Polymer Electrolyte Membrane for Low Hydrogen Crossover Fuel Cells
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Solution Overview
Problem
Current polymer electrolyte fuel cells exhibit suboptimal power generation characteristics and hydrogen gas utilization efficiency, particularly when using perfluoropolymer membranes with high hydrogen gas permeation coefficients and inappropriate thicknesses.
Innovation Solution
A polymer electrolyte membrane with a hydrogen gas permeation coefficient of no more than 2.4×10−9 cm3·cm/(s·cm2·cmHg) at 80° C. and 10% relative humidity, and a thickness between 7 to 20 μm, composed of a perfluoropolymer with perfluoromonomer units including perfluorovinyl ether and perfluoroallyl ether units, is used to enhance fuel cell performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a perfluoropolymer membrane is used as the polymer electrolyte, then the membrane exhibits good chemical stability and ion conductivity, but the hydrogen gas permeation coefficient is too high which reduces hydrogen gas utilization efficiency
Solution Approach 1:
The patent changes the chemical structure parameters of the perfluoropolymer by introducing specific monomer units (perfluorovinyl ether and perfluoroallyl ether) with controlled ratios. This modifies the membrane's physical properties including hydrogen gas permeation coefficient and ion conductivity, achieving optimal balance between chemical stability and hydrogen utilization efficiency
Solution Approach 2:
The patent creates a composite perfluoropolymer structure by copolymerizing multiple monomer units (perfluorovinyl ether, perfluoroallyl ether, and other perfluoromonomers) in specific proportions. This composite structure combines the advantages of different monomer units to achieve both low hydrogen permeation and high ion conductivity while maintaining chemical stability
2Power
If the membrane thickness is reduced to lower resistance and improve power generation characteristics, then the membrane resistance decreases, but the mechanical strength and durability are compromised
Solution Approach 1:
The patent optimizes the membrane thickness parameter to a specific range (5-20 μm, preferably 7-15 μm) that balances electrical resistance and mechanical strength. This parameter optimization, combined with the modified polymer structure, achieves low resistance while maintaining sufficient durability for practical application
3Loss of energy
If the hydrogen gas permeation coefficient is reduced to improve hydrogen gas utilization efficiency, then hydrogen crossover is reduced, but the ion conductivity and power generation characteristics may be affected
Solution Approach 1:
The patent modifies the polymer structure parameters (monomer composition, molecular weight, crosslinking degree) to reduce hydrogen gas permeation coefficient while maintaining ion conductivity. The specific structure changes create a denser polymer matrix that hinders hydrogen diffusion but allows ion transport
Solution Approach 2:
The patent uses a composite perfluoropolymer structure with specific monomer units that work synergistically: perfluorovinyl ether and perfluoroallyl ether units provide low hydrogen permeation pathways while maintaining ion conductivity channels, achieving both high hydrogen utilization efficiency and good power generation characteristics
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 configuration significantly improves power generation characteristics and hydrogen gas utilization efficiency by reducing hydrogen crossover and lowering membrane resistance, resulting in a more efficient polymer electrolyte fuel cell.
Implementation Method 1
hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10%, is at most 2.4×10−9 cm3·cm/(s·cm2·cmHg)
Data Source
AI summary
To provide a polymer electrolyte membrane capable of producing a polymer electrolyte fuel cell excellent in power generation characteristics and excellent in hydrogen gas utilization efficiency, as well as a membrane electrode assembly and a polymer electrolyte fuel cell obtainable by using it.The polymer electrolyte membrane of the present invention comprises a polymer electrolyte, of which the hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.4×10−9 cm3·cm/(s·cm2·cmHg) and has a membrane thickness of from 7 to 20 μm.