Notebook computers are complex devices. Figure 1 depicts the basic elements that comprise a notebook computer and shows how they fit together. It includes the operating environment and user, as well as the computer, battery pack, and the fundamental electrochemical cell that drives its operation. Since notebooks are portable, it is essential to have a lightweight, sealed battery to prevent leakage of electrolyte into the computer case. Two types of batteries are found in a notebook computer. One is a rechargeable battery pack that provides the energy for its operation. The pack is usually composed of several lithium-ion cells in series and parallel arrangements along with an electronic battery management unit to control the operation and to provide communication between the battery pack and the computer.
