Orph, I do know how to cook as well. I'm a multi-diverse individual.
Myrk. No, you can have the battery in while the laptop is on and charging. With some laptops that's the only way they can charge (like mine, now, for some reason).
Lithium Ions, just for some fun facts, has a controller chip in them which monitors the battery (which, most often times turns out to be like ten AA Panasonic batteries, just not Alkaline) That chip will deactivate the battery if it senses something wrong with the laptop that could cause some serious damage either way (or at least it should).
I had this issue with my dad's laptop, since him and I both have ThinkPad 600s, where his laptop would "turn off" any battery put into it, he's killed two of my batteries.
ANYWAY, the most important thing you can do is to try to "fully discharge" (until the laptop can't be powered anymore) and then charge back up. And, when you turn the laptop off for days at a time make sure the battery has a decent charge. This is only really important when you leave it alone for months or years, but it'll die if left greatly depleted for a long period of time.
Also, don't completely drain the batteries (you can't through the laptop, but don't do it through a fan motor or something as such). This will deplete the battery and it will not work ever again.
I knew someone who said they would deplete it all the way and I called them a moron. They yelled, then tried it again and bitched that the battery stopped working.
Try looking around some laptop manufacturer sites for some specific information on the battery. :smile:
I'm sure Tracer will waltz over at some point and give you the chemical composition of a Li-On battery ... or just give more information on how it works exactly, thus allowing you to understand the why. But, as far as I've experience, read, and conversed, this should answer your questions.
I hope this helps.
Blame it on Microsoft, God does.