Fuel Cell Stack Thermal Isolation via Fluid Heat Transfer

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Solution Overview

Problem

Existing fuel cell modules face temperature unevenness issues due to direct heating from overheated combustors, leading to decreased electricity-generating efficiency and shortened fuel cell service life, requiring complex design adjustments and thermal simulations for each configuration change.

Innovation Solution

A fuel cell module design where the fuel cell stack is arranged independently of the housing, with a reformer and combustor housed within the housing, using fluid passages for heat transfer, and heat insulating material to isolate the stack from direct radiation heat, allowing for uniform temperature control and independent design of the housing components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the combustor is arranged inside the casing to heat the fuel cell stack, then the temperature of the fuel cell stack can be maintained, but temperature unevenness occurs due to radiation heat from the overheated combustor

Engineering Contradiction:
Improvetemperature of fuel cell stackVSAvoidtemperature uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The system is divided into separate functional modules: the combustor is positioned outside the fuel cell stack assembly, with dedicated heat transfer fluid circulation paths. This segmentation allows independent optimization of combustion temperature and fuel cell operating temperature, preventing direct thermal coupling that causes temperature unevenness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat transfer fluid (water or dielectric fluid) acts as an intermediary between the combustor and the fuel cell stack. The fluid absorbs heat from the combustor in a heat exchanger and transports it uniformly to the fuel cell stack, eliminating direct radiation heat transfer that causes temperature hotspots and unevenness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the arrangement of combustor and fuel cell stack is changed, then adaptability is improved, but temperature unevenness reoccurs requiring redesign

Engineering Contradiction:
Improvearrangement flexibilityVSAvoidtemperature uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The housing design integrates multiple functions: it contains the fuel cell stack, accommodates the reformer, provides pathways for heat transfer fluid circulation, and serves as a structural enclosure. This universal design allows different combustor configurations and fuel cell stack arrangements without compromising temperature uniformity, as the fluid-based heat transfer system adapts to various layouts.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses hydraulic principles with liquid heat transfer fluid circulating through closed-loop channels. The fluid dynamically carries thermal energy from the combustor to the fuel cell stack, providing adaptable and uniform heat distribution that is insensitive to spatial arrangement changes of components within the housing.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Manufacturing precision

If dedicated thermal simulation and prototype testing are performed for each configuration change, then temperature uniformity is maintained, but development time and cost increase

Engineering Contradiction:
Improvetemperature uniformityVSAvoiddevelopment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The heat transfer fluid system automatically self-regulates temperature distribution based on the thermal demands of the fuel cell stack and the heat output of the combustor. This self-balancing mechanism eliminates the need for complex external control systems and extensive iterative testing, as the system inherently maintains temperature uniformity across different configurations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system controls temperature by adjusting parameters of the heat transfer fluid (flow rate, volume, specific heat capacity) rather than relying on fixed geometric arrangements. This parametric control approach allows temperature uniformity to be maintained across different configurations through fluid property adjustments rather than redesigning the entire thermal field, reducing development time.

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

This configuration ensures uniform temperature distribution in the fuel cell stack, reducing the impact of housing component changes on temperature distribution and allowing for mass production with a single housing model, decreasing manufacturing costs and maintaining efficiency.

Implementation Method 1

a reformer that generates fuel gas containing hydrogen by reforming raw fuel gas

Methodology Applied
Scientific EffectReforming: Chemical Transport Reactions

Implementation Method 2

a combustor that combusts remaining fuel gas which has not been used for generating electricity and which has remained in the fuel cell stack, and thereby that heats the reformer

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

heat insulating material to isolate the stack from direct radiation heat

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentEP3486988A1Fuel cell module and fluid supply device used therefor
Publication Date: 2019.05.22 MORIMURA SOFC TECH CO LTD
  • EP3486988A1 patent drawingFigure 1
  • EP3486988A1 patent drawingFigure 2
  • EP3486988A1 patent drawingFigure 3

AI summary

The present invention provides a fuel cell module (1) including a fuel cell stack (2) having a plurality of fuel cells (2a); a reformer (36) that generates fuel gas by reforming raw fuel gas; a combustor (38) that combusts remaining fuel gas and thereby that heats the reformer; and a housing (6) that houses the reformer and the combustor. The fuel cell stack is arranged outside the housing independently from the housing.