Solid Oxide Fuel Cell Cold Start Heating via Electric Resistance

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Solution Overview

Problem

Solid oxide fuel cell systems face inefficiencies in warming up from a cold start and maintaining standby temperature without consuming hydrocarbon fuel, leading to fuel wastage and potential damage from thermal stresses.

Innovation Solution

The integration of electric resistance heating elements within the 'hot zone' of the system, combined with the use of waste heat from sources like vehicle exhaust gas or off-peak grid electricity, to warm up and maintain the system at optimal temperatures without relying on hydrocarbon fuel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If hydrocarbon fuel combustion is used to warm up the fuel cell system from cold start, then the system reaches operating temperature, but fuel is wasted and thermal stresses damage components

Engineering Contradiction:

Improveoperating temperatureVSAvoidfuel consumption

Core Design Contradiction:

TemperatureVSLoss of substance

Solution Approach 1:

The patent replaces the chemical combustion process with an electrical heating system. Electric heating elements powered by the vehicle's electrical system (alternator, battery, or regenerative braking) provide the necessary heat to warm up the fuel cell stack and reformer, eliminating the need for hydrocarbon fuel combustion during cold start.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary electrical heating system that acts as a mediator between the vehicle's electrical power source and the fuel cell thermal requirements. This intermediary system transfers energy in a controlled manner, avoiding the harmful direct combustion of hydrocarbon fuel while still achieving the necessary temperature rise.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If continuous fuel combustion is used to maintain standby temperature, then the system remains ready for quick start-up, but fuel consumption increases

Engineering Contradiction:

Improvestandby readinessVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces continuous fuel combustion with electrical heating elements for maintaining standby temperature. The electrical system can provide intermittent or continuous heating as needed to maintain the fuel cell and reformer at optimal standby temperatures, eliminating ongoing hydrocarbon fuel consumption while preserving quick start-up capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs periodic or intermittent electrical heating action to maintain standby temperature rather than continuous combustion. The electrical heating system can be activated only when and where needed to maintain minimum operational temperatures, reducing overall energy consumption while ensuring rapid transition to full operation when required.

Inventive Principle:

Principle #19Periodic action

3Loss of time

If rapid warm-up is achieved through fuel combustion, then start-up time is reduced, but thermal stresses increase and damage components

Engineering Contradiction:

Improvestart-up timeVSAvoidthermal stresses

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent replaces uncontrolled combustion heating with controlled electrical heating elements that can be precisely regulated. This allows rapid warm-up to be achieved through controlled electrical power delivery while distributing heat evenly through the stack and reformer, avoiding the localized thermal shocks and excessive temperature gradients that cause thermal stress damage in combustion-based systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces fuel consumption, minimizes thermal stresses, and allows for rapid start-up and efficient standby operation, utilizing waste heat to maintain system temperatures during periods of low demand.

Implementation Method 1

electric resistance heating elements disposed within the 'hot zone' of the system

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an auxiliary heat exchanger 72 disposed within the hot zone and in communication with a source of heated gas 69

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS8356682B2Fuel cell system using external heat sources for maintaining internal temperature

Publication Date: 2013.01.22 APTIV TECHNOLOGIES AG

AI summary

A solid oxide fuel cell system including electric resistance elements for heating of space and components within the “hot zone” enclosure of the system, preferably in combination with means for using “waste” heat from other sources, to assist in warm-up from a cold start and/or to maintain a stand-by temperature of reformer and fuel cell elements within the system and/or to maintain optimum operating temperatures within the system during periods of very low electrical demand on the system. A method is included for using off-peak grid electricity, battery-stored onboard electricity, or vehicle-generated electricity to energize the resistance heaters, as well as utilizing gaseous waste heat sources such as vehicle exhaust gas to complement the resistance heating.