The present invention relates to 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, comprising a spiral electrode formed by spirally twisting two or more wire-type inner current collectors coated with an inner electrode active material on the 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.
The core for supplying lithium ions, which comprises an electrolyte, according to the present invention is disposed in the inner electrode having an open structure and comprising a spiral electrode, from which 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. Thus, the cable-type secondary battery of the present invention has the core for supplying lithium ions to exhibit good capacity and superior cycle characteristics.