An electrochemical generator (e.g. a battery) which is rechargeable electrochemically with liquid electrolyte having negative electrodes of zinc and the positive non-porous electrodes that are contacted on the same face by the electrolyte and an oxygen-containing gas. The generator or battery comprises a repetitive unit of groups of thin, plate-like, components, each group having a total thickness that is preferably smaller than about 1 millimeter and comprising an impervious bipolar electrode, a microporous membrane, and means for maintaining an essentially constant spacing between said bipolar electrode and the membrane. These generators are capable of providing long service lives and/or a large specific power or output.