Fuel Cell Hydrogen Recirculation via Electrochemical Pump

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Solution Overview

Problem

Ion-exchange membrane fuel cells face performance decay and potential lifetime reduction due to nitrogen and water build-up when fed with pure hydrogen, leading to hydrogen dilution and flooding issues, and existing solutions like external hydrogen recirculation pumps are inefficient and prone to mechanical stress on the membrane.

Innovation Solution

Integration of a hydrogen-transfer electrochemical cell with the fuel cell, where hydrogen exhaust is recycled internally, eliminating the need for external pumps and addressing flow rate distribution issues by using a unitary ratio of hydrogen feed to recycled hydrogen, ensuring consistent hydrogen flow regardless of assembly imperfections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external hydrogen recirculation pumps are used to maintain hydrogen flow, then nitrogen and water levels can be controlled, but mechanical stress on the membrane increases and system complexity increases

Engineering Contradiction:

Improveperformance stabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the mechanical pump component from the system by using a hydrogen transfer cell that provides internal recirculation through electrochemical means, thereby reducing device complexity while maintaining the ability to control nitrogen and water levels

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical recirculation pump with an electrochemical hydrogen transfer cell that uses electrical energy to drive hydrogen ion transport, substituting a mechanical system with an electrochemical one to eliminate mechanical stress on the membrane

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If external recirculation pumps are used, then hydrogen flow can be maintained, but abnormal mechanical solicitation of the membrane occurs

Engineering Contradiction:

Improveoperational reliabilityVSAvoidmembrane mechanical stress

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention replaces mechanical pumping action with electrochemical hydrogen ion transport through the membrane, eliminating abnormal mechanical solicitation while maintaining hydrogen flow and operational reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If pure hydrogen is fed to the fuel cell, then conventional platinum catalysts can be used, but nitrogen and water build-up causes performance decay

Engineering Contradiction:

Improvecatalyst reliabilityVSAvoidperformance stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention implements a self-service mechanism where the hydrogen transfer cell automatically recirculates hydrogen internally to prevent nitrogen and water build-up, maintaining performance stability while using pure hydrogen and conventional platinum catalysts

Inventive Principle:

Principle #25Self-service

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 internal hydrogen recirculation system maintains low nitrogen and water levels, enhances operational reliability by eliminating mechanical components, and simplifies system regulation, while maintaining overall volume and weight efficiency.

Implementation Method 1

the anode provides to the ionisation of hydrogen to protons which migrate across the membrane and are recombined on the opposite side at the cathode, producing pure hydrogen

Methodology Applied

Scientific EffectIonisation: Ionisation

Implementation Method 2

a unit formed by common lamination of an ion-exchange membrane fuel cell with an electrochemical ion-exchange membrane hydrogen-transfer cell

Methodology Applied

Scientific EffectIon Exchange: Ion Exchange

Implementation Method 3

converting the chemical energy of combination of a fuel and an oxidant directly into electrical energy

Methodology Applied

Scientific EffectFuel Cell: Fuel Cell

Implementation Method 4

ion-exchange membrane fuel cells

Methodology Applied

Scientific EffectIon Exchange: Ion Exchange

Implementation Method 5

passage across suitable separation units, based for instance on metal or polymer selective membranes

Methodology Applied

Scientific EffectSemipermeable Membrane: Semipermeable Membrane

Implementation Method 6

the capacity of the nitrogen contained in the air on the fuel cell cathode compartment to diffuse across the ion-exchange membrane

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS7887961B2Fuel cell with hydrogen internal recirculation

Publication Date: 2011.02.15 NUVERA FUEL CELLS LLC

AI summary

A unit consisting of a fuel cell, provided with a first ion-exchange membrane, and an electrolysis cell, equipped with a second ion-exchange membrane, capable of operating as an electrochemical hydrogen pump in which the electrolysis cell sucks in the discharge gas of the fuel cell anodic compartment which contains hydrogen as the main component, ionizes the hydrogen on a suitable anodic catalyst, sends the so formed protons across the second ion-exchange membrane to a suitable cathodic catalyst where the protons are reconverted to hydrogen which is mixed to the fuel cell hydrogen feed.