Fuel Cell Rapid Warm-Up Pump Control
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Solution Overview
Problem
Conventional rapid warm-up operations in fuel cell systems starting below freezing temperatures can lead to clogging in anode flow paths, causing hydrogen depletion and nitrogen deposition, which lowers cell voltage and hampers startability, while stopping the anode gas circulating pump improves startability but deteriorates durability.
Innovation Solution
A fuel cell system with a clogging determination unit and rapid warm-up controller that selectively performs a rapid warm-up operation by adjusting the circulating pump's operation based on clogging severity, optimizing the termination conditions to prevent durability and startability deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode gas circulating pump is revolved during rapid warm-up operation, then durability is improved by uniform hydrogen gas distribution, but clogging occurs in anode flow paths causing hydrogen depletion and nitrogen deposition
Solution Approach 1:
The pump operation mode is dynamically changed based on temperature conditions. During rapid warm-up operation when temperature is below freezing point, the pump is stopped to prevent clogging. When temperature exceeds the freezing point, the pump operates to ensure uniform hydrogen distribution. This dynamic adjustment resolves the contradiction between preventing clogging and maintaining durability.
Solution Approach 2:
The operational parameters of the circulating pump are changed based on temperature conditions. The control unit determines whether to operate the pump based on the freezing point of water, switching between pump operation and stop states. This parameter change allows the system to avoid clogging during cold start while maintaining durability through uniform gas distribution when conditions permit.
2Ease of operation
If the anode gas circulating pump is stopped to prevent clogging, then startability is improved, but durability deteriorates due to non-uniform hydrogen gas distribution
Solution Approach 1:
The pump operation mode is dynamically changed based on temperature conditions. During rapid warm-up operation when temperature is below freezing point, the pump is stopped to prevent clogging. When temperature exceeds the freezing point, the pump operates to ensure uniform hydrogen distribution. This dynamic adjustment resolves the contradiction between preventing clogging and maintaining durability.
Solution Approach 2:
The pump operates periodically - stopped during the rapid warm-up phase below freezing point, then activated after the freezing point is exceeded. This periodic operation pattern allows the system to prioritize startability during critical cold conditions while restoring durability maintenance once safe operating temperature is achieved.
3Temperature
If rapid warm-up operation is performed with high electric power loss, then the fuel cell temperature is rapidly raised above freezing point, but electric power generation efficiency is reduced
Solution Approach 1:
The pump operates periodically - stopped during the rapid warm-up phase below freezing point, then activated after the freezing point is exceeded. This periodic operation pattern allows the system to prioritize startability during critical cold conditions while restoring durability maintenance once safe operating temperature is achieved.
Solution Approach 2:
The system rapidly transitions through the critical sub-freezing temperature phase by intentionally accepting high electric power loss during rapid warm-up operation. Once the freezing point is exceeded, the system skips the prolonged inefficient operation by activating the pump to restore efficiency. This rushing through of the problematic temperature zone minimizes overall energy loss.
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 system optimizes the time to stop the circulating pump according to clogging state, enhancing startability while minimizing durability degradation by varying termination conditions and limiting heat and current generation during non-uniform power generation.
Implementation Method 1
a fuel cell stack which is supplied with a fuel gas and an oxidation gas to generate electric power by an electrochemical reaction
Implementation Method 2
a circulating pump which feeds under pressure the fuel off-gas in the circulation path to the supply path
Implementation Method 3
a rapid warm-up operation to generate the electric power at an air stoichiometric ratio lower than that at starting at ordinary temperature... the fuel cell can rapidly be warmed up by intentionally setting the electric power loss to be larger
Data Source
AI summary
A fuel cell system includes a fuel cell stack and a fuel gas piping system which supplies a fuel gas to the fuel cell stack, and is capable of, at starting below a freezing point, selectively performing a rapid warm-up operation to generate electric power at an air stoichiometric ratio lower than that at starting at ordinary temperature, while revolving a circulating pump, and the fuel cell system further includes a clogging determination unit which determines whether or not clogging arises from freezing in a fuel gas passage of the fuel cell stack, or the fuel gas piping system, wherein when the clogging arises, the circulating pump is stopped in the rapid warm-up operation, and termination conditions of the rapid warm-up operation are changed in accordance with a clogging volume.