Melody, laptop batteries are a bit complicated.

This laptop had one for many years - they are automatically charged through the mains power connection which means that if you unplug the laptop and take it somewhere else it will get power from the battery.

But, after a while, laptop batteries die - this has happened to this one (it stopped charging) so I pulled the battery out which means that if I unplug the laptop from the mains power it will stop.

One of my NY missions is to buy a new battery (they are fairly cheap, often less than $100) and put it in, which is an easy job - that means that if I use this laptop with mains power (which I usually do) the battery will stay powered and (flexibility) if I unplug it and take it somewhere else it will work through battery power.