Electrical storage system

An electrical storage system comprising:

• a plurality of serially connected electrical storage blocks each including at least one electrical storage element connected to a load and configured to be charged or discharged;
• a voltage detection circuit connected to each of the electrical storage blocks via corresponding voltage detection lines and configured to detect a voltage of each of the electrical storage blocks;
• a protection circuit including an overvoltage protection element connected in parallel with each of the electrical storage blocks via the corresponding voltage detection lines and a first resistor connected in series with the overvoltage protection element, and the protection circuit being provided in correspondence with each of the electrical storage blocks;
• a discharge circuit connected in parallel with each of the overvoltage protection elements via the corresponding voltage detection lines and connected in series with the first resistor, the discharge circuit including a second resistor having a larger resistance value than the first resistor;
• and
• a controller configured to compare a voltage between the electrical storage blocks using the detected voltages of the corresponding voltage detection circuits and detect an abnormality in the overvoltage protection elements, wherein
• the controller is configured to detect an abnormality in the overvoltage protection elements by, in a state where the electrical storage elements are not connected to the load, comparing a voltage of a first electrical storage block among the electrical storage blocks, which is placed in a discharged state where current is caused to flow through the corresponding second resistor by activating the corresponding discharge circuit, with a voltage of a second electrical storage block among the electrical storage blocks, which is not placed in the discharged state caused by activating the corresponding discharge circuit.