CPC H01M 10/44 (2013.01) [G01R 27/08 (2013.01); G01R 31/389 (2019.01); H01M 10/48 (2013.01); H02J 7/007182 (2020.01)] | 8 Claims |
1. An internal resistance detection device configured to detect an internal resistance of a power storage unit in an in-vehicle power source system that includes a power source unit and the power storage unit configured to be charged based on power from the power source unit, the internal resistance detection device comprising:
a current detection unit configured to detect a current that flows through a predetermined conduction path that is a path with which power is supplied from the power source unit to the power storage unit;
a charging circuit unit configured to convert power from the power source unit and to supply charging current to the power storage unit; and
an internal resistance detection portion configured to detect an internal resistance of the power storage unit, wherein
the charging circuit unit is configured to raise an output voltage to a target voltage by performing constant current operation in which the charging current is output at a target charging current, and, when the output voltage reaches the target voltage, to control power such that the charging current is lowered by performing constant voltage operation in which the output voltage is fixed at the target voltage, and
the internal resistance detection unit is configured to detect the internal resistance of the power storage unit based on the target charging current, a drop time, which is the time that passes from when constant voltage operation starts to when the charging current drops to a predetermined current value, and a capacity of the power storage unit.
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