Joint of copper terminal and aluminium conductor and ultrasonic welding method thereof

An ultrasonic welding method for forming a joint of a copper terminal and an aluminum wire, wherein the ultrasonic welding method comprises the following steps of:

• 1) fixing, by an electroplating process or an electromagnetic welding process or an arc spraying process or a pressure welding process, a metal spacer layer to a zone of the to-be-welded copper terminal or aluminum wire, wherein the zone at least comprises a welding zone, and preferably, the metal spacer layer is fixed to the zone of the to-be-welded copper terminal or aluminum wire by an electroplating process;
• 2) joining the copper terminal and the aluminum wire and fixing the joined copper terminal and aluminum wire to a mold or a tool of an ultrasonic welding device;
• 3) starting the ultrasonic welding device, and welding the joined copper terminal and aluminum wire by using the vibration energy of the ultrasonic welding device transferred to the ultrasonic mold or tool, wherein the copper terminal and the aluminum wire are melted due to heat generated by high-speed friction between the copper terminal and the aluminum wire, and the welding process is performed under a pressure.