Abstract: A metal foil for secondary battery generating less cutting chips at the time of forming an opening and allowed to have a higher aperture ratio without reducing strength and a secondary battery in which short circuit caused by generation of electrode debris can be suppressed are provided. A metal foil 1 for secondary battery is provided with a metal thin plate 2, plural first convex portions 3A formed on a first principal surface 2a of the thin plate 2 by plastic forming and plural second convex portions 3B formed on a second principal surface 2b opposite to the first principal surface 2a by the plastic forming, wherein the convex portions 3A and 3B each have an opening 31 of which aperture plane 31a is orthogonal or substantially orthogonal to the principal surfaces 2a and the 2b.

Abstract: In a method for manufacturing a metal-made three-dimensional substrate, a metal foil is passed between a pair of rollers 21 and 22 . Each surface S of a pair of the rollers 21 and 22 is provided with protrusion portions 23 arranged in a grid pattern, and the protrusion portions 23 are arranged so that protrusions 23 of the one roller 22 are oriented toward the center 27 of a virtual quadrangle having four adjacent protrusion portions 23a to 23d of the other roller 21 as the apices.

Abstract: A metal foil for secondary battery generating less cutting chips at the time of forming an opening and allowed to have a higher aperture ratio without reducing strength and a secondary battery in which short circuit caused by generation of electrode debris can be suppressed are provided. A metal foil 1 for secondary battery is provided with a metal thin plate 2, plural first convex portions 3A formed on a first principal surface 2a of the thin plate 2 by plastic forming and plural second convex portions 3B formed on a second principal surface 2b opposite to the first principal surface 2a by the plastic forming, wherein the convex portions 3A and 3B each have an opening 31 of which aperture plane 31a is orthogonal or substantially orthogonal to the principal surfaces 2a and the 2b.