Patent ID: 6195251
Filing Date: 2001-02-27
Classification: H01G,Y02E

Abstract:
An electrode assembly for an electric double layer capacitor, comprising a current collector made of an aluminum foil, and an electrode comprising a carbonaceous material having a specific surface area of at least 500 m.sup.2 /g and a binder, bonded on at least one side of the current collector,wherein the aluminum foil has a roughened layer having a thickness of from 0.5 to 5 .mu.m on the surface on the side bonded to the electrode,wherein a dumbbell specimen of the aluminum foil has a breaking energy of at least 3 kg.multidot.mm, andwherein the dumbbell specimen comprisesa rectangular center that is 40 mm long and 10 mm wide, has two ends, and is bisected by a longitudinal axis; andtwo outer sections that are each 40 mm long, and are each connected to respective ends of the rectangular center, whereeach outer section comprises a rectangular portion and a junction portion;the rectangular portion is 25 mm wide and 15 mm long;the width of the rectangular portion is bisected by the longitudinal axis;the junction portion has two sides arranged symmetrically on either side of the longitudinal axis;each of the two sides varies smoothly along a first arc and a second arc from a first end 10 mm wide connected to the rectangular center to a second end 25 mm wide connected to the rectangular portion;the first arc has a radius of 21 mm and is centered at a point 26 mm from the longitudinal axis along a line extending from the first end perpendicular to the longitudinal axis on the same side of the longitudinal axis as the first arc; andthe second arc has a radius of 25 mm and is centered at a point 12.5 mm from the longitudinal axis along a line extending from the second end perpendicular to the longitudinal axis on the opposite side of the longitudinal axis as the second arc.