| abstract |
A battery packaging material wherein a sheet-like laminated body is formed by sequentially stacking at least a base layer, a metal layer, and a sealant layer, said battery packaging material being equipped with a substantially rectangular space that is formed so as to protrude from the sealant layer side toward the base layer side, and that accommodates a battery element on the sealant layer side. In addition, when the battery packaging material is viewed in a planar view from the base layer side, a first curved section and a second curved section are provided in order from the center portion toward the end portions of the battery packaging material, in a cross section in the thickness direction on a line connecting opposing corner parts protruding in a substantially rectangular shape. In addition, the thickness (a) of the metal layer at the first curved section, the thickness (c) of the metal layer at the second curved section, and the thickness (b) of the metal layer at the section located between the first curved section and the second curved section, satisfy the following relationship a ≥ b > c or a ≥ c > b. |