Fuel Cell Coolant Valve Switching for COD Heater Shutdown Purging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In fuel cell systems, residual hydrogen and oxygen can cause corrosion at the cathode, degrading the fuel cell stack's endurance, and existing thermal management systems struggle to efficiently control the shutdown process, leading to potential short circuits and performance degradation.
Innovation Solution
A fuel cell system with a coolant control valve that integrates a pump and a cathode oxygen depletion heater, allowing for controlled coolant flow paths during shutdown, utilizing a shutdown sequence that includes setting pump RPM, valve openings, and activating the COD heater to consume residual power and oxygen as thermal energy, ensuring the fuel cell stack's endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fuel cell stack is shutdown with residual hydrogen and oxygen, then the shutdown process is simple, but carbon corrosion occurs at the cathode and endurance is degraded
Solution Approach 1:
The system performs preliminary actions before shutdown by detecting residual hydrogen and oxygen concentrations and activating the COD heater in advance to consume residual power through thermal energy, preventing carbon corrosion before it occurs during shutdown
Solution Approach 2:
The residual power that would normally cause harmful carbon corrosion is converted into beneficial thermal energy by the COD heater, which uses the electrical energy to generate heat and thermally consume the remaining hydrogen and oxygen, transforming a harmful effect into a protective one
2Ease of operation
If separate valves are used to control coolant flow paths, then flow control is precise, but device complexity increases
Solution Approach 1:
Multiple separate valves are merged into a single integrated coolant control valve that can perform multiple flow path switching functions, reducing the number of components while maintaining precise control over coolant flow to the COD heater and other system components
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 solution effectively removes residual oxygen and power from the fuel cell stack during shutdown, preventing corrosion and ensuring the stack's longevity by consuming them as thermal energy, while also allowing rapid and controlled fluid passage management.
Implementation Method 1
power generated through the reaction of hydrogen and oxygen remaining in a fuel cell stack by a cathode oxygen depletion heater is consumed in the form of thermal energy
Implementation Method 2
coolant control valve to switch a flowing path of a coolant through a first fluid passage passing through a fuel cell stack and a second fluid passage passing through a cathode oxygen depletion (COD) heater
Implementation Method 3
a pump to circulate the coolant
Data Source
AI summary
Described herein is a fuel cell system including a coolant control valve to switch a flowing path of a coolant through a first fluid passage passing through a fuel cell stack and a second fluid passage passing through a cathode oxygen depletion (COD) heater, and a controller to perform a shutdown sequence and control a valve opening amount of the coolant control valve connected to the first fluid passage and the second fluid passage, when shutdown is requested for the fuel cell stack. The coolant control valve is formed by integrating a first valve to switch a flowing path of the coolant flowing into a pump with a second valve to switch a flowing path of a coolant pumped by the pump.