Fuel Cell Selectively Conducting Anode Mitigates Startup Degradation

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Solution Overview

Problem

Solid polymer electrolyte fuel cells face challenges in reducing noble metal catalyst usage for cost-effectiveness while maintaining performance and durability, especially during repeated startup and shutdown cycles, which leads to degradation issues due to corrosion and high potential spikes at the cathode.

Innovation Solution

Incorporating a selectively conducting component with low electrical resistance in the presence of hydrogen and high resistance in the presence of air in series with the anode components, specifically using a tin oxide layer with platinum deposited on it, to mitigate degradation and enhance durability, particularly with PtCo alloy catalysts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If noble metal catalyst loading is reduced for cost reduction, then manufacturing cost is improved, but durability during startup and shutdown cycles deteriorates due to increased degradation rates

Engineering Contradiction:

Improvemanufacturing costVSAvoiddurability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A selectively conducting component is introduced as an intermediary element in electrical series with the anode components. This component has low electrical resistance in the presence of hydrogen and high resistance in the presence of air, thereby mediating the electrical circuit behavior during different operational states and preventing harmful high potentials at the cathode during air-fuel transitions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical resistance parameter of the selectively conducting component changes dynamically based on the presence of hydrogen or air. This parameter change allows the system to automatically adapt its electrical characteristics, maintaining low resistance during normal hydrogen operation and high resistance during air ingress conditions to prevent cathode degradation

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If air is present at the anode during startup and shutdown, then system operation is simplified, but cathode potential spikes occur causing carbon corrosion and platinum catalyst dissolution

Engineering Contradiction:

Improvesystem operationVSAvoidcathode corrosion

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The selectively conducting component acts as a protective intermediary that blocks harmful electrical current flow during air-fuel transitions. By being positioned in electrical series with the anode, it prevents the formation of high cathode potentials that would otherwise occur when air is present at the anode, thereby protecting the cathode from corrosion without requiring complex operational procedures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The component exploits the presence of air itself to trigger its high-resistance state, converting the harmful condition (air ingress causing potential spikes) into a protective mechanism. When air reaches the anode, the selectively conducting component automatically increases its resistance, preventing the harmful electrical effects rather than requiring active prevention measures

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 results in a marked improvement in durability, with fuel cells showing up to an order of magnitude increase in resistance to startup/shutdown-related degradation, making them more suitable for automotive applications by maintaining high power density and efficiency over numerous cycles.

Implementation Method 1

a selectively conducting component with low electrical resistance in the presence of hydrogen and high resistance in the presence of air

Methodology Applied

Scientific EffectSelective electrical conduction: Electrical Resistance

Implementation Method 2

anode components comprise an anode and a selectively conducting component... specifically using a tin oxide layer with platinum deposited on it

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS9564642B2Durable fuel cell with platinum cobalt alloy cathode catalyst and selectively conducting anode

Publication Date: 2017.02.07 CELLCENTRIC GMBH & CO KG

AI summary

The degradation associated with repeated startup and shutdown of solid polymer electrolyte fuel cells comprising PtCo alloy cathode catalysts can be particularly poor. However, a marked and unexpected improvement in durability is observed as a result of incorporating a selectively conducting component in electrical series with the anode components in the fuel cell.