Next, FIG. 24 is a view illustrating a state in a case where the protrusion of the laminate film, which accommodates the electrodes, is sealed on four sides without performing a process in advance. When electrode group 207 is interposed between flat laminate film 201 on the upper side and flat laminate film 202 on the lower side and the four sides of the laminate films are sealed, steps of an electrode group accommodating section, which is formed in the laminate film, cause wrinkling 214 to appear on the four corners. Sealing reliability is lowered due to the wrinkling.

In view of the above problems of the related art, as well as other concerns, a battery is provided in which wrinkling or cracking does not appear in a laminate film, even when, the laminate film is curved upward or downward in any direction.

In order to achieve the above object, the battery according to an embodiment has a protrusion which is formed in advance on a laminate film to match a shape of an electrode group at a portion in which the electrode group is inserted, and then a concave-convex shape is formed on the laminate film, such that the laminate film is extended in any direction. In this state, an external force is applied to the battery and the battery is deformed and curved in every direction.

As above, a battery according to an embodiment has a protrusion, on a laminate film and a concave-convex shape is formed on the laminate film such that, even when an external force is applied to cause deformation or curvature, a problem such as leakage of an electrolyte is solved without wrinkling or cracking in the laminate film, and thus it is possible to improve quality and reliability.