Capacitive Layer in Fuel Cell Membrane Electrode Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cells face limitations in maximum operating current delivery, leading to excessive sizing, weight, and cost, as well as performance degradation due to stop/start cycles and uneven catalyst loading between anode and cathode, resulting in electrical losses and corrosion.
Innovation Solution
Incorporating capacitive layers made of a mixture of high-specific-surface-area carbon and proton conducting materials in connection zones of the membrane/electrode assembly to balance capacitance and optimize current supply without increasing thickness, thus minimizing electrical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuel cell is sized to deliver maximum transient current peaks, then the current supply capability is improved, but the size, weight and cost of the fuel cell become excessive
Solution Approach 1:
The fuel cell system is segmented into two functional parts: a base fuel cell unit sized for average current delivery, and a separate capacitive layer integrated into the membrane electrode assembly for transient current peaks. This segmentation allows the fuel cell to be sized appropriately for normal operation while the capacitor handles transient demands.
Solution Approach 2:
The capacitive layer integrated into the membrane electrode assembly serves multiple functions: it stores electrical energy for transient current peaks, balances capacitance between anode and cathode, and maintains structural integrity. This multi-functionality eliminates the need for separate capacitor components.
2Reliability
If the catalyst loading is increased at the cathode to balance capacitance, then the capacitance balance is improved, but electrical losses increase due to higher contact resistance
Solution Approach 1:
The capacitive layer is applied locally in connection zones where capacitance balancing is needed, rather than uniformly across the entire electrode. This localized application provides capacitance balance without unnecessarily increasing catalyst loading and contact resistance in active reaction zones.
Solution Approach 2:
The capacitive layer uses a composite material structure combining conductive materials with capacitive properties, integrated into the membrane electrode assembly. This composite structure provides both electrical conductivity and capacitance without requiring excessive catalyst loading.
3Adaptability or versatility
If stop/start cycles are operated to meet varying power demands, then the adaptability is improved, but corrosion of the cathode support material occurs due to reverse currents
Solution Approach 1:
The capacitive layer is positioned to provide protective cushioning during stop/start cycles. It absorbs and mitigates the harmful effects of reverse currents before they can reach and corrode the cathode support material, particularly when the cathode is made of carbon nanomaterial.
4Reliability
If the membrane electrode assembly thickness is increased to balance anode and cathode capacitance, then the capacitance balance is improved, but electrical losses increase due to increased contact resistance
Solution Approach 1:
Instead of balancing capacitance by increasing thickness in the vertical dimension, the invention uses lateral extension of capacitive layers in the horizontal plane within connection zones. This dimensional approach provides capacitance balance without increasing the path length for electron transport and contact resistance.
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
Enhances the fuel cell's ability to manage transient current peaks and balance capacitance between anode and cathode, reducing electrical losses and corrosion, while maintaining structural integrity and performance.
Implementation Method 1
a capacitive layer (71, 72) is present on a connection zone (22)
Implementation Method 2
a mixture of carbon having a BET specific surface at least equal to 200 m2/g and of a proton conducting material
Implementation Method 3
carbon having a BET specific surface at least equal to 200 m2/g
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a fuel cell (1) comprising: - a membrane/electrode assembly (14) that includes a proton exchange membrane (2), an anode (31) which is in contact with the membrane, a first active region (21) that is covered by the anode (31), and a first joining region (22) that is not covered by the anode (31); - flow guiding plates between which the membrane/electrode assembly is located and which are penetrated by at least one first flow collector that communicates with the anode; the first joining region (22) is located between said first flow collector and the first active region. The membrane/electrode assembly (14) further includes a first capacitive layer (71) that contains a mixture of carbon having a minimum specific surface area BET of 200m²/g and a proton conductor material disposed on the first joining region (22).