More than meets the eye.
Laptop batteries are the most important battery in the field of rechargeable batteries, but they are also the most complicated and regulated of all rechargeable batteries. The process alone to manufacture a laptop battery is long. How laptop batteries interact with the computer to function properly is another lengthy process. Manufacturers are also working constantly to improve laptop battery technology.
The process used to created laptop batteries involves a system of tests and re-tests to insure safety and reliability. Inside that plastic case that is the finished product, there are a number of components besides the battery that make it work. Inside the casing, there are safety fuses, breakers, thermistors, and charge electronics which all aid in the functionality of laptop batteries. The battery pack casing is welded together in a specific process and is then sent on for final inspection. During final inspection, tests are documented for form, fit and function and once the battery passes the test, it is labeled with a lot and date code.
All those extra components added to the battery pack are essential for laptop battery...