positive to the negative terminal this is the flow of current as we know it. This
flow continues until the electrolyte loses its acidity. When the battery is charged the
ions are restored to their place in the cell and the electrolyte regains its acidity ready
to generate electricity in the cell once again. This process is always the same
irrespective of the type of battery.
The process of charging or discharging of the battery is controlled by hardware built
into your laptop. This hardware ensures the proper functioning of the cells in the battery
and warns you of the tile left before you need to recharge the battery. This indicator is
displayed in the right bottom corner of the screen in most notebooks or laptops.
Though the laptop battery is rechargeable, like everything it does have a life span and
cannot go on serving you for eternity. Proper care will ensure that the battery lasts
longer than it would without the proper care. A battery will normally last between 500-700
charge cycles before it will need to be replaced with a new one. The number of charge
cycles of the battery will depend on the usage of the laptop. The more often you need to
charge your laptop the sooner you will have to replace the battery.
Every laptop model is designed to suit a particular function and so is the battery
designed to match the power requirements of the laptop. The design of the battery depends
on the weight and size of the laptop. A small light-weight laptop will have its design
defeated if the battery weighs more than the laptop itself, so the battery has to be
designed to suit the model of the laptop.
Anmol Taneja is a Gadget enthusiast, and critique. He has written several articles on
various aspects of gadgets and the role they play in our day to day lives. Anmol is
involved with several organizations involved in the evaluation and review of gadgets
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