The present invention provides a secondary battery, including an electrode assembly, a housing, a top cover assembly, and an insulating member. The electrode assembly includes two first surfaces and two second surfaces, and the two first surfaces are located respectively at two ends of the electrode assembly in the thickness direction. The second surfaces are extended from the ends of the first surfaces along a width direction, and intersecting lines are formed between the first surfaces and the second surfaces. The housing has an opening and forms an accommodating cavity. The electrode assembly is located inside the accommodating cavity of the housing, and the top cover assembly is connected to the opening of the housing and seals the housing. The insulating member includes two first insulating sheets, and the two first insulating sheets are disposed respectively at two sides of the electrode assembly along the thickness direction.