Bipolar Plate Welding With Polygon-Scanned Pulsed Laser Seams
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Solution Overview
Problem
Laser welding of fuel cell components, particularly bipolar plates, often results in pore formation and warpage due to excessive heat input, leading to leaks and production inefficiencies in fuel cell assembly.
Innovation Solution
A method using a pulsed laser beam directed onto a rotating mirrored polygon wheel to create a joint line with overlapping point-like and/or line-shaped joining locations, reducing heat input and enabling efficient joining of fuel cell components with minimal warpage, including the integration of a membrane electrode assembly with a bipolar plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous laser welding is used to join bipolar plates, then welding speed and productivity are improved, but excessive heat input causes pore formation, warpage, and leaks
Solution Approach 1:
The patent applies periodic pulsed laser action instead of continuous laser welding. The laser emits discrete pulses at controlled intervals, allowing the material to cool between pulses. This prevents excessive heat accumulation that causes pores and warpage, while maintaining adequate welding speed through optimized pulse frequency and duration
Solution Approach 2:
The continuous weld seam is segmented into discrete overlapping pointlike and line-shaped joining locations. Each pulse creates a separate joining zone that overlaps with adjacent zones, forming a continuous weld path without requiring continuous heat input. This segmentation allows heat dissipation between pulses while maintaining weld integrity
2Loss of time
If high power laser is used to reduce processing time, then productivity is improved, but heat-induced warpage and material damage increase
Solution Approach 1:
The pulsed laser delivers high peak power during brief intervals to maintain fast processing, followed by cooling periods that prevent heat accumulation. The pulse duration and frequency are optimized to achieve adequate melting and bonding while allowing heat dissipation, thus preventing warpage
Solution Approach 2:
The laser parameters (power, pulse duration, frequency) are dynamically adjusted based on the welding conditions and material properties. The polygon wheel rotation speed is also dynamically controlled to optimize the overlap and spacing of joining locations, adapting to different component geometries and material thicknesses
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 significantly reduces heat-induced warpage and leak risks, enabling faster, more reliable production of fuel cell components with improved sealing and assembly efficiency.
Implementation Method 1
directing a pulsed laser beam of a laser apparatus onto a rotating mirrored polygon wheel
Implementation Method 2
the laser beam melts sealing material for example so much that it develops adhesive properties
Implementation Method 3
directing a pulsed laser beam of a laser apparatus onto a rotating mirrored polygon wheel, by which the laser beam forms a joint line consisting of a plurality of overlapping pointlike and/or line-shaped joining locations
Data Source
AI summary
A method for joining at least two components of a fuel cell, especially for joining two single plates of a fuel cell to make a bipolar plate, comprises: providing a first component of the fuel cell and providing at least one second component of the fuel cell; and directing a pulsed laser beam of a laser apparatus onto a rotating mirrored polygon wheel, by which the laser beam forms a joint line consisting of a plurality of overlapping pointlike and/or line-shaped joining locations on the components. A device for carrying out the method is also provided.