Fuel Cell Thermal Management With Isolated Coolant Loops
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Solution Overview
Problem
Integrating thermal management systems for fuel cell and braking systems in electric vehicles poses challenges due to potential current leakage and reduced power output from ion introduction through conductive coolants, which can result from leaching, degradation, and corrosion of system materials.
Innovation Solution
An integrated thermal management system that includes a fuel cell coolant loop, brake resistor coolant loop, HVAC coolant loop, and a heat exchanger loop, utilizing separate coolants and ion exchange mechanisms to manage heat transfer and minimize conductivity, with operating modes for efficient thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coolant loop is used for both fuel cell and brake resistor cooling, then system complexity is reduced, but ion contamination and current leakage occur
Solution Approach 1:
The patent divides the thermal management system into separate coolant loops: a first coolant loop for the fuel cell system and a second coolant loop for the brake resistor system. This segmentation prevents ion contamination from the brake resistor coolant from reaching the fuel cell, thereby eliminating current leakage while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary component between the first and second coolant loops. This heat exchanger enables thermal energy transfer from the brake resistor coolant to the fuel cell coolant without direct fluid contact, thus preventing ion contamination while still achieving heat recovery and improving overall system efficiency.
2Reliability
If separate coolant loops with heat exchanger are used, then ion contamination is prevented, but system complexity increases
Solution Approach 1:
The patent merges the two separate coolant loops through a common heat exchanger unit, allowing thermal energy transfer while maintaining fluid separation. This combining approach reduces the overall system complexity compared to having completely independent cooling systems, while still preventing ion contamination through the heat exchanger barrier.
3Loss of energy
If waste heat is recovered from brake resistor, then thermal efficiency increases, but coolant conductivity and current leakage occur
Solution Approach 1:
The heat exchanger serves as an intermediary that enables waste heat recovery from the brake resistor coolant while preventing direct contact between the coolants. This allows thermal energy transfer for improved efficiency while the physical barrier prevents ion contamination and current leakage.
Solution Approach 2:
The patent extracts only the thermal energy from the brake resistor coolant through the heat exchanger, leaving the coolant itself isolated in its own loop. This extraction approach enables waste heat recovery while removing the harmful aspect (ion contamination) from the fuel cell cooling system.
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
Enhances thermal efficiency, reduces system complexity and costs, and increases vehicle uptime by effectively managing heat from fuel cells and brake resistors while preventing ion-induced issues, thus optimizing power usage and reducing failure points.
Implementation Method 1
a heat exchanger loop comprising a coolant-coolant heat exchanger thermally and fluidly coupled to the fuel cell coolant loop and the brake resistor coolant loop
Implementation Method 2
a fuel cell coolant loop comprising a fuel cell radiator thermally and fluidly coupled to the fuel cell system
Implementation Method 3
a brake resistor coolant loop comprising a brake resistor radiator thermally and fluidly coupled to the brake resistor
Data Source
AI summary
An integrated thermal management system for a fuel cell electric vehicle is disclosed. The integrated thermal management system includes a fuel cell system, a brake resistor, a fuel cell coolant loop that includes a fuel cell radiator thermally and fluidly coupled to the fuel cell system, a brake resistor coolant loop that includes a brake resistor radiator thermally and fluidly coupled to the brake resistor, and a heat exchanger loop that includes a coolant-coolant heat exchanger thermally and fluidly coupled to the fuel cell coolant loop and the brake resistor coolant loop. In a fuel cell cooling operating mode, heat is transferred from the fuel cell system to an ambient environment through the fuel cell radiator and the brake resistor radiator.