Electrical storage system

An electrical storage system comprising:

• an electrical storage device;
• a load;
• a positive electrode line that connects the electrical storage device to the load;
• a negative electrode line that connects the electrical storage device to the load;
• a first relay provided in the positive electrode line;
• a second relay provided in the negative electrode line;
• a third relay connected in series with a first resistive element, the third relay and the first resistive element being connected in parallel with the first relay, the first resistive element being provided in the positive electrode line;
• a drive circuit including a coil, a first power line, a second power line, and a sensor,
• the coil being configured to generate electromagnetic force for switching the second relay and the third relay from a non-energized state to an energized state by energization at a first current value, the coil being configured to generate electromagnetic force for switching the first relay, the second relay and the third relay from a non-energized state to an energized state by energization at a second current value larger than the first current value, the energized state being on state, the non-energized state being off state,
• the first power line including a first switch element and a second switch element connected in series with each other, the first power line being configured to supply current having the second current value from a power supply to the coil,
• the second power line including a second resistive element and a third switch element connected in series with each other, the second power line being configured to supply current having the first current value from the power supply to the coil, and
• the sensor being configured to change an output signal on the basis of whether each switch element is in the energized state or the non-energized state,
• the drive circuit being configured to cause both the second and third relays and the first relay to operate at different timings;
• and
• a controller configured to:
• (a) control operation of the drive circuit,
• (b) output a control signal for setting each switch element to the non-energized state, and
• (c) determine whether any one of the switch elements has a failure in the energized state on the basis of the output signal of the sensor.