CABLE-TYPE SECONDARY BATTERY

The present invention provides a cable-type secondary battery having a horizontal cross section of a predetermined shape and extending longitudinally, comprising: a core for supplying lithium ions, which comprises an electrolyte; an inner electrode surrounding the outer surface of the core for supplying lithium ions, and comprising an inner current collector in the form of a pipe having a three-dimensional network structure, the inner current collector being coated with an inner electrode active material on the outer surface thereof; a separation layer surrounding the outer surface of the inner electrode to prevent a short circuit between electrodes; and an outer electrode surrounding the outer surface of the separation layer and comprising an outer electrode active material layer and an outer current collector. In accordance with the present invention, the core for supplying lithium ions, which comprises an electrolyte, is disposed in the inner electrode having an open structure, which comprises an inner current collector in the form of a pipe having a three-dimensional network structure, so the electrolyte of the core for supplying lithium ions can be easily penetrated into an electrode active material, thereby facilitating the supply and exchange of lithium ions. Accordingly, the cable-type secondary battery of the present invention has such a core for supplying lithium ions to exhibit superior capacity and cycle characteristics.