Cylindrical cell with improved closure assembly

An electrochemical cell (10) of cylindrical type, comprising a metal can (12) open at one end, an anode (18), a separator (20) and a cathode (14), arranged concentrically in one another, an aqueous alkaline electrolyte solution, and a closure assembly hermetically closing said open end of the can;

• wherein said closure assembly comprises a plastic top (28) inserted in the open end of the can and having an outer cylindrical zone (31), a lower rim (40), a central portion (34) defining a central bore, and an intermediate portion interconnecting said central portion with said lower rim, a current collect nail (26) inserted through said central bore of said central portion and penetrating into said anode, and a negative cap (24) of a metal shoot material forming the negative terminal of the cell and closing said opening;
• characterized in, that said negative cap has a flange portion (47) ending in an inwardly bent rim (48), said can has a bead (30) at a selected distance from said open end serving as an abutment member for said assembly when inserted in the can, said plastic top defines a conforming support surface for said inwardly bent rim substantially at a connection zone of said outer cylindrical zone and said lower rim, and said can has a gasket zone (31) above said bead;
• wherein a sealant is provided to cover the inside surface of said can at said gasket zone, and the end portion of said gasket zone is crimped over said inwardly bent rim so that said outer cylindrical zone of said plastic top is pressed and crimped therebetween;
• whereby said inwardly bent rim provides a spring action pressing said outer cylindrical zone in radial direction towards said gasket and in axial direction towards said bead.