Abstract: A method of producing a positive electrode active material, the method includes: contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element, wherein the lithium transition metal composite oxide has a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium in a range of from 0.7 to less than 1; mixing the second particles and a boron compound to obtain a mixture; and heat-treating the mixture at a temperature in a range of from 100° C. to 450° C.

Abstract: A method of producing a positive electrode active material, the method includes: contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element, wherein the lithium transition metal composite oxide has a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium in a range of from 0.7 to less than 1; mixing the second particles and a boron compound to obtain a mixture; and heat-treating the mixture at a temperature in a range of from 100° C. to 450° C.

Abstract: A grid interconnection system for a power grid includes: a storage battery; a power conversion device that converts power from the storage battery into AC; and an interconnection control device that supplies power from a commercial power supply to a load and supplies power from the power conversion device to the load when the commercial power supply fails. When the commercial power supply is restored, the interconnection control device starts supply of power from the commercial power supply to the load, and stops supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started.

Abstract: An object is to provide a power system interconnection system and a method of installing the power system interconnection system that are able to supply a load with required power. A power system interconnection system comprises a storage battery an AC-DC power conversion device for the storage battery a charge and discharge station for an electric-powered automobile and an interconnection control device that are installed on a parking lot. The interconnection control device supplies a first load with power from at least one of the charge and discharge station and the AC-DC power conversion device in a case where the electric power system is in an emergency situation.

Abstract: A grid interconnection system for a power grid includes: a storage battery; a power conversion device that converts power from the storage battery into AC; and an interconnection control device that supplies power from a commercial power supply to a load and supplies power from the power conversion device to the load when the commercial power supply fails. When the commercial power supply is restored, the interconnection control device starts supply of power from the commercial power supply to the load, and stops supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started.

Abstract: An object is to provide a power system interconnection system and a method of installing the power system interconnection system that are able to supply a load with required power. A power system interconnection system comprises a storage battery an AC-DC power conversion device for the storage battery a charge and discharge station for an electric-powered automobile and an interconnection control device that are installed on a parking lot. The interconnection control device supplies a first load with power from at least one of the charge and discharge station and the AC-DC. power conversion device in a case where the electric power system is in an emergency situation.