Laptop battery, notebook computer battery pack

Laptop or notebook computers are characterized in that the entire computing functionality is incorporated into a single package. A notebook computer includes an integral CPU, keyboard, mouse, hard drive, CD-ROM or DVD drive, rechargeable battery, and video output device (such as a LCD display), such components are powered by either an internal battery or a single AC power connection. As a power source for a notebook computer, a battery is an important element. Generally, in a laptop computer, a battery pack which includes a number of cylindrical lithium-ion secondary batteries within a plastic outer case having flat and rectangular shaped top and bottom is employed as a power source. The battery is installed in inside space of the laptop computer by a battery connecting apparatus. The battery connecting apparatus commonly includes a battery housing, a base and a battery connector. The battery housing is used for receiving the battery therein. The battery connector is assembled with the base for electrically connecting the battery to a power supply circuit of the notebook computer. To reduce the size and weight of the electronic apparatus, increase in the capacity of the battery and reduction in the volume of the same have been required. Commonly used laptop rechargeable battery packs include lithium-ion battery (Li-ion), nickel-cadmium battery (NiCd) and nickel mercury secondary battery (NiMH). Lithium batteries, which are lightweight and have high energy density, are taking the initiative in the market as an energy source of typical portable information devices, such as notebook personal computers, personal digital assistants (PDAs), mobile phone terminals. This lithium secondary battery is advantageous in that it has high operating voltage and high energy density and can discharge a large current. The lithium ion secondary battery is based on a cell reaction by which lithium ion is intercalated between layers of a carbonaceous material, such as graphie, constituting the anode. Laptop battery packs are provided with a variety of protective functions for preventing damage to the battery caused by abnormal use such as overcharging, over discharging, short-circuiting between the positive and negative electrodes. A lithium ion rechargeable battery is normally provided with a battery protection circuit to prevent overcharging, over discharging, and so forth. Such battery protection circuit is generally unitized with the battery as part of battery pack configuration.