Blue Laser Copper Foil Welding Without Spatter Or Porosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current laser welding techniques for copper, particularly using infrared lasers, face challenges due to high reflectivity, thermal conductivity, and heat capacity, leading to issues like micro-explosions, spatter, and unpredictable weld quality, especially when welding copper foils or stacks.
Innovation Solution
The use of a blue laser beam with specific properties, including at least 500 Watts of power, a beam parameter product of about 44 mm mrad and less, a spot size of about 400 μm and less, an average intensity of at least 400 kW/cm², and a peak intensity of at least 800 kW/cm², along with a non-oxidizing beam clearing gas, to achieve stable and high-quality laser welding of copper foils and other metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If infrared 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 (450 nm), which fundamentally alters the interaction with copper. Blue laser light is absorbed much more efficiently by copper, allowing welding at lower power densities that prevent rapid vaporization and keyhole formation, thereby eliminating micro-explosions and spatter while maintaining welding capability
Solution Approach 2:
The patent employs periodic modulation of the laser beam, using pulsed or alternating patterns to control heat input. This periodic action allows the copper to heat and cool cyclically, preventing continuous rapid vaporization and keyhole instability, thus reducing micro-explosions and spatter during the welding process
2Manufacturing precision
If high power infrared laser is used to initiate keyhole weld, then welding penetration is improved, but process control becomes difficult and defects increase
Solution Approach 1:
The patent changes the laser wavelength from infrared to blue, which increases copper absorption and enables effective welding at lower power levels. This parameter change allows for better process control and reduced defects while achieving sufficient penetration, as the blue laser efficiently couples energy into the copper without requiring high-power keyhole modes that are difficult to control
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 laser welding system. This substitution eliminates the mechanical sonotrode that wears during production, thereby removing the source of process variability associated with sonotrode degradation while maintaining the ability to weld copper foils effectively
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 the production of welds with no visible splatter and no visible porosity, achieving high reproducibility and reliability, and is particularly effective for welding copper foils and stacks, as well as other metals like aluminum and stainless steel.
Implementation Method 1
the laser attempts to weld the copper, it initially heats it up to the melting point
Implementation Method 2
directing a blue laser beam along a laser beam path at the plurality of pieces of cooper foil
Implementation Method 3
it rapidly transitions into vaporizing the copper. Once the copper vaporizes the keyhole is formed
Implementation Method 4
providing a non-oxidizing beam clearing gas in a space along the laser beam path where the laser beam travels in free space
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.