Device for producing a metal foil stack, comprising - an ultrasonic welding device for introducing an embossed surface into a metal foil stack, in particular for a cell of a lithium-ion battery, - wherein the ultrasonic welding device has a sonotrode and an anvil, and - wherein the anvil or the sonotrode has a number of first projections which protrude from its work surface (4c or 6a) and are intended for forming the, in particular web-like, embossed surface by compacting the metal foil stack, - wherein if the sonotrode has the first projections, the anvil has a contour, or if the anvil has the first projections, the sonotrode has the contour, - wherein the contour is formed by a number of second projections which protrude from the respective work surface (4c or 6a) or by a number of recesses, in particular corresponding to the first projections, in the respective work surface (4c or 6a), and - wherein the anvil and the sonotrode are aligned in relation to one another such that the first projections and the recesses are situated opposite one another in a direction perpendicular to the work surfaces (4c, 6a), or such that the first projections are offset relative to the second projections with respect to a direction parallel to the working surfaces (4c, 6a), in particular in the manner of a raster, - wherein the first projections, the recesses and/or the second projections have a height of between 0.02 mm and 1.0 mm, in particular between 0.05 mm and 0.5 mm, and - a laser apparatus for generating a laser beam for welding the metal foils of the metal foil stack in the region of the embossed surface, wherein the laser apparatus is aligned with respect to the sonotrode. - an ultrasonic welding device for introducing an embossed surface into a metal foil stack, in particular for a cell of a lithium-ion battery, - wherein the ultrasonic welding device has a sonotrode and an anvil, and - wherein the anvil or the sonotrode has a number of first projections which protrude from its work surface (4c or 6a) and are intended for forming the, in particular web-like, embossed surface by compacting the metal foil stack, - wherein if the sonotrode has the first projections, the anvil has a contour, or if the anvil has the first projections, the sonotrode has the contour, - wherein the contour is formed by a number of second projections which protrude from the respective work surface (4c or 6a) or by a number of recesses, in particular corresponding to the first projections, in the respective work surface (4c or 6a), and - wherein the anvil and the sonotrode are aligned in relation to one another such that the first projections and the recesses are situated opposite one another in a direction perpendicular to the work surfaces (4c, 6a), or such that the first projections are offset relative to the second projections with respect to a direction parallel to the working surfaces (4c, 6a), in particular in the manner of a raster, - wherein the first projections, the recesses and/or the second projections have a height of between 0.02 mm and 1.0 mm, in particular between 0.05 mm and 0.5 mm, and - wherein the ultrasonic welding device has a sonotrode and an anvil, and - wherein the anvil or the sonotrode has a number of first projections which protrude from its work surface (4c or 6a) and are intended for forming the, in particular web-like, embossed surface by compacting the metal foil stack, - wherein if the sonotrode has the first projections, the anvil has a contour, or if the anvil has the first projections, the sonotrode has the contour, - wherein the contour is formed by a number of second projections which protrude from the respective work surface (4c or 6a) or by a number of recesses, in particular corresponding to the first projections, in the respective work surface (4c or 6a), and - wherein the anvil and the sonotrode are aligned in relation to one another such that the first projections and the recesses are situated opposite one another in a direction perpendicular to the work surfaces (4c, 6a), or such that the first projections are offset relative to the second projections with respect to a direction parallel to the working surfaces (4c, 6a), in particular in the manner of a raster, - wherein the first projections, the recesses and/or the second projections have a height of between 0.02 mm and 1.0 mm, in particular between 0.05 mm and 0.5 mm, and - a laser apparatus for generating a laser beam for welding the metal foils of the metal foil stack in the region of the embossed surface, wherein the laser apparatus is aligned with respect to the sonotrode.