An electrochemical device having an electrode plate assembly. The electrode plate assembly includes (a) at least one first electrode, (b) at least one second electrode, and (c) a separator interposed between the first electrode and the second electrode. The first electrode includes a first current collector sheet and at least one first electrode mixture layer carried thereon. The second electrodeincludes a second current collector sheet and at least one second electrode mixture layer carried thereon. At least one of the first current collector sheet and the second current collector sheet hasa conductive area and an insulating area.