Nickel-plated, heat-treated steel sheet for battery cans

A nickel-plated heat-treated steel sheet for a battery can, comprising:

• an iron-nickel diffusion layer formed on a first surface of a steel sheet to be an inner surface of the battery can,
• a first nickel layer constituting an outermost layer with a nickel amount of 4.4 to 26.7 g/m2 on the iron-nickel diffusion layer, and
• a second nickel layer constituting an outermost layer on a second surface of the steel sheet to be an outer surface of the battery can,
• wherein when an Fe intensity and a Ni intensity are continuously measured along a depth direction from the first surface of the nickel-plated heat-treated steel sheet for a battery can, by using a high frequency glow discharge optical emission spectrometric analyzer, a difference (D2-D1) between a depth (D1) at which the Fe intensity exhibits a first predetermined value and a depth (D2) at which the Ni intensity exhibits a second predetermined value is less than 0.04 μm,
• wherein the depth (D1) exhibiting the first predetermined value is the depth exhibiting an intensity of 10% of a saturated value of the Fe intensity measured by the above-described measurement, and
• the depth (D2) exhibiting the second predetermined value is the depth exhibiting an intensity of 10% of a maximum value when the measurement is further performed along the depth direction after the Ni intensity shows the maximum value by the above-described measurement,
• wherein the outermost layer on the iron-nickel diffusion layer consists of nickel and the outermost layer on the second surface of the steel sheet consists of nickel.