Blue Laser Copper Welding for Stable Low-Spatter Battery Joints
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Solution Overview
Problem
Laser welding of copper is challenging due to 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 battery manufacturing.
Innovation Solution
Using a blue laser beam with a wavelength of 405-500 nm, which achieves high absorption in copper, allowing for efficient power coupling and stable welding through conduction and keyhole modes, minimizing spatter and micro-explosions, and ensuring consistent weld quality by maintaining similar microstructures and hardness across the weld zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If IR laser welding is used on copper, then welding capability is achieved, 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-green (405-500 nm) to match copper's absorption characteristics. This parameter change allows efficient heating without rapid vaporization, eliminating micro-explosions and spatter while maintaining welding capability.
Solution Approach 2:
The patent employs periodic modulation of laser power to maintain stable keyhole welding. By cycling the power between high and low states, the process prevents runaway vaporization while sustaining the keyhole, thereby avoiding micro-explosions.
2Length of stationary object
If high-power IR laser is used to initiate keyhole weld, then welding depth is improved, but process control becomes difficult leading to defects
Solution Approach 1:
The patent changes the laser wavelength from infrared to blue-green, which increases copper absorption and allows keyhole initiation at lower power levels. This improves process control and reliability while achieving adequate welding depth.
Solution Approach 2:
The patent uses periodic laser power modulation to maintain stable keyhole welding at controlled power levels. This prevents runaway vaporization and ensures consistent process control for reliable deep welds.
3Ease of manufacture
If ultrasonic welding is used for copper foils, then welding is achieved, but sonotrode wear causes process variability
Solution Approach 1:
The patent replaces the mechanical ultrasonic welding system with a blue-green laser welding system. This eliminates sonotrode wear and its associated process variability, providing a more reliable and consistent welding process for copper foils.
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
The method provides high-quality, reproducible welds with minimal spatter and micro-explosions, achieving welds with hardness and microstructure identical to the base material, suitable for high-performance electronic components and batteries.
Implementation Method 1
the blue laser beam has been absorbed by the copper based material to a much greater extent than the infrared laser beam
Implementation Method 2
heat the copper based material to a melting temperature to melt the copper based material
Implementation Method 3
the blue laser beam is focused to a spot size of from about 10 μm to about 500 μm
Data Source
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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.