Fuel Cell Membrane Humidifier With Bidirectional Off-Gas Flow
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Solution Overview
Problem
The existing fuel cell membrane humidification systems suffer from decreased efficiency due to the slow flow of off-gas through the humidification module, leading to a gradual decrease in the concentration of materials transmitted through the hollow fiber membranes, which reduces the overall performance of the fuel cell.
Innovation Solution
The introduction of a fuel cell membrane humidifier design that includes off-gas inlets on both sides of the mid-case, allowing the off-gas to flow in both directions and forming an inclined angle, which increases the flow time and efficiency by partitioning the inner space into separate areas for enhanced moisture exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If off-gas flows through the humidification module in a single direction, then the structure is simple, but the flow time is insufficient and concentration decreases gradually
Solution Approach 1:
The inner space of the mid-case is divided into multiple spaces by partition walls, with off-gas inlets and outlets positioned at different locations to create multi-directional flow paths. This segmentation allows off-gas to flow through different regions sequentially, increasing contact time with hollow fiber membranes while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent transitions from single-direction linear flow to multi-directional three-dimensional flow by positioning inlets and outlets at different locations and orientations. Off-gas enters through inlets on different sides and exits through outlets positioned to create complex flow patterns, effectively utilizing the three-dimensional space within the humidification module to increase flow path length and contact time.
2Duration of action of moving object
If off-gas flow path is extended to increase contact time, then humidification efficiency improves, but pressure loss increases
Solution Approach 1:
The flow path is divided into multiple segments using partition walls and multiple inlet/outlet positions. Instead of one long continuous path, off-gas flows through several shorter segments in sequence, reducing localized pressure losses while achieving extended total contact time. Each segment maintains relatively low resistance while the cumulative effect increases flow time.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement to create extended flow paths without excessive length in any single direction. By positioning inlets and outlets at different locations and using partition walls to guide flow through multiple regions, the system achieves long effective contact time while maintaining compact dimensions that minimize overall pressure loss.
3Productivity
If multiple off-gas inlets and outlets are added, then flow distribution improves, but manufacturing complexity increases
Solution Approach 1:
The mid-case is segmented into multiple functional zones with dedicated inlet and outlet positions. Partition walls are used to define these zones, creating a modular internal structure that improves flow distribution while maintaining a relatively simple manufacturing process. The segmentation is achieved through straightforward structural divisions rather than complex integrated features.
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 design minimizes the decrease in concentration of materials transmitted through the hollow fiber membranes, thereby improving the overall humidification efficiency and performance of the fuel cell.
Implementation Method 1
a selective permeable membrane used in the membrane humidification scheme is preferably a hollow fiber membrane having a large permeable area per unit volume
Implementation Method 2
moisture and heat contained in an off-gas discharged with a high temperature from the fuel cell can be recovered and can be reused through the humidifier
Data Source
AI summary
The present invention relates to a fuel cell membrane humidifier and a fuel cell system comprising same, wherein exhaust gas discharged from a fuel cell stack is introduced into a fuel cell membrane humidifier in both directions, whereby the humidification efficiency can be improved. The fuel cell system according to an embodiment of the present invention comprises: a blower which supplies dry gas; a fuel cell stack; and a fuel cell membrane humidifier which includes a mid-case, a first exhaust gas inlet formed at one surface of the mid-case, a second exhaust gas inlet formed at the other surface of the mid-case, and one exhaust gas outlet formed at the other surface of the mid-case.