What Are The Different
Types of Rechargeable Battery Chemistries?
Batteries in portable consumer devices
(laptops and notebooks, camcorders, cellular phones, etc.) are principally
made using either Nickel Cadmium (NiCad), Nickel Metal Hydride (NiMH)
or Lithium Ion (Li-Ion) technologies. Each type of rechargeable battery
technology has its own unique characteristics:
The main difference between
the two is the fact that NiMH batteries (the newer of the two technologies)
offer higher energy densities than NiCads. In other words, pound for
pound, NiMH delivers approximately twice the capacity of its NiCad
counterpart. What this translates into is increased run-time from
the battery with no additional bulk to weigh down your portable device.
NiMH also offers another major advantage: NiCad batteries tend to
suffer from what is called the "memory effect".
NiMH batteries are less prone to develop this dreaded affliction and
thus require less maintenance and care. NiMH batteries are also more
environmentally friendly than their NiCad counterparts since they
do not contain heavy metals (which present serious landfill problems).
Li-Ion has quickly become the
emerging standard for portable power in consumer devices. Li-Ion batteries
produce the same energy as NiMH batteries but weigh approximately
35% less. This is crucial in applications such as camcorders or notebook
computers where the battery makes up a significant portion of the
device's weight. Another reason Li-Ion batteries have become so popular
is that they do not suffer from the memory
effect AT ALL. They are also environmentally friendly because
they don't contain toxic materials such as Cadmium or Mercury.
This is a newer type of Li-Ion
battery. It uses a solid polymer electrolyte that looks like a plastic
film. It contains a gelled electrolyte which is less susceptible to
leaking and uses a bag type enclosure rather than a rigid metal case.
This leads to a lighter and thinner battery and it is considered safer
because the gelled electrolyte is less likely to leak. It is also
more resistant to overcharge.