Harm to battery if laptop left plugged in?

sadbluescreener

TS Booster
Hi all, I am curious about any possible damage that might happen to a laptop battery if after the battery has been completely charged, it is left plugged in.

I've been told that I should remove the battery if I'm going to leave it plugged in because it may overheat and become damaged. Could someone shed some light on this for me please?