SECONDARY BATTERY

A secondary battery includes: an electrode assembly; a case accommodating the electrode assembly; and a cap assembly coupled to the case to seal the case, and the case includes a bottom portion, long side portions bent and extended from the bottom portion, a first short side portion bent and extended from the bottom portion, and second short side portions bent and extended from the long side portions, and the first short side portion and the second short side portions are connected to one another to define a short side portion.