Patent ID: 8440347

Claim:
A secondary battery, comprising an electrode assembly; a can accommodating the electrode assembly; a cap assembly sealing the can; and an insulating case interposed between the electrode assembly and the cap assembly, the insulating case including two facing long side walls and two facing short side walls, the two facing long side walls and two facing short side walls including inner surfaces and outer surfaces, the two facing long side walls and two facing short side walls forming a continuous raised perimeter extending in a direction toward the cap assembly from a bottom surface of the insulating case; wherein: the two facing long side walls include opposing end portions and opposing central portions, and a distance between the outer surfaces of the facing long side walls at the opposing end portions of the facing long side walls is greater than a distance between the outer surfaces of the facing long side walls at the opposing central portions of the facing long side walls, and a thickness of the short side walls in a direction between the inner surfaces and the outer surfaces of the short side walls is greater than a thickness of the long side walls in a direction between the inner surfaces and the outer surfaces of the long side walls.