Method for reducing temperature peaks in a fuel cell with a two phase cooling system
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Solution Overview
Problem
Temperature spikes during the start-up phase of fuel cells using two-phase cooling systems lead to increased degradation and reduced durability due to delayed boiling and overheating.
Innovation Solution
A method involving a pressure control module to adjust the coolant's saturation pressure during the start-up phase, setting it below the fuel cell's maximum operating temperature, and adjusting it to a higher pressure when temperature peaks are detected to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a two-phase cooling system is used to cool the fuel cell, then cooling performance is improved, but temperature peaks occur during start-up due to delayed boiling
Solution Approach 1:
The patent applies preliminary action by pre-heating the coolant to near-saturation temperature before it enters the fuel cell during start-up. This preliminary heating ensures that boiling begins immediately upon contact with the fuel cell, preventing the delayed boiling phenomenon that causes temperature peaks. The coolant is prepared in advance to be ready for immediate phase change, eliminating the harmful temperature spike.
2Temperature
If saturation pressure is reduced to prevent temperature peaks, then temperature control is improved, but heat dissipation capability is reduced
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the saturation pressure of the coolant based on the operational phase. During start-up, pressure is reduced to prevent temperature peaks. During normal operation, pressure is increased to maximize heat dissipation capability. This dynamic adjustment allows the system to optimize both temperature control and heat dissipation performance at different operational stages.
Solution Approach 2:
The patent applies periodic action by implementing distinct operational phases with different pressure settings. The cooling system operates in different modes: a start-up phase with lower pressure to prevent temperature peaks, and a normal operation phase with higher pressure for maximum heat dissipation. This periodic switching between operational modes allows the system to address both contradictory requirements at appropriate times.
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
Precise control of coolant saturation pressure minimizes temperature spikes, ensuring optimal cooling performance and extending the fuel cell's lifespan and reliability.
Implementation Method 1
The two-phase cooling circuit is based on the phase transitions in the fuel cells (evaporator) and in the heat exchanger to the environment (condenser).
Implementation Method 2
The two-phase cooling circuit is based on the phase transitions in the fuel cells (evaporator) and in the heat exchanger to the environment (condenser).
Implementation Method 3
This utilizes the latent heat of vaporization to remove large amounts of heat from the fuel cells.
Implementation Method 4
Adjusting the saturation pressure of a coolant, via a pressure control module, to a first saturation pressure such that a maximum temperature induced by boiling delay of the coolant is below a maximum operating temperature of the fuel cell
Data Source
Figure 1~2B
Figure 3~4
AI summary
A method (100) and a system (10) for reducing temperature peaks during the start-up of a fuel cell (12) with a two-phase cooling system is disclosed, comprising the following steps: adjusting (102) a saturation pressure of a coolant, via a pressure control module (14), to a first saturation pressure such that a maximum temperature induced by boiling delay of a coolant is below a maximum operating temperature of the fuel cell; starting (104) the fuel cell; in response to the fact that the maximum temperature induced by boiling delay of the coolant has been exceeded, adjusting (106) the saturation pressure of the coolant, via the pressure control module (14), to a second saturation pressure, wherein the second saturation pressure is higher than the first saturation pressure.