Fuel Cell System Warm-Up Control for Catalyst Protection
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Solution Overview
Problem
Existing fuel cell systems face issues with oxidative degradation of the anode catalyst and adverse effects on heat resistance due to unbalanced warm-up progress between the fuel cell stack and the reformer, where the start-up combustor is operated before the reformer is fully warmed up.
Innovation Solution
A fuel cell system with a controller that adjusts the heating amount of off-gas and air supplied to the fuel cell stack based on the temperatures of the fuel cell and reformer, using a heat source device and fuel cell heating device to control the warm-up of both components in parallel, ensuring balanced warm-up progress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the start-up combustor is operated before the reformer reaches reforming temperature, then the warm-up of the fuel cell stack is promoted, but oxidative degradation of the anode catalyst occurs and heat resistance deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-heating the air supplied to the fuel cell stack using the fuel cell heating device before the reformer reaches operating temperature. This allows the fuel cell stack to warm up in advance without immediately operating the start-up combustor, thereby promoting stack warm-up speed while preventing oxidative degradation of the anode catalyst by controlling the timing and conditions of combustor operation.
Solution Approach 2:
The controller monitors the temperature of both the reformer and fuel cell stack, and adjusts the operation of the fuel cell heating device and start-up combustor based on this feedback. When the reformer temperature reaches a predetermined threshold, the controller activates the fuel cell heating device to warm the stack; when the stack temperature reaches another threshold, the controller activates the start-up combustor. This feedback-based control ensures coordinated warm-up while preventing catalyst degradation.
2Loss of time
If the start-up combustor is operated early to warm up the fuel cell stack, then the warm-up process is accelerated, but the heat resistance of the fuel cell is adversely affected
Solution Approach 1:
The patent introduces the fuel cell heating device as an intermediary between the reformer and the fuel cell stack during the warm-up process. This intermediate heating device transfers heat from the heated air to the fuel cell stack gradually, allowing the stack to warm up without direct exposure to the high-temperature combustion environment. This mediates the warm-up process to reduce thermal shock and protect the heat resistance of the fuel cell while still accelerating the warm-up time.
3Productivity
If the warm-up of the fuel cell stack progresses faster than the reformer, then the start-up time is reduced, but unbalanced warm-up causes oxidative degradation
Solution Approach 1:
The patent employs dynamic control by continuously adjusting the operation of the fuel cell heating device and start-up combustor based on the real-time temperature difference between the reformer and fuel cell stack. The controller dynamically switches between these two heating modes: using the fuel cell heating device when the reformer is cooler, and using the start-up combustor when the reformer is sufficiently hot. This dynamic adjustment maintains balanced warm-up progress between the two components, achieving fast start-up while preventing oxidative degradation of the anode catalyst.
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 prevents oxidative degradation and maintains heat resistance by synchronizing the warm-up of the fuel cell stack and reformer, optimizing the heating process to prevent undesirable oxidation reactions and ensure efficient operation.
Implementation Method 1
a heat source device configured to heat an off-gas discharged from the fuel cell to produce a heating gas
Implementation Method 2
configured to heat the reformer
Implementation Method 3
a fuel cell heating device configured to heat the air to be supplied to the fuel cell using the heating gas
Data Source
AI summary
A fuel cell system includes a fuel cell configured to be supplied with fuel and air to generate electricity, a reformer configured to reform the fuel to be supplied to the fuel cell, a heat source device configured to heat an off-gas discharged from the fuel cell to produce a heating gas and configured to heat the reformer, a fuel cell heating device configured to heat the air to be supplied to the fuel cell using the heating gas, a fuel cell temperature acquisition unit configured to acquire a temperature of the fuel cell, and a reformer temperature acquisition unit configured to acquire a temperature of the reformer. The fuel cell system includes a controller configured to, in a warm-up operation to perform a warm-up of the reformer and a warm-up of the fuel cell, control at least one of the heat source device and the fuel cell heating device based on the temperature of the reformer and the temperature of the fuel cell to adjust at least one of a heating amount of the off-gas and a heating amount of the air by the heating gas.