Research Progress of Liquid Carbon Dioxide Energy Storage System Based on Different Liquefaction Methods

[Introduction] With the large-scale application of new energy, the challenges faced by the grid connection of new energy power generation are growing, and the importance of energy storage system is increasing. carbon dioxide energy storage (CES) technology is a kind of compressed gas energy storage technology emerging in recent years, with the advantages of high energy storage density, long service life and high design flexibility. For liquid carbon dioxide energy storage (LCES) technology, CO2 is stored as liquid phase in both HP and LP sides of the system, which has high energy storage density and strong operation stability. [Method] Firstly, the operation principle and key technical indicators of the LCES system was introduced and the importance of carbon dioxide liquefaction and common liquefaction processes were clarified. Then, the research status of CO2 liquefaction on the LP side of the LCES system was introduced, including the use of mixed energy storage working medium, self-condensation, the LNG cold energy, and the regenerator. The characteristics of each method were analyzed in detail. [Result] The research indicates that the application of regenerator is the most effective method. It is necessary to further analyze the challenges faced by current cold storage liquefaction technology and its development direction. [Conclusion] The research could provide guidance for the further development of CO2 liquefaction technology for the LCES system.