SOFC Stop Control Using Excess Fuel Flow to Prevent Membrane Damage
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Solution Overview
Problem
Solid oxide fuel cells with proton-conductive electrolyte membranes face damage from fuel shortages during operation stop processes due to the difficulty in controlling fuel supply based on drawn current, as the actual fuel consumption deviates from calculated values.
Innovation Solution
A fuel cell system with a controller that supplies fuel at a higher flow rate than the fuel consumed in the open circuit state to prevent fuel shortages, ensuring safe operation stop without damaging the proton-conductive electrolyte membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel is continuously supplied to the anode with current drawn to the outside during stop control, then anode oxidation degradation is reduced, but fuel shortages occur in proton-conductive electrolyte membrane fuel cells
Solution Approach 1:
The invention changes the control parameter from current-based fuel supply control to voltage-based fuel supply control. By monitoring cell voltage and comparing it to a predetermined threshold voltage, the system determines when to stop fuel supply, rather than relying on current measurements that are inaccurate for proton-conductive electrolyte membranes. This parameter change resolves the contradiction by enabling reliable fuel supply control that prevents both anode oxidation degradation and fuel shortages.
2Productivity
If fuel supply is controlled based on drawn current, then fuel consumption can be managed, but actual fuel consumption deviates from calculated values in proton-conductive electrolyte membrane fuel cells
Solution Approach 1:
The invention introduces cell voltage as an intermediary parameter to indirectly control fuel supply. Instead of directly measuring and controlling fuel consumption based on current, the system uses voltage as a mediator that reflects the actual fuel consumption state in proton-conductive electrolyte membrane fuel cells. This intermediary approach allows accurate fuel consumption management despite the inability to directly measure current-based consumption in these specialized fuel cells.
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 prevents fuel shortages and allows for safe operation stop of solid oxide fuel cells with proton-conductive electrolyte membranes by controlling fuel supply based on actual consumption rates, minimizing damage and ensuring reliable operation.
Implementation Method 1
a solid oxide fuel cell that produces electricity from an electrochemical reaction by using a fuel and air and that includes a membrane electrode assembly including a proton-conductive electrolyte membrane
Implementation Method 2
a solid oxide fuel cell that produces electricity from an electrochemical reaction by using a fuel and air
Data Source
AI summary
A fuel cell system according to the present disclosure includes: a solid oxide fuel cell that produces electricity from an electrochemical reaction by using a fuel and air and that includes a membrane electrode assembly including a proton-conductive electrolyte membrane, a cathode disposed on a first main surface of the electrolyte membrane, and an anode disposed on a second main surface of the electrolyte membrane; and a controller. In the operation stop process for stopping operation of the fuel cell system, the controller is configured to control supply of the fuel at a higher flow rate than the flow rate of the fuel consumed in the solid oxide fuel cell in an open circuit state.