US Patent 10128477 Cap assembly and secondary battery including the same

A cap assembly includes a current interrupt portion; a cap-up electrically connected with the current interrupt portion; and a gasket fixing the current interrupt portion and the cap-up, wherein the current interrupt portion comprises a vent portion comprising a safety vent configured to fracture when a predetermined pressure is applied thereon, and a cap-down comprising at least one hole configured to allow gas to flow in a direction toward the cap-up; and wherein an overall area of the at least one hole is about 0.12% to about 1.61% of a cross-sectional area of the gasket based on an outer diameter of the gasket.