Gas Diffusion Layer Thermal Gradient for PEM Fuel Cell Water Control
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Solution Overview
Problem
Fuel cell performance and durability are compromised in dynamic operational conditions due to inadequate thermal and water management capabilities of existing gas diffusion layers (GDLs) in proton exchange membrane (PEM) fuel cells, particularly when operating in hot and dry or cold and wet conditions.
Innovation Solution
A GDL with a non-uniform thermal conductivity along its thickness direction, featuring a higher thermal conductivity region adjacent to the catalyst layer and a lower thermal conductivity region adjacent to the flow field plate, or a gradient of thermal conductivity, to optimize water condensation location and prevent adverse effects on catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a GDL with uniform thermal conductivity is used, then the manufacturing process is simple, but the thermal and water management capabilities are inadequate under dynamic operational conditions
Solution Approach 1:
The GDL is designed with non-uniform thermal conductivity where different regions have different thermal conductivity values. Specifically, the thermal conductivity varies along the thickness direction and/or in-plane directions, with higher thermal conductivity regions positioned to enhance thermal management where needed and lower thermal conductivity regions positioned to optimize water management, thereby resolving the contradiction between improved reliability and increased device complexity.
2Loss of substance
If water condensation occurs near the catalyst layer, then water removal is facilitated, but catalyst performance deteriorates due to flooding and degradation
Solution Approach 1:
The GDL incorporates regions with different thermal conductivity values strategically positioned to control water condensation location. By having higher thermal conductivity in certain regions and lower thermal conductivity in other regions, the design shifts water condensation away from the catalyst layer to safer regions, preventing catalyst flooding and degradation while maintaining effective water removal from the fuel cell system.
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 enhances the thermal and water management capabilities of PEM fuel cells, improving performance and durability by shifting water condensation away from the catalyst layer, thus reducing degradation and maintaining optimal operational conditions across varying conditions.
Implementation Method 1
The GDL may have a first region and a second region along a thickness direction of the fuel cell. The first region may be adjacent to the catalyst layer and may have a first thermal conductivity. The second region may be adjacent to the flow field plate and may have a second thermal conductivity lower than the first thermal conductivity.
Data Source
AI summary
A fuel cell includes a gas diffusion layer (GM) situated between a catalyst layer of the fuel cell and a flow field plate of the fuel cell. The GM has a first region and a second region along a thickness direction of the fuel cell. The first region is adjacent to the catalyst layer and has a first thermal conductivity. The second region is adjacent to the flow field plate and has a second thermal conductivity lower than the first thermal conductivity.