POWER STORAGE DEVICE PACKAGING MATERIAL, METHOD FOR PRODUCING THE SAME, AND POWER STORAGE DEVICE

A power storage device packaging material including a heat-sealable resin layer containing polypropylene and polyethylene, in which whitening and a decrease in the insulation properties due to molding are prevented. A laminate with at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order from an outer side toward an inner side, wherein the heat-sealable resin layer contains polypropylene and polyethylene; a cross section of the heat-sealable resin layer in a thickness direction parallel to TD, a sea-island structure is observed in a cross-sectional image obtained with scanning electron microscope; the cross-sectional image is such that when the total thickness of a layer positioned closer to inner side than the barrier layer is taken as 100%, the cross-sectional image is obtained within a range of thicknesses of up to 12.5% from a surface opposite to the barrier layer side of the heat-sealable resin layer.