Patent ID: 7550225

Claim:
A battery comprising: a battery element including a cathode and an anode; a safety valve electrically connected to said battery element said safety valve having a support plate; an insulating plate arranged between said battery element and said safety valve; an inversion plate on said support plate; an insulating member between said inversion plate and said support plate; an opening in a central portion of said support plate; a contact plate on said central portion at a side opposite of said inversion plate and welded to a lead to form an electrical connection to said battery element; a plurality of vent holes to transmit a change in the internal pressure of a battery container to said inversion plate around said central portion of said support plate; and a protrusion which protrudes from said central portion to said battery element side inserted in said opening of the support plate and in contact with said contact plate, wherein, said inversion plate electrically connects said battery cover to the lead through a Positive Temperature Coefficient device, said battery cover functions as a cathode terminal when an increase in the internal pressure of said battery container is transmitted to said inversion plate through said opening of the support plate, said inversion plate is deformed towards the battery cover side to reduce the increase in the internal pressure and to block the electrical connection with the lead to block the electrical connection between the battery cover and the battery device, and said insulating plate has seven or more openings facing said vent holes in a circumferential direction.