Abstract: An energy storage device is disclosed that includes an axial structure with two or more rigid energy storage units and conductive flexible components separating adjacent rigid energy storage units. The rigid energy storage units include a plurality of folded layers, including an anode layer, a cathode layer, a first current collector layer, a second current collector layer, one or more separator layers, and one or more tape layers. The adjacent rigid energy storage units are produced by folding the plurality of layers one or more times onto themselves at a plurality of locations along the axial structure. The axial structure is then sealed in an aluminized casing along with an electrolyte material. The energy storage device exhibits high energy density, high foldability, and excellent electrochemical performances by virtue of the folded rigid energy storage segments connected by the flexible components.