Angled Gas Diffusion Layer for Fuel Cell Freeze-Thaw Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell stacks face reduced durability due to increased contact resistance and ice generation under freeze-thaw cycles, which damages the interfaces between components and affects electrochemical performance.
Innovation Solution
A gas diffusion layer (GDL) with increased stiffness in the width direction perpendicular to the major flow field direction of the bipolar plate is achieved by cutting the GDL material at a specific angle, reducing contact resistance and minimizing intrusion into gas channels, thereby preventing ice formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GDL stiffness in the width direction is increased by cutting at a specific angle, then contact resistance is reduced and freeze-thaw durability is improved, but the manufacturing complexity increases
Solution Approach 1:
The GDL is cut at a specific angle (e.g., 45 degrees) relative to the machine direction rather than parallel or perpendicular, creating an asymmetric orientation that optimizes stiffness distribution. This asymmetric cutting angle increases stiffness in the width direction perpendicular to the major flow field, reducing GDL intrusion and contact resistance while improving freeze-thaw durability
Solution Approach 2:
The GDL cutting angle is predetermined and optimized before assembly into the fuel cell stack. By pre-determining the optimal cutting angle based on theoretical analysis and testing, the design eliminates the need for complex adjustable mechanisms or post-assembly adjustments, thereby improving reliability while maintaining manufacturing simplicity
2Productivity
If the GDL stiffness is increased to reduce intrusion into gas channels, then electrochemical performance is improved, but the contact resistance may increase
Solution Approach 1:
The GDL is designed with directionally dependent stiffness properties through selective cutting at a specific angle. This creates local quality optimization where the GDL exhibits higher stiffness in the width direction (perpendicular to major flow field) to prevent intrusion and improve electrochemical performance, while maintaining appropriate compliance in the flow field direction to ensure good contact with bipolar plates and minimize contact resistance
3Ease of manufacture
If the GDL is cut parallel to the major flow field direction, then the manufacturing process is simplified, but the stiffness in the width direction is insufficient causing increased intrusion
Solution Approach 1:
Instead of cutting the GDL parallel to the major flow field direction (conventional approach), the GDL is cut at a specific angle (e.g., 45 degrees) to create asymmetric stiffness distribution. This asymmetric orientation provides sufficient stiffness in the width direction to prevent GDL intrusion into gas channels while remaining compatible with standard manufacturing processes
Data Source
AI summary
The present invention provides a fuel cell stack with enhanced freeze-thaw durability. In particular, the fuel cell stack includes a gas diffusion layer between a membrane-electrode assembly and a bipolar plate. The gas diffusion layer has a structure that reduces contact resistance in a fuel cell and is cut at a certain angle such that the machine direction (high stiffness direction) of GDL roll is not in parallel with the major flow field direction of the bipolar plate, resulting in an increased GDL stiffness in a width direction perpendicular to a major flow field direction of a bipolar plate.