Fuel Cell Cold-Start Cooling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fuel cell systems experience slower and non-uniform temperature rise during cold starts due to the cessation of cooling water circulation, which hampers the efficiency and uniformity of temperature distribution within the fuel cell stack.
Innovation Solution
A fuel cell system with a cold-start controller that adjusts the circulation volume of the cooling medium based on the temperature relationship between the supplied and discharged cooling medium, allowing for increased circulation volume when the temperatures equalize, thereby enhancing the rate and uniformity of temperature rise within the fuel cell stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the circulation of cooling water is stopped when the internal temperature of the fuel cell is equal to or lower than 0°C, then the heat value immediately after a sub-zero start increases and the rate of temperature rise of the fuel cell stack increases, but the temperature rise becomes slower in the stacking direction and uniform temperature rise in the entire fuel cell stack cannot be achieved
Solution Approach 1:
The pump's circulation volume is made dynamically adjustable with multiple discrete settings (first, second, and third circulation volumes). The controller selectively switches between these circulation volumes based on real-time temperature conditions, transforming a static cooling system into a dynamic one that adapts to changing thermal states during cold start
Solution Approach 2:
The system changes the circulation volume parameter of the cooling medium at different stages of cold start. Initially, a smaller first circulation volume is used to maximize heat value and temperature rise rate. When the supplied cooling medium temperature equals the discharged cooling medium temperature, the system transitions to a larger third circulation volume to achieve uniform temperature distribution throughout the stack
2Stability of the object's composition
If the circulation volume of cooling medium is increased to achieve uniform temperature rise in the stacking direction, then the temperature distribution uniformity improves, but the rate of temperature rise decreases
Solution Approach 1:
The cooling system operates in distinct periodic stages during cold start. The first stage uses a smaller circulation volume to rapidly increase temperature, and the second stage uses a larger circulation volume to distribute heat uniformly. This periodic switching of circulation volumes allows the system to sequentially achieve both rapid heating and uniform temperature distribution
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 achieves a faster and more uniform temperature rise across the fuel cell stack, ensuring efficient start-up and operation by optimizing the circulation volume of the cooling medium during cold starts.
Implementation Method 1
a pump that is provided to drive the cooling medium in the circulation flow path and thereby circulate the cooling medium to inside of the fuel cell stack
Implementation Method 2
a supply-side temperature sensor that is configured to detect a supplied cooling medium temperature which is temperature of the cooling medium supplied to the cooling medium supply port; a discharge-side temperature sensor that is configured to detect a discharged cooling medium temperature which is temperature of the cooling medium discharged from the cooling medium discharge port
Data Source
AI summary
A fuel cell system comprises a fuel cell stack, a circulation flow path of a cooling medium, a pump provided in the circulation flow path, a supply-side temperature sensor provided to detect a supplied cooling medium temperature, a discharge-side temperature sensor provided to detect a discharged cooling medium temperature, and a cold-start controller configured to control a circulation volume of the cooling medium by the pump at a cold start of the fuel cell stack. The cold-start controller estimates a fuel cell internal temperature and selectively sets the circulation volume of the cooling medium between a reduced volume and a normal volume, based on a magnitude relationship between the internal temperature and the discharged cooling medium temperature. When the supplied cooling medium temperature becomes equal to the discharge cooling medium temperature after setting the circulation volume, the cold-start controller sets the circulation volume of the cooling medium to an increased volume (maximum circulation volume).