A rechargeable battery includes an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first and second electrode plates, an electrolyte having viscosity of about 1 Pa·s to about 15 Pa·s at a temperature from about 20° C. to about 25° C., a can having an opening on one surface through which the electrode assembly is inserted, the electrode assembly and the electrolyte being accommodated inside the can, and a cap plate that seals the opening of the can. A ratio of the height of the can to a cross-sectional area of the can is from about 12.5% to about 25%.