Fuel Cell Stop Mode Control via Partial Hydrogen Pressure

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing fuel cell systems in vehicles experience rapid aging and prolonged restart times due to frequent switching between operational and stop modes, leading to inefficient energy management and potential corrosion from residual gases.

Innovation Solution

Maintaining electric contact with the fuel cell during stop mode, reducing hydrogen supply pressure, and using recirculation and energy storage to manage residual gases, while controlling voltage and air flow to prevent corrosion and facilitate quick restarts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the fuel cell system is completely switched off during stop mode, then energy consumption and emissions are reduced, but rapid ageing occurs and restart time increases significantly

Engineering Contradiction:

Improveenergy consumptionVSAvoidfuel cell lifespan

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies partial action by maintaining minimal hydrogen supply pressure (reduced but not completely switched off) and keeping electric contact during stop mode. This partial operation prevents complete shutdown while still achieving energy savings, and simultaneously avoids the rapid ageing and long restart times associated with complete shutdown.

Inventive Principle:

Principle #16Partial or excessive action

2Loss of energy

If the fuel cell system is completely switched off during stop mode, then energy consumption is reduced, but restart time becomes prolonged

Engineering Contradiction:

Improveenergy consumptionVSAvoidrestart time

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The patent applies preliminary action by maintaining reduced hydrogen supply pressure and electric contact during stop mode, keeping the fuel cell in a standby state. This preliminary maintenance of operational readiness enables rapid restart when needed, avoiding the prolonged restart times that would result from complete shutdown.

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If hydrogen supply is completely switched off during stop mode, then energy consumption is reduced, but differential pressure between anode and cathode regions increases excessively

Engineering Contradiction:

Improveenergy consumptionVSAvoiddifferential pressure

Core Design Contradiction:

Loss of energyVSStress or pressure

Solution Approach 1:

The patent applies partial action by maintaining minimal hydrogen supply pressure rather than complete shutdown. This partial supply is sufficient to prevent excessive differential pressure buildup between anode and cathode regions while still achieving significant energy savings compared to full operation.

Inventive Principle:

Principle #16Partial or excessive action

4Loss of energy

If air supply is completely switched off during stop mode, then energy consumption is reduced, but residual oxygen causes harmful voltages and corrosion

Engineering Contradiction:

Improveenergy consumptionVSAvoidcorrosion

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies continuity of useful action by maintaining electric contact during stop mode. This continuous electrical connection allows residual oxygen to be removed through the fuel cell's electrochemical process, preventing harmful voltages and corrosion while still achieving energy savings from reduced gas supply.

Inventive Principle:

Principle #20Continuity of useful action

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

Extends fuel cell lifespan, reduces energy consumption, and enables rapid restarts by managing pressure and gas flow, thereby improving operational efficiency and comfort in stop/start vehicle operations.

Implementation Method 1

a fuel cell system (4) for a vehicle (1)

Methodology Applied

Scientific EffectElectrochemical reaction: Fuel Cell

Implementation Method 2

combustion gas that is not consumed in the fuel cell system is fed from a region after the anode via a recirculation conveying device together with fresh combustion gas from the valve device to the combustion gas supply of the anode

Methodology Applied

Scientific EffectGas recirculation: Convection

Implementation Method 3

it is furthermore possible for a current to be drawn from the fuel cell so that residual media, and here in particular residual oxygen, are removed in the region of the fuel cell

Methodology Applied

Scientific EffectElectrochemical oxygen removal: Fuel Cell

Data Source

PatentUS9034529B2Method for operation of a fuel cell system in a vehicle

Publication Date: 2015.05.19 CELLCENTRIC GMBH & CO KG

AI summary

A method of operating a fuel cell system in a vehicle that is switchable to a temporary stop mode and restarted from the stop mode. When, in certain driving situations, it is required to switch to the stop mode, it is then checked whether the operating conditions of the fuel cell system allow a switch to the stop mode. If the switch is allowed it takes place. When a restart of the fuel cell system is required on the basis of the vehicle the settings of the stop mode are cancelled again. The switch to the stop mode involves, with further existing electric contacting of the fuel cell, the air mass flow conveyed by the air conveying device being switched off or reduced to a predefined value and the pressure of the combustion gas supplied being reduced to a predefined value.