Blue Laser Copper Welding for Stable, Spatter-Free Joints
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Solution Overview
Problem
Laser welding of copper is challenging due to its high reflectivity, thermal conductivity, and heat capacity, leading to issues such as micro-explosions, spatter, and unpredictable weld quality, particularly in high-performance electronics and automotive applications where reliable bonding of copper foils and thicker materials is required.
Innovation Solution
The use of a blue laser with a wavelength range of 405 nm to 500 nm for copper welding, which achieves efficient power coupling and stable welding by minimizing vaporization and spatter, allowing for conduction and keyhole mode welding with high-quality welds that match the base material's microstructure and hardness, and enabling the welding of copper to itself and other metals with improved reproducibility and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an IR laser source at 1030 nm is used to weld copper, then the welding process can be initiated, but the high reflectivity of copper at this wavelength makes it difficult to couple power into the material, requiring high-power levels (>1 kW) to initiate a keyhole weld
Solution Approach 1:
The patent changes the laser wavelength parameter from infrared (1030 nm) to blue-green (450-480 nm) to match the absorption characteristics of copper. This parameter change enables efficient power coupling at much lower power levels (10-100 W) while maintaining effective welding, directly resolving the contradiction between power coupling efficiency and required laser power.
2Productivity
If a high-power IR laser is used to initiate a keyhole weld in copper, then welding can proceed, but the vapor in the keyhole causes micro-explosions that spray molten copper and create defects
Solution Approach 1:
By changing the laser wavelength to blue-green (450-480 nm), the patent achieves efficient copper absorption at lower power densities. This prevents the runaway vaporization process that causes micro-explosions in IR laser welding, thereby maintaining high welding speeds while producing defect-free, reliable welds with consistent microstructure.
Solution Approach 2:
The patent converts the high reflectivity of copper, which normally causes poor energy absorption, into a benefit by selecting a blue-green wavelength that is naturally absorbed by copper. This eliminates the need for high power levels that cause harmful vaporization and micro-explosions, transforming the material's optical property into an advantage for controlled, high-quality welding.
3Ease of manufacture
If IR laser welding is used on copper, then welding can be performed, but the process has narrow processing windows and uncontrolled spatter
Solution Approach 1:
The patent changes the laser wavelength parameter to blue-green (450-480 nm), which fundamentally improves process control by matching copper's absorption characteristics. This enables wide processing windows with stable weld pools, controlled keyhole formation, and minimal spatter, directly achieving both ease of manufacture and manufacturing precision simultaneously.
4Productivity
If ultrasonic welding methods are used to bond copper foils, then welding can be performed, but the sonotrodes wear during production resulting in process variabilities and incomplete welds
Solution Approach 1:
The patent replaces the mechanical ultrasonic welding system with a blue-green laser welding system. This substitution eliminates the mechanical sonotrode contact and wear issues, using optical energy instead of mechanical vibration. The result is improved manufacturing yield with no tool wear, as the laser beam does not physically contact the copper foils during welding.
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 results in high-quality, spatter-free welds with consistent microstructure and hardness, enabling efficient welding of copper-based materials, including foils and thicker components, with increased speed and reliability, addressing the limitations of existing IR laser welding methods.
Implementation Method 1
directing a blue laser beam at the work piece, whereby a weld is formed... welding copper with a blue laser with a wavelength range of 405 nm to 500 nm, which achieves efficient power coupling
Implementation Method 2
directing a blue laser beam at the work piece, whereby a weld is formed between the first piece of copper based material and the second piece of copper based material
Data Source
AI summary
A visible light laser system and operation for welding materials together. A blue laser system that forms essentially perfect welds for copper based materials. A blue laser system and operation for welding conductive elements, and in particular thin conductive elements, together for use in energy storage devices, such as battery packs.