Pouch forming method and pouch forming device

A pouch forming device for forming an accommodation part that accommodates an electrode assembly in a pouch sheet, the pouch forming device comprising:

• a lower die defining a forming groove in an upper portion thereof, the upper portion of the lower die configured to receive the pouch sheet;
• a punch unit disposed above the lower die and comprising a punch and a punch moving part for moving the punch in a vertical direction to press the pouch sheet towards of the forming groove of the lower die to form the accommodation part in the pouch sheet in a shape that corresponds to the forming groove;
• a stripper unit including a stripper and a stripper moving part for moving the stripper, the stripper arranged to press an outer portion of the accommodation part of the pouch sheet to support the pouch sheet on the lower die;
• a vacuum unit connected to the forming groove of the lower side to apply vacuum to the pouch sheet seated on a top surface of the lower die to elongate the accommodation part of the pouch sheet;
• and
• a control unit for controlling the punch moving part and the stripper moving part, wherein the control unit is configured to control gradual ascension of the stripper away from the pouch sheet, and simultaneously, control a descension of speed of the punch as the punch descends in the vertical direction towards the forming groove.