Fuel Cell Coolant Cooling via Outlet Stream Heat Exchange

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Solution Overview

Problem

Fuel cell systems with low-temperature fuel cells require powerful cooling, leading to insufficient cooling at high loads and limited performance, especially in vehicles at high ambient temperatures, and existing solutions like heat pumps reduce overall efficiency due to electrical energy consumption.

Innovation Solution

A fuel cell system with a cooling device that utilizes the cooler outlet stream to cool the coolant, potentially through a turbine or humidification device, where the outlet stream is cooled before passing through a cooling element, allowing it to cool the coolant further without significantly impairing system efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a powerful cooler is used to cool the fuel cell, then the cooling capacity is improved, but the device complexity and size increase

Engineering Contradiction:
Improvecoolant temperatureVSAvoidcooler size
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines the cooling function with the existing outlet stream flow path. The outlet stream, which already flows through the fuel cell system, is utilized to cool the coolant in a heat exchanger, merging the cooling function with the existing gas flow path rather than adding a completely separate cooling system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The outlet stream serves multiple functions: it exits the fuel cell, flows through a turbine to generate power, and simultaneously cools the coolant in the heat exchanger. This multi-functionality reduces the need for dedicated cooling components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If a heat pump is used to extract heat from the cooling circuit, then the cooling capacity is improved, but the energy consumption increases

Engineering Contradiction:
Improvecoolant temperatureVSAvoidelectrical energy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent converts the waste heat in the outlet stream into a useful cooling resource. Instead of treating the outlet stream as mere waste heat to be removed, it utilizes this heat to cool the coolant, turning a potentially harmful thermal byproduct into a beneficial cooling source.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The outlet stream from the fuel cell directly cools the coolant through the heat exchanger without requiring external power input. The system uses its own internal thermal resources (the temperature difference between outlet stream and coolant) to achieve cooling, making it self-sufficient.

Inventive Principle:
Principle #25Self-service

3Temperature

If the cooler is dimensioned very large, then the cooling capacity is improved, but the device complexity and space requirements increase

Engineering Contradiction:
Improvecoolant temperatureVSAvoidcooler volume
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The cooling function is merged with the existing outlet stream path and turbine system. The heat exchanger utilizes the outlet stream that already flows through the system, eliminating the need for a large dedicated cooler and reducing overall system volume.

Inventive Principle:
Principle #5Merging (Combining)

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 improves coolant cooling efficiency, allowing for a smaller cooler design and maintaining system performance even at high loads and ambient temperatures, without substantial energy loss.

Implementation Method 1

at least one cooling element is arranged in the outlet stream, by which the outlet stream can be cooled

Methodology Applied
Scientific EffectHeat extraction: Heat Exchanger

Implementation Method 2

a cooling device is arranged in the outlet stream in the direction of flow of the outlet stream behind the cooling element, in which the coolant can be cooled by the outlet stream

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

where the outlet stream is cooled before passing through a cooling element

Methodology Applied
Scientific EffectTurbine expansion: Turbine

Data Source

PatentEP2472660B1Fuel cell system
Publication Date: 2018.05.30 ROBERT BOSCH GMBH
  • EP2472660B1 patent drawingFigure 1
  • EP2472660B1 patent drawingFigure 2
  • EP2472660B1 patent drawingFigure 3

AI summary

The fuel cell system (10) has a cooling device (30) for cooling a fuel cell (11), in which coolant is circulated. The reactant is supplied to fuel cell through inflow streams (13,20) and product is discharged from the fuel cell through exhaust streams (14,21). The cooling elements (22,23) are arranged to cool the exhaust streams. The cooling units (31,36) are arranged behind the cooling elements in the flow direction, in order to cool the exhaust streams through coolant. An independent claim is included for method for cooling coolant of fuel cell system.