US Patent 8399125 Cap assembly and secondary battery using the same

A cap assembly and a secondary battery using the cap assembly, the cap assembly including: a cap-up having a groove; a PTC thermistor disposed in the groove; and inner components disposed below the cap-up. The inner components can include a vent disposed under the cap-up; a cap-down disposed under the vent; a sub-plate disposed under the cap-down; and an insulating vent disposed between the vent and the cap-down The secondary battery includes: an electrode assembly; a can containing the electrode assembly, having an opening at one side; and the cap assembly to seal the opening of the can.