Fuel Cell Control Device Warm-Up Voltage Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During fuel cell system warm-up operations, insufficient oxygen supply to the cathode can lead to the generation of 'pumping hydrogen,' causing inefficiencies and potential oxygen shortages, which are not adequately addressed by existing technologies.
Innovation Solution
A fuel cell system with a control device that manages oxidant gas supply and current sweep to ensure sufficient oxygen is provided to the cathode, implementing stand-by control to maintain constant current until sufficient voltage is reached, and normal current control to prevent excessive current sweeps, thereby reducing hydrogen pumping and maintaining power generation stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current sweep is started during warm-up operation with reduced oxidant gas supply, then warm-up efficiency is improved, but pumping hydrogen is generated at the cathode due to oxygen shortage
Solution Approach 1:
The control device determines a voltage condition that must be satisfied before starting current sweep during warm-up operation. By establishing this preliminary voltage threshold, the system ensures sufficient oxygen is available at the cathode before high current is applied, preventing pumping hydrogen generation while still enabling efficient warm-up once the condition is met
Solution Approach 2:
The control device continuously monitors the voltage of the fuel cell stack and uses this feedback to determine when to start current sweep. The voltage condition serves as a feedback mechanism that dynamically controls the timing of current sweep based on real-time stack voltage levels, ensuring oxygen availability before high current operation
2Power
If oxidant gas supply is reduced during warm-up operation, then power generation output is improved, but oxygen shortage at cathode causes pumping hydrogen and potential oxygen depletion
Solution Approach 1:
The system dynamically adjusts oxidant gas supply based on operational phase and voltage conditions. During warm-up, oxidant gas supply is reduced to improve power output, but the control device dynamically determines when to start current sweep based on voltage conditions, creating a dynamic balance between power output and oxygen availability that prevents pumping hydrogen
3Speed
If current command value changes rapidly during warm-up, then response speed is improved, but voltage instability occurs and pumping hydrogen is generated
Solution Approach 1:
The control device establishes a voltage condition as a preliminary requirement before allowing current sweep to start. This preliminary voltage threshold ensures that the fuel cell stack is in a stable state with sufficient oxygen availability before rapid current changes are permitted, thereby maintaining voltage stability while enabling fast response when conditions are appropriate
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 effectively reduces the generation of pumping hydrogen, ensures stable power generation, and controls the charge/discharge of secondary batteries within acceptable limits by maintaining optimal oxygen supply and power balance during warm-up operations.
Implementation Method 1
a fuel cell stack 116 that has a plurality of stacked fuel cells 11
Implementation Method 2
a temperature sensor 73 configured to measure a temperature related to the fuel cell system
Implementation Method 3
a voltage sensor 91 configured to measure a voltage of the fuel cell stack 116
Implementation Method 4
an oxidant gas supply system 30A configured to supply the cathode with an oxidant gas containing oxygen
Implementation Method 5
a fuel gas supply system 50A configured to supply the anode with a fuel gas
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fuel cell system (10) includes a fuel cell stack (116) and a control device (60). The control device (60) raises the voltage of the fuel cell stack (116) until a predetermined voltage condition is met, by supplying a cathode with an oxidant gas before current sweep is started when the fuel cell system (10) is started and a value measured by a temperature sensor (38) is equal to or less than a temperature determined in advance. The control device (60) executes stand-by control, in which a current command value is kept constant, when a measured voltage value reaches a control start voltage value smaller than a voltage command value in a transition period, and ends the stand-by control by permitting a change in the current command value when the measured voltage value reaches a permission voltage value equal to or more than the voltage command value during execution of the stand-by control.