Metal welding | electrical wire welding:

Electrical wire splice welding
Electrical wire welding and terminal welding
Precision and reliability are the standard requirements for wiring harness welding in the automobile industry
Ultrasonic welding can still maintain optimum conductivity on the welded parts even over many years

Metal welding diagram

Splice welding of electrical wires

Welding of copper wires & terminals 

Welding of aluminum & copper wires

Multi-wire splice welding

Welding of electrical wires