Bipolar Plate Laser Joining With Pulsed Polygon-Wheel Scanning
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Solution Overview
Problem
Laser welding of fuel cell components, particularly bipolar plates, often results in excessive heat input leading to pore formation, leaks, and distortion due to long weld seams, which negatively impacts the fuel cell production process.
Innovation Solution
A method using a pulsed laser beam and a rotating mirrored polygonal wheel to create a series of overlapping point-shaped and line-shaped joints, reducing heat input and enabling efficient joining of fuel cell components with minimal distortion, suitable for forming bipolar plates and other fuel cell components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous laser welding is used to join bipolar plates, then productivity is improved, but excessive heat input causes pore formation, leaks, and distortion
Solution Approach 1:
The patent applies periodic action by using pulsed laser welding instead of continuous laser welding. The laser beam is applied in periodic pulses, creating a series of overlapping point-shaped and line-shaped joining points that form a continuous joining line. This periodic application of heat allows the material to cool between pulses, preventing excessive heat accumulation, pore formation, and distortion while maintaining welding productivity.
Solution Approach 2:
The patent segments the continuous welding process into discrete pulsed segments. The joining line is formed by multiple overlapping point-shaped and line-shaped joining points created by sequential laser pulses. This segmentation of the welding process into discrete pulses allows for better heat control and prevents the harmful effects of continuous heat input while maintaining structural integrity of the weld seam.
2Loss of time
If high power laser is used to reduce joining time, then productivity is improved, but heat-induced distortion increases
Solution Approach 1:
The pulsed laser delivery system applies high power in periodic bursts rather than continuous high power input. Each pulse delivers sufficient energy to create a joining point quickly, but the intervals between pulses allow heat to dissipate, preventing cumulative heat buildup that causes distortion. This periodic high-power application reduces total joining time while maintaining component shape integrity.
Solution Approach 2:
The patent employs dynamic control of the laser parameters, adjusting pulse duration, frequency, and power levels to optimize the joining process. The pulsed laser system dynamically controls heat input by varying the timing and intensity of pulses, enabling rapid joining while minimizing thermal distortion through adaptive parameter adjustment during the welding process.
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 significantly reduces heat-induced distortion and leak risks, enhancing the production efficiency and quality of fuel cell components by minimizing heat input and ensuring reliable sealing and electrical contacting.
Implementation Method 1
emitting a pulsed laser beam from a laser device onto a rotating, mirrored polygon wheel
Implementation Method 2
emitting a pulsed laser beam from a laser device onto a rotating, mirrored polygon wheel
Implementation Method 3
The laser beam melts, for example, sealing material to such an extent that it develops adhesive properties and, upon cooling, bonds the individual components together
Implementation Method 4
The laser beam melts, for example, sealing material to such an extent that it develops adhesive properties
Data Source
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AI summary
The invention relates to a method for joining at least two components of a fuel cell (218), in particular for joining two individual plates (200, 202) of a fuel cell (218) to form a bipolar plate (216), comprising the steps of: - providing a first component of the fuel cell (218) and providing at least a second component of the fuel cell (218), - emitting a pulsed laser beam (110) of a laser apparatus (108) onto a rotating metallised polygon wheel (114), as a result of which the laser beam (110) forms a joining line (122) on the components, the joining line consisting of a plurality of overlapping, adjoining, point-shaped and/or line-shaped joining points (120). The invention also relates to a device (100) for carrying out the method.