NOVELTY - The battery (100) has an electrode assembly comprising a positive electrode plate on which a positive active material is formed, a negative electrode plate on which a negative active material is formed, and a separator separating the positive and negative electrode plates. A tin (120) accommodates the electrode assembly and includes an inner surface facing the electrode assembly. An inner active material layer is formed on the inner surface of the tin. A securing layer covers the inner active material layer. Thickness of the securing layer about 2-6 microns.    USE - Secondary battery for use in a portable device such as notebook computer, digital camera and camcorder.    ADVANTAGE - The battery ensures that a beading part firmly fixes and supports a cap assembly to the tin so as to prevent the cap assembly from being separated and prevent electrolyte from leaking to outside. The battery increases a contact area between the ceramic layer and the inner active material layer so as to enhance function of preventing the inner active material layer from being separated although shock is applied to an external surface of the secondary battery and function of the ceramic layer to increase battery overcharging stability and reduce danger of heating and explosion due to overcharging. The inner active material layer is formed in the inner surface of the tin so as to increase filling amount of active material according to an area of the inner surface of the tin, thus enhancing performance of the secondary battery. The electrode assembly acts as the negative electrode plate in which the negative active material is formed when the electrode assembly is close to the inner surface of the tin, so that charging and discharging capacity of the battery can be improved.    DETAILED DESCRIPTION - The securing layer is made of ceramic material, heat resistant resin material e.g. aramid resin, polyamideimide resin and polyimide resin, metal oxide, metal nitride, metal hydroxide or metal phosphide e.g. aluminum, titanium, chromium, zirconium, calcium, silicon and magnesium. The inner active material layer is made of positive and negative active materials.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a secondary battery.    Secondary battery (100)    Tin (120)    Beading part (121)    Cap assembly (130)