Electric storage apparatus and power path switch apparatus

An electric storage apparatus, comprising:

• an electric storage device;
• and
• a protective circuit for cutting off a power path when detecting abnormality including overcharge, the protective circuit being connected to an outside connecting terminal, to which a power generator and an outside load operated by electric power from the electric storage apparatus are connected,
• wherein the protective circuit includes:
• a charging or discharging path connecting the electric storage device to the outside connecting terminal;
• a potential difference measuring unit for measuring a potential difference at two points on the charging or discharging path, the two points on the charging or discharging path being located between a positive electrode of the electric storage device and the outside connecting terminal;
• a self-holding switch disposed between the two points on the charging or discharging path;
• a current measuring unit for measuring a current flowing through the two points on the charging or discharging path;
• a switch controller for controlling switching of the self-holding switch, based on at least a state of the electric storage device, to an open state of the self-holding switch or a closed state of the self-holding switch;
• and
• an operational state determining unit for determining an operational state of the self-holding switch, as one of an open operational state and a closed operational state, based on a control state of the switch controller and at least one of a result measured by the potential difference measuring unit and a result measured by the current measuring unit.