Types of batteries for laptop computers
Batteries for laptop computers currently tend to be lithium ion batteries,
with more recent laptop computers using the new lithium ion polymer batteries.
These two technologies have largely replaced the older nickel metal-hydride
laptop computer batteries.
Lithium Ion (Li-Ion) batteries for laptop computers
use Lithium Oxide and a Carbon compound (usually Graphite) as the electrodes.
The electrodes are separated by a microporous film which contains an organic
solvent acting as the electrolyte. Compared to NiCd and NiMH batteries
for laptop computers, Li-Ion batteries are smaller and lighter. Unlike
NiCd and NiMH batteries, Li-Ion batteries for laptop computers do not
suffer from the memory effect. Li-Ion battery cells also have much lower
levels of self discharging. Li-Ion batteries for laptop computers are
however more expensive. Li-Ion batteries will be good for around 400 recharges.
Lithium Ion Polymer (LiPo) batteries for laptop computers
have similar characteristics to standard Lithium Ion batteries but use
a thin polymer as the electrolyte. The dry polymer design allows the fabrication
of this type of laptop battery to be cheaper and smaller. The polymer
electrolyte is also flexible and can moulded to suit the desired application.
Like standard Li-Ion, Li-Ion polymer batteries for laptop computers can
be recharged about 400 times.
Nickel Metal Hydride (NiMH) batteries for laptop computers
use Nickel and other rare earth metals as the electrodes and Potassium
Hydroxide as the electrolyte. NiMH batteries for laptop computers are
constructed from non-toxic metals making it more environmentally friendly
than other battery designs. NiMH batteries are similar to NiCd batteries
for laptop computers in that they suffer from the memory effect, however
they are much lighter and have a higher capacity, thus a higher power
to weight ratio. The NiMH battery has a much shorter life span than Li-Ion
batteries for laptop computers, it can only sustain around 200 recharges.