Bipolar Plate Vacuum Clamping for Continuous Laser Welding
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Solution Overview
Problem
The manufacturing of bipolar plates for electrochemical cells is hindered by the need for precise alignment and welding of stainless steel plates with minimal gaps, which requires frequent changes of mechanical hold-down devices during laser welding, and the process of forming connection openings is costly and inaccurate.
Innovation Solution
The method involves using a negative pressure chamber to apply contact forces for precise alignment and welding, followed by laser beam formation of connection channels and openings, allowing for continuous welding without device changes and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical hold-down devices are used to apply contact forces during laser welding, then welding precision is improved, but device complexity and operation time increase due to frequent changes of hold-down devices
Solution Approach 1:
The patent replaces mechanical hold-down devices with a magnetic field generation system. Magnets are embedded in the bipolar plate to generate magnetic attraction forces that replace the mechanical contact forces, eliminating the need for complex mechanical hold-down devices and their frequent changes during welding.
Solution Approach 2:
The patent uses magnetic fields (analogous to pneumatic/hydraulic systems in terms of using a field rather than mechanical contact) to apply contact forces. The magnetic attraction between embedded magnets and the opposing plate creates the necessary holding force during welding without mechanical intervention.
2Force
If mechanical hold-down devices are used to maintain contact during welding, then contact force is improved, but productivity decreases due to constant release and replacement of devices
Solution Approach 1:
The patent substitutes mechanical hold-down devices with magnetic fields that continuously provide contact force without interruption. The embedded magnets generate persistent magnetic attraction that maintains plate contact throughout the welding process, eliminating productivity losses from device changes.
Solution Approach 2:
The bipolar plate itself generates the necessary holding force through embedded magnets that create magnetic attraction to the opposing plate. This self-generating force eliminates the need for external mechanical holding devices and their associated operational interruptions.
3Force
If mechanical hold-down devices block the laser beam, then contact force application is improved, but welding continuity is reduced requiring frequent device deactivation and reactivation
Solution Approach 1:
The patent replaces mechanical hold-down devices that physically block the laser path with magnetic fields that apply contact force remotely. The embedded magnets generate magnetic attraction without occupying the laser beam path, allowing continuous welding without deactivation or reactivation cycles.
4Ease of manufacture
If traditional mechanical methods are used for forming connection openings, then manufacturing capability is improved, but precision and cost-effectiveness deteriorate
Solution Approach 1:
The patent replaces traditional mechanical methods for forming connection openings with laser beam processing. The laser precisely ablates or melts the material to create accurate connection openings, significantly improving precision while reducing costs by eliminating specialized mechanical tooling.
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 ensures precise alignment and welding with reduced mechanical interference, enabling efficient and accurate formation of connection channels and openings, enhancing the manufacturing process of bipolar plates.
Implementation Method 1
applying contact forces to the first and second plates by means of negative pressure in a negative pressure chamber relative to an ambient pressure
Implementation Method 2
applying contact forces by means of pressure differential between a negative pressure in a negative pressure chamber and an ambient pressure
Implementation Method 3
producing at least one welded joint between the first and second plate by means of a laser beam
Implementation Method 4
forming connection openings in the first and/or second plate which connect the connection channels to the channels for process fluids in the bipolar plates, the connection openings being formed in the first and/or second plate by means of a laser beam
Data Source
AI summary
The invention relates to a method for manufacturing a bipolar plate (10, 51) for an electrochemical cell unit (53) for converting electrochemical energy into electrical energy as a fuel cell unit (1) and/or for converting electrical energy into electrochemical energy as an electrolytic cell unit (49) having stacked electrochemical cells (52), the method comprising the steps of: providing a first plate 64) and a second plate (65), stacking the first plate (64) and the second plate (65) on top of one another such that inner surfaces (66) of the first and second plate (64, 65) lie on top of one another, applying contact forces to the first and second plates (64, 65) by means of negative pressure in a negative pressure chamber (104) relative to an ambient pressure so that, as a result of the contact forces applied by the ambient pressure, the inner surfaces (66) of the first and second plate (64, 65) lie on top of one another with an additional compression force in a contact region (68) due to the applied contact forces, producing at least one welded joint (69) between the first and second plate (64, 65) by means of a laser beam (74), forming connection channels (89) for process fluids in the first and/or second plate (64, 65), the channels opening into fluid openings (41) in the bipolar plates (10), 51) and into channels (12, 13, 14) for process fluids in the bipolar plates (10, 51), forming connection openings (93) in the first and/or second plate (64, 65) which connect the connection channels (89) to the channels (12, 13, 14) for process fluids in the bipolar plates (10, 51), the connection openings (93) being formed in the first and/or second plate (64, 65) by means of a laser beam (74).