Relay device

A relay device that is used in an in-vehicle power supply system including a first conduction path that is electrically connected to a first power storage unit and is a path for supplying power to a load via a first fuse portion, a second conduction path that is electrically connected to a second power storage unit and is a path for supplying power to the load via a second fuse portion, and a third conduction path whose one side is connected to the first conduction path on a first power storage unit side relative to the first fuse portion and the other side is connected to the second conduction path on a second power storage unit side relative to the second fuse portion, the relay device comprising:

• a first relay unit configured to be switched between ON and OFF states at a position on a load side relative to the first fuse portion in the first conduction path;
• a second relay unit configured to be switched between ON and OFF states at a position on the load side relative to the second fuse portion in the second conduction path;
• a first current detection unit configured to detect, at least, a direction of current flowing through the first conduction path;
• a second current detection unit configured to detect, at least, a direction of current flowing through the second conduction path;
• and
• a switching control unit configured to maintain the ON state of the first relay unit and the second relay unit if a current flows in a normal direction, which is a direction toward the load, in each of the first conduction path and the second conduction path, and configured to switch, if the current flows in a reverse direction to the normal direction in one of the first conduction path and the second conduction path, that one of the first relay unit and the second relay unit that is provided in a reverse flow path in which the current flows in the reverse direction, to the OFF state.