Fuel Cell Stack Self-Service Cold Start at Sub-Zero Temperatures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell systems face challenges in starting up at sub-zero temperatures due to high electrical power requirements for heating, which is undesirable for weight and space constraints, especially in mobile applications, as they need a large battery to power the heating device, fan, compressor, and coolant pump before generating power.
Innovation Solution
A method where the fuel cell stack operates at low capacity to generate power for the heating device and coolant pump, allowing the system to heat up and reduce battery energy needs, with the heating device being switched off once a preset temperature is reached, enabling the stack to provide full power more quickly and reducing component size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large battery is used to provide electrical power for the heating device, fan, compressor, and coolant pump during cold start, then the fuel cell system can be started at sub-zero temperatures, but the weight and space requirements increase significantly
Solution Approach 1:
The fuel cell stack is operated in a self-service mode during cold start by using its own generated electrical power to drive the heating device and coolant pump, eliminating the need for a large external battery. The stack generates just enough power to maintain its temperature and operate necessary components during the cold start phase.
Solution Approach 2:
The heating device is operated periodically rather than continuously during cold start. The system monitors the fuel cell stack temperature and switches the heating device on and off as needed to maintain temperature, reducing overall power requirements and allowing for a smaller battery.
2Reliability
If a large battery is used to provide electrical power for the heating device, fan, compressor, and coolant pump during cold start, then the fuel cell system can be started at sub-zero temperatures, but the space requirements increase
Solution Approach 1:
The fuel cell stack serves itself during cold start by generating its own electrical power for the heating device and coolant pump, eliminating the need for a large external battery and reducing system volume.
Solution Approach 2:
The heating device operates periodically based on temperature feedback, reducing the total energy storage requirement and allowing for a more compact battery design.
3Loss of time
If the heating device operates at high power to heat the fuel cell stack quickly, then the start-up time is reduced, but the electrical power requirements increase
Solution Approach 1:
The fuel cell stack generates its own power for heating during cold start, creating a self-sustaining system that eliminates the need for high external power input while maintaining reasonable start-up times.
Solution Approach 2:
The system dynamically adjusts the heating power based on the fuel cell stack's own generation capacity and temperature requirements, optimizing the balance between start-up speed and power consumption.
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 method allows for rapid heating and reduced battery energy requirements, enabling shorter start-up times and multiple start-ups without additional external heat, while using a smaller starter battery and more compact components.
Implementation Method 1
The heat generated by the burner of the heating device may be used to heat a cooling fluid, which circulates in a coolant loop that serves to cool the fuel cell stack during the subsequent operation of the fuel cell stack. The coolant heated by the burner of the heating device circulates in the coolant loop and in this manner transfers the thermal energy to the fuel cell stack to preheat the fuel cell stack.
Implementation Method 2
a heating device connected upstream of the fuel cell stack to heat a cooling agent to be circulated by a coolant pump
Implementation Method 3
The cold fuel cell stack is operated at a capacity that generates enough power to operate the heating device and the coolant pump. The power generated by the fuel cell is used to operate the heating device for heating the coolant and the coolant pump for circulating the coolant between the fuel cell stack and the heating device
Data Source
AI summary
In a method to cold-start a fuel cell system at sub-zero temperatures, the fuel cell system comprises a fuel cell stack, upstream of which is connected a heating device to heat a cooling agent to be circulated by a coolant pump. To reduce the demand for stored electrical energy, the cold fuel cell stack is operated at such a capacity that it generates power that is sufficient only to operate the heating device and the coolant pump. The power generated by the fuel cell stack is used to operate the heating device for heating the cooling agent as well as the coolant pump, whereby the coolant pump circulates the cooling agent between the fuel cell stack and the heating device. The heating device is switched off as soon as the fuel cell stack reaches a preset temperature that is higher than the original temperature.