Fuel Cell Warm-Up Control With Preheated Off-Gas Combustor

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Solution Overview

Problem

The warming-up process of a fuel cell system is inefficient at the early stage, leading to uncombusted gases being discharged outside without being combusted, as the discharged air combustor does not effectively combust the remaining anode and cathode gases during the fuel cell's warming-up phase.

Innovation Solution

A fuel cell system configuration that includes a control method to manage the warming-up process by pre-heating the discharged air combustor and using a cutoff valve to ensure that anode off-gas is directed to the combustor only when it has reached a suitable temperature, allowing for complete combustion of both anode and cathode gases within the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the fuel cell is warmed up by supplying heating gas at high temperature, then the fuel cell temperature rises to enable electric generation, but the discharged air combustor warming-up is insufficient and uncombusted gases are discharged outside

Engineering Contradiction:
Improvefuel cell temperatureVSAvoidcombustor warming-up sufficiency
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The discharged air combustor is warmed up in advance before the fuel cell warming-up begins. The control unit performs combustor warming-up control prior to fuel cell warming-up control, ensuring the combustor reaches sufficient temperature to combust uncombusted gases before they are discharged outside during the fuel cell warming-up process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The discharged air combustor acts as an intermediary device that processes the cathode off-gas and heating gas. By pre-warming the combustor, it ensures that any uncombusted gases passing through during fuel cell warming-up are combusted before discharge, serving as a safety intermediary between the fuel cell and the external environment

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the warming-up process is accelerated, then the fuel cell reaches operating temperature faster, but uncombusted gases are discharged outside without being combusted

Engineering Contradiction:
Improvewarming-up speedVSAvoiduncombusted gas discharge
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The combustor is prepared in advance by warming it up before the fuel cell warming-up accelerates. This preliminary action ensures that even when the fuel cell warming-up proceeds quickly, the combustor is already at sufficient temperature to immediately combust any uncombusted gases that pass through

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The potential harm of uncombusted gas discharge during rapid warming-up is converted into a benefit by using the combustor as a safety device. The combustor, being pre-warmed, transforms the harmful uncombusted gases into combusted exhaust before discharge, turning a potential safety issue into a protective feature that enables faster warming-up without harmful emissions

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 approach ensures that all gases are combusted within the system, preventing uncombusted gases from being discharged outside during the warming-up phase, thereby enhancing the efficiency and effectiveness of the fuel cell's warming-up process.

Implementation Method 1

a heating device 66 that heats the discharged air combustor 58

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a discharged air combustor 58 that combusts the anode off-gas 26C

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

a fuel cell stack 12 that generates electromotive force by use of an anode gas 26A and a cathode gas 42A

Methodology Applied
Scientific EffectFuel cell electrochemical reaction: Fuel Cell

Data Source

PatentEP3392946B1Fuel cell system and control method for fuel cell system
Publication Date: 2023.09.13 NISSAN MOTOR CO LTD
  • EP3392946B1 patent drawingFigure 1
  • EP3392946B1 patent drawingFigure 2
  • EP3392946B1 patent drawingFigure 3

AI summary

A fuel cell system including a fuel cell; a first combustor coupled to a discharged air side of the fuel cell; a heating device that heats the first combustor; and a warming-up control unit that performs a warming-up control of the fuel cell after warming up the first combustor by the heating device.