Patent ID: 7521893

Claim:
A battery apparatus for controlling a discharge over time of a battery cell that provides an electric current at a voltage that decreases during the discharge, the battery apparatus comprising: a voltage setting unit that retains a setting of an end voltage of the battery cell and that causes the discharge to end when the voltage decreases to the end voltage; and an end voltage controller that varies the setting of the end voltage of the battery cell based on at least an ambient temperature, number of discharge times, and impedance of the battery cell so that the remaining power providing time of the battery cell is kept approximately at a predetermined period; wherein said end voltage controller comprises: charge/discharge times detecting means for detecting the number of charge/discharge times by detecting a change of a voltage at the time of said battery cell is charged/discharged; and first end voltage setting changing means for reducing said setting of said end voltage in accordance with a previously specified number of charge/discharge times, if said charge/discharge times detecting means detects said previously specified number of charge/discharge times corresponding to the increase in a pseudo resistance of said battery cell.