Copper Connecting Part Indentations for Laser Welding
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Solution Overview
Problem
The inefficiency of laser welding copper parts due to low absorption of laser energy, leading to unsatisfactory welds, and the need to adjust laser power based on copper shininess, which is not practically implemented, resulting in inconsistent weld quality.
Innovation Solution
Creating a connecting part with regularly spaced indentations on its surface, such as triangular or pyramidal shapes, to increase the absorption of laser energy and enhance the welding process without additional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser welding is used on copper parts, then welding speed and automation are improved, but welding quality deteriorates due to low laser energy absorption
Solution Approach 1:
The copper surface is pre-treated by creating a micro-structured pattern (dimples or grooves) before welding. This preliminary action modifies the surface geometry to enhance laser energy absorption, allowing the subsequent welding process to proceed effectively with improved quality and consistency
Solution Approach 2:
The surface geometry parameter of the copper part is changed from smooth to micro-structured. This parameter change increases the absorption coefficient of laser energy by trapping light through multiple reflections within the micro-features, thereby improving welding quality while maintaining high welding speed
2Reliability
If laser power is increased to compensate for low absorption, then welding quality improves, but energy consumption and risk of damage increase
Solution Approach 1:
Instead of changing the laser power parameter, the invention changes the copper surface geometry parameter to improve absorption efficiency. This allows effective welding at lower laser power levels, reducing energy consumption and minimizing the risk of thermal damage to surrounding components
3Reliability
If additional nickel parts are added to improve laser absorption, then welding quality improves, but device complexity and cost increase
Solution Approach 1:
Instead of adding separate nickel parts, the invention applies local quality modification directly to the copper surface by creating micro-structured features at the weld zone. This localized treatment enhances absorption only where needed, eliminating the need for additional parts while maintaining welding reliability
Solution Approach 2:
The invention creates a composite structure at the surface level by combining copper substrate with micro-structured geometric features. This composite surface structure provides enhanced laser absorption properties without requiring separate nickel intermediate layers, thereby reducing part complexity
4Adaptability or versatility
If copper surface shininess varies, then manufacturing flexibility is improved, but welding consistency deteriorates due to variable absorption
Solution Approach 1:
The copper surface is pre-treated with a standardized micro-structuring process that creates a consistent geometric pattern regardless of the initial surface shininess. This preliminary action eliminates the variability caused by different copper finishes, ensuring uniform welding results across all parts
Solution Approach 2:
The invention transforms the absorption characteristics from being dependent on surface shininess (variable parameter) to being dependent on micro-structure geometry (controlled parameter). This parameter change decouples absorption efficiency from variations in copper surface finish, improving weld consistency
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 method increases the energy absorption and transmission, allowing for improved weld quality, reduced energy requirements, and increased adjustment margin for laser power, resulting in reliable mechanical and electrical connections.
Implementation Method 1
The laser beam is directed perpendicularly to the surface of the connecting part. The energy provided by the laser beam melts the contact between the end region 8a of the connecting part and the portion of the electrodes foil not covered with active material
Implementation Method 2
transmit thermal energy from the laser to the copper to be welded
Implementation Method 3
pure copper (type Cua1, Cub1 or Cuc1) have an absorbency (equal to 1−reflectivity) of between a few % up to about 20% maximum. Part of the energy emitted by the laser beam is no longer absorbed by the copper
Data Source
AI summary
In a connecting part for connecting electrodes of an electrochemical cell to a current output terminal of the secondary cell, the connecting part has a surface at least a portion of which includes a plurality of indentations regularly spaced in two directions in the plane defined by the surface.