Membrane-Catalyst Assembly Bonding With Water Droplets

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Solution Overview

Problem

Existing methods for manufacturing membrane-catalyst assemblies in polymer electrolyte fuel cells face challenges in achieving satisfactory adhesion between the electrolyte membrane and the catalyst layer under relaxed thermocompression bonding conditions, leading to issues like interfacial resistance, wrinkles, and reduced productivity.

Innovation Solution

A method involving the application of a water-containing liquid to the catalyst layer in a droplet form, followed by thermocompression bonding, which improves adhesion and relaxes pressing conditions, allowing for high productivity while preventing membrane deformation and maintaining low manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high temperature and high pressure are applied for long time to improve adhesion between catalyst layer and electrolyte membrane, then adhesion is improved, but catalyst layer is compressed and deformed resulting in reduced gas diffusivity and poor power generation performance

Engineering Contradiction:
Improveadhesion between catalyst layer and electrolyte membraneVSAvoidpower generation performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the bonding mechanism from mechanical compression (pressure-based) to chemical bonding (temperature-based). By controlling the temperature to melt the electrolyte membrane and bond it chemically with the catalyst layer, the need for high pressure is eliminated, preventing compression and deformation of the catalyst layer while achieving strong adhesion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical pressing system with a thermal bonding system. Instead of using mechanical pressure to achieve adhesion, the electrolyte membrane is heated to its melting point to enable chemical bonding with the catalyst layer, substituting mechanical action with thermal action.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If temperature and pressure of pressing are reduced to reduce damage to catalyst layer and electrolyte membrane, then damage is reduced, but pressing time needs to be increased resulting in greatly reduced productivity

Engineering Contradiction:
Improvedurability of membrane-catalyst assemblyVSAvoidmanufacturing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention changes the bonding parameter from pressure-time relationship to temperature-based bonding. By controlling the temperature to precisely melt and bond the electrolyte membrane, the process achieves strong adhesion quickly without requiring prolonged pressing time, thus maintaining high productivity while ensuring durability.

Inventive Principle:
Principle #35Parameter changes

3Shape

If solvent in catalyst solution is evaporated completely before bonding, then membrane deformation is prevented, but adhesion between catalyst layer and electrolyte membrane becomes insufficient

Engineering Contradiction:
Improveflatness of electrolyte membraneVSAvoidadhesion between catalyst layer and electrolyte membrane
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The invention replaces the solvent-based bonding mechanism with a melting-based bonding mechanism. Instead of relying on solvent to facilitate adhesion (which causes membrane swelling), the electrolyte membrane is heated to melt and bond chemically with the catalyst layer, achieving both flatness and strong adhesion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes the phase transition of the electrolyte membrane from solid to liquid state at its melting point. By heating the membrane to melt it temporarily for bonding, then allowing it to solidify, strong chemical adhesion is achieved without the need for solvents that would cause swelling and deformation.

Inventive Principle:
Principle #36Phase transitions

4Strength

If solvent is left in catalyst layer to improve adhesion, then adhesion is improved, but electrolyte membrane swells and develops wrinkles

Engineering Contradiction:
Improveadhesion between catalyst layer and electrolyte membraneVSAvoidsurface flatness of electrolyte membrane
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention replaces solvent-based adhesion with melting-based adhesion. By heating the electrolyte membrane to its melting point, chemical bonding occurs between the membrane and catalyst layer without requiring solvents, thereby achieving strong adhesion while preventing membrane swelling and wrinkle formation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enhances adhesion between the catalyst layer and the electrolyte membrane, reduces interfacial resistance, and improves the durability and power generation performance of the membrane-catalyst assembly, while also lowering production costs and environmental impact.

Implementation Method 1

the liquid is a water-containing liquid, and the water-containing liquid is applied to the surface of the catalyst layer in a droplet form

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a thermocompression bonding step of bonding, to the electrolyte membrane, the catalyst layer to which the liquid is applied by thermocompression bonding

Methodology Applied
Scientific EffectThermal compression bonding: Heating

Data Source

PatentEP3832766B1Method of manufacturing and device for manufacturing membrane-catalyst assembly
Publication Date: 2024.02.28 TORAY INDUSTRIES INC
  • EP3832766B1 patent drawingFigure 1
  • EP3832766B1 patent drawingFigure 2
  • EP3832766B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide, in the manufacture of a membrane-catalyst assembly including a polymer electrolyte membrane and a catalyst layer bonded to the polymer electrolyte membrane, a method that achieves both the relaxation of thermocompression bonding conditions and the improvement of adhesion between the catalyst layer and the electrolyte membrane with high productivity. A main object of the present invention is to provide a method of manufacturing a membrane-catalyst assembly including an electrolyte membrane and a catalyst layer bonded to the electrolyte membrane, the method including a liquid application step of applying a liquid to a surface of the catalyst layer before bonding, and a thermocompression bonding step of bonding, to the electrolyte membrane, the catalyst layer to which the liquid is applied by thermocompression bonding.