Fuel Cell Water Content Estimation for Scavenging Control
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Solution Overview
Problem
Conventional fuel cell systems face issues with prolonged water scavenging, leading to electrolyte membrane deterioration and excessive battery power consumption, especially in low temperature conditions, resulting in inefficient power generation and reduced marketable quality.
Innovation Solution
A fuel cell system equipped with a water content measuring means and scavenging period determining means, which estimates water content based on power generation stop period, temperature, and humidity to optimize scavenging gas usage, preventing unnecessary scavenging and power waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel cell system scavenges water for a pre-determined period, then the electrolyte membrane is protected from freezing damage, but the scavenging period becomes unnecessarily long causing electrolyte membrane deterioration and excessive battery power consumption
Solution Approach 1:
The patent changes the scavenging control parameter from a fixed time-based approach to a water-content-based approach. The scavenging period determining means adjusts the scavenging duration based on measured water content in the fuel cell, environmental temperature, and power generation stop period, thereby optimizing the scavenging period to be just long enough to prevent freezing without causing membrane deterioration or excessive power consumption.
2Reliability
If the fuel cell system scavenges water for a pre-determined period, then the electrolyte membrane is protected from freezing damage, but battery power is wasted excessively
Solution Approach 1:
The patent changes the scavenging control parameter from a fixed time-based approach to a water-content-based approach. The scavenging period determining means adjusts the scavenging duration based on measured water content in the fuel cell, environmental temperature, and power generation stop period, thereby optimizing the scavenging period to be just long enough to prevent freezing without causing membrane deterioration or excessive power consumption.
3Duration of action of stationary object
If the fuel cell system uses an appropriate amount of scavenging gas, then electrolyte membrane deterioration is reduced, but the system complexity increases
Solution Approach 1:
The patent implements a feedback control mechanism where the water content measuring means continuously monitors the water content in the fuel cell, and the scavenging period determining means uses this feedback information along with environmental temperature and power generation stop period to dynamically adjust the scavenging duration. This feedback loop enables appropriate scavenging without requiring complex additional hardware.
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 allows for appropriate scavenging gas usage, reducing electrolyte membrane deterioration and battery power consumption, ensuring efficient power generation and improved marketable quality by determining the optimal scavenging period based on measured water content and environmental conditions.
Implementation Method 1
a water content measuring means for measuring a water content in the fuel cell
Implementation Method 2
a scavenging means for introducing scavenging gas to the fuel cell after the fuel cell stops generating the power
Data Source
AI summary
A fuel cell system is provided which estimates a water content in a fuel cell based on a predetermined map using an integrated value of electric current generated by the fuel cell (ST4) before power generation is stopped (ST5). When a temperature of the fuel cell has fallen lower than a predetermined value (ST7) after the power generation is stopped (ST5), the fuel cell system determines a dry degree in the fuel cell (ST8) and an anode scavenging period (ST9) based on predetermined maps. Scavenging is performed in an anode in the fuel cell for the anode scavenging period (ST10).