Blue Laser Copper Joining to Prevent Spatter in Deep Welds
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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 beam 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 or keyhole mode welding with identical microstructures and hardness profiles to the base material, thereby producing high-quality welds with reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high-power IR laser (>1 kW) is used to initiate keyhole weld, then welding penetration is improved, but micro-explosions and spatter occur due to rapid vaporization
Solution Approach 1:
The patent changes the laser wavelength parameter from infrared (1030 nm) to blue/violet (405-500 nm) range. This parameter change fundamentally alters the interaction with copper material, achieving high absorption without the runaway vaporization effect that causes micro-explosions. The blue laser provides stable keyhole welding with controlled energy coupling.
Solution Approach 2:
The patent converts the high reflectivity of copper, which traditionally causes poor energy coupling, into a beneficial effect. By using blue laser wavelengths that are strongly absorbed by copper, the previously harmful reflection is transformed into useful energy absorption, enabling efficient welding without excessive power levels.
2Adaptability or versatility
If IR laser at 1030 nm is used for copper welding, then equipment availability is improved, but power coupling efficiency deteriorates due to high reflectivity
Solution Approach 1:
The patent changes the wavelength parameter from infrared (1030 nm) to blue/violet (405-500 nm). This parameter change exploits the wavelength-dependent optical properties of copper, where blue light is strongly absorbed while infrared is reflected. This resolves the contradiction by achieving high power coupling efficiency at the new wavelength.
3Strength
If ultrasonic welding method is used for copper foils, then bonding capability is improved, but process reliability deteriorates due to sonotrode wear and debris
Solution Approach 1:
The patent replaces the mechanical ultrasonic welding system with a laser-based thermal welding system. This substitution eliminates the mechanical contact between sonotrodes and workpiece, removing the source of wear and debris generation. The laser welding process provides consistent, contactless bonding with no tool wear.
4Manufacturing precision
If rapidly modulating laser power is used to prevent defects, then defect reduction is improved, but process complexity increases
Solution Approach 1:
The patent changes the fundamental wavelength parameter to blue/violet range, which inherently prevents the runaway vaporization phenomenon. This parameter change eliminates the need for complex rapid power modulation to control defects, as the blue laser naturally provides stable energy coupling without transitioning to excessive vaporization.
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 high-quality, reliable, and reproducible welds with minimal spatter and porosity, achieving deep penetration and uniform microstructures, suitable for high-performance electronic components and automotive applications, while reducing the need for high-power IR lasers and minimizing process variability.
Implementation Method 1
Laser welding of copper has proven to be very challenging due to high reflectivity... The use of a blue laser beam with a wavelength range of 405 nm to 500 nm for copper welding, which achieves efficient power coupling
Implementation Method 2
directing a blue laser beam at the work piece, whereby a weld is formed... high thermal conductivity... of copper
Implementation Method 3
the laser attempts to weld the copper, it initially heats it up to the melting point... wherein a microstructure of the copper based material, the HAZ and the resolidification zone are identical
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.