Fuel Cell Humidifier with Pressure-Actuated Variable Passage
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Solution Overview
Problem
Fuel cell systems face challenges in maintaining optimal moisture levels within the fuel cell stack, leading to performance degradation due to either insufficient humidification during high power output or flooding during low power output, which affects the efficiency and durability of the system.
Innovation Solution
A fuel cell humidifier with a variable member that adjusts the cross-sectional area of the supply air inflow passage based on pressure differences, allowing for active modulation of moisture input to match varying operating conditions without external power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed humidifier system is used to supply moisture to the fuel cell stack, then the structure is simple, but the system cannot actively adjust the amount of added moisture based on varying operating conditions, leading to performance degradation
Solution Approach 1:
The patent applies the dynamics principle by making the supply air passage area variable rather than fixed. A movable partition wall is introduced that can change the cross-sectional area of the supply air passage in response to pressure changes during fuel cell operation. This allows the humidifier to dynamically adjust moisture addition based on operating conditions (high power output requiring more humidification vs. low power output requiring less), resolving the contradiction between adaptability and device complexity.
2Reliability
If more moisture is added to the supply air, then the fuel cell stack is adequately humidified during high power output, but the stack may flood during low power output, reducing efficiency
Solution Approach 1:
The patent implements feedback control through pressure-sensitive automatic adjustment. The movable partition wall responds to pressure changes in the supply air passage, which reflect the fuel cell stack's moisture needs. When pressure is high (indicating need for humidification), the partition moves to increase passage area and moisture addition. When pressure is low (indicating sufficient humidity), the passage area decreases, preventing flooding. This feedback mechanism ensures reliable moisture maintenance while optimizing power generation efficiency.
3Adaptability or versatility
If a bypass passage is used to introduce part of the supply air directly to the fuel cell stack without humidification, then the system can control moisture addition, but the overall system becomes complex
Solution Approach 1:
The patent applies segmentation by dividing the supply air flow into two paths: one path goes through the humidifying membrane for moisture addition, while the other path bypasses the membrane. The movable partition wall dynamically controls the distribution ratio between these two segments. This segmentation approach provides adaptive moisture control without requiring a completely separate complex humidification system, as the bypass portion naturally provides dry air when needed.
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 adjusts humidifying performance to prevent drying or flooding, thereby enhancing the efficiency and durability of the fuel cell stack by ensuring optimal moisture levels across different power output conditions.
Implementation Method 1
a membrane part having a humidifying membrane accommodated therein
Data Source
AI summary
A humidifier for a fuel cell is provided. The humidifier includes a membrane having a humidifying membrane, a first cap coupled to a first side of the membrane to feed supply air into the humidifying membrane, and a second cap coupled to a second side of the membrane to release humidified supply air. An exhaust air inlet is coupled to the second side of the membrane to inject exhaust air from a fuel cell stack into the membrane, and an exhaust air outlet coupled to the first side of the membrane to release dehumidified exhaust air to an exhaust line. The first cap includes a supply air inflow passage and a variable member that has at least a portion capable of entering the supply air inflow passage. The variable member is moved in an inward direction or in an outward direction based on pressure inside the supply air inflow passage.