Fuel Cell Anode Gas Flow Control During Idle Stop
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Solution Overview
Problem
Fuel cells experience a reduction in power generation performance when the power supply to a load is stopped due to oxygen permeation from the cathode to the anode, leading to anode oxidation and wasteful fuel consumption during idle stop states.
Innovation Solution
A control method for a fuel cell system that continues to supply anode gas to the fuel cell during idle stop states, suppressing oxygen inflow from the cathode and maintaining the fuel cell in a suitable state for power generation by controlling the flow rates of anode and cathode gases, thereby preventing anode oxidation and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel gas supply to the anode is stopped during autonomous operation, then fuel consumption is reduced, but oxygen permeates from the cathode to the anode causing anode oxidation and power generation performance reduction
Solution Approach 1:
The patent applies the continuity of useful action principle by maintaining a small flow of fuel gas to the anode during autonomous operation. Instead of completely stopping fuel supply, the system continues to supply fuel at a reduced rate, which prevents oxygen from permeating to the anode and causing oxidation, while still achieving significant fuel consumption reduction compared to normal operation. This resolves the contradiction by making the fuel supply action continuous but at a minimal necessary level.
2Reliability
If fuel gas is continuously supplied to the anode during autonomous operation, then anode oxidation is prevented, but fuel consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting the fuel gas flow rate parameter during autonomous operation. The system transitions from normal operation flow rates to a reduced flow rate specifically during autonomous mode. This parameter adjustment maintains sufficient fuel supply to prevent anode oxidation while minimizing fuel consumption, directly resolving the contradiction between reliability and energy loss.
3Speed
If the fuel cell operates in autonomous mode to maintain power generation capability, then the fuel cell remains ready for quick start, but anode oxidation occurs due to oxygen permeation
Solution Approach 1:
The patent maintains the continuity of useful action by keeping a small fuel flow to the anode during autonomous operation, which prevents oxidation and maintains power generation performance. Simultaneously, the system remains in autonomous mode with the fuel cell stack active, preserving thermal and electrical readiness for quick responsiveness. This dual approach resolves the contradiction between speed and reliability.
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 maintains the fuel cell's power generation performance and reduces fuel consumption by preventing anode oxidation during idle stop states, ensuring quick responsiveness when returning to power generation mode.
Implementation Method 1
since oxygen permeates from a cathode to the anode in the fuel cell during the autonomous operation
Implementation Method 2
an anode part may be oxidized
Data Source
AI summary
A control method for a fuel cell system with a gas supplying device configured to supply fuel gas and oxidant gas to a fuel cell, includes a power generating operation step of performing a power generating operation for causing the fuel cell to generate power by controlling the fuel gas and the oxidant gas to be supplied to the fuel cell on the basis of a load required of the fuel cell. Further, the control method includes an autonomous operation step of performing an autonomous operation of the fuel cell when the load drops to or below a predetermined value. In the autonomous operation, power supply from the fuel cell system to the load is stopped and the fuel gas is passed to an anode of the fuel cell.