Patent ID: 6537693
Filing Date: 2003-03-25
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
A method of manufacturing a secondary battery having a disconnect assembly for cutting off a current path when a pressure in the battery is abnormal, disposed in an open end of an outer casing, said disconnect assembly including a rupture disk sealing the open end of said outer casing, a cap electrically connected to a portion of a surface of said rupture disk and serving as an outer terminal of the battery, a weld plate joined to a portion of another surface of said rupture disk and serving as an inner terminal of the battery and having vent holes, and an insulating gasket sealing a gap between said rupture disk and said outer casing and holding said rupture disk and said weld plate in an electrically insulated fashion, except for a space around a junction between said rupture disk and said weld plate, said method comprising the step of:joining a portion of said rupture disk and said weld plate with an ultrasonic welding machine by finishing the diffusion of atoms at a junction interface in an initial stage, wherein said initial stage comprises a stage where an area of diffusion-joined regions formed of nuggets is at most 50% of the joined surfaces.