Patent ID: 7579811

Claim:
A battery pack which uses a software control to implement a secondary battery protection function, the battery pack comprising: discharge current cutoff means for selectively cutting off a discharge current in the secondary battery; charge current cutoff means for selectively cutting off a charge current in the secondary battery; voltage detection means for digitizing and outputting a voltage between a positive electrode and a negative electrode of the secondary battery; protection process means for, based on at least an output voltage value from the voltage detection means, determining a state of the secondary battery out of overcharge, normal operation, and over-discharge states and, according to a determined state, controlling operations of the discharge current cutoff means and the charge current cutoff means, wherein specified threshold values needed for a startup state are stored in an active software memory which is read immediately after the startup of the protection process means; and overcurrent detection means for providing control to enable the discharge current cutoff means in preference to the protection process means when the secondary battery is determined to be in an overcurrent state based on a charge and discharge current size of the secondary battery.