TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: In the battery: the electrode assembly further includes interface portions between the curved surface portions and the plane surface portion, and the pressing member further includes a first pressing portion and a second pressing portion that face each other and press respective parts of the interface portions and the plane surface portion in a surface contact manner, and a support portion that connects the first pressing portion and the second pressing portion. The pressing member includes a first pressing member coupled to a first curved surface portion at an upper portion of the electrode assembly; and a second pressing member coupled to a second curved surface portion at a lower portion of the electrode assembly. The support portion of the first pressing member includes a through-hole that faces the first curved surface portion; the electrode assembly further includes interface portions between the curved surface portions and the plane surface portion, electrode assembly is provided as many electrode assemblies, and the pressing member includes a first pressing portion and a second pressing portion that press respective parts of the interface portions and plane surface portion of two electrode assemblies disposed at outermost sides among the electrode assemblies, and a support portion connecting the first pressing portion and the second pressing portion in a surface contact manner, where the pressing member further includes at least one third pressing portion connected to the support portion between the first pressing portion and the second pressing portion, the third pressing portion extends between two adjacent ones of the electrode assemblies so that two sides of the third pressing portion press facing parts of the interface portions and the plane surface portion of the adjacent ones of the electrode assemblies in a surface contact manner, and the support portion of the pressing member includes at least one through-hole that faces toward the curved surface portions of each of the electrode assemblies; or the electrode assembly further includes an interface portion between the curved surface portions and the plane surface portions, and the pressing member includes a first pressing portion and a second pressing portion that respectively include inner protrusions that face toward each other and press respective parts of the interface portion, and a support portion connecting the first pressing portion and the second pressing portion. The pressing member has a structure so that: when the first pressing portion and the second pressing portion are in a state of not pressing the respective parts of the interface portions and the plane surface portion, a distance between the first pressing portion and the second pressing portion gradually decreases as a distance from the support portion increases; and when the first pressing portion and the second pressing portions are pressing the respective parts of the interface portions and the plane surface portion, the first pressing portion and the second pressing portion form a right angle with the support portion, and thus, maintain a parallel state between them. The support portion is curved to correspond to one curved surface portion of the curved surface portions of the electrode assembly, where the support portion supports the one curved surface portion in a surface contact manner, and the support portion includes a through-hole that faces the one curved surface portion. The first pressing portion, the support portion, and the second pressing portion have a same thickness along the plane surface portion and the one curved surface portion. A thickness of each of the first pressing portion, the support portion, and the second pressing portion is gradually increased from the plane surface portion toward the one curved surface portion.