Fuel Cell Cooling Loop With Dual Buffers for Peak Load Cooling

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Solution Overview

Problem

Existing fuel cell cooling systems are oversized to handle high-load situations, increasing costs and space requirements, and there is a need for a more efficient and compact cooling solution capable of managing both normal and high-load operations.

Innovation Solution

A cooling system with a dual buffer tank arrangement and a movable separator in a common tank, allowing for a buffer of cooled cooling medium to be built up during low-load operations, which can be utilized during high-load situations, combined with a heat exchanger and pump configuration to manage cooling medium flow efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cooling system is oversized to handle high-load situations, then the cooling capability during high-load operation is improved, but the costs and space requirements increase

Engineering Contradiction:
Improvecooling capability during high-load operationVSAvoidspace requirements
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies preliminary action by building up a buffer of cooled cooling medium in the second buffer tank during low-load operation periods. This pre-cooled buffer is then available for immediate use during high-load situations, eliminating the need for oversized cooling components while ensuring adequate cooling capability when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics through a movable separator that dynamically adjusts the volume distribution between the first and second buffer tanks based on operating conditions. During low-load operation, the separator positions to allow cooling medium accumulation in the second tank, while during high-load operation, it facilitates optimal flow distribution to meet increased cooling demands.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the cooling system is oversized to handle high-load situations, then the cooling capability during high-load operation is improved, but the costs increase

Engineering Contradiction:
Improvecooling capability during high-load operationVSAvoidcosts
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system performs preliminary cooling action during low-load periods, accumulating pre-cooled medium in the second buffer tank. This eliminates the need for expensive oversized cooling components by utilizing time-based load variation to pre-produce cooling capacity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the operational parameters of the cooling system by introducing variable volume buffer zones through the movable separator. This allows the system to adapt its cooling medium storage and flow characteristics based on load conditions, replacing the need for permanently oversized expensive components.

Inventive Principle:
Principle #35Parameter changes

3Volume of stationary object

If a buffer of cooled cooling medium is built up during low-load operations, then the space and cost are reduced, but the system complexity increases

Engineering Contradiction:
Improvespace requirementsVSAvoidsystem complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the cooling buffer function with the existing cooling loop by integrating the first and second buffer tanks into the cooling medium circulation path. The movable separator is incorporated within the common tank structure, combining multiple functions (buffering, separation, volume adjustment) into a unified system rather than adding separate independent components.

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

The system effectively manages cooling demands across varying loads, reducing space and cost by utilizing a buffer tank system to optimize cooling medium flow, ensuring efficient operation without the need for oversized components.

Implementation Method 1

a first heat exchanger for cooling of the cooling medium

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

heat is transferred from the coolant to the hydrogen

Methodology Applied
Scientific EffectHeat exchange between cooling medium and hydrogen: Heat Exchanger

Implementation Method 3

a fuel cell stack where a fuel, such as a fuel with first and second fuel components hydrogen and oxygen, is converted in a fuel cell stack while producing electricity

Methodology Applied
Scientific EffectFuel cell electrochemical conversion: Fuel Cell

Implementation Method 4

the hydrogen is stored in a pressure tank and fed to the fuel cell stack via an expander device where the pressure of the hydrogen is significantly reduced. Due to the pressure decrease the hydrogen cools down

Methodology Applied
Scientific EffectAdiabatic cooling: Adiabatic Cooling

Data Source

PatentEP4275242B1Cooling system for a fuel cell system
Publication Date: 2025.11.26 VOLVO TRUCK CORP
  • EP4275242B1 patent drawingFigure 1
  • EP4275242B1 patent drawingFigure 2
  • EP4275242B1 patent drawingFigure 3

AI summary

The invention relates to a cooling system (30) for cooling of a fuel cell assembly (10), wherein the cooling system (30) comprises: a cooling loop (31) for recirculation of a cooling medium, a cooling medium flow line (32) comprising a first cooling medium buffer tank (4a), a first heat exchanger (2) for cooling of the cooling medium, and a second cooling medium buffer tank (4b), wherein the first cooling medium buffer tank (4a) is arranged upstream the first heat exchanger (2) so as to allow collection, storing and discharge of cooling medium before it reaches the first heat exchanger (2), and wherein the second cooling medium buffer tank (4b) is arranged downstream of the first heat exchanger (2) so as to allow collection, storing and discharge of cooling medium that has passed through and been cooled in the first heat exchanger (2). The invention also relates to a fuel cell system (20) provided with such a cooling system (30) and to methods for operating such systems.