Laser welding method to weld two adjacent metal elements of a stator winding with rigid bars for an electric machine

A laser welding method to weld two adjacent metal elements (10;

• 18;
• 28;
• 30;
• 32;
• 34) of a stator winding (8) with rigid bars (9) for an electric machine (1) for establishing an electrical connection between the two adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34);
• wherein the two adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34) are arranged one beside the other and have respective upper surfaces (43), which are arranged coplanar to one another and have at least one common edge (44);
• the laser welding method comprises the step of aiming at the upper surfaces (43) of the two adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34);
• a first laser beam (38), which is suited to melt the metal making up the adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34) for forming a first molten metal bath (46) and is fed along a first straight welding line (45), which is perpendicular to the common edge (44) and extends through the common edge (44);
• and
• a second laser beam (38), which is suited to melt the metal making up the adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34) for forming a second molten metal bath (48) and is fed along a second straight welding line (47), which is perpendicular to the common edge (44), extends through the common edge (44), is parallel to and spaced apart from the first straight welding line (45) and has a length that is smaller than the one of the first straight welding line (45);
• wherein the second molten metal bath (48) merges with the previously generated first molten metal bath (46) for forming a single and common molten metal bath establishing, once cooled down, the electrical connection between the two adjacent metal elements (10;
• 18;
• 28;
• 30;
• 32;
• 34).