Laptop batteries, will slowly stop holding their charge. Eventually they'll need to be replaced, though it often takes years for them to reach this state. If your battery has reached this level, you can check and see what kind of battery you need depending on your laptop. One word of caution: It's always recommended to replace your battery with one from the company that made your laptop.
One of the easiest ways to determine what kind of battery you have is to turn off and unplug your laptop and then remove the battery to look at it. Most batteries will have a set of printed information on them, including the battery type, its model number, a part number, its voltage and a charging current. Presently, the lithium-ion battery -- usually listed as Li-ion -- is the most common type, though older laptops may have a nickel-cadmium or nickel-metal hydride battery
Examples of HP and Compaq part numbers:
Not all batteries are easy to remove or even clearly marked, so there are some third-party utilities that can be used to determine what type of battery should be put into a laptop. HP-Battery and Notebook Hardware Control (links in Resources) are free pieces of software that provide a lot of detailed information on a computer's battery, covering everything needed when searching for a replacement. HP-Battery (link in Resources) gives even more information on your specific battery, such as its chemistry, and is free for the first 30 days.
If the computer having battery problems is new, always check to see if its battery has been recalled. Computer makers like Lenovo typically have websites setup for battery information, including installations and recalls. Many have downloadable software that can check whether your battery has been recalled, removing the need to take the battery out of the laptop to check. If your battery is on the recall list, contact the laptop maker for a typically free replacement as soon as possible. Avoid using a recalled battery unless it's absolutely necessary.