Stator Lead Surface Modification for Laser Welding
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Solution Overview
Problem
Existing methods for joining stator leads to bus bars in electrical machines face challenges due to low absorptivity of infrared light, leading to ineffective laser welding and potential damage from high-powered laser applications, especially with highly conductive materials like copper, which reflect laser light and fail to form suitable welds.
Innovation Solution
The implementation of surface modifications such as knurling or roughening on stator leads to increase absorptivity of infrared light, allowing for controlled laser welding with minimal heat generation and precise joining of stator windings to bus bars without consumable materials or complex setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-powered laser is applied to weld copper leads to bus bars, then welding penetration is achieved, but copper reflects laser light causing ineffective welding and potential damage
Solution Approach 1:
The patent applies surface modification techniques (knurling, roughening, or applying dark-colored coatings) to change the optical parameters of the copper lead surface. This increases the absorptivity of infrared laser light by altering the surface properties, enabling effective laser welding of highly reflective copper materials without requiring excessive laser power that could cause damage.
2Reliability
If traditional joining methods are used for stator leads, then connection is achieved, but consumable materials and complex setups are required
Solution Approach 1:
The patent replaces traditional mechanical joining methods (such as crimping, soldering, or mechanical fasteners that require consumable materials and complex tooling) with laser welding. This substitution eliminates the need for consumable joining materials and simplifies the setup while maintaining or improving joining reliability through precise, controlled thermal bonding.
3Productivity
If laser welding is attempted on unmodified copper leads, then welding speed is increased, but heat generation causes distortion and damage
Solution Approach 1:
By modifying the surface properties of the copper leads to increase laser light absorptivity, the patent enables efficient energy transfer at lower laser power levels. This allows for fast welding speeds while maintaining controlled heat input, preventing thermal distortion and damage to the stator leads and bus bars.
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 enables efficient, instantaneous, and reliable laser welding with adequate penetration and minimal heat impact, allowing for high production rates and precise assembly of electrical machine components without distortion or foreign material introduction.
Implementation Method 1
increase absorptivity of infrared light
Implementation Method 2
laser welding the lead of the stator winding to the bus bar
Implementation Method 3
controlled laser welding with minimal heat generation
Data Source
AI summary
Certain aspects relate to systems and methods to join leads of stator windings to components of an electric machine, such as a bus bar of a stator of the electric machine. Systems and methods include modifying a surface of the lead and laser welding the surface-modified lead to the bus bar. Systems and methods can include reducing the reflectivity of the lead by imparting a non-smooth surface on the lead, thereby allowing a laser to deliver concentrated energy onto the lead. The surface-modified lead can include knurled surface, a pattern of raised grooves stamped into the surface of the lead, or a roughened surface.