Battery Cell Foil-to-Plate Welding with Vacuum and Ultrasonic Compaction
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Solution Overview
Problem
Existing laser beam welding methods for connecting electrode foils in battery cells, particularly in lithium-ion batteries, suffer from poor reproducibility and quality issues due to the erratic behavior of materials like copper and aluminum, leading to irregular weld joints with defects such as holes, pores, and spattering, which are exacerbated by the use of infrared lasers.
Innovation Solution
A method involving compaction of the foil stack and contact plate using a combination of pressure and ultrasonic excitation, followed by generating negative pressure to remove air, and then performing laser welding to create high-quality weld seams, allowing for longer welds without defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser beam welding is used to connect cell foils to contact plates, then welding speed and productivity are improved, but weld joint quality deteriorates due to material erratic behavior, vaporization, and spattering
Solution Approach 1:
The patent changes the laser wavelength parameter from conventional infrared (1050 nm) to green laser (532 nm) to improve material absorption and reduce erratic behavior during welding, thereby maintaining high welding speed while improving weld joint quality
Solution Approach 2:
The patent uses pulsed laser welding instead of continuous welding, applying periodic laser energy to control heat input, prevent material vaporization, and reduce spattering while maintaining productivity
2Reliability
If weld seam length is increased to provide larger cross-sectional surface area for current transmission, then electrical conductivity is improved, but weld joint quality deteriorates due to accumulated defects and irregularities
Solution Approach 1:
The patent changes the laser wavelength to green (532 nm) which provides better material absorption and more stable welding process over longer distances, enabling long weld seams to be produced with uniform quality and without accumulated defects
Solution Approach 2:
The patent enables continuous long weld seams to be produced with consistent quality by using green laser technology that maintains stable material interaction throughout the entire welding process, avoiding the quality degradation that normally occurs with extended weld lengths
3Productivity
If infrared laser welding is used for mass production, then productivity is improved, but process stability deteriorates due to poor laser light coupling and high thermal conductivity of materials
Solution Approach 1:
The patent changes the laser wavelength from infrared to green, which dramatically improves laser light coupling with copper and aluminum materials, thereby stabilizing the welding process while maintaining high productivity for mass production
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 produces weld seams with improved quality, reducing defects like pores and spattering, enabling longer welds that meet the demands of increased current transmission and mass production requirements.
Implementation Method 1
generating a negative pressure at least in a connecting region of the foil stack and contact plate by means of a vacuum device
Implementation Method 2
connecting the foil stack to the contact plate in the connecting region via the at least one weld seam produced using a laser welding process
Implementation Method 3
laser welding process
Implementation Method 4
compaction of the foil stack and contact plate using a combination of pressure and ultrasonic excitation
Data Source
AI summary
A method for manufacturing a component, the component having a multiplicity of cell foils for storing electrical energy that are stacked on top of one another and at least one contact plate, wherein the cell foils form a foil stack in a connection portion, and the foil stack is connected to the contact plate by at least one weld seam for the electrical contacting of the cell foils via the contact plate. Furthermore, a corresponding component and a device for manufacturing such a component are also specified.