Copper laser welding from 3m/min to 35m/min at 8kW thanks to beam shaping with Multi-Plane Light Conversion

Authors: Avinash Kumar¹, Adeline Orieux¹, Nicolas Gaillard², David Lamaitre², Gwenn Pallier¹, Guillaume Labroille¹ 

1 Cailabs, FRANCE

2 Institut Maupertuis, FRANCE 

Abstract

Copper is a widely used material in the electric vehicle industry due to its excellent electrical conductivity and high thermal conductivity. However, welding copper can be challenging due to the high thermal conductivity and low absorptivity at 1µm. We discuss a new method of copper laser welding that utilizes beam shaping based on Multi-Plane Light Conversion (MPLC) technology to stabilize the melt pool for a broad range of speed and power.

The welding performance of different shapes based on MPLC technology is discussed including the penetration depth from 4 to 8kW and from 3 to 15m/min welding. In addition, live X-ray analysis has been performed as well as post-processing X-ray showing that no pores were inside the welds. The X-ray analysis including pores counting and capillary length for different welding parameters is described.

The developed system allows for deep penetration welding up to 2.8mm at 8kW and 3m/min, which may be applied to busbars welding. On the other side, deep penetration welding up to 35m/min at 8kW has been possible too, paving the way for applications such as hair pins welding.

The welding performance of the MPLC technology based system versus a beam shaping based on double fiber laser technology system in similar conditions as well as versus no beam-shaping is shown. It includes the process window comparison with the welding penetration depth analysis and pores analysis. It demonstrates that the MPLC system enables lower speed as well as higher speed high quality welding.