Laser Beam Welding Paths for Fast Wide Lap Joints
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Solution Overview
Problem
Existing laser beam welding methods for battery cell connections face limitations in process speed due to the inertia of scanner mirrors and the requirement for high laser power, leading to reduced seam width and compromised electrical resistance and mechanical strength.
Innovation Solution
A method for laser beam welding that uses a smaller focus diameter and superimposed beam forming to achieve a high process speed while maintaining a secure weld seam connection with minimal contact resistance and high mechanical strength. This involves guiding the laser beam along a meandering or spiral-shaped target welding track, adjusting the track spacing, and reducing laser power during the welding process to control heat accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam oscillation is used to achieve large seam width and closed connection surface, then electrical contact resistance is reduced and mechanical strength is improved, but process speed is limited due to scanner mirror inertia
Solution Approach 1:
The patent segments the welding process into multiple linear passes that collectively build up the connection zone. Instead of using oscillation to create width in a single pass, the method divides the welding task into sequential linear tracks that are deposited one after another, each contributing to the overall closed-surface connection zone.
Solution Approach 2:
The patent employs periodic deposition of linear weld tracks where each track is deposited sequentially. The process alternates between moving the laser beam along a linear path and repositioning for the next track, creating a periodic pattern of weld deposition that builds the connection zone systematically.
2Area of stationary object
If large focus diameter is used to achieve large seam width, then connection area is increased, but laser power requirement increases leading to overheating and decomposition of insulating layers
Solution Approach 1:
The patent segments the heat input into multiple small linear passes rather than one large concentrated heat source. Each linear track deposits a small amount of heat that dissipates before the next track is deposited, preventing cumulative overheating while still building up a large overall connection area through the accumulation of multiple tracks.
Solution Approach 2:
The patent applies partial action by using multiple small linear tracks instead of one large oscillating beam. Each individual track provides partial welding action, and the cumulative effect of many partial actions achieves the desired large connection area without the excessive heat input that would result from a single large-focus beam.
3Productivity
If scanner mirror oscillation amplitude is increased to maintain seam width at high feed speed, then path fidelity cannot be achieved due to mirror inertia
Solution Approach 1:
The patent extracts the oscillation function from the scanner mirror system entirely. Instead of using the mirror to oscillate the beam laterally, the method removes this requirement and achieves seam width through the deposition of multiple adjacent linear tracks, eliminating the inertia-related limitations of oscillating mirrors.
Solution Approach 2:
The patent replaces the mechanical oscillation system (scanner mirrors with moving masses) with a computational path planning approach. The desired seam width is achieved through software-controlled deposition of multiple linear tracks rather than through mechanical beam oscillation, substituting a mechanical system with a control-based solution.
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 enables a significant increase in process speed while ensuring a robust weld seam connection that meets the requirements of electrical resistance and mechanical strength, without exceeding the limit temperature for electrically insulating plastic layers and seals.
Implementation Method 1
laser beam welding of at least two joint partners (1, 3) which are placed on top of each other in a lap joint and are welded together by a linear seam
Implementation Method 2
welded together by a linear seam while forming a preferably closed-surface connection zone or connection surface
Data Source
AI summary
A method for laser beam welding at least two joint partners which are placed one above the other in a lap joint. The two joint partners are welded to one another by a linear seam to form a preferably closed-surface connection zone. In order to form the connection zone, the laser beam is guided along a target welding track in the welding process according to any path planning strategy, in particular while forming a weld seam path, the adjacent path sections of which build up the preferably closed-surface connection zone.