Low-temperature energy storage power generation system and running method thereof

The invention discloses a low-temperature energy storage power generation system and a running method thereof, and relates to the technique of energy storage. During energy storage, a motor consumes electric energy to drive a compression unit I and an expansion unit I which have a stage intercooling function, and low-temperature cold energy is generated and is stored in a low-temperature cold-storage medium in a cold energy storage through a heat exchanger. When energy is released, working fluid in cold energy release and power generation circulation absorbs the low-temperature cold energy in the cold energy storage through another heat exchanger to be liquefied. The liquefied working fluid is vaporized through an evaporator after pressure is increased through a pump, and a power generator is driven by an expansion unit II to generate power. The low-temperature energy storage power generation system has the advantages of being large, low in cost and high in efficiency, free of generation of greenhouse gas, capable of recycling medium-and-low-temperature (heat value) waste heat and the like, and is particularly suitable for large-scale long-time electric energy storage.