Self-active welding machine system for storing energy by using shielding gas and use method of self-active welding machine system

The invention relates to a self-active welding machine system utilizing shielding gas to store energy and a using method thereof. The self-active welding machine system comprises a pressure container, high-pressure liquid shielding gas is stored in the pressure container, the output end of the pressure container is connected to a first inlet of a first heat exchanger, and the rear portion of a first outlet, communicated with the first inlet, in the first heat exchanger is communicated to a gas outlet of a welding gun; a pump is connected behind a second outlet of the first heat exchanger, and the output end of the pump is connected to a welded piece and the welding gun and then communicates with a second inlet of the first heat exchanger to form flowing circulation of the organic working medium. A first expansion machine is further connected between the first outlet of the first heat exchanger and the welding gun in series, the power output end of the first expansion machine is connected with a generator, and