Abstract: The present invention solves the problem that a connecting portion between a horn and a vibration transmission rod has a tendency to get damaged and the problem associated with the structure in which a chip is attached to an end of the vibration transmission rod, which occur with the known ultrasonic vibration welder. A vibration transmission rod has an end surface serving as a vibration-and-pressure application surface, and a polygonal cross section. The vibration transmission rod is disposed at an end of a horn in such a manner that they vibrate together. The vibration transmission rod and a mass are formed separately. The mass applies pressure to a projection formed at a nodal point of the vibration transmission rod.

Abstract: The present invention solves the problem that a connecting portion between a horn and a vibration transmission rod has a tendency to get damaged and the problem associated with the structure in which a chip is attached to an end of the vibration transmission rod, which occur with the known ultrasonic vibration welder. A vibration transmission rod has an end surface serving as a vibration-and-pressure application surface, and a polygonal cross section. The vibration transmission rod is disposed at an end of a horn in such a manner that they vibrate together. The vibration transmission rod and a mass are formed separately. The mass applies pressure to a projection formed at a nodal point of the vibration transmission rod.

Abstract: A secondary battery has 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. The disconnect assembly includes a rupture disk sealing the open end of the outer casing, a cap electrically connected to a portion of a surface of the rupture disk and serving as an outer terminal of the battery, a weld plate joined to a portion of another surface of the rupture disk and serving as an inner terminal of the battery and having vent holes, and an insulating gasket sealing a gap between the rupture disk and the outer casing and holding the rupture disk and the weld plate in an electrically insulated fashion, except for a space around a junction between the rupture disk and the weld plate. A portion of the rupture disk and the weld plate are so joined that the diffusion of atoms at a junction interface is in an initial stage. An ultrasonic welding machine is used to carry out the above joining.