ENERGY STORAGE APPARATUS AND FAILURE DIAGNOSIS METHOD

An energy storage apparatus includes: an external terminal; an energy storage cell; a current interruption device that has one end electrically connected to the external terminal and the other end electrically connected to the energy storage cell; a discharge circuit that discharges electricity from the energy storage cell via a path that does not pass through the current interruption device; and a failure diagnosis device. The failure diagnosis device discharges electricity from the energy storage cell using the discharge circuit, and diagnoses a failure of the current interruption device based on a change in voltage ΔV of the external terminal before and after discharging electricity.