Fuel Cell Separator Corners That Prevent Gas Diffusion Layer Sinking

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Solution Overview

Problem

The gas diffusion layers in fuel cells can deform and sink into groove passages, increasing reactant gas pressure loss due to resistance, which affects the efficiency of the fuel cell.

Innovation Solution

Incorporating conductive porous restricting portions at the corner sections of the groove passages to prevent the gas diffusion layers from sinking, while maintaining gas diffusivity by ensuring the porosity of these portions matches or exceeds that of the gas diffusion layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gas diffusion layer is placed in contact with groove passages, then reactant gas can flow through the groove passages, but sections of the gas diffusion layer deform and sink into the groove passages causing resistance and increased pressure loss

Engineering Contradiction:

Improvereactant gas flowVSAvoidpressure loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

A restricting portion made of conductive porous material is introduced as an intermediary element between the groove passage and the gas diffusion layer. This restricting portion prevents the gas diffusion layer from sinking into the groove passage while still allowing reactant gas to pass through via diffusion, thus eliminating the harmful deformation and associated pressure loss without blocking gas supply

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The restricting portion is constructed from conductive porous material that allows gas molecules to diffuse through it. This porous structure enables reactant gas to reach the gas diffusion layer through the restricting portion, maintaining gas supply functionality while preventing the gas diffusion layer from deforming into the groove passage and causing pressure loss

Inventive Principle:

Principle #31Porous materials

2Loss of energy

If the gas diffusion layer is restricted from sinking into groove passages, then pressure loss is reduced, but gas diffusivity may be compromised

Engineering Contradiction:

Improvepressure lossVSAvoidgas diffusivity

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The restricting portion is designed with specific parameters including porosity in the range of 30-80% and a thickness of 10-100 μm. These parameter optimizations ensure that the restricting portion is sufficiently porous to allow adequate gas diffusion while being thin enough to maintain effective reactant gas supply to the gas diffusion layer, thus balancing pressure loss reduction with gas diffusivity preservation

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If a restricting portion is added to prevent gas diffusion layer sinking, then pressure loss is minimized, but device complexity increases

Engineering Contradiction:

Improvepressure lossVSAvoidseparator structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The restricting portion is not implemented across the entire separator surface but is specifically localized at the corner portions of the groove passages where the gas diffusion layer deformation and sinking occurs. This localized approach addresses the problem at its specific origin without adding unnecessary complexity to the entire separator structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The restricting portion is made of conductive porous material that combines electrical conductivity with porosity. This composite material property allows the restricting portion to serve multiple functions: preventing gas diffusion layer sinking, maintaining electrical conductivity for fuel cell operation, and allowing gas diffusion, thus achieving multiple benefits without adding excessive structural complexity

Inventive Principle:

Principle #40Composite materials

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 solution effectively restricts the gas diffusion layers from sinking into the groove passages, reducing contact resistance and maintaining reactant gas diffusivity, thereby enhancing fuel cell performance.

Implementation Method 1

The restricting portion is a conductive porous body

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS12603302B2Single cell for fuel cell

Publication Date: 2026.04.14 TOYOTA BOSHOKU KK

AI summary

A single cell for a fuel cell includes a power generating unit and two separators that hold the power generating unit in between. Each separator includes a facing surface, which faces the power generating unit. Each facing surface includes groove passages and ribs. Each of the ribs includes a top wall portion, two side wall portions, and corner portions. The top wall portion is in contact with the power generating unit. The side wall portions are located at the opposite sides of the top wall portion. Each corner portion is located between the top wall portion and one of the side wall portions. A restricting portion is provided at a section of each corner portion that faces the groove passage. The restricting portion restricts the gas diffusion layer from sinking into the groove passage. The restricting portion is a conductive porous body.