The invention relates to an electrical energy storage system (100) comprising at least one coiled electrical energy storage element placed inside an envelope (200), said envelope (200) containing the coiled electrical energy storage element in a main body (210) of the envelope (200) and including at least one lid (230, 240), characterized in that said lid (230, 240), placed at one end of the main body of the envelope (200) and electrically connected by electrical connection means (280) to the coiled electrical energy storage element, is fastened to the main body (210) of the envelope (200) by a bonding means (600). The invention is particularly applicable in the production of electrical energy storage assemblies such as supercapacitors, batteries or generators.