A process for manufacturing an elementary gas electrode electrochemical cell of metal-gas type, configured to be integrated into an electrochemical assembly module of a system for storing energy and including: an electrochemical core including at least one negative electrode and at least one positive electrode, at least one negative electrode as a gas electrode and at least one positive electrode as a metal electrode or vice versa, the process including: producing the electrochemical core of the cell by winding, folding, and/or stacking a plurality of layers including at least one negative-electrode layer, one positive-electrode layer, and one electrolyte layer, and forming gas flow spaces channeling the gas to the one or more gas electrode layers.