Method for storing compressed air energy

A method for storing compressed air energy comprising, a compression step of converting electricity into energy of compressed air and storing the compressed air in one or more vessels, and an expansion step of expanding the stored compressed air to recover the electricity, the compression step and the expansion step being performed alternately,

• wherein the vessels are such that, in all or part of the vessels, a single film or a plurality of films to form spaces having surfaces with freely deformable shapes is disposed within each vessel, thereby forming a plurality of partial spaces within the vessel,
• by the start of the compression step, the partial space formed on one side of the surfaces of the film within the vessel is filled with a cushion gas,
• in the compression step, the compressed air is stored in the partial space on the other side of the surfaces of the film within the vessel without being mixed with the cushion gas, and
• the cushion gas is changed into a fluid with a reduced volume while retained within the vessel or sent to the outside of the vessel, thereby increasing the amount of the compressed air stored in the partial space on the other side of the surfaces, and
• in the expansion step, the fluid present within or outside the vessel is vaporized and restored as the cushion gas in the partial space on the one side of the surfaces within the vessel, thereby decreasing the amount of the compressed air remaining within the vessel.