Fuel Cell Shutdown Control via Gas Replacement
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Solution Overview
Problem
Conventional fuel cell power generation systems face inefficiencies during operation stop processes, leading to unnecessary energy loss and catalyst degradation due to improper management of electric power generation and gas supply, resulting in reduced durability and increased costs.
Innovation Solution
A fuel cell power generation system with a controller that reduces electric power extraction, stops oxidizing gas supply, and manages gas passages to replace oxidizing gas with fuel gas, maintaining internal pressure and preventing external air entry, thereby minimizing energy loss and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fuel cell power generation system performs DSS operation with frequent start-ups and stops, then heating and lighting expenses are reduced and CO2 emission reduction effect is enhanced, but oxygen remains within the fuel cell or external air flows into the fuel cell causing electrode catalyst degradation
Solution Approach 1:
The system performs preliminary actions before stopping operation: it continues supplying hydrogen to consume residual oxygen, and applies external current in the same direction as power generation to prevent oxygen accumulation and catalyst degradation during shutdown periods
Solution Approach 2:
The system converts the harmful effect of residual oxygen into a beneficial process by using it for power generation through continued hydrogen supply, and transforms the shutdown period into a recovery period by applying external current to restore catalyst performance
2Temperature
If the operation is stopped, then the internal temperature of the fuel cell decreases, but this causes a decrease in internal pressure resulting in air flowing into the fuel cell
Solution Approach 1:
The system performs preliminary pressure equalization by continuing fuel supply and controlling oxidation reactions before complete shutdown, preventing negative pressure formation that would cause air inflow during the subsequent cooling period
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 reduces energy loss, maintains fuel cell performance, and improves durability by optimizing the operation stop process, ensuring efficient power management and gas handling within the fuel cell system.
Implementation Method 1
a fuel cell configured to generate electric power by causing a reaction between the fuel gas supplied to the anode and the oxidizing gas supplied to the cathode
Implementation Method 2
a fuel generator configured to generate the fuel gas by causing a reforming reaction between a raw material gas supplied from a raw material gas supply device and water supplied from a water supply device
Implementation Method 3
the oxidizing gas in the oxidizing gas channel is consumed by the fuel gas that has cross-leaked to the oxidizing gas channel through the electrolyte membrane
Data Source
AI summary
A fuel cell power generation system including a fuel cell, a fuel generator, an oxidizing gas supply device, an output controller, an open-close mechanism, and a controller. The controller is configured such that in a stop process, the controller controls the output controller to stop supplying the electric power to an external load; controls the oxidizing gas supply device to stop supplying an oxidizing gas and controls the open-close mechanism to close a passage upstream from an oxidizing gas channel; after the passage upstream from the oxidizing gas channel is closed, stops a raw material gas supply device and a water supply device when a predetermined period has elapsed, during which period a gas in the oxidizing gas channel is replaced by a fuel gas.