High-Purity Gas Diffusion Layer With Low-Ion Water Jet Consolidation
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Solution Overview
Problem
Existing gas diffusion layers for fuel cells often contain high concentrations of extraneous ions, such as metal cations, which can contaminate the electrolyte membrane and affect cell performance, necessitating the development of layers with low ionic concentrations without compromising mechanical properties.
Innovation Solution
A method for producing high-purity carbon fiber nonwovens using aqueous fluid jets with conductivity-limited water, followed by pyrolysis and hydrophobizing, to create gas diffusion layers with low ionic concentrations and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional water jet consolidation is used to produce gas diffusion layers, then manufacturing efficiency is improved, but ionic concentration increases due to contamination from extraneous metal cations
Solution Approach 1:
The patent changes the electrical conductivity parameter of the water used in jet consolidation from conventional levels (potentially containing high ionic concentrations) to highly purified water with conductivity of at most 250 microsiemens/cm. This parameter change directly reduces the introduction of extraneous metal cations during the consolidation process, thereby lowering the ionic concentration in the final gas diffusion layer while maintaining manufacturing efficiency
Solution Approach 2:
The patent employs a disposable approach to water quality by using highly purified water specifically for the jet consolidation process. Rather than attempting to recycle or repeatedly use the same water (which would accumulate ions), fresh purified water is used for consolidation, ensuring low ionic concentration without compromising productivity
2Ease of manufacture
If water with high conductivity is used for jet consolidation, then ionic concentration in the gas diffusion layer increases, but manufacturing process remains simple
Solution Approach 1:
The patent modifies the water conductivity parameter to at most 250 microsiemens/cm for the jet consolidation process. This parameter change introduces a purification step but maintains overall process simplicity by not requiring complex equipment modifications, only changing the water quality input to achieve low ionic concentration in the final product
3Object-affected harmful factors
If highly purified water is used for jet consolidation, then ionic concentration is reduced, but water cost increases
Solution Approach 1:
The patent uses highly purified water as a disposable consumable for the jet consolidation process. The water is used once to consolidate the fibrous web and then discarded, preventing contamination accumulation. This approach justifies the higher water cost by ensuring the final gas diffusion layer has low ionic concentration, which is critical for fuel cell performance and longevity
Solution Approach 2:
The patent specifies a conductivity threshold of at most 250 microsiemens/cm for the purified water used in jet consolidation. This quantitative parameter provides a clear specification for water purification level, balancing the cost of purification with the required reduction in ionic concentration to achieve the desired low-ionic 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 gas diffusion layers exhibit a very low ionic concentration, reduced nozzle strip defects, and comparable mechanical properties to conventional layers, leading to longer fuel cell lifetimes.
Implementation Method 1
consolidating the fibrous web by exposure to aqueous fluid jets
Implementation Method 2
consolidating the fibrous web by exposure to aqueous fluid jets to form a nonwoven
Implementation Method 3
If the fiber composition comprises precursors of carbon fibers, the nonwoven is subjected to pyrolysis at a temperature of at least 1000° C.
Implementation Method 4
followed by pyrolysis and hydrophobizing
Data Source
AI summary
A method for producing a gas diffusion layer for a fuel cell, including providing a fiber composition which includes carbon fibers and/or precursors of carbon fibers and subjecting the fiber composition to a method for producing a fibrous web. The method further includes consolidating the fibrous web by exposure to aqueous fluid jets to form a nonwoven, water used by the aqueous fluid jets having a conductivity of at most 250 microsiemens/cm at 25° C. If the fiber composition includes precursors of carbon fibers, the nonwoven is subjected to pyrolysis at a temperature of at least 1000° C.