Battery Module Busbar Welding With Laser Oscillation Feedback
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Solution Overview
Problem
The challenge in manufacturing vehicle battery modules lies in quickly and reliably welding busbars to the terminals of cylindrical cells, particularly on small areas, which can lead to inconsistent welds and increased manufacturing time.
Innovation Solution
A method of laser welding that involves oscillating the laser beam about the weld centerline to spread energy evenly, combined with real-time depth measurement using Inline Coherent Imaging (ICI) to ensure accurate weld depth, and the use of copper-plated busbar components with nickel or titanium layers for improved weld quality and reduced reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser welding is performed on small areas of cell terminals to meet design requirements, then weld location precision is improved, but weld reliability deteriorates due to difficulty in achieving consistent welds
Solution Approach 1:
The patent applies laser beam oscillation (a form of mechanical vibration) to move the laser focal point along a predetermined oscillation path during welding. This oscillation spreads the laser energy over a larger effective area, preventing excessive heat concentration on small terminal areas while maintaining precise weld location control. The oscillation parameters (amplitude, frequency, path) are optimized to ensure consistent weld penetration and reliability without sacrificing location precision.
Solution Approach 2:
The patent introduces dynamic control of the laser beam position through oscillation during the welding process. Instead of a static focal point, the laser beam dynamically moves along an oscillation path, allowing the weld pool to distribute heat more evenly across the small terminal area. This dynamic approach enables reliable welding on small areas by preventing heat buildup while maintaining precise spatial control of the weld zone.
2Productivity
If welding speed is increased to improve productivity, then manufacturing time is reduced, but weld quality consistency deteriorates
Solution Approach 1:
The laser beam oscillation enables faster welding speeds while maintaining weld quality consistency by continuously moving the heat source along an oscillation path. This prevents heat accumulation and ensures uniform energy distribution even at high speeds. The oscillation frequency and amplitude are synchronized with the welding speed to maintain optimal weld geometry and penetration depth throughout the process.
Solution Approach 2:
The patent incorporates real-time monitoring and control systems that adjust laser parameters based on feedback from the welding process. This feedback mechanism ensures that weld quality remains consistent even when welding speed varies, by dynamically adjusting oscillation parameters, laser power, and focal position to compensate for speed changes and maintain uniform weld characteristics.
3Strength
If laser energy is concentrated to achieve deep penetration welds, then weld strength is improved, but risk of cell interior penetration increases
Solution Approach 1:
The laser beam oscillation distributes the concentrated laser energy along an oscillation path, creating a broader heat-affected zone with controlled penetration depth. This prevents excessive heat concentration that could lead to cell interior penetration while still achieving sufficient weld strength through optimized oscillation parameters. The oscillation effectively 'smears' the energy distribution to achieve strong but controlled welds.
Solution Approach 2:
The patent transitions from a one-dimensional concentrated laser beam to a two-dimensional oscillating beam path. By adding the spatial dimension of oscillation, the energy is distributed across a larger area, reducing peak heat density and penetration depth while maintaining overall weld strength through increased heat-affected zone volume. This dimensional change prevents harmful cell interior penetration.
4Device complexity
If traditional welding methods are used on cylindrical cell terminals, then process simplicity is maintained, but manufacturing time increases
Solution Approach 1:
The laser beam oscillation is implemented through relatively simple optical components (mirrors, oscillation modules) that can be integrated into existing laser welding systems. This adds minimal complexity to the welding apparatus while dramatically improving welding speed and productivity. The oscillation parameters are easily programmable and adjustable, maintaining process simplicity while enabling faster manufacturing.
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 faster, more reliable welding with consistent weld quality, reducing the need for rework and improving the strength and reliability of connections between busbars and cell terminals, while minimizing penetration into the cell casing to prevent damage.
Implementation Method 1
welding the tab comprises controlling the laser to produce a weld comprising oscillations about a centreline of the weld shape
Implementation Method 2
welding the tab to the terminal by controlling a laser welding system to produce a weld
Implementation Method 3
the use of copper-plated busbar components with nickel or titanium layers for improved weld quality and reduced reflectivity
Implementation Method 4
measuring a depth of the weld in the straight portion during the step of welding the tab to the terminal
Data Source
AI summary
Embodiments of the present disclosure provide components for batteries, and methods of manufacture of batteries or battery modules. In some embodiments, the methods comprise producing a plurality of sub-assemblies comprising a group of mechanically-connected cells and an associated busbar assembly, and subsequently assembling the sub-assemblies within a housing and electrically connecting the busbar assemblies to produce a battery module.