If you are asking should you remove it, then I would say probably not as it wont make that much difference. Laptops use a smart charging circuit which cuts off the charge current to the battery when it has been charged up so leaving it connected after this point is not really doing anything to it. What it is doing however is protecting your work in the event that the AC Mains failed as the battery would take over rather than the unit just switching off.
What tends to be the bigger issue for battery is heat. It should be avoided storing them in hot places as this can shorten the battery life.