Power storage unit control device

A power storage unit control device in an in-vehicle power source system that includes a power source unit, a charging circuit configured to perform charging based on power from the power source unit, a power storage unit configured to be charged by the charging circuit, and a discharging circuit configured to discharge from the power storage unit to a load, the power storage unit control device comprising:

• the discharging circuit;
• a control unit configured to control the discharging circuit;
• and
• a switching unit configured to monitor a first voltage, which is a voltage of the power source unit that is applied to a wiring unit, the wiring unit coupled to one side of an ignition relay, the ignition relay switches to an ON state in a case where a predetermined start operation for starting a vehicle is performed and switches to an OFF state in the case where a predetermined stop operation for stopping the vehicle is performed, is provided between the power source unit and the ignition relay, and a second voltage, which is a voltage on the other side of the ignition relay that is applied to a conduction path, the switching unit electrically connected to both the wiring unit and the first conduction path via a first path and a second path so as to monitor the first voltage and the second voltage, the ignition relay being interposed between the first path and the second path and, when the first voltage is larger than a predetermined value in a case where the second voltage switches from a state of being larger than a predetermined value to a state of being smaller than the predetermined value, to execute a discharge prohibition mode in which discharge control of the discharging circuit by the control unit is prohibited, and, when the first voltage is smaller than the predetermined value in a case where the second voltage switches from a state of being larger than a predetermined value to a state of being smaller than the predetermined value, to execute a discharge permission mode in which discharge control of the discharging circuit by the control unit is permitted,
• wherein the control unit causes the discharging circuit to perform a discharging operation in a case where a voltage of the power source unit is less than or equal to a predetermined value in a state where the switching unit is executing the discharge permission mode, and does not cause the discharging circuit to perform the discharging operation in a case where the voltage of the power source unit is less than or equal to a predetermined value in a state where the switching unit is executing the discharge prohibition mode.