Battery

A battery is a hardware component that supplies power to a device, enabling that device to work without a power cord. Batteries are often capable of powering a laptop computer for several hours depending on how much power it requires. Today, many high-end devices such as computer laptops and cell phones use rechargeable batteries that allow a user to recharge the battery once depleted of energy. In the picture to the right, is an example of what a laptop battery may look like when removed from the laptop.
Types of computer batteries
There are three types of computer batteries found on a computer. First, is the backup battery, which is commonly referred to as the CMOS battery. This battery is what holds your computer's settings, such as the time and date. This allows the computer to remember basic computer settings without having to entering those settings each time the computer starts.
Next, the bridge battery is only found in portable computers as a temporary backup for the main battery. This allows the user to remove the main battery and replace it with a good battery without having to turn off the computer.
Finally, the main battery as explained in the first paragraph is also only used with portable computers as an alternate source of energy for when the computer is not connected to a standard wall outlet.
Battery technologies
There are several different types of battery technologies that allow a battery to work. Below is a listing of some of the major types you're most likely to encounter.

• LI-ION (Lithium Ion)
• Li-polymer (Lithium Polymer)
• NICAD (Nickel-Cadmium)
• NIMH (Nickel-Metal Hydride)