The battery electrode of a mobile phone is made of layered polymer coated on aluminum foils and the hot rolling is applied to increase the density per volume of an electrode for a high capacity battery. The flatness of batteries surfaces should be les...
The battery electrode of a mobile phone is made of layered polymer coated on aluminum foils and the hot rolling is applied to increase the density per volume of an electrode for a high capacity battery. The flatness of batteries surfaces should be less than 2 ㎛. To satisfy the required flatness, the deformations of roll surface due to bending and heating of the roll should be minimized. There are many hot oil paths of 100℃ inside the roll for heating the polymer layers. FEA was used to calculate thermal deformations and temperatures distributions of the roller. Based on FEA, a modified surface curvature called a crown roll was suggested and this gave the area of 35% improved flatness compared with a flat roll. The flat roll satisfied the flatness of 2 ㎛ in the length of 340 ㎜ and the crown roll resulted in 460 ㎜. Experiments to measure the temperature distribution and thermal strain were performed and compared with FEA. There were only 6% difference between two results.