Power accumulation system and vehicle including the same

A power accumulation system comprising:

• a power accumulation device;
• a relay device provided in a pair of power lines disposed between the power accumulation device and a power conversion device that exchanges power with the power accumulation device;
• a capacitor provided between the pair of power lines between the relay device and the power conversion device;
• and
• an electronic control device that controls the relay device, wherein:
• the relay device includes a first relay provided in one of the pair of power lines, a second relay provided in the other of the pair of power lines, and a precharge circuit connected in parallel with the second relay;
• the precharge circuit includes a third relay and a limiting resistor connected in series with the third relay;
• each of the first relay and the second relay is a contact relay;
• the electronic control device is configured to execute a predetermined foreign matter removal process when it is not possible to bring one of the first relay and the second relay from a power blocking state to a conductive state;
• and
• the foreign matter removal process includes a process of bringing a relay that is not the one of the relays that is not possible to be brought into the conductive state into the conductive state in a state in which the first to third relays are in the power blocking state, and then outputting a conduction command to the relay that is not possible to be brought into the conductive state.