Does a laptop computer have a backup battery for the clock?

I know that desktop computers have a little battery that keeps the clock going for years. Since a laptop has a large battery that is constantly charging does it also have a backup battery? I would think is needs something to keep the clock going when the large battery is removed.

CR2032 battery is in the laptop as well as desktop machines. This battery holds the time and information stored in the BIOS while the computer is shut down. These batteries usually last approx. 5 years (generally).

Yes there is a battery, the same as desktops there is a CMOS battery on the mainboard that serves the same purpose.

Also known as a RTC/NVRAM or CMOS RAM, CMOS is short for Complementary Metal-Oxide Semiconductor. In the Mac the equivalent is PRAM

Normally the battery is of the same coin cell type as a desktop PC, often smaller and not easily accessable. On older laptops to get at this battery you often have to take the casing apart and remove the board, though some brands and models are much easier than others. The newer Laptops the battery is often just under the top panel of the casing by the display but still not that easy to get at.

In addition to the other answer the CMOS Battery is located on the motherboard, and in most cases it is not easy to access...

You would have to open the laptop in order to change it.

The CMOS battery is the same as in desktop computers.