Fuel Cell Air Supply Control for Brake Resistor Cooling

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Solution Overview

Problem

Electric vehicles with fuel cell systems face challenges in managing excessive energy generated during braking, which can lead to inefficient energy dissipation and oversizing of battery systems, particularly due to the limitations of conventional brake resistors and cooling systems.

Innovation Solution

An energy management system with an air-cooled brake resistor and an air compressor arrangement connected to a fuel cell system, controlled by a controllable valve assembly, dynamically distributes compressed air to manage excessive energy by prioritizing its use in the brake resistor or fuel cell based on operational needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a brake resistor is used to dissipate excessive energy during braking, then energy dissipation capability is improved, but the cooling system capacity must be increased to handle the heat

Engineering Contradiction:
Improveenergy dissipation capabilityVSAvoidcooling system capacity
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The air compressor arrangement is designed to serve dual functions: providing compressed air to the fuel cell system for power generation and providing compressed air to the brake resistor for cooling during braking operations. This multi-functionality eliminates the need for separate cooling systems, directly resolving the contradiction between energy dissipation capability and cooling system capacity requirements

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

2Quantity of substance

If battery system capacity is increased to store more energy from regenerative braking, then energy storage capability is improved, but vehicle weight increases

Engineering Contradiction:
Improveenergy storage capabilityVSAvoidvehicle weight
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The system converts the previously harmful waste heat from brake resistors into a useful resource by using it to drive the air compressor. This compressed air is then utilized by the fuel cell system, creating a beneficial cascade that reduces the need for large battery capacity while maintaining energy efficiency, thereby reducing vehicle weight

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

3Temperature

If air compressor arrangement is used to cool the brake resistor, then cooling efficiency is improved, but compressed air consumption increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcompressed air consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The system recovers and utilizes the compressed air that would otherwise be wasted during brake resistor cooling operations. By integrating the brake resistor cooling function into the fuel cell air supply system, the compressed air used for cooling is subsequently utilized by the fuel cell stack, transforming a discarded resource into a valuable input for power generation

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

This system efficiently manages excessive energy by optimizing the distribution of compressed air, enhancing energy recuperation and reducing the need for oversized batteries, while ensuring adequate operation of the fuel cell system.

Implementation Method 1

an air compressor arrangement in fluid communication with the cathode side

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a fuel cell system having at least one fuel cell with an anode side and a cathode side

Methodology Applied
Scientific EffectFuel cell electrochemical conversion: Fuel Cell

Implementation Method 3

an air-cooled brake resistor in fluid communication with the air compressor arrangement

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4242038B1A system, a method of controlling a system, and a vehicle comprising a system
Publication Date: 2025.09.03 VOLVO TRUCK CORP
  • EP4242038B1 patent drawingFigure 1
  • EP4242038B1 patent drawingFigure 2
  • EP4242038B1 patent drawingFigure 3

AI summary

The present disclosure relates to an energy management system (10) for a vehicle (1), comprising: a fuel cell system (100) having at least one fuel cell (102) with an anode side and a cathode side, an air inlet conduit (104) connected to an inlet end (106) of the cathode side for supplying air to the cathode side of the at least one fuel cell, and further having an air compressor arrangement (112) disposed in the air inlet conduit and in fluid communication with the cathode side; wherein said energy management system further comprises an air-cooled brake resistor (120) in fluid communication with the air compressor arrangement; and a control system (130) in communication with the air compressor arrangement and with a controllable valve assembly (134) arranged and configured to control supply of compressed air from said air compressor arrangement to any one of the at least one fuel cell and the air-cooled brake resistor via a first fluid conduit (105) and a second fluid conduit (119), respectively.