PURPOSE: To provide a service life determining device which can determine the service life of a battery even when the battery is somewhat deteriorated.
CONSTITUTION: A battery 10 is connected to one end of a dummy load 12 through a switch 11. The switch is opened/closed by a control signal from an arithmetic processing section 14 and, at the time of diagnosis, the switch is closed so that a constant current can be discharged. When the constant current is discharged, a voltage detector 13 detects the voltage of the battery 10 and a temperature detector 15 detects the temperature of the battery 10. The capacity (residual capacity) of the battery highly correlates with the voltage changing rate of the battery during a fixed period of time (from t1 to t2) after the discharge is started and the changing rate becomes larger as the capacity of the battery 10 becomes smaller. In addition, the capacity of the battery 10 becomes larger when the temperature of the battery 10 becomes higher even when the changing rate does not change. Therefore, the arithmetic processing section 14 estimates the capacity of the battery 10 by finding the changing rate of the discharge voltage from the voltage of the battery 10 at two points of time t1 and t2, converts temperature data into the capacity of the battery 10 at a standard temperature, and estimates the degree of deterioration.
TAKEMOTO MIKIO
TSURUKAWA YUJI
OKA SEIJI
OMRON TATEISI ELECTRONICS CO
| JPH06281709A | 1994-10-07 | |||
| JPH06242193A | 1994-09-02 | |||
| JPS59109875A | 1984-06-25 | |||
| JPS61124876A | 1986-06-12 | |||
| JPH03251052A | 1991-11-08 | |||
| JP1156477B | ||||
| JPH05281309A | 1993-10-29 |
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