Conductor End Welding Path to Reduce Pores in Hairpin Stators

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing welding methods for conductor ends in electrical machines, particularly in hairpin stators, suffer from unreliable and low-quality welded joints due to pore formation during laser beam welding, which are not reproducible and require additional system technology.

Innovation Solution

A method and device that involves directing a welding jet onto the joining area of conductor ends to create a molten pool and then moving the jet out of the area into an edge region, terminating the emission outside the weld pool, while using position detection and control systems to ensure precise positioning, applicable to all laser types and geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the welding jet is directed onto the joining area to create a molten pool, then the welded joints achieve mechanical strength and electrical conductivity, but pore formation occurs during the welding process reducing joint quality

Engineering Contradiction:
Improvemechanical strength of welded jointVSAvoidquality of welded joint
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The welding jet is directed into the edge region before actually terminating the welding process. This preliminary action of moving the jet to the edge region allows the molten pool to cool and solidify properly, preventing pore formation while ensuring complete welding of the joining area. The jet position is adjusted in advance to optimize both weld quality and pore prevention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of terminating the welding jet directly after welding the joining area (conventional approach), the method inverts the sequence by first moving the jet to the edge region and then terminating emission. This reversal ensures that the molten pool is properly controlled and cooled, preventing pore formation while maintaining weld integrity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If conventional welding methods are used, then the welding process is simple, but additional system technology is required to reduce pore formation and improve joint quality

Engineering Contradiction:
Improvesimplicity of welding processVSAvoidquality of welded joint
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The welding jet position is dynamically adjusted during the welding process. The jet is moved from the joining area to the edge region in a controlled manner, and the emission timing is dynamically optimized based on the welding progress. This dynamic control achieves pore-free welds without requiring additional complex system technology.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The method changes the temporal and spatial parameters of the welding jet emission. By adjusting when and where the jet is directed (into the edge region before termination), the process achieves better weld quality without adding complex equipment. The emission timing and jet position are optimized parameters that prevent pore formation.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reliably reduces pore formation and enhances the quality of welded joints, ensuring mechanical strength and electrical conductivity without additional system technology, suitable for large-scale industrial production of electric motors and hairpin stators.

Implementation Method 1

Directing a welding jet onto the joining area of the conductor end group to create a molten pool

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP4699730A1Method and device for welding conductor ends
Publication Date: 2026.02.25 GROB WERKE & K G
  • EP4699730A1 patent drawingFigure 1
  • EP4699730A1 patent drawingFigure 2
  • EP4699730A1 patent drawingFigure 3a~4e

AI summary

The invention relates to a welding method for welding conductor ends (24, 24.1, 24.2) of a component (26) for an electrical machine grouped in a conductor end group (64), wherein at least a first conductor end (24, 24.1) of the conductor end group (64) and a second conductor end (24, 24.2) of the conductor end group (64) are to be joined together in a joining area (66) of the conductor end group (64), where the first conductor end (24.1) and the second conductor end (24.2) are located next to each other. To improve the quality of the weld, it is proposed that the welding process includes the following steps: a) directing a welding jet (68) towards the joining area (66) of the conductor end group (64) to create a weld pool (70), and b) moving the welding jet (68) out of the joining area (66) into an edge area (72) of the conductor end group (64) and terminating the emission of the welding jet (64) there.