Blue Laser Welding of Stacked Copper Foils With Uniform Gaps
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Solution Overview
Problem
Laser welding of copper-based materials is challenging due to high reflectance, thermal conductivity, and heat capacity, leading to variable welding intervals and reduced efficiency, which affects the quality and stability of stacked metal foils used in batteries and electronic devices.
Innovation Solution
A laser welding method using a blue laser beam with a jig having tapered surfaces to maintain consistent intervals between copper foils, employing a control system to adjust laser focus and direction, ensuring uniform melting and solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser welding is used on copper-based materials, then welding speed can be maintained, but welding interval consistency deteriorates due to high reflectance and thermal conductivity
Solution Approach 1:
The method performs preliminary pressing and crimping of the stacked metal foils before laser welding to pre-establish consistent intervals between adjacent foils. This preliminary mechanical preparation ensures that the foils are properly positioned and spaced, which maintains welding interval consistency during the subsequent laser welding process despite copper's high reflectance and thermal conductivity
Solution Approach 2:
The system uses feedback control by detecting thermal radiation light from the melt pool during laser welding. The intensity of thermal radiation light is monitored and used to adjust welding parameters in real-time, ensuring consistent welding intervals are maintained throughout the welding process even when facing copper's challenging thermal properties
2Ease of manufacture
If laser irradiation is applied to copper-based foils, then welding can be achieved, but interval variation increases due to material properties
Solution Approach 1:
The stacked metal foils are pressed and crimped in advance before laser welding to establish uniform intervals between adjacent foils. This preliminary mechanical preparation compensates for the material properties of copper that would otherwise cause interval variation during welding, ensuring consistent spacing is maintained throughout the welding process
3Device complexity
If stacked metal foils are welded without preliminary pressing, then process simplicity is maintained, but welding quality deteriorates due to interval variation
Solution Approach 1:
The method incorporates preliminary pressing and crimping of the stacked metal foils as a preparatory step before laser welding. This preliminary action ensures consistent intervals between adjacent foils, which directly improves welding quality and reliability by preventing interval variation that would otherwise occur during the welding process
Solution Approach 2:
The system implements feedback control by monitoring thermal radiation light intensity from the melt pool during welding. This feedback mechanism detects welding quality in real-time and allows for adjustments to maintain consistent welding intervals, thereby improving reliability without significantly complicating the overall process
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 achieves consistent welding intervals and high-quality laser welding, reducing the risk of foil breakage and improving electrical conductivity in stacked metal foils.
Implementation Method 1
irradiating the stacked metal foils with a blue laser beam
Implementation Method 2
irradiating the prescribed welding portion with a laser beam
Implementation Method 3
a melted region generated in the stacked metal foils
Data Source
AI summary
After the irradiation with the blue laser beam, in a cross section of the stacked metal foils along a stacking direction of the copper-based foils, intervals between the adjacent copper-based foils along the stacking direction in a vicinity of a melted region generated in the stacked metal foils are smaller than a thickness of each of the copper-based foils.