Ni-plated steel sheet for battery can having excellent press formability

A Ni-plated steel sheet for a battery can having excellent press formability, wherein

• an Fe—Ni diffusion layer and a softened Ni layer formed on the Fe—Ni diffusion layer are formed on a surface of a steel sheet corresponding to an outer surface of the battery can,
• a semi-bright Ni plating layer is formed on the softened Ni layer,
• a Ni coating weight of the Fe—Ni diffusion layer and the softened Ni layer formed on the Fe—Ni diffusion layer is set smaller than a Ni coating weight of the semi-bright Ni plating layer,
• average roughness Ra of the semi-bright Ni plating layer measured by a traceable roughness gauge is 1.0 μm or more and 2.0 μm or less, and a maximum height Ry of the semi-bright Ni plating layer measured by the traceable roughness gauge is 5 μm or more and 20 μm or less, and
• surface roughness Ra′ of a surface of the semi-bright Ni plating layer in an area of 2.5 μm×2.5 μm which is obtained by an atomic force microscope falls within a range from 5 to 22 nm.