Prismatic battery having electrolyte injection-hole capable of providing excellent sealing ability

Abstract

Disclosed herein is a secondary battery having an electrode assembly mounted in a prismatic container, wherein the inside of an electrolyte injection hole formed in a base plate mounted to an open upper end of the prismatic container includes an upper part having a chamfered structure in which the diameter of the electrolyte injection hole is gradually decreased downward and a lower part having a non-chamfered structure continuously formed from the chamfered structure, and, when a sealing member is pressed into the electrolyte injection hole, the sealing member deformed into a shape corresponding to the electrolyte injection hole comes into tight contact with the chamfered structure due to shear stress between the chamfered structure and the sealing member and forms a sealed state due to frictional interaction between the non-chamfered structure and the sealing member. Consequently, it is possible to reduce a defect rate of secondary batteries and to improve sealability of the electrolyte injection hole without welding.