HTPEM Fuel Cell Stack Start-Up Using Staged Coolant Heating
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Solution Overview
Problem
The start-up process for high temperature proton exchange membrane (HTPEM) fuel cell stacks in aircraft is time and energy intensive, requiring significant electrical energy from batteries, which adds weight and reduces performance.
Innovation Solution
A method using coolant heaters and the existing thermal management systems to start HTPEM fuel cell stacks by heating and circulating the fuel cell stack coolant, where a subset of stacks is initially heated to operating temperature using onboard batteries, and then generates power to heat the remaining stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If all fuel cell stacks are heated simultaneously using onboard batteries, then all stacks reach operating temperature, but the battery weight and energy consumption increase significantly
Solution Approach 1:
The patent divides the fuel cell stack startup process into segments: first heating a subset of stacks to operating temperature, then using those stacks to generate power for heating the remaining stacks. This segmentation reduces the peak power demand and total battery energy consumption compared to heating all stacks simultaneously.
Solution Approach 2:
The patent performs preliminary heating of a subset of fuel cell stacks before the aircraft flight. These pre-heated stacks are then used to generate electrical power that heats the remaining stacks, reducing the energy burden on onboard batteries during critical flight operations.
2Temperature
If all fuel cell stacks are heated simultaneously using onboard batteries, then all stacks are ready for power generation, but the startup time and energy consumption increase
Solution Approach 1:
The patent implements a self-service mechanism where the first subset of heated fuel cell stacks generates electrical power that is used to heat the second subset of stacks. This reduces the total energy consumption from onboard batteries compared to an external power source heating all stacks.
3Weight of moving object
If a subset of fuel cell stacks is heated first using onboard batteries, then battery weight is reduced, but the startup process becomes more complex
Solution Approach 1:
The patent makes the fuel cell stacks serve multiple functions: first as heating targets, then as power generation sources, and finally as heating sources for other stacks. This multi-functionality reduces the need for separate external heating equipment, simplifying the overall system despite the staged startup process.
4Use of energy by moving object
If coolant circulation system is used to heat fuel cell stacks, then heating efficiency improves, but the system complexity increases
Solution Approach 1:
The patent makes the coolant circulation system serve dual functions: cooling the fuel cell stacks during operation and heating them during startup. This eliminates the need for separate heating equipment, improving heating efficiency while minimizing additional system complexity.
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 approach reduces the total energy and time required to start multiple HTPEM fuel cell stacks, minimizing battery weight and improving startup efficiency, while also allowing for faster startup when ground power is available.
Implementation Method 1
The heater system is configured to heat a coolant
Implementation Method 2
The pump system is configured to circulate the heated coolant through the conduit system
Implementation Method 3
the heated coolant causes the subset of the fuel cell stacks to reach an operating temperature
Data Source
AI summary
Aircraft comprises a heater system, a conduit system thermally connected to fuel cell stacks, a pump system, and a controller. The heater system is configured to heat a coolant. The coolant flows through the conduit system. The pump system is configured to circulate the coolant through the conduit system to the fuel cell stacks. The controller is configured to control the heater system to heat the coolant to form a heated coolant. The controller is configured to control the pump system to circulate the heated coolant through the conduit system. The controller is configured to control the conduit system to circulate the heated coolant to a subset of the fuel cell stacks, wherein the heated coolant causes the subset of the fuel cell stacks to reach an operating temperature.