An assembly of elements is described comprising a separator comprising first and second opposing faces, a first electrode on the first face of the separator, a second electrode on the second face of the separator, a collector on the first electrode, and a terminal in electrical connection with the collector. A conductive element is interposed between the collector and the terminal, in contact with both the collector and the terminal. Manufacturing methods are also described. The assembly may be used as part of a cell within an electrochemical energy storage device, for example a primary battery, secondary battery or a supercapacitor.