NOVELTY - A flat-type lithium secondary battery comprises some positive and negative electrodes made by applying their electrode mixtures to the corresponding current collectors, in which the required electrode mixture contains specific electrode-active material and solid or gel electrolyte in layer form with full integration. The positive electrode and negative electrode are opposed with electrolyte layers interleaved.    USE - The secondary battery can be used in mobile phones, lap-top PCs and other portable electronic gadgets.    ADVANTAGE - The batteries have high and stable performance, lightweight and miniaturizability.    DETAILED DESCRIPTION - A flat-type lithium secondary battery comprises some positive and negative electrodes made by applying their electrode mixtures to the corresponding current collectors, in which the required electrode mixture contains specific electrode-active material and solid or gel electrolyte in layer form with full integration. The positive electrode and negative electrode are opposed with electrolyte layers interleaved.    An INDEPENDENT CLAIM is also included for a process for making the battery in which (a) the electrode-active material is mixed with an organic solvent for application to a current collect, drying and pressing into an electrode-active sheet; (b) a mixture of electrolyte and organic monomer containing not less than 2 polymerizable functional groups at the molecular terminal is used to impregnate the electrode-active sheet; and (c) polymerizing the organic monomer to provide a layer of electrolyte in solid or gel on the electrode-active sheet; or by coating the electrode-active material with the electrolyte-containing monomer mixture first before application to the current collector, forming sheet and polymerization; and then the thus obtained electrodes and electrolyte layers are assembled.    DESCRIPTION OF DRAWING(S) - Longitudinal cross-section of the battery.    Positive electrode (1)    positive electrode mixture (11)    aluminum foil positive electrode current collector (12)    negative electrode (2)    negative electrode mixture (21)    copper foil negative electrode current collector (22)    electrolyte layers (3, 23)