Fuel Cell Stack Moisture Recirculation Without a Humidifier
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Solution Overview
Problem
The addition of a humidifier in fuel cell stacks increases manufacturing costs and power consumption, and there is a demand for improved energy efficiency.
Innovation Solution
A fuel cell stack design that includes an oxidant gas supply passage connected to an off-gas flow passage through a communication passage with a pressure differential, allowing moisture circulation without additional devices like a humidifier, and a narrowed passage diameter to enhance moisture circulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a humidifier is added to the oxidant gas supply passage, then the electrolyte membrane can be kept in a wet state, but manufacturing costs increase and power consumption increases
Solution Approach 1:
The patent merges the oxidant gas supply passage and oxidant off-gas flow passage through a communication passage, allowing the off-gas (containing water vapor) to be reused for humidifying the supply gas. This eliminates the need for a separate humidifier device while maintaining electrolyte membrane wetness.
Solution Approach 2:
The system uses its own off-gas containing water vapor to humidify the incoming oxidant gas, creating a self-sustaining moisture circulation system. The off-gas that would otherwise be wasted is recycled to maintain the necessary humidity in the electrolyte membrane.
2Reliability
If a humidifier is added to the oxidant gas supply passage, then the electrolyte membrane can be kept in a wet state, but manufacturing costs increase
Solution Approach 1:
The patent merges the oxidant gas supply passage and oxidant off-gas flow passage through a communication passage, allowing the off-gas (containing water vapor) to be reused for humidifying the supply gas. This eliminates the need for a separate humidifier device while maintaining electrolyte membrane wetness.
Solution Approach 2:
The system uses its own off-gas containing water vapor to humidify the incoming oxidant gas, creating a self-sustaining moisture circulation system. The off-gas that would otherwise be wasted is recycled to maintain the necessary humidity in the electrolyte membrane.
3Reliability
If a humidifier is added to the oxidant gas supply passage, then the electrolyte membrane can be kept in a wet state, but power consumption increases
Solution Approach 1:
The patent merges the oxidant gas supply passage and oxidant off-gas flow passage through a communication passage, allowing the off-gas (containing water vapor) to be reused for humidifying the supply gas. This eliminates the need for a separate humidifier device while maintaining electrolyte membrane wetness.
Solution Approach 2:
The system uses its own off-gas containing water vapor to humidify the incoming oxidant gas, creating a self-sustaining moisture circulation system. The off-gas that would otherwise be wasted is recycled to maintain the necessary humidity in the electrolyte membrane.
4Productivity
If the diameter of the oxidant gas supply passage is narrowed at the first opening, then moisture circulation efficiency is enhanced, but gas flow resistance increases
Solution Approach 1:
The patent applies local quality by narrowing the passage diameter only at the specific location of the first opening where moisture circulation is needed, while maintaining larger diameter in other portions of the passage. This localized narrowing enhances moisture circulation efficiency without significantly increasing overall gas flow resistance.
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
Suppresses electrolyte membrane drying, reduces manufacturing costs and power consumption, and enhances energy efficiency by circulating moisture without additional devices.
Implementation Method 1
A pressure at a first opening (e.g., first opening 41) through which the communication passage is connected to the oxidant gas supply passage is lower than a pressure at a second opening (e.g., second opening 42) through which the communication passage is connected to the oxidant off-gas flow passage
Data Source
AI summary
A fuel cell stack includes an electrolyte membrane-electrode structure in which a solid polymer electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and is configured to generate power by an electrochemical reaction between an oxidant gas and a fuel gas. The fuel cell stack includes: a cell to which the oxidant gas and/or the fuel gas is supplied; an oxidant gas supply passage for supplying the oxidant gas to the cell; an oxidant off-gas flow passage through which the oxidant gas discharged from the cell flows; and a communication passage connecting the oxidant gas supply passage and the oxidant off-gas flow passage. A pressure at a first opening through which the communication passage is connected to the oxidant gas supply passage is lower than a pressure at a second opening through which the communication passage is connected to the oxidant off-gas flow passage).