Selectively Gas Permeable Anode Flow Field for CO2 Removal
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Solution Overview
Problem
Conventional serpentine anode flow field designs in direct formic acid fuel cells inefficiently remove carbon dioxide (CO2), limiting fuel cell performance and requiring additional recycling loops for complete fuel conversion.
Innovation Solution
An advanced electrically conductive selectively gas permeable anode flow field design with a hydrophobic semi-permeable separator allows CO2 removal perpendicular to the active area, minimizing electron transfer path length and enhancing fuel cell performance by separating anode flow fields into gaseous and liquid sides for efficient CO2 transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional serpentine anode flow field design is used, then the fuel cell structure is simple, but CO2 removal efficiency is poor
Solution Approach 1:
The anode flow field is segmented into two separate flow fields (gaseous flow field and liquid flow field) divided by a semi-permeable separator. This segmentation allows CO2 to be removed through a dedicated gaseous flow path while liquid fuel is supplied through the liquid flow field, thereby improving CO2 removal efficiency without compromising structural simplicity
Solution Approach 2:
A hydrophobic semi-permeable separator is introduced as an intermediary component between the gaseous and liquid flow fields. This separator enables selective gas permeability for CO2 transport while maintaining structural integrity and electrical conductivity, resolving the contradiction between improved CO2 removal and structural complexity
2Productivity
If CO2 removal path is extended, then CO2 removal efficiency improves, but electron transfer path length increases
Solution Approach 1:
By segmenting the flow field into separate gaseous and liquid paths with a semi-permeable separator, CO2 can be removed perpendicular to the active area through the gaseous flow field without requiring electrons to travel along extended paths, thus improving CO2 removal efficiency while minimizing electron transfer path length
Solution Approach 2:
The invention changes the CO2 removal direction from in-plane (along the serpentine channel) to out-of-plane (perpendicular to the active area through the semi-permeable separator). This dimensional change allows efficient CO2 transport without extending the electron transfer path in the planar direction
3Power
If fuel concentration is increased, then power output increases, but CO2 accumulation worsens
Solution Approach 1:
The segmented flow field design with separate gaseous and liquid flow paths enables high fuel concentration operation by efficiently removing generated CO2 through the gaseous flow field, preventing CO2 accumulation that would otherwise limit fuel concentration and power output
Solution Approach 2:
The hydrophobic semi-permeable separator acts as an intermediary that facilitates selective CO2 transport from the liquid fuel side to the gaseous flow field, enabling high fuel concentration operation without CO2 accumulation by maintaining efficient gas-liquid separation
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 increases power output, reduces fuel cell size, and achieves nearly 100% fuel conversion without recycling loops, making direct liquid fuel cells suitable for portable power applications, surpassing battery technology in power rating, size, and continuous operation.
Implementation Method 1
The separator comprises a hydrophobic semi-permeable separator for CO2 diffusive gas transport from the liquid side (with formic acid, water, and CO2) to the gaseous side
Implementation Method 2
The separator comprises an electrically conductive material, which minimizes the electron transfer path length and increases fuel cell performance. In one embodiment, the separator comprises a hydrophobic macro/micro carbon-based material
Data Source
AI summary
An improved or advanced electrically conductive selectively gas permeable anode flow field (SGPFF) design, allowing for efficient removal of CO2 perpendicular to the active area near the location where it is formed in the catalyst layer. The anode plate design includes two mating flow fields (an anode gaseous flow field, and an anode liquid flow field) separated by a semi-permeable separator. The separator comprises a hydrophobic semi-permeable separator for CO2 diffusive gas transport from the liquid side (with acid, water, and CO2) to the gaseous side (allowing for CO2 removal to the atmosphere).