Electrical storage system, and control method for electrical storage system

An electrical storage system configured to supply electric power to a drive motor for a vehicle, the electrical storage system comprising:

• a first electrical storage stack constituted by a plurality of electrical storage elements;
• a second electrical storage stack constituted by a plurality of electrical storage elements and connected in series with the first electrical storage stack;
• a voltage monitoring unit including a plurality of detection lines, the voltage monitoring unit being configured to receive potentials of both positive and negative electrode terminals of each of the first and second electrical storage stacks via the detection lines and detect voltages of the first and second electrical storage stacks;
• a current interrupter detachably provided in a current path between the first and second electrical storage stacks, and configured to interrupt the current path by being removed from the current path;
• and
• a controller configured to control charging and discharging operations of each of the first and second electrical storage stacks, wherein
• the detection lines include a first detection line, a second detection line and a third detection line,
• the first detection line is connected to a first terminal of the first electrical storage stack,
• the second detection line is connected to a second terminal of the first electrical storage stack,
• the second electrical storage stack is connected to the second terminal of the first electrical storage stack via the current interrupter,
• the third detection line is connected to a portion of the current path, located on the second electrical storage stack side of the current interrupter, and
• the controller is configured to control charging and discharging operations of each of the first and second electrical storage stacks on the basis of the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line.