Cylindrical secondary battery of improved safety

摘要

Provided is a cylindrical battery in which an electrode assembly fabricated by rolling a cathode/separator/anode and an electrolyte are provided in a cylindrical can, wherein a cap assembly mounted on the opening top of the cylindrical can comprises: a safety vent provided with a predetermined notch, to allow breakage due to high-pressure gas of the battery, a current interruptive device to interrupt current, welded to the bottom of the safety vent, and a gasket for the current interruptive device to surround the periphery of the current interruptive device, wherein the current interruptive device comprises two or more through holes to allow exhaustion of gas, wherein the through holes have a size of 20 to 50% with respect to the total area of the current interruptive device.

主权项

1. A cylindrical battery comprising:
(a) an electrode assembly and an electrolyte in a cylindrical can, the electrode assembly having a cathode, anode, and separator rolled together; (b) a cap assembly mounted on the opening top of the cylindrical can, said cap assembly comprises:
a safety vent, which breaks under increased pressure,wherein the safety vent has a recess located in a center of the safety vent, said recess having an upper bend and a lower bend,
said upper bend has a first notch,
wherein said first notch has a first arcuate shape region and a first non-notched region, andsaid lower bend has a second notch,
wherein the second notch has a second arcuate shaped region, a third arcuate shaped region, a second non-notched region, and a third non-notched region, wherein said second non-notched region and said third non-notched region are located diametrically opposite to one another;a current interruptive device, which upon activation interrupts current,wherein the current interruptive device includes:
a protrusion protruding upwardly, said protrusion welded to the bottom of a recess of the safety vent, said protrusion provided at a center of the current interruptive device,a cathode lead connected to the cathode through the bottom of the current interruptive device in a region other than the protrusion; anda bridge, provided with first through holes and a third notch, said third notch connecting the adjacent first through holes,
wherein said first through holes and said third notch concentrically surround the center of the protrusion,two or more second throughholes to allow exhaustion of gas,
wherein the second through holes have a total area of 20 to 50% with respect to the total area of the current interruptive device,wherein the second through holes are arranged such that the second through holes are spaced from one another by a distance in the form of a circular arc with a length corresponding to an angle of 50 to 80 degrees, based on the center of the current interruptive device; and (c) a gasket surrounding the periphery of thecurrent interruptive device.