Abstract: A roughened nickel-plated sheet including a roughened nickel layer on at least one surface of a metal substrate as the outermost layer thereof, the roughened nickel layer being formed of a plurality of nickel protrusions. When the structure of the roughened nickel-plated sheet is observed at height positions with a focused ion beam scanning electron microscope (FIB-SEM), the absolute value of the change rate of the nickel occupancy is equal to or less than a predetermined value, and the nickel occupancy and the number of nickel protrusions present at a height position located 2.0 ?m from the base position of the roughened nickel layer toward the surface in the height direction are equal to or more than predetermined values, respectively.

Abstract: [Object] To provide a surface treated steel foil having hydrogen barrier properties suitable for a bipolar battery. [Solving Means] A surface treated steel foil having a first surface and a second surface located on a side opposite to the first surface, the surface treated steel foil including a base material composed of a low carbon steel or an ultra low carbon steel, and an iron-nickel alloy layer laminated on the base material on at least one surface side of the first surface side and the second surface side. Fe1Ni1 is included as an alloy phase in the iron-nickel alloy layer, an orientation index in X-ray diffraction of a (220) plane of Fe1Ni1 in the surface having the iron-nickel alloy layer is not less than 1.0, and the ratio of the maximum value of diffraction intensity of the (220) plane of Fe1Ni1 and the maximum value of diffraction intensity of a Fe(200) plane satisfies the following formula (1).