The present invention relates to an electrochemical cell (20) comprising a bipolar plate (26); an annular support next to the bipolar plate (26); a first electrode (22) separated from the bipolar plate (26) defining a first half-cell (10′) (cationic or anionic) together with the plate and the annular support. The cell also has a membrane (23) next to the first electrode (22); a second electrode (24) next to the membrane (23); and a closure element (21) defining a second half-cell (10″) (cationic or anionic depending on the nature of the second electrode) together with the second electrode (24). In the present invention the closure element (21) is housed within the annular support (25).