Ultrasonic welding is a common and indispensable technology in the packaging of power electronics. Typical applications are terminals and power contacts, e.g. in motor drive or inverter modules, as well as busbar connections. The process control requirements for welding power electronics connectors or bus bars, e.g. on batteries, are increasingly overlapping with requirements typical for heavy wire bonding. Smart ultrasonic welding is a new technology combining the force and ultrasonic power of conventional ultrasonic welding equipment with the flexibility, precision, speed and advanced process control features of wire bonding machines.
This contribution discusses the characteristics of smart welding equipment and presents process results for two different smart welding applications. On the low power end, smart welding and wire bonding are compared in the production of cylindrical cell battery packs, using a 100 W ultrasound system and aluminium connectors. Towards the high power end, 3 × 1.2 mm2 copper leads are welded to DBC with a contact area of 3 × 3 mm2, using a 1.5 kW ultrasound system. Both applications demonstrate advantages of smart welding over conventional ultrasonic welding.