New welding solution for more efficient production of EV power electronics

A new laser welding solution from Trumpf makes the production of power electronics for electric cars more efficient and reliable. The company has developed an automated process that enables users to weld copper electrical conductors directly to copper busbars. Manufacturers can now replace the screw connections traditionally used with this new technology.

“The key lies in the interplay between laser, sensor technology, AI and data,” says Woo-Sik Chung, who is responsible for the new laser welding solution at Trumpf. “Only when all components work in perfect harmony can highly automated and stable processes for series production be realised.”

Voltage distributors in electric cars operate more efficiently thanks to laser technology

The new laser solution creates a firmly fused joint with low electrical resistance, thereby making the power electronics more efficient. The process is primarily intended for use in the manufacture of voltage distributors in electric and plug-in hybrid vehicles. These components distribute the high voltage from the vehicle battery to the electric motor, lighting and other electrical consumers, and are fitted in every electric car.

Until now, manufacturers have had to produce conventional mechanical connections for voltage distributors in several process steps. This process is time-consuming and can lead to errors. Furthermore, mechanical screw connections are susceptible to vibrations and exhibit higher electrical resistance, which leads to energy losses and additional heat generation.

AI ensures reliable welding processes

At the heart of the solution is the interaction between laser, sensor technology and AI. First, an AI-supported image processing system identifies the component and positions the laser beam with pixel-level precision. A 9 kW fibre laser then welds the copper strands. During the process, an optical coherence tomography (OCT) system monitors the welding depth in real time to prevent the component from being welded right through.

After welding, another camera-based system checks the quality of the weld seam. AI is also used here. Just a few training images are sufficient to enable a reliable assessment of seam quality. All process steps, from component recognition through welding to quality control, take place in a single laser station. Component recognition and laser beam positioning occur within milliseconds.

“The entire process takes well under a second and is therefore designed for high-productivity series production,” says Woo-Sik Chung. “Our goal is seamless process control in real time, without slowing down the production flow.”

The 9 kW fibre laser is suitable for welding copper to a depth of several millimetres reliably and at high speed. For larger cross-sections, users can employ more powerful Trumpf lasers.