Membrane Electrode Assembly with Localized Cerium Ion Distribution

Solution Overview

Problem

Solid polymer fuel cells face durability issues due to hydrogen peroxide radical generation, which can be exacerbated by excessive cation content hindering proton conduction and reducing power generation performance, while insufficient cation content leads to decreased durability.

Innovation Solution

A membrane electrode assembly with a solid polymer electrolyte membrane, anode, and cathode catalyst layers, featuring a higher cerium ion content in the power-generation region compared to the non-power-generation region, where cerium ions act as radical quenchers to capture radicals and maintain proton conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If excessive cation content is added to the solid polymer electrolyte membrane, then durability against hydrogen peroxide radicals is improved, but proton conduction is hindered and power generation performance is reduced

Engineering Contradiction:

ImprovedurabilityVSAvoidpower generation performance

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies local quality by creating distinct regions within the membrane electrode assembly with different cerium ion concentrations. The power-generation region (central area) has a first cerium ion content optimized for maintaining proton conduction and power output, while the non-power-generation region (peripheral area) has a second cerium ion content optimized for radical scavenging and durability. This spatial differentiation allows each region to perform its primary function without compromising the other.

Inventive Principle:

Principle #3Local quality

2Power

If insufficient cation content is present in the solid polymer electrolyte membrane, then power generation performance is maintained, but durability against hydrogen peroxide radicals decreases

Engineering Contradiction:

Improvepower generation performanceVSAvoiddurability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements preliminary action by pre-distributing cerium ions throughout the solid polymer electrolyte membrane before operation, with higher concentrations strategically placed in the peripheral non-power-generation regions. This advance preparation ensures that radical scavenging capacity is already in place to protect against hydrogen peroxide radicals generated during power generation, preventing durability degradation before it occurs.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If uniform high cation content is distributed throughout the membrane, then durability is improved, but proton resistance increases and efficiency decreases

Engineering Contradiction:

ImprovedurabilityVSAvoidpower generation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by creating distinct regions within the membrane electrode assembly with different cerium ion concentrations. The power-generation region (central area) has a first cerium ion content optimized for maintaining proton conduction and power output, while the non-power-generation region (peripheral area) has a second cerium ion content optimized for radical scavenging and durability. This spatial differentiation allows each region to perform its primary function without compromising the other.

Inventive Principle:

Principle #3Local quality

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 balances durability and power generation performance by ensuring radical capture at the start of power generation, suppressing proton resistance and maintaining efficient fuel cell operation.

Implementation Method 1

cerium ions act as radical quenchers to capture radicals

Methodology Applied

Scientific EffectRadical quenching: Absorption (physical)

Implementation Method 2

Protons of the cation exchange group are partially replaced by the metal ion

Methodology Applied

Scientific EffectProton conduction: Conduction (electrical)

Data Source

PatentUS11515554B2Membrane electrode assembly and solid polymer fuel cell

Publication Date: 2022.11.29 TOYOTA JIDOSHA KK

AI summary

A membrane electrode assembly for the fuel cell includes a solid polymer electrolyte membrane, an anode catalyst layer assembled to one surface of the solid polymer electrolyte membrane, and a cathode catalyst layer assembled to another surface of the solid polymer electrolyte membrane. The membrane electrode assembly contains cerium ions. The membrane electrode assembly includes a power-generation region and a non-power-generation region. The power-generation region includes the catalyst layers on both surfaces of the solid polymer electrolyte membrane in a center portion. The non-power-generation region is without the catalyst layer on at least one surface of the solid polymer electrolyte membrane in an outer periphery portion. A cerium ion content per area in the power-generation region is larger than a cerium ion content per area in the non-power-generation region.