Cap for electrochemical cell

A method comprising:

• providing a flow of electric current through a cap that closes at least one opening of an electrochemical cell, the electrochemical cell comprising a cell can with electrolyte and an active-material roll inside, wherein the cap comprises a substantially flat member that covers the opening, the substantially flat member having a separation portion defined therein, the electric current flowing through a connector attached to the separation portion;
• upon occurrence of a first pressure inside the electrochemical cell, interrupting the flow of the electric current by way of the separation portion being severed from a remainder of the substantially flat member, wherein a diaphragm on an inside of the substantially flat member prevents leakage out of the electrochemical cell;
• and
• upon occurrence of a second pressure inside the electrochemical cell after interruption of the flow of the electric current, venting the electrochemical cell by way of the diaphragm being ruptured so that fluid escapes through an opening left by the separation portion.