A power-cell packaging material including a layered body obtained by layering at least a substrate layer, a metal layer, an insulating layer, and a sealant layer, in this order. The insulating layer has a hardness in the range of 10-300 MPa, when measured by using a nanoindenter and pressing the indenter 5 μm into the insulating layer from a cross-section of the layered body in the layering direction thereof.