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.