Patent ID: 7514902

Claim:
A battery pack comprising a battery cell and being capable of calculating a remaining battery power according to a number of charge/discharge cycles and temperature during operation, comprising: temperature measurement means for measuring temperature of said battery cell; charge/discharge cycle counting means for counting a number of charge/discharge cycles; correction value storage means for storing correction values as a function of a range of the number of charge/discharge cycles and a range in temperature, each correction value corresponding to one range of charge/discharge cycles and one range in temperature; and remaining power calculation means for specifying one correction value by searching the correction value storage means based on the measured temperature and the counted number of charge/discharge cycles, and calculating the remaining battery power corresponding to the specified correction value, wherein at a low temperature range, the correction values change the remaining battery power of the battery pack on a stepwise basis every predetermined number of cycles up to a specified number of cycles and thereafter linearly changes the remaining battery power every predetermined number of cycles.