Fuel Cell Container Heater for Cold-Start Protection

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Solution Overview

Problem

Fuel cells struggle to start at low ambient temperatures due to frozen water in the stack, which causes damage from repeated thawing and freezing, limiting their use in applications like rail vehicles.

Innovation Solution

A fuel cell system with a heater in the container, controlled by a temperature sensor, heats the system to prevent damage during startup, allowing the fuel cell to be started at low temperatures by reaching specific temperature limits and using waste heat for thawing, with optional latent heat accumulators to reduce energy requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the fuel cell is started at low ambient temperatures without heating, then the startup process is simple and quick, but the residual water in the cell freezes and causes damage to the membrane

Engineering Contradiction:
Improvestartup simplicityVSAvoidfuel cell durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The heating device is activated before the fuel cell startup to preheat the cell and evaporate residual water. This preliminary action prevents freezing damage during cold weather operation, allowing the fuel cell to start reliably without compromising the membrane structure.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a heating device is added to prevent freezing damage, then the fuel cell can operate reliably at low temperatures, but the system complexity and energy consumption increase

Engineering Contradiction:
Improvefuel cell durabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heating device is controlled to operate automatically based on temperature sensors and operational status. The system self-regulates the heating process, eliminating the need for complex manual control systems while ensuring reliable operation at low temperatures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The waste heat from the fuel cell operation is utilized to maintain temperature and prevent freezing during idle periods. This heat recovery approach reduces the energy consumption of the heating device and improves overall system efficiency.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If the heating device operates continuously to prevent freezing, then the fuel cell is protected from temperature-related damage, but the energy consumption increases

Engineering Contradiction:
Improvefuel cell protectionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The heating device operates periodically rather than continuously, activating before startup to evaporate residual water and during idle periods to prevent freezing. The controller monitors temperature and operational status to determine when heating is necessary, reducing overall energy consumption while maintaining protection.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The waste heat generated during fuel cell operation is recovered and used to maintain temperature during idle periods. This heat recovery system reduces the energy required for active heating while ensuring the fuel cell remains protected from freezing damage.

Inventive Principle:
Principle #34Discarding and recovering

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 safe and reliable startup of fuel cells at low temperatures, preventing damage and extending their lifespan, making them suitable for rail vehicles by ensuring the fuel cell system can operate without temperature-related issues.

Implementation Method 1

providing at least one outer wall (10) of a container, in which a fuel cell (30), a feed line (34) for the fuel and possibly other components of the fuel cell system are accommodated, with a heater (21)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The first limit temperature, which is determined using a temperature sensor arranged in the container

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Implementation Method 3

Fuel cells generate electrical energy in the form of direct current in an electro-chemical process. A fuel such as hydrogen reacts with another substance such as oxygen in an exothermic reaction.

Methodology Applied
Scientific EffectElectrochemical reaction: Fuel Cell

Implementation Method 4

Operation produces waste heat, which is used to further heat the fuel cell. This dissolves ice crystals in the cell.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4086990A1Fuel cell system and method for operating the same
Publication Date: 2022.11.09 SIEMENS MOBILITY GMBH
  • EP4086990A1 patent drawingFigure 1
  • EP4086990A1 patent drawingFigure 2
  • EP4086990A1 patent drawing

AI summary

A fuel cell system with improved cold-start capability comprises a fuel cell array in a container that has a heater on at least one of its outer walls. The container houses at least the fuel cell and a fuel supply line. During the starting process, the container is heated in an initial warm-up phase; only then is the fuel cell started.