Use a soldering iron to directly solder the wire or use a simple spot welding method to solder a thin conductive part.
1. The first method is to use a soldering iron to directly solder the wires.
2. The second method is to use simple spot welding to solder thin conductive sheets. When soldering copper wires directly with a soldering iron, you should use diluted hydrochloric acid as a cleaning agent and lead-tin solder wire as a flux. You can make your own simple spot welding machine. Nickel foils are generally used to solder thin conductive foils.