Management device and power supply system

A power supply system comprising:

• a management device for managing a second power storage device that reinforces a first power storage device for supplying electricity to loads in a vehicle,
• a first switch that controls a power supply from the second storage device to the loads in the vehicle,
• wherein the first power storage device and the second power storage device are connected in parallel,
• the management device including:
• a power supply unit that steps down a voltage supplied from the first power storage device;
• a control unit that uses, as a power supply voltage, the voltage generated by the power supply unit and monitors a state of the second power storage device to control charging and discharging of the second power storage device;
• and
• a second switch that electrically connects or disconnects the second power storage device to or from the power supply unit, wherein a first diode that is inserted between the first power storage device and the power supply unit in a direction where a cathode of the first diode is disposed at the power supply unit side;
• and
• a second diode that is inserted between the second switch and a connecting point between a cathode terminal of the first diode and the power supply unit, in a direction where a cathode of the second diode is disposed at the connecting point side, and
• an anode of the second diode is connected to a connection point between the second storage device and the first switch.