Patent ID: 8445131

Claim:
A case for secondary battery having an interior and exterior portion, said interior portion housing an electrode assembly, comprising: a case body having first and second long-side walls opposite to each other, separated by first and second short-side walls, a bottom wall connected to one end portions of the two long-side walls and the two short-side walls, and an opening positioned at the other end portions of the two long-side walls and the two short-side walls while being opposite to the bottom wall; and a first rib disposed on the interior portion of the case body, the first rib extending from a middle portion of the first long-side wall to a middle portion of the second long-side wall via the second short-side wall, said first rib having a width less than a longitudinal length of any one of the two long side walls or the two short side walls, wherein a length (L 1 ) of the first rib extending from the second short side wall to the middle portion of first or second long side wall is approximately greater than 60% and approximately less than 100% of a longitudinal length of an electrode assembly inserted in the case body.