When protrusion 103 is disposed only on one side illustrated in (A)-(C) of FIG. 11, the top surface of protrusion 103 only extends in the case of the downward, curvature, and is only compressed in the case of the upward curvature; however, the degree thereof is significant. However, as illustrated in (A) of FIG. 12, when the protrusions are disposed on both sides, during the downward curvature and the upward, curvature, the top surface of the protrusion, on the one side extends and the top surface of the protrusion on the other side shrinks; however, the degree thereof is small. Therefore, in a case where the height of the protrusion is significant, the protrusions are set on both sides as illustrated in (A) of FIG. 12, and thereby it is also effective in that wrinkling does not appear during the curvature.

In this embodiment, it is possible to further achieve effects that wrinkling or cracking does not appear during deformation and curvature by combining a plurality of embodiments.

As an example, FIG. 13 is a view illustrating a state in a case in which protrusions 115 and 116 are set on laminate film 101 on the upper side and on laminate film 102 on the lower side, and a concentric concave-convex wave shape (concentric crest ridges or trough furrows 111) is formed on the top surface of protrusions 115 and 116 so as to extend or shrink in any direction, and in which side surface 113 of the protrusion is gradually inclined and the wave shape is formed. Depending on a usage circumstance or a required specification of the battery, there is a need to select an optimal laminate film.