Hydroentangled Carbon Fiber Gas Diffusion Layer for Low-Ion Fuel Cells
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Solution Overview
Problem
Existing gas diffusion layers (GDLs) for fuel cells contribute to the contamination of the membrane electrode assembly (MEA) with foreign ions, particularly metal cations, which affect cell performance, and there is a need for GDLs with low ion concentrations without compromising mechanical properties.
Innovation Solution
A method for manufacturing GDLs using carbon fibers or precursors subjected to hydroentanglement with water of optimized pH (5.5 to 8.0) and low conductivity (≤250 microsiemens/cm) to produce high-purity nonwovens, followed by thermal and mechanical treatments, and optionally coating with a microporous layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional water jet entanglement is used to bond carbon fiber nonwovens, then mechanical bonding strength is achieved, but foreign ions (especially metal cations) contaminate the gas diffusion layer
Solution Approach 1:
The patent changes the chemical parameters of the bonding water by adjusting pH to 5.5-8.0 and reducing conductivity to ≤250 microsiemens/cm. This removes harmful metal cations from the water before bonding, preventing ion contamination while maintaining the mechanical bonding function of the water jet entanglement process
Solution Approach 2:
The patent extracts and removes foreign ions (especially metal cations) from the bonding water through pH adjustment and conductivity control. This separates the harmful ionic components from the beneficial bonding function, allowing clean water to perform only the mechanical bonding task
2Object-generated harmful factors
If water with low ion concentration is used for hydroentanglement, then ion contamination is reduced, but bonding effectiveness may be compromised
Solution Approach 1:
The patent optimizes water parameters by setting pH to 5.5-8.0 and conductivity to ≤250 microsiemens/cm. This creates a balanced water quality that is clean enough to prevent contamination while maintaining sufficient chemical properties for effective mechanical bonding of carbon fibers
3Ease of manufacture
If pH of bonding water is not optimized, then processing is simpler, but ion contamination and defects increase
Solution Approach 1:
The patent sets specific pH ranges (5.5-8.0) and conductivity limits (≤250 microsiemens/cm) for the bonding water. These optimized parameters prevent ion contamination and defects in the final product while maintaining a relatively simple water treatment process
4Stability of the object's composition
If conventional GDLs are used, then mechanical stability is provided, but service life is reduced due to ion contamination of MEA
Solution Approach 1:
The patent removes foreign ions from the bonding water through pH adjustment and conductivity control, preventing ion contamination of the gas diffusion layer. This extraction of harmful ions allows the GDL to maintain both mechanical stability and extended service life by preventing degradation of the membrane electrode assembly
Solution Approach 2:
The patent uses optimized water as a temporary bonding medium that is discarded after use. This water serves its purpose of bonding carbon fibers and is then discarded, having already fulfilled its function without leaving harmful residues in the final product
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
The resulting GDLs have very low ion concentrations, reduced defects, and maintain good mechanical properties, leading to fuel cells with extended service life and improved performance.
Implementation Method 1
bonding the fibrous web to form a nonwoven by action of aqueous fluid jets
Implementation Method 2
subjecting the nonwoven obtained in step c) to a thermal and/or mechanical treatment for drying and/or further bonding
Implementation Method 3
subjecting the nonwoven to pyrolysis at a temperature of at least 1000° C. based on whether the fiber composition used in step a) comprises precursors of carbon fibers
Data Source
AI summary
The present invention relates to a method for producing a gas diffusion layer, wherein nonwovens made of carbon fibers or carbon fiber precursors are subjected to entanglement with water-containing fluid jets of a certain water quality. The invention also relates to the gas diffusion layer obtainable according to the method and to a fuel cell that contains such a gas diffusion layer.