Gas diffusion system with high purity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas diffusion layers for fuel cells often contain high concentrations of foreign ions, such as metal cations, which can contaminate the electrolyte membrane and affect cell performance, necessitating the development of layers with low ion concentrations without compromising mechanical properties.
Innovation Solution
A gas diffusion layer is produced using a hydroentanglement process with water of low conductivity, resulting in carbon fiber nonwovens with extremely low ion concentrations, and optionally coated with a microporous layer, to minimize ion contamination and maintain mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waterjet bonding processes are used to produce carbon fiber nonwovens, then mechanical bonding and consolidation are achieved, but high concentrations of foreign ions (especially metal cations) are introduced into the fuel cell
Solution Approach 1:
The invention changes the key parameter of water quality by specifying use of deionized or distilled water with conductivity ≤250 µS/cm at 25°C during the hydroentanglement process. This parameter change reduces foreign ion introduction from conventional levels (up to 1000 µS/cm) to controlled low levels, directly addressing the contamination problem while maintaining bonding effectiveness
Solution Approach 2:
The invention introduces purified water as an intermediary medium in the hydroentanglement process. This intermediary (deionized/distilled water) replaces conventional process water and serves as a clean bonding agent that achieves mechanical consolidation without introducing harmful metal cations and foreign ions into the fuel cell system
2Object-generated harmful factors
If water with low conductivity is used in the hydroentanglement process, then ion contamination is reduced, but the bonding effectiveness and mechanical properties may be compromised
Solution Approach 1:
The invention optimizes the water conductivity parameter to a specific range (≤250 µS/cm) that balances two requirements: low enough to minimize ion contamination in the fuel cell, yet sufficient to provide the water solubility and流动性 needed for effective hydroentanglement bonding. This optimized parameter range resolves the contradiction between purity and bonding effectiveness
Solution Approach 2:
The invention replicates the essential bonding function of conventional waterjet processes using purified water, demonstrating that the mechanical consolidation effect can be achieved through water jet hydroentanglement with deionized or distilled water without requiring conventional process water, thereby copying the beneficial mechanical effect while eliminating the harmful contamination
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 gas diffusion layers exhibit a significantly longer service life for fuel cells with improved mechanical properties and reduced ion contamination, enhancing the performance and durability of the fuel cells.
Implementation Method 1
consolidating the fiber web to form a nonwoven fabric by exposure to water-containing fluid jets
Implementation Method 2
The impulse force of the water jets leads to a mechanical anchoring of the fibers in the product
Implementation Method 3
subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000 °C
Implementation Method 4
the water used has a conductivity of at most 250 microsiemens/cm at 25 °C
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method for producing a gas diffusion system with high purity, the gas diffusion system obtainable by this method, and a fuel cell which contains such a gas diffusion system. A fibrous web comprising carbon fibres and/or precursors of carbon fibres is solidified by the action of aqueous fluid jets to form a nonwoven fabric, the water used having a conductivity of at most 250 microsiemens/cm at 25 degrees Celsius.