An electrode assembly and a secondary battery using the same, the electrode assembly including: first and second electrode plates, which are wound with a separator disposed therebetween; and first and second electrode tabs respectively adhered to the first and second electrode plates. At least the second plate has at least one groove formed therein. Under most embodiments, the composite material has a higher stiffness to weight ratio than a metal. The segment the ball lands in is sensed and the award associated with the landed in segment is paid out to the player.