TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Process: All of the materials interposed between the electrically conductive bipolar sheets (2) along the path of the perforation are displaced and a direct contact between the electrically conductive bipolar sheets and the conductive material is effected. The perforation is accomplished with a drill. The recess(es) is obtained through the insertion by pounding of a conductor provided with a conic-shaped or wedge-shaped tip, i.e. a metallic awl. The process further includes hydraulic by-passing of the elementary electrochemical cell (1) which is effected prior to the short-circuiting.Preferred Materials: The interposed materials comprise materials lacking electronic conductivity and materials having electronic conductivity. The materials having electronic conductivity comprise current collectors (4) and the perimetral sealing gaskets (3).    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The drill is provided with a metallic tip and that, after accomplishing the perforation, the metallic tip is left inside the recess(es). The filter-press structure comprises clamping tie-rod traversing the main surface of the elementary electrochemical cells, and that the recess(es) is obtained in correspondence of the passage zone of a tie-rod, after removal of the tie-rod. The perimetral sealing gaskets comprise predisposed perforation zones, such as, notches or indentations.    TECHNOLOGY FOCUS - METALLURGY - Preferred Material: The conductive material is a material with elongated shape, such as, rods, bars, cables, bundles of fibers, and wires, or a material retaining a residual elasticity under compression. The conductive material may also be in the form of tubes, spiraled rods, rods with V-shaped section, rods with omega-shaped section, rods with elliptic sector-shaped section. The conductive material may also be a metallic material with high electric conductivity optionally coated with a layer of noble metal, or a conductive paste such as metallic pastes or carbon-based pastes.    TECHNOLOGY FOCUS - POLYMERS - Preferred Materials: The materials lacking electronic conductivity is a polymeric membrane. The perimetral sealing gasket is formed of thermoplastic material and the perforation zones are formed of elastomeric material.