Fuel Cell Stack Ventilation Control for Low Oxygen Stability

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Solution Overview

Problem

Fuel cell systems face instability in power generation due to decreased oxygen concentration, leading to reduced voltage, especially when air supply is limited or ventilation is excessive, causing unnecessary cooling and temperature deviations.

Innovation Solution

A fuel cell system with a control unit that detects low oxygen concentration and adjusts air flow rate or activates a ventilation unit to introduce outside air, ensuring optimal oxygen stoichiometry and temperature management within rated ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a ventilation unit is continuously driven to maintain oxygen concentration, then oxygen concentration is maintained, but the fuel cell stack and auxiliary machine are cooled more than necessary, causing temperature deviation from rated range and unstable power generation

Engineering Contradiction:
Improveoxygen concentrationVSAvoidtemperature stability
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The ventilation unit operates intermittently rather than continuously. The control unit activates the ventilation unit when oxygen concentration falls below a predetermined level and deactivates it when the level is sufficient, creating a periodic on-off action that maintains oxygen concentration while avoiding excessive cooling

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit monitors oxygen concentration levels and uses this feedback to control the ventilation unit's operation. When oxygen concentration drops below a threshold, the ventilation unit is activated; when it rises above the threshold, the unit is deactivated, creating a closed-loop control system that prevents both oxygen deficiency and excessive cooling

Inventive Principle:
Principle #23Feedback

2Device complexity

If air supply is limited in vehicles without front air supply ports or at low speeds, then vehicle design is simplified, but oxygen concentration decreases and voltage is reduced

Engineering Contradiction:
Improveair supply system complexityVSAvoidpower generation stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control unit continuously monitors oxygen concentration or voltage levels and activates the ventilation unit when power generation stability is compromised due to low oxygen concentration, providing feedback-based correction without requiring complex air supply system design

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses its own ventilation unit to self-correct oxygen concentration issues when natural air intake is insufficient, allowing the fuel cell system to maintain its own operational conditions without external intervention or complex modifications to vehicle air supply design

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

Stabilizes power generation by maintaining optimal oxygen levels and temperatures, preventing voltage reduction and ensuring efficient operation even in environments with limited air supply.

Implementation Method 1

processing to ventilate the interior of the fuel cell stack by controlling an operation of a ventilation unit

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

an air compressor that supplies air to the fuel cell stack

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

a fuel cell stack

Methodology Applied
Scientific EffectElectrochemical reaction: Fuel Cell

Data Source

PatentEP4329023A1Fuel cell system
Publication Date: 2024.02.28 TOYOTA INDUSTRIES CORP
  • EP4329023A1 patent drawingFigure 1
  • EP4329023A1 patent drawingFigure 2
  • EP4329023A1 patent drawingFigure 3

AI summary

The present disclosure stabilizes power generation of a fuel cell stack (FCS) in an environment in which an oxygen concentration in a fuel cell system (1) readily decreases. In a case where it is detected that the oxygen concentration is lower than a predetermined concentration or where a phenomenon caused by the oxygen concentration being lower than the predetermined concentration is detected, processing to increase a flow rate of air supplied to the fuel cell stack (FCS) or processing to ventilate the interior of the fuel cell stack (FCS) by controlling an operation of a ventilation unit (F) is performed.