| abstract |
The present invention relates to a method of preparing a pouch type secondary battery, and particularly to a method of preparing a pouch type secondary battery which includes preparing a pouch type preliminary secondary battery by accommodating an electrode assembly in an inner space of a pouch type case, disposing a metallic ultrasonic member by being closely attached to both surfaces of the pouch type preliminary secondary battery, injecting a composition for a gel polymer electrolyte into the pouch type preliminary secondary battery, applying ultrasonic vibration to the pouch type preliminary secondary battery while pressurizing the pouch type preliminary secondary battery using the ultrasonic member, performing formation on the pouch type preliminary secondary battery, curing the composition for a gel polymer electrolyte, and degassing, wherein the ultrasonic member is maintained at a temperature of 30° C. to 80° C., and the pressurizing of the pouch type preliminary secondary battery is performed while applying a pressure of 0.1 kgf/cm2 to 3,000 kgf/cm2 per area of the pouch type preliminary secondary battery. |