Battery cell and manufacturing method thereof

A battery cell comprising:

• an electrode assembly including a first separator, a negative electrode plate, a second separator and a positive electrode plate having a rectangular shape that are sequentially stacked;
• a negative electrode tab protruding from the negative electrode plate;
• and
• a positive electrode tab protruding from the positive electrode plate,
• wherein the first separator and the second separator each have a larger length and a larger width than a respective length and width each of the negative electrode plate and the positive electrode plate, and entire tab edge portions of the first and second separators aligned with the positive electrode tab and the negative electrode tab and a part of opposite side edge portions of the first and second separators adjacent to the tab edge portions are adhered to each other,
• wherein an adhesion width of the first and second separators at the tab edge portions is smaller than an adhesion width at corners of the first and second separators where each tab edge portion and the side edge portions are connected,
• wherein the positive electrode plate has a larger length and a larger width than a respective length and width of the negative electrode plate, and the negative electrode plate has recessed portions at four corners of the negative electrode plate, so that the negative electrode plate does not overlap adhered portions of the first and second separators, and
• wherein the recessed portions have a shape complementary to a shape of bonded regions of the side edge portions of the first and second separators.