Fuel Cell Anode Chamber Shutdown to Block CO at High Temperature

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Solution Overview

Problem

Conventional methods for shutting down fuel cell generator units do not adequately prevent the formation of nickel tetracarbonyl and anode oxidation, which can reduce the operational life and efficiency of the fuel cell, and pose safety risks due to the toxic nature of nickel tetracarbonyl.

Innovation Solution

A method involving the shutdown of current generation, detection of anode temperature, and blocking the escape of carbon monoxide from the anode chamber when the temperature is above a specific limit, followed by partial removal of carbon monoxide using ambient air once the temperature falls below this limit, to prevent nickel tetracarbonyl formation and minimize anode oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon monoxide is allowed to escape from the anode chamber during shutdown, then the shutdown process is simpler and faster, but nickel tetracarbonyl forms and anode oxidation occurs, reducing fuel cell reliability and operational life

Engineering Contradiction:
Improvefuel cell operational lifeVSAvoidshutdown process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by blocking the anode chamber with a closure element before carbon monoxide can escape and cause harmful reactions. The closure is activated during the shutdown process when the temperature is still above the nickel tetracarbonyl formation temperature, preventing the harmful chemical reactions from occurring in the first place. This resolves the contradiction by adding a preventive measure that protects reliability without significantly complicating the overall shutdown procedure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates an inert environment by blocking the anode chamber to prevent oxygen from entering and reacting with carbon monoxide to form nickel tetracarbonyl. By isolating the anode chamber and controlling the atmosphere within it during shutdown, the harmful chemical reactions are prevented. This approach maintains reliability by eliminating the conditions necessary for nickel tetracarbonyl formation and anode oxidation.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If carbon monoxide is removed from the anode chamber at high temperatures, then nickel tetracarbonyl formation is prevented, but energy is wasted and the removal process becomes less efficient

Engineering Contradiction:
Improvenickel tetracarbonyl formationVSAvoidenergy consumption for CO removal
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by blocking the anode chamber before carbon monoxide removal begins, ensuring that harmful reactions cannot occur regardless of temperature conditions. This allows the system to remove carbon monoxide at lower temperatures where the process is more energy-efficient, while still preventing nickel tetracarbonyl formation through the protective barrier. The closure element ensures safety is maintained while optimizing energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the temperature parameter by delaying carbon monoxide removal until after the fuel cell has cooled down. Since nickel tetracarbonyl does not form below its formation temperature, the system can safely remove carbon monoxide at lower temperatures where the process is more energy-efficient. The closure element maintains protection throughout this temperature transition, allowing parameter optimization without compromising safety.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the anode chamber is blocked during shutdown, then nickel tetracarbonyl formation is prevented, but carbon monoxide accumulates inside the chamber requiring additional removal steps

Engineering Contradiction:
Improveprevention of toxic compound formationVSAvoidcarbon monoxide accumulation
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by blocking the anode chamber during shutdown to prevent harmful reactions, then subsequently removing the closure element to allow carbon monoxide removal. This two-stage approach ensures that nickel tetracarbonyl formation is prevented during the critical high-temperature period, then addresses the carbon monoxide accumulation issue in a second step. The closure element is removed once the temperature is safe, allowing the accumulated carbon monoxide to be purged without risk of harmful reactions.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If shutdown is performed without temperature monitoring, then the process is simpler and faster, but harmful reactions cannot be prevented at critical temperatures

Engineering Contradiction:
Improveshutdown operation simplicityVSAvoidprevention of harmful reactions
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies self-service by using the fuel cell's own temperature sensor and control system to monitor and control the shutdown process. The existing temperature monitoring infrastructure is utilized to detect when the anode chamber temperature is above the nickel tetracarbonyl formation temperature, automatically triggering the closure mechanism. This resolves the contradiction by using already-available system resources to provide temperature-based protection without requiring entirely new monitoring systems, thus maintaining operational simplicity while ensuring reliability.

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

This approach extends the operational life of the fuel cell, reduces emissions, and minimizes the formation of toxic nickel tetracarbonyl, while ensuring safety by preventing its escape and oxidation of the anode, thereby maintaining fuel cell efficiency and performance.

Implementation Method 1

The electrolyte in this type of cell in one embodiment comprises a solid ceramic material that can conduct oxygen ions and simultaneously has an insulating effect for electrons. The oxygen-ion-conduction electrolyte is preferably provided as a thin membrane in order to be able to transport the oxygen ions using minimal energy.

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

The operation of the fuel cell device is based here on the redox reaction, in which the reduction and oxidation take place in physical separation, specifically at an interface between anode and electrolyte or between electrolyte and cathode.

Methodology Applied
Scientific EffectRedox reaction: Redox Reactions

Implementation Method 3

detection of at least one anode temperature of an anode of the fuel cell device, during a cool-down process

Methodology Applied
Scientific EffectThermal detection:

Data Source

PatentEP3494609B1Method for shutting down a generator unit having a fuel cell device
Publication Date: 2024.05.01 AVL LIST GMBH
  • EP3494609B1 patent drawingFigure 1

AI summary

The present invention relates to a method for shutting down a generator unit (1) comprising a fuel cell device (100) having the steps (a) shutdown of a current generation via a control unit (510); (b) detection of at least one anode temperature of an anode (122) of the fuel cell device (100), in particular during a cool-down process; (c) blocking of an escape of carbon monoxide from an anode chamber (120) in which the anode (122) is arranged at least partially, in particular, at least for the most part, completely, if the anode temperature is higher than the first limit temperature T1; (d) at least partial removal of carbon monoxide from an anode chamber (120) in which the anode (122) is arranged at least in part, in particular, at least for the most part, completely, if the anode temperature falls below a first limit temperature T1. The present invention further relates to a generator unit (1), a vehicle having this generator unit (1) and a use of this generator unit (1).