Fuel Cell Membrane Electrode Assembly with Insulating Barrier

Solution Overview

Problem

In fuel cells with a stepped-type membrane electrode assembly, the area where the larger electrode catalyst layer is only on the outer portion of the electrolyte membrane experiences high potential or potential gradients, leading to metal ion dissolution from the metal separators, which can damage the solid polymer electrolyte membrane.

Innovation Solution

A frame-shaped barrier layer with electrical insulating and metal ion impermeable properties is provided around the electrode catalyst layers to prevent metal ion dissolution and protect the electrolyte membrane from potential gradients and water stagnation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stepped-type membrane electrode assembly is used with different electrode surface sizes, then the mechanical strength in peripheral areas is improved, but metal ion dissolution occurs from metal separators due to high potential gradients

Engineering Contradiction:

Improvemechanical strengthVSAvoidmetal ion dissolution

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

An insulating film is introduced as an intermediary layer between the electrode and the electrolyte membrane in the peripheral areas. This insulating film mediates the interaction by providing electrical insulation that prevents the formation of high potential gradients, thereby stopping metal ion dissolution while maintaining the stepped-type structure's mechanical strength benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating film is applied selectively only to the peripheral areas where electrodes have different surface sizes and where high potential gradients occur. This local application provides targeted protection against metal ion dissolution without affecting the overall electrode performance or requiring modification of the entire electrode structure.

Inventive Principle:

Principle #3Local quality

2Strength

If electrodes have different surface areas with asymmetric positioning, then mechanical strength in peripheral areas is improved, but the structure complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The insulating film is applied selectively only to the peripheral areas where electrodes have different surface sizes and where high potential gradients occur. This local application provides targeted protection against metal ion dissolution without affecting the overall electrode performance or requiring modification of the entire electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

An insulating film is introduced as an intermediary layer between the electrode and the electrolyte membrane in the peripheral areas. This insulating film mediates the interaction by providing electrical insulation that prevents the formation of high potential gradients, thereby stopping metal ion dissolution while maintaining the stepped-type structure's mechanical strength benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 suppresses metal ion dissolution from the metal separators and minimizes degradation of the solid polymer electrolyte membrane, ensuring the fuel cell's longevity and performance.

Implementation Method 1

a frame shaped barrier layer is provided at least around the second electrode catalyst layer or around the first electrode catalyst layer... metal ion impermeability

Methodology Applied

Scientific EffectIon impermeability: Diffusion Barrier

Implementation Method 2

a frame shaped barrier layer is provided at least around the second electrode catalyst layer or around the first electrode catalyst layer... electrical insulating capability

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS9203102B2Fuel cell

Publication Date: 2015.12.01 HONDA MOTOR CO LTD

AI summary

A membrane electrode assembly of a fuel cell includes a solid polymer electrolyte membrane, a cathode, and an anode. The surface size of a cathode side electrode catalyst layer of the cathode is smaller than the surface size of an anode side electrode catalyst layer of the anode. An inner end of a gas impermeable film provided around the anode side electrode catalyst layer and an outer end of a cathode side electrode catalyst layer are overlapped with each other on both sides of the solid polymer electrolyte membrane.