| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem of a residual amount displaying device of a conventional current accumulation type battery that the charging/discharging efficiency gradually changes due to the repeated charging/discharging cycle, and generates an error at a prescribed value while calculating the capacity by multiplying the charged/discharged current amount per unit time by the charging/discharging efficiency. SOLUTION: A CPU, a current detection circuit, a voltage detection circuit, a ROM memorizing a program of counting the frequency of charging/discharging, a data composed of the frequency of charging/discharging and a coefficient, and a data of charging/discharging efficiency, are stored in a battery pack. The CPU receives the charged/discharged current amount per unit time from the current detection circuit, and calculates the capacity by multiplying the charged/discharged current amount per unit time by the charging/discharging efficiency and adding or subtracting them one after the other. Further, the capacity is corrected by reading the coefficient corresponding to the frequency of charging/discharging memorized in the ROM when a prescribed current/voltage are detected. By the above, the capacity can be displayed without error. COPYRIGHT: (C)2004,JPO
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