Fuel Cell Controller Timing for Abnormality Detection
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Solution Overview
Problem
Existing fuel cell systems fail to determine abnormalities in the fuel cell stack when the air flow rate is insufficient, such as during cold starts or due to compressor friction, as they rely on reaching predetermined air flow rates to measure output voltage for diagnosis.
Innovation Solution
A fuel cell system with a controller that controls the fuel gas and air suppliers to ensure hydrogen supply completion before starting air supply, calculates an integrated air flow rate over a predetermined period, and determines abnormalities based on both air supply and output voltage thresholds, even if the air flow rate is not sufficiently increased.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air compressor actuation is suppressed to protect the battery during cold start, then the battery protection is improved, but the air flow rate becomes insufficient
Solution Approach 1:
The controller supplies fuel gas to the fuel cell stack before starting the air compressor, ensuring that hydrogen is already present in the stack when air supply begins. This preliminary action prevents hydrogen depletion and allows the system to operate reliably even with limited air flow rate during cold start conditions.
2Reliability
If the air compressor actuation is suppressed due to friction, then the compressor protection is improved, but the air flow rate becomes insufficient
Solution Approach 1:
The controller starts supplying fuel gas to the fuel cell stack before the air compressor becomes operational, ensuring hydrogen is already available in the stack. This allows the system to maintain operation even when air flow rate is limited by compressor friction or delayed startup.
3Ease of operation
If the air flow rate is not sufficiently increased, then the system operation is maintained, but the abnormality determination fails
Solution Approach 1:
The controller supplies fuel gas to the fuel cell stack in advance before air supply starts, ensuring that hydrogen depletion does not occur during the period when air flow rate is insufficient. This maintains both system operation and enables accurate abnormality determination once adequate air flow is achieved.
Solution Approach 2:
The controller monitors the output voltage of the fuel cell stack and uses this feedback to determine whether an abnormality exists. By comparing the monitored voltage against expected values, the system can accurately diagnose abnormalities even during the transitional period when air flow rate is insufficient.
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
Enables accurate determination of fuel cell system abnormalities even with insufficient air flow rates, ensuring sufficient air supply and preventing catalyst degradation from hydrogen depletion, thereby enhancing system reliability and performance.
Implementation Method 1
a fuel cell configured to generate electric power by a reaction of a fuel gas and the air
Data Source
AI summary
A fuel cell system comprises: a fuel gas supplier: an air supplier; an air flow rate acquirer that obtains a flow rate of the air that is supplied to a fuel cell; a voltage acquirer that obtains an output voltage of the fuel cell; and a controller. At the time of starting the fuel cell system, the controller controls the fuel gas supplier to supply a fuel gas to the fuel cell for a first time period. After elapse of the first time period, the controller controls the air supplier to start supply of the air. The controller calculates an integrated value of the flow rate for a second time period after the supply of the air is started. When the integrated value becomes greater than a predetermined amount and the output voltage is less than a predetermined voltage, the controller determines that the fuel cell system has an abnormality.