Lithium ion electrochemical cell with safety valve electrical disconnect

In a compact electrochemical cell comprising:

• a can housing internally a generator unit including an anode, a cathode, a separator separating said anode and cathode, an electrolyte, an explosion-proof valve, electrical disconnect assembly including an explosion-proof vent valve contact disk sealing said can, electrical circuit means including said vent valve contact disk and a juxtaposed stripper contact disk welded thereto at a weld point by a weld nugget electrically connecting one of said anode and said cathode to said vent valve contact disk, and wherein said explosion-proof vent valve contact disk is deformable upon an increase of internal pressure within said can to cause initially electrical separation of the vent valve contact disk from said stripper contact disk at said weld connection to break said electrical circuit prior to rupturing of the valve vent contact disk at a further increased pressurization internally of said sealed can,
• the improvement wherein:
• said vent valve contact disk at said weld point includes a thinned, localized weakened portion within said stripper contact disk for facilitating rupture of said stripper contact disk at said weld point between the weld weakened portion and the center of said juxtaposed stripper contact disk such that said weakened portion of said stripper contact disk separates from the stripper contact disk to open said circuit means.