To control a battery charging properly according to a battery temperature with a compact structure, by comparing the temperature with a plurality of temperature threshold values by one comparator.
Temperature of a battery 10 being charged is detected by a temperature sensor 13. The comparator 17 compares the detected temperature alternately at a prescribed cycle with a preset high temperature abnormal threshold value TH1 or low temperature abnormal threshold value TL1 by changing over switches 15, 16 by a control device 19. This control device 19 stops the charging operation of a charger 12 if the battery temperature exceeds the high temperature abnormal threshold value TH1 or low temperature abnormal threshold value TL1. Then, the control device 19 controls the switches 15, 16 to change over to a high temperature reset threshold value TH2 when the charging is stopped on high temperature abnormality, and to a low temperature reset threshold value TL2 when stopped on low temperature abnormality. The comparator 17 compares the threshold value with the temperature of the battery whose charging is being stopped. Then, the charging operation of the charger 12 is resumed when the battery temperature drops below the high temperature reset threshold value TH2 or exceeds the low temperature reset threshold value TL2.
Hironori Honda
Toshimitsu Ichikawa
Takeshi Takamatsu
Yuriko Hamada
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