PEM Stack for High Temperature Fuel Cell Startup

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Solution Overview

Problem

High temperature fuel cell systems, such as solid oxide fuel cell (SOFC) systems, require significant heat-up times and cool down times, necessitating inefficient power sources like grid power or diesel generators, and need stored anode purge gas to prevent oxidation, occupying valuable space.

Innovation Solution

A fuel cell system incorporating a proton exchange membrane (PEM) stack that provides power during start-up and shut-down modes and hydrogen in steady-state mode, reducing the need for external power sources and anode purge gas storage by using a catalytic partial oxidizing reactor to generate hydrogen-rich reformate for purging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If external power sources (grid or diesel generator) are used during start-up, then the fuel cell system can operate during heat-up, but energy efficiency deteriorates and emissions increase

Engineering Contradiction:

Improvepower availability during start-upVSAvoidenergy efficiency

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The fuel cell system serves itself by generating its own startup power through the PEM fuel cell stack during the heat-up period, eliminating dependence on external power sources and improving energy efficiency

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The PEM fuel cell stack is activated in advance during the heat-up period to generate power for auxiliary components before the main high-temperature fuel cell stack is ready for operation

Inventive Principle:

Principle #10Preliminary action

2Reliability

If stored anode purge gas is used to prevent anode oxidation, then the anode is protected during shutdown, but system complexity and space requirements increase

Engineering Contradiction:

Improveanode protectionVSAvoidpurge gas storage space

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The system generates its own protective purge gas on-demand through the PEM fuel cell stack during shutdown, eliminating the need for external storage containers and reducing system complexity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The operating mode of the PEM stack changes from power generation to hydrogen production during shutdown, providing protective hydrogen atmosphere without requiring storage infrastructure

Inventive Principle:

Principle #35Parameter changes

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 system achieves reduced energy requirements for start-up, lower emissions, and eliminates the need for separate anode purge gas storage, enhancing overall efficiency and system compactness by utilizing the PEM stack for both power generation and hydrogen supply.

Implementation Method 1

A fuel cell system incorporating a proton exchange membrane (PEM) stack that provides power during start-up and shut-down modes

Methodology Applied

Scientific EffectElectrochemical reaction: Fuel Cell

Implementation Method 2

using a catalytic partial oxidizing reactor to generate hydrogen-rich reformate for purging

Methodology Applied

Scientific EffectCatalytic oxidation: Catalysis

Data Source

PatentUS7846599B2Method for high temperature fuel cell system start up and shutdown

Publication Date: 2010.12.07 BLOOM ENERGY CORP

AI summary

A fuel cell system includes a fuel cell stack and a PEM stack for providing power to the system in a start up or shut down operating mode and hydrogen to the fuel cell stack in a steady state operating mode.