Supercapacitor sealing lid

Sealing lid for sealing a compartment of a supercapacitor housing electrodes and electrolytic material, said supercapacitor comprising:

• a casing internally defining said compartment and having a longitudinal axis, a side wall extending around the longitudinal axis, an axial bottom wall and an axial opening for accessing the compartment arranged on the axially opposite side of the side wall with respect to the bottom wall;
• and
• at least one terminal electrically connected to one of said electrodes and protruding outside of said compartment through said axial opening;
• said lid being configured to close said axial opening and comprising an elastomeric element having:
• an internal through hole configured to receive said terminal and delimited by an internal wall configured to cooperate in fluid-tight contact with said terminal;
• and
• a peripheral wall configured to cooperate in fluid-tight contact with said side wall;
• said lid comprising an insert made of rigid material, preferably metallic, incorporated at least partially in said elastomeric element;
• wherein said internal wall has at least one groove defining at least two successive ridges along the internal wall itself, the ridges being configured to cooperate in fluid-tight contact with the terminal.