Humidifier for fuel cell
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Solution Overview
Problem
Conventional fuel cell humidifiers with hollow fiber membranes struggle to maintain sufficient moisture levels during sudden increases in gas flow, leading to insufficient humidification and instantaneous output decreases, particularly during high-speed driving.
Innovation Solution
A fuel cell humidifier design featuring a membrane housing with a bundle of hollow fiber membranes and a sponge-shaped or braid-shaped humidity retainer made of polyethylene or polypropylene, which allows for efficient moisture retention and distribution, ensuring sufficient moisture supply even during rapid acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the hollow fiber membrane is increased to increase humidity content, then the moisture storage capacity is improved, but the moisture transfer efficiency deteriorates
Solution Approach 1:
The hollow fiber membrane is designed with non-uniform wall thickness, featuring a thinner section specifically positioned for moisture transfer. This local variation in thickness allows the membrane to simultaneously maintain sufficient overall humidity content while ensuring efficient moisture transfer through the thinner region, resolving the contradiction between storage capacity and transfer efficiency.
2Power
If the gas inflow speed is increased during sudden acceleration, then the power demand is met, but the humidification performance deteriorates
Solution Approach 1:
The humidity retainer is pre-filled with water before operation, creating a reservoir that can rapidly supply moisture when needed. During sudden acceleration events, this pre-prepared water source immediately compensates for the increased gas flow, maintaining humidification performance without requiring manual intervention or system adjustments.
Solution Approach 2:
The humidity retainer acts as a cushioning reservoir that anticipates and prepares for sudden increases in power demand. By storing water in advance, it provides a buffer that can be rapidly drawn upon during high-power events, preventing humidification performance deterioration before it occurs.
3Weight of moving object
If a polymer separation membrane is used for humidification, then the humidifier size and weight are reduced, but the moisture retention capacity is insufficient
Solution Approach 1:
The invention merges two previously separate components into a single integrated system: the polymer separation membrane for vapor transmission and the humidity retainer for water storage. This combination allows the lightweight membrane to function effectively while the retainer provides the necessary moisture reservoir, achieving both weight reduction and sufficient moisture retention capacity.
Solution Approach 2:
The humidity retainer serves as an intermediary component between the water source and the polymer membrane. It mediates the moisture supply by storing water and allowing it to evaporate and pass through the membrane, thus enabling the lightweight membrane design to achieve adequate moisture retention through the intermediate storage function.
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 humidifier effectively maintains moisture levels, preventing output drops during high-speed driving by uniformly distributing high-humidity unreacted gas and rapidly supplying moisture to the hollow fiber membranes, ensuring continuous fuel cell operation.
Implementation Method 1
The membrane humidifying method uses a membrane which allows only the vapor contained in the exhaust gas to pass therethrough, to thereby supply the vapor to the polymer electrolyte membrane.
Implementation Method 2
a humidity retainer provided in the inner space of the membrane housing... capable of containing a large amount of moisture
Data Source
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AI summary
Disclosed is a humidifier for a fuel cell having an enhanced humidifying performance and thus being able to prevent an instantaneous decrease of the output of a car which might occur at the time of high-speed driving. The humidifier comprises a membrane housing with first and second ends; a bundle of hollow fiber membranes provided in an inner space of the membrane housing, wherein both ends of the hollow fiber membrane are respectively potted into the first and second ends of the membrane housing; a humidity retainer provided in the inner space of the membrane housing; a first cover mounted on the first end of the membrane housing, the first cover including an inlet for introducing unreacted gas of high-humidity discharged from a stack; and a second cover mounted on the second end of the membrane housing, the second cover including an outlet for discharging the unreacted gas used for humidification.