CAP ASSEMBLY, SECONDARY BATTERY INCLUDING THE SAME, AND CAP ASSEMBLY MANUFACTURING METHOD

A cap assembly includes a base portion having a through-hole, a protrusion joined to the base portion, the protrusion extending downward from a lower end of the through-hole, an electrode terminal at least partially inserted into the protrusion, the electrode terminal sealing the through-hole, and a sealing member between the protrusion and the electrode terminal.