Metal Bipolar Plate Laser Welding for Thermal Deformation Control
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Solution Overview
Problem
Current laser welding methods for metal bipolar plates in hydrogen fuel cells face challenges such as poor thermal control, leading to risks of perforation, weak or incomplete welds, and significant thermal deformation, resulting in leakage and aesthetic issues.
Innovation Solution
A laser welding method that adjusts the movement speed and power of the laser beam based on the movement distance along a preset weld path, specifically reducing speed and power after reaching a certain threshold to maintain stable thermal input and prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high laser power and constant speed are used for welding, then welding speed is maintained, but thermal control deteriorates leading to perforation risk
Solution Approach 1:
The patent applies dynamics by transitioning from constant laser parameters to dynamic adjustment. The laser beam movement speed and power are adjusted in real-time based on the welding position, particularly reducing speed and power at the end of the weld path where thermal accumulation occurs. This dynamic adaptation allows maintaining high welding speed overall while achieving precise thermal control at critical locations.
Solution Approach 2:
The patent implements parameter changes by modifying laser beam movement speed and power levels during the welding process. Specifically, the method reduces laser beam movement speed and/or power when approaching the end of the weld path, transforming the fixed parameters approach into a variable parameters approach that adapts to thermal conditions at different welding stages.
2Strength
If high laser power is used to ensure weld strength, then weld strength is improved, but thermal deformation increases causing plate bulging
Solution Approach 1:
The patent applies local quality by differentiating laser parameters for different regions of the weld path. The end of the weld path receives reduced laser power and/or slower movement speed compared to the beginning, creating localized thermal control that ensures adequate weld strength at the critical end region while minimizing overall thermal deformation and maintaining plate flatness.
3Productivity
If fast welding speed is used to increase productivity, then productivity is improved, but weld quality deteriorates with leakage and defects
Solution Approach 1:
The patent implements periodic action through the cyclical pattern of laser parameter adjustment. The laser beam movement speed and power are periodically modified during the welding process, with reductions occurring at specific intervals (particularly near the end of the weld path). This periodic adjustment ensures adequate thermal input for quality welds while maintaining high overall welding speed.
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 achieves high-speed welding with improved weld quality, preventing perforations and thermal deformation, while ensuring secure connections and reducing leakage in bipolar plates.
Implementation Method 1
Laser welding primarily illuminates the metal surface with a laser beam, rapidly transferring heat from an upper plate to a lower plate after melting
Implementation Method 2
rapidly transferring heat from an upper plate to a lower plate after melting, forming a melt pool and curing to form a weld
Data Source
AI summary
A laser welding method, a device, a metal bipolar plate, a hydrogen fuel cell, and a vehicle are disclosed. The laser welding method is used for a metal bipolar plate of a hydrogen fuel cell, the metal bipolar plate being preset with a weld path, the weld path including a weld starting point and a weld end point. The laser welding method including (S1) applying and moving a laser beam along the weld path from the weld starting point, (S2) judging whether the movement distance of the laser beam reaches a movement distance threshold, and if yes, performing step S3, and (S3) reducing the movement speed of the laser beam and simultaneously reducing or maintaining the laser power of the laser beam.