Fuel Cell Thermal Management via Dual Cooling Circuit
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Solution Overview
Problem
The challenge of efficiently managing thermal energy in fuel cells to prevent premature degradation and reduce radiator surface requirements in vehicles, while ensuring stable power delivery, is unresolved in existing technologies.
Innovation Solution
A dual cooling circuit system is implemented, utilizing a high-temperature main circuit for fuel cells and a low-temperature secondary circuit for vehicle subsystems like the cabin and batteries, with a coupling heat exchanger to exchange thermal energy, and a low-temperature tank to stabilize temperatures and enhance cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cooling liquid temperature is reduced to improve fuel cell thermal management, then the temperature difference with ambient air increases improving heat dissipation capacity, but the system complexity increases due to need for additional cooling circuits
Solution Approach 1:
The patent merges the fuel cell cooling function with the cabin cooling function into a single integrated thermal management system. The low-temperature secondary cooling circuit serves dual purposes: cooling the fuel cell stack and providing cabin air conditioning. This consolidation allows the system to achieve improved heat dissipation capacity while avoiding the complexity of completely separate cooling systems, as the same cooling medium and infrastructure serve multiple functions.
Solution Approach 2:
The secondary cooling circuit is designed with multi-functionality, serving both as a cooling medium circulation system for the fuel cell and as a cabin air conditioning system. The cooling liquid circulated in the secondary circuit performs multiple thermal management tasks simultaneously, including cooling the fuel cell stack, pre-cooling intake air, and providing cabin comfort. This universal approach reduces the need for dedicated single-purpose cooling systems.
2Quantity of substance
If a low-temperature secondary cooling circuit is added to improve thermal management efficiency, then the thermal capacity is increased, but the device complexity increases
Solution Approach 1:
The patent combines the thermal management functions of the fuel cell stack and the cabin cooling system into a unified secondary cooling circuit. By merging these functions, the system achieves increased thermal capacity to handle both cooling loads simultaneously, while the shared infrastructure (pumps, radiators, cooling liquid loops) reduces the overall complexity compared to having separate dedicated systems for each function.
3Loss of energy
If the radiator surface area is increased to improve heat dissipation, then the heat dissipation capacity is improved, but the vehicle space requirement increases
Solution Approach 1:
The patent changes the operating temperature parameter of the cooling liquid in the secondary circuit to a lower temperature range (around 70°C or lower) compared to conventional systems. This parameter change increases the temperature difference between the cooling liquid and ambient air, thereby enhancing the heat dissipation capacity per unit area of the radiator. As a result, the system achieves improved heat dissipation without requiring proportionally larger radiator surface areas.
4Loss of energy
If the fuel cell operates at partial loads to reduce thermal management demands, then the power delivery is reduced, but the thermal management burden is decreased
Solution Approach 1:
The secondary cooling circuit is designed to handle multiple thermal loads simultaneously, including fuel cell cooling and cabin air conditioning. This multi-functional capability allows the system to manage the thermal burden effectively even when the fuel cell operates at varying power levels, as the cooling system can dynamically adjust to serve different thermal demands without requiring the fuel cell to be restricted to partial loads only.
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 stabilizes fuel cell temperatures, reduces radiator size, and minimizes power fluctuations, thereby extending fuel cell lifespan and improving thermal management efficiency.
Implementation Method 1
The thermal energy between main and secondary circuits is exchanged by means of a coupling heat exchanger
Implementation Method 2
the presence of the low temperature tank permits to stabilize the working temperature of the secondary circuit and to compensate temporary increased cooling needs
Implementation Method 3
the secondary circuit is cooled by means of a heat exchanger or a heat pump arranged to cool the secondary medium
Data Source
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AI summary
Method for thermal management of fuel cells of a vehicle, the fuel cells (FCS) being cooled through a main circuit (HTCC) where at least one pump (P, P1) is arranged to circulate a cooling liquid through a radiator (R), the method including a step of selectively thermally connecting the main circuit to a secondary circuit (LTCC) arranged to cool at least one subsystem of the vehicle, such as the vehicle cabin, and/or batteries arranged to cooperate with the fuel cells (FCS), or other subsystems of the vehicle that require cooling or refrigeration.