Fuel Cell Stack Hot Swap via Inert Gas Preparation

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Solution Overview

Problem

Existing fuel cell systems require a complete shutdown to replace a non-functional fuel cell stack, which is inefficient and disrupts continuous operation.

Innovation Solution

A method where the non-functional fuel cell stack is separated, media connections are disconnected, and the operating medium spaces are prepared in an auxiliary device with inert gases and degassed cooling water, allowing for hot swapping without shutting down the entire system, enabling quick and simple replacement of the stack while maintaining system operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire fuel cell system is switched off to replace a non-functional fuel cell stack, then the replacement can be performed safely, but the system operation is interrupted and downtime increases

Engineering Contradiction:
Improvesafe replacementVSAvoidsystem downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The fuel cell system is divided into multiple independent fuel cell stacks, each with its own media connections and control systems. This segmentation allows one stack to be replaced while others continue operating, eliminating the need to shut down the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The new fuel cell stack is prepared in advance in an auxiliary device where media connections are pre-established and the stack is pre-tested. This preliminary preparation allows for quick installation and commissioning without interrupting system operation.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the new fuel cell stack is installed without proper preparation of operating medium spaces, then installation is faster, but reactants may contaminate the system or create safety hazards

Engineering Contradiction:
Improveinstallation speedVSAvoidsystem safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The new fuel cell stack is prepared in advance in an auxiliary device where hydrogen and oxygen media spaces are evacuated to below water vapor pressure, cooling water is degassed, and all connections are pre-checked. This preliminary preparation ensures safety and proper composition before installation into the operating system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The auxiliary device creates a controlled environment where media spaces are evacuated to remove reactive gases, and inert conditions are maintained during preparation. This prevents unwanted chemical reactions and ensures safety during the preparation and installation process.

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

3Ease of operation

If media connections are not disconnected before removing the fuel cell stack, then the replacement process is simpler, but operating media leakage and system contamination occur

Engineering Contradiction:
Improvereplacement simplicityVSAvoidmedia leakage
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

Media connections are disconnected from the removed stack and reconnected to the new stack as a preliminary step before installation. This ensures that no operating media leak during the replacement process and that the new stack receives properly prepared media.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An auxiliary device serves as an intermediary between the operating fuel cell system and the new stack being installed. Media connections are transferred through this auxiliary device, which acts as a buffer to prevent leakage and contamination during the transition.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the replacement of fuel cell stacks without interrupting the operation of the fuel cell system, ensuring continuous functionality and reducing downtime by preparing the new stack in a controlled state before installation, with a pressure maintenance test ensuring tightness and safety.

Implementation Method 1

The vacuum pressure should be below the water vapor pressure, i.e. less than 200 mbar

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

the gas spaces no longer contain any reactants, but are instead filled with inert gases

Methodology Applied
Scientific EffectGas displacement:

Implementation Method 3

the cooling water space is emptied. The new fuel cell stack can then be installed in the fuel cell system and connected to the appropriate media, power and process connections

Methodology Applied
Scientific EffectDegassing:

Data Source

PatentEP3437151B1Method for replacing a fuel cell stack in a fuel cell system
Publication Date: 2019.09.18 SIEMENS AG
  • EP3437151B1 patent drawingFigure 1

AI summary

The invention relates to a method for exchanging a fuel cell stack in a fuel cell system operated with hydrogen (H2) and oxygen (O2) and supplied with a cooling agent (KW) when in operation, wherein after removing the fuel cell stack which is to be exchanged from the fuel cell system (3), a new fuel cell stack (2) with evacuated oxygen media space or an evacuated oxygen and hydrogen media space is introduced into the fuel cell system (3) and is filled therefrom with oxygen (O2) or oxygen (O2) and hydrogen (H2).