Types of Laptop Batteries
All laptops use batteries, but not all batteries are the same. It pays to know about the differences between lithium-ion, NiCad, and NiMH batteries, even before you buy a laptop.
Nickel-cadmium (NiCad): Of all the rechargeable types of consumer-electronics batteries, the NiCad is the oldest. It's frowned on now, mostly because it suffered terribly from The Dreaded Memory Effect. Even so, NiCads offer great performance, and they dominated the portable power storage market until the better battery technologies came along.
Nickel-metal hydride (NiMH): This type of battery was one of the first successful alternatives to the NiCad. A NiMH battery is longer lasting than a NiCad, but, sadly, it suffers from The Dreaded Memory Effect just as badly as the NiCad.
Lithium-ion: This is the type of battery you want to have in your laptop. This type is lightweight and performs better than the other types of batteries. Unlike NiCad or NiMH batteries, lithium-ion batteries don't have The Dreaded Memory Effect, where you have to fully discharge the battery, all the way down to empty, before you even consider recharging the thing. There’s also usually a rapid-charging option with lithium-ion batteries, which is good when you're in a time crunch. Finally, this type of battery is more environmentally friendly than the other types.
Of all these batteries, odds are very good that your laptop has the lithium-ion type. That's pretty much state of the art.
If you haven't yet purchased a laptop, ensure that you get one that has a lithium-ion battery.
Using unapproved batteries in your laptop may lead to bad things, such as, oh, the laptop exploding.