A secondary battery, comprising an electrode assembly, a housing and a top cover assembly, wherein the housing is a cuboid and has an accommodating chamber, the accommodating chamber having an opening, and the electrode assembly being accommodated in the accommodating chamber; the electrode assembly comprises a plurality of electrode units, the plurality of electrode units being stacked in an axial direction of the accommodating chamber, the axial direction of the accommodating chamber is parallel to an extending direction of the accommodating chamber and is perpendicular to a plane where the opening is located; the top cover assembly comprises a top cover plate, a first electrode terminal and a second electrode terminal, the top cover plate being connected to the housing and located on a side of the electrode assembly in the axial direction, and the first electrode terminal and the second electrode terminal both protruding from the top cover plate and being electrically connected to the electrode assembly; and in a lengthwise direction of the top cover plate, the first electrode terminal and the second electrode terminal are respectively located on two sides of the center of the top cover plate, and a distance between the first electrode terminal and the second electrode terminal is D1, a distance between an edge of the top cover plate close to the first electrode terminal and the first electrode terminal is D2, and the value of D1/D2 is 1-6; wherein each of the plurality of electrode units comprises a first electrode plate, a second electrode plate and a membrane, which are coiled as a whole, the electrode unit has a main body region and corner regions, the corner regions being arranged at two ends of the main body region in a width direction, the main body regions of two adjacent electrode units being in contact with each other, and the main body regions of the electrode units being arranged opposite to the top cover plate; wherein a ratio of a width of the main body region in a width direction to a thickness of the top cover plate in a height direction is 10-60. the housing is a cuboid and has an accommodating chamber, the accommodating chamber having an opening, and the electrode assembly being accommodated in the accommodating chamber; the electrode assembly comprises a plurality of electrode units, the plurality of electrode units being stacked in an axial direction of the accommodating chamber, the axial direction of the accommodating chamber is parallel to an extending direction of the accommodating chamber and is perpendicular to a plane where the opening is located; the top cover assembly comprises a top cover plate, a first electrode terminal and a second electrode terminal, the top cover plate being connected to the housing and located on a side of the electrode assembly in the axial direction, and the first electrode terminal and the second electrode terminal both protruding from the top cover plate and being electrically connected to the electrode assembly; and in a lengthwise direction of the top cover plate, the first electrode terminal and the second electrode terminal are respectively located on two sides of the center of the top cover plate, and a distance between the first electrode terminal and the second electrode terminal is D1, a distance between an edge of the top cover plate close to the first electrode terminal and the first electrode terminal is D2, and the value of D1/D2 is 1-6; wherein each of the plurality of electrode units comprises a first electrode plate, a second electrode plate and a membrane, which are coiled as a whole, the electrode unit has a main body region and corner regions, the corner regions being arranged at two ends of the main body region in a width direction, the main body regions of two adjacent electrode units being in contact with each other, and the main body regions of the electrode units being arranged opposite to the top cover plate; wherein a ratio of a width of the main body region in a width direction to a thickness of the top cover plate in a height direction is 10-60.