A storage device for electrical energy with a plurality of flat storage cells for the storage and the discharge of electrical energy with opposing flat-shaped conductors, spacer elements for maintaining a predetermined space between the storage cells and a clamping means for the clamping of the cells into a stack. The spacer elements have pressure surface areas, wherein the conductors of the cells, each are clamped between the pressure surface areas of two spacer elements by the clamping means by means of force closure. In the area of opposing pressure surface areas of a spacer element, either a contacting element for establishing an electrical connection between the opposing pressure surface areas or an insulating structure is provided. The spacer elements are provided such, that the compressions between the pressure surface areas with an insulating structure and between the pressure surface areas with a contacting element, are ajusted to each other.