Wave-shaped crest ridge or trough furrow 105 is in a state of being alternately parallel to side surfaces 106 of protrusion 103 in the right-left direction and to side surfaces 107 thereof in the front-rear direction, and of being continuous in a step shape. In this manner, since wave-shaped crest ridge or through, furrow 105 exists in a state of being parallel to right and left side surfaces 106 and front and rear side surfaces 107 of protrusion 103 and the top surface of protrusion 103 of the laminate film on the upper side extends in front-rear and right-left directions, wrinkling or cracking does not appear, even when the battery is curved in the right-left direction and the front-rear direction.

FIG. 3 is a view of a manufacturing process of the battery according to an exemplary embodiment. First, protrusion 103 is formed in laminate film 101 on the upper side to match the size of electrode group 108 so as to accommodate electrode group 108. Next, concave-convex wave shape 105 is formed on the top surface of protrusion 103. Then, electrode group 100 is interposed between laminate film 101 on the upper side and laminate film 102 on the lower side and the four sides thereof are sealed.

In the present manufacturing process, protrusion 103 which accommodates the electrode group is formed before the four sides are sealed, and thereby it is possible to prevent wrinkling from appearing on the four corners when the sealing is performed, as in the related, art. In the present, embodiment, after protrusion 103 is formed, wave shape 105 is formed. However, protrusion 103 and the wave shape may be simultaneously formed. The present manufacturing process is applied to all of the following embodiments.