Pouch unit and battery cell including the same

A battery cell comprising:

• an electrode assembly;
• and
• a pouch unit accommodating the electrode assembly, the pouch unit being sealed,
• wherein the pouch unit includes:
• a pouch sheet having an inner surface contacting the electrode assembly and an outer surface opposite the inner surface;
• an accommodation portion formed on the pouch sheet and accommodating the electrode assembly, the accommodation portion including a first accommodation portion facing a surface of the electrode assembly and a second accommodation portion facing another surface of the electrode assembly;
• a first perimeter portion formed on the pouch sheet, the first perimeter portion extending from the first accommodation portion and leading to a first pouch side of the perimeter of the pouch sheet;
• a second perimeter portion formed on the pouch sheet, the second perimeter portion extending from the second accommodation portion and leading to a second pouch side of the perimeter of the pouch sheet, the second perimeter portion facing and contacting the first perimeter portion;
• a first notch portion extending alongside a side of the first accommodation portion at the first perimeter portion, the first notch portion being concave on the inner surface of the pouch sheet;
• and
• a second notch portion extending alongside a side of the second accommodation portion at the second perimeter portion, the second notch portion being concave on the inner surface of the pouch sheet.