BATTERIES HAVING COILED ELECTRODE PLATE GROUP
A battery (100) comprises a coiled electrode plate group which comprises a positive electrode plate (120), a negative electrode (130) plate and an insulating separator sheet (140). The separator sheet (140) provides electrical insulation between the positive and negative plates (120, 130). The insulating separator sheet (140) comprises a first longitudinal portion, a second longitudinal portion and a intermediate perforated portion (148) between the first and second longitudinal portions.