Fuel Cell Separator Assembly With Exposed Laser Weld Zone
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Solution Overview
Problem
The existing separator assemblies for fuel cells face issues with corrosion and weld failure due to laser welding, particularly when stainless steel or other metal plates are used, as the process can cause film melting and evaporation, leading to inadequate energy for successful welding.
Innovation Solution
A separator assembly for fuel cells where a film with conductive particles is applied to the surface of one separator, and laser welding is performed on the exposed base of the adjacent separator, preventing film irradiation and reducing corrosion and weld failure risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding is performed on separators with films coating the bases, then the separators can be joined to each other, but the films may melt and enter the welded parts causing corrosion and weld failure
Solution Approach 1:
The separator surface is divided into two distinct regions: a film-coated region for electrical contact and an exposed base region for laser welding. This segmentation allows the welding process to occur on a material (metal base) that can withstand laser energy without melting or corroding, while the film remains intact on the contact surface.
Solution Approach 2:
Different surfaces of the separator are given different properties: one surface has a conductive film for electrical contact with the membrane electrode assembly, while another surface has an exposed metal base for laser welding. This local differentiation of material properties enables both electrical functionality and welding reliability.
2Reliability
If laser energy is used to vaporize the films during welding, then the films are removed, but the energy needed to weld the bases may be insufficient resulting in weld failure
Solution Approach 1:
The film is selectively positioned or removed from the welding area before the laser welding process begins. This preliminary action ensures that the laser energy is directly applied to the metal base without being consumed by vaporizing the film, providing sufficient energy for successful welding.
3Reliability
If a film is applied to the entire surface of the separator base, then corrosion resistance is improved, but laser welding becomes difficult due to film interference
Solution Approach 1:
The separator manufacturing process is segmented to apply the conductive film only to specific areas that require corrosion protection and electrical contact, while leaving the welding areas as exposed metal base. This selective film application maintains corrosion resistance where needed while enabling successful laser welding where required.
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 limits corrosion and weld failure by ensuring proper energy input during laser welding and maintaining the integrity of the separator assembly, enhancing the durability and performance of the fuel cell stack.
Implementation Method 1
the first separator and the second separator are joined to each other through laser welding
Implementation Method 2
the joined portion is formed by irradiating the exposed portion of the first separator with laser
Implementation Method 3
laser irradiation may cause evaporation (ablation) to occur locally in the films
Data Source
Figure 1~2
Figure 3A~3C
AI summary
A separator assembly for a fuel cell includes a first separator, a second separator, and a joined portion. In the joined portion, the first separator and the second separator are joined to each other through laser welding. The first separator includes a first surface that is intended to be opposed to the membrane electrode assembly. The first surface of the first separator includes an exposed portion where the base of the first separator is exposed. The second separator includes a second surface that is intended to be opposed to the membrane electrode assembly. A film including conductive particles is arranged on the entire second surface of the second separator. The joined portion is formed by irradiating the exposed portion of the first separator with laser.