To provide a full charge determination device of a battery for a vehicle for determining a full charge state independent of influence by hysteresis.
A microcomputer 60 conducts plural samplings based on detecting values of an ammeter 40 and a voltmeter 50, and calculates the incline of a primary straight line showing the relation between voltage variation caused by polarization produced within a battery B and a polarization index showing the degree of the polarization based on plural sampling data obtained by both samplings. The microcomputer 60 determines a full charge state by comparing the calculated gradient with the gradient of a straight line showing the relation between the voltage variation in a previously set full charge state and the polarization index.
NAKAMURA TSUTOMU
OKAZAKI YOSHINORI
MORIYA TAKANORI
TOYOTA MOTOR CORP
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