Porous Layer Material Production via Spray Drying for Fuel Cell Gas Diffusion

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Solution Overview

Problem

Conventional methods for forming porous layers in fuel cells face issues such as slurry penetration into the gas diffusion layer, leading to water accumulation, reduced gas dispersibility, uneven particle dispersion, and low productivity, along with high costs and complexity.

Innovation Solution

A production method involving spray drying of a mixed solution containing carbon and a water-repellent resin to create uniformly dispersed particles, which are then extruded or rolled into a sheet-like form, preventing penetration and enhancing uniformity, combined with a membrane electrode and gas diffusion layer assembly process that applies different forces to prevent short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If slurry is applied to form porous layer, then porous layer is formed between catalyst layer and gas diffusion layer, but slurry penetrates into gas diffusion layer causing water accumulation and reduced gas dispersibility

Engineering Contradiction:

Improveporous layer formationVSAvoidwater drainage performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the physical state and properties of the porous layer material by controlling the dispersion quality of carbon and PTFE particles, the viscosity of the slurry, and the drying conditions. These parameter changes ensure the porous layer forms a uniform, non-penetrating coating that maintains proper water drainage and gas dispersibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material consisting of carbon particles and PTFE (polytetrafluoroethylene) dispersed in a slurry. This composite structure provides both the porosity needed for gas diffusion and the water-repellent properties of PTFE, preventing water accumulation while maintaining gas dispersibility

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If carbon particles and PTFE fine powder are mixed using blender, then mixture is obtained, but uneven dispersion of particles occurs due to significant difference in particle diameters

Engineering Contradiction:

Improvemixing processVSAvoidparticle dispersion uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-dispersing carbon particles and PTFE fine powder separately in appropriate media before combining them. This pre-dispersion step ensures uniform distribution of both particle types, preventing aggregation and ensuring homogeneous mixing in the final slurry

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a dispersant or binder as an intermediary substance that facilitates uniform mixing of carbon particles and PTFE fine powder. This intermediary material helps overcome the difficulty of mixing particles with significantly different sizes and surface properties, ensuring homogeneous dispersion

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If precipitating agent is added to coprecipitate carbon and PTFE, then coprecipitate is obtained, but homogeneity of PTFE deteriorates with elapse of time and precipitation takes long time

Engineering Contradiction:

Improvecoprecipitate homogeneityVSAvoidprecipitation time

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-mixing carbon particles and PTFE fine powder in a slurry before application, rather than coprecipitating them after application. This reverses the sequence of operations, ensuring uniform distribution before the material is deposited, which eliminates the homogeneity deterioration problem that occurs with time-dependent coprecipitation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent inverts the conventional approach by mixing particles in a slurry state before application rather than coprecipitating them after application. This inversion of the process sequence allows for better control of particle distribution and eliminates the time-dependent homogeneity loss associated with coprecipitation methods

Inventive Principle:

Principle #13The other way round (Inversion)

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 method improves water drainage and gas dispersibility, reduces unevenness, increases productivity, and prevents short circuits, resulting in higher power generation performance and cost-effectiveness.

Implementation Method 1

obtaining particles containing carbon and a water-repellent resin by spray drying a mixed solution including the carbon and the water-repellent resin

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS9472810B2Production method of porous layer material and production method of membrane electrode and gas diffusion layer assembly including porous layer material

Publication Date: 2016.10.18 TOYOTA JIDOSHA KK

AI summary

A production method of a porous layer material for forming a porous layer includes the steps of obtaining particles that contain carbon and a water-repellent resin by spray drying a mixed solution that includes the carbon and the water-repellent resin, producing a paste that includes the particles, and extruding or rolling the paste to obtain the porous layer material in a sheet-like form.