Fuel Cell Joint Separator Laser Welding Warpage Control
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Solution Overview
Problem
The production of joint separators for fuel cell stacks via laser welding often results in heat distortion and warpage, leading to inaccurate stacking and non-uniform contact surface pressure, which can cause leakage of reactant gases and coolant.
Innovation Solution
A method and apparatus that involves fixing metal plates between a base and a holder, welding them using a laser light emitting unit, and subsequently applying additional pressure to the welded area using a pressing member to distribute residual stress and correct warpage, ensuring accurate stacking and uniform pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser welding is used to join metal plates together, then welding efficiency and precision are improved, but heat distortion and warpage occur
Solution Approach 1:
The invention applies preliminary fixing by holding the metal plates between a base and holder before laser welding, and performs preliminary pressing during the welding process to suppress warpage before it fully develops. This preliminary action prevents the heat distortion from causing significant warpage while maintaining welding efficiency.
Solution Approach 2:
The invention uses periodic pressing during the welding process, where the pressing member applies pressure in a controlled manner during welding and then releases it. This periodic action allows the metal plates to be suppressed during heat input while avoiding excessive constraint that would interfere with the welding process.
2Manufacturing precision
If additional pressing is applied after welding, then warpage is corrected and manufacturing precision is improved, but production time increases
Solution Approach 1:
The invention performs the pressing action during the welding process itself rather than as a separate post-welding step. By applying pressure while the metal is still hot and pliable, the warpage is corrected in-situ, eliminating the need for additional time-consuming post-welding operations.
Solution Approach 2:
The invention merges the welding process and the warpage correction process into a single integrated operation. The pressing member is positioned to apply pressure during welding, combining two functions (welding and warpage suppression) into one simultaneous process, thereby avoiding additional production time.
3Manufacturing precision
If metal plates are fixed between base and holder during welding, then warpage is suppressed and manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The fixing apparatus is segmented into simple, modular components: a base, a holder, and a pressing member. Each component performs a specific function and can be independently positioned and adjusted. This segmentation allows for precise warpage suppression while keeping each individual component simple and easy to implement.
Solution Approach 2:
The holder acts as an intermediary between the base and the metal plates, providing a simple mechanical interface for fixing and pressing. This intermediary component enables precise control over the metal plates during welding without requiring a complex integrated system.
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 effectively reduces warpage and improves the uniformity of contact surface pressure between the membrane electrode assembly and separators, preventing leakage and ensuring accurate fuel cell stacking.
Implementation Method 1
welding the two metal plates together after the fixing step, by radiating a laser light to the metal plates from a laser light emitting unit, through a gap provided in the holder
Implementation Method 2
performing an additional pressing step after the welding step, by moving a pressing member ahead through the gap, in a state where two metal plates are held between the base and the holder, to press an area welded by the laser light, by the pressing member
Data Source
AI summary
In a production method and a production apparatus for producing a joint separator, in the state where first and second separators are stacked together, a step of fixing the first and second separators by holding the first and second separators between a base and a holder is performed. Thereafter, a step of welding the first and second separators by radiating a laser light from laser light emitting units, through gaps provided in the holder is performed. After the welding step, an additional pressing step of moving pressing members ahead through the gaps to press heat affected zones welded by the laser light, by the pressing members is performed.