| 摘要 |
PROBLEM TO BE SOLVED: To certainly detect abnormal heating of a heater together with a temperature detecting means by discriminating whether abnormal heating occurs or not based on value of charged but not yet discharge opening voltage of a battery. SOLUTION: Because a voltage of sodium-sulfur battery depends on temperature, temperature in an insulating container can be formed by measuring voltage, and abnormal heating of the battery can be detected. As the measured voltage, a voltage at a rest stage from completion of a charge stage to start of a next discharge stage, namely a charged but not yet discharge opening voltage is used. Inside of the insulating container at the rest stage after the charge stage is controlled at 320 deg.C, and the charged but not yet discharge opening voltage is 2.075 V/cell if a heater normally operates. Thus, when the charged but not yet discharge opening voltage becomes smaller than this value as a reference voltage, the battery determines abnormal heating to stop an operation of the heater. Therefore, using it together with a temperature detecting means, the abnormal heating of the heater can be detected even when it failures.
|
