Cast Fuel Cell Stack Sealing to Block Hydrogen Permeation
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Solution Overview
Problem
Existing fuel cell stacks face issues with hydrogen permeability through seals, leading to hydrogen loss and air ingress during restart, causing damage, and require continuous ventilation to prevent gas exchange.
Innovation Solution
Embedding the cell series in an electrically insulating casting material within the fuel cell stack housing, which reduces hydrogen leakage and prevents air penetration, while enhancing mechanical stability and eliminating the need for ventilation by using materials with low gas permeability and incorporating lateral overhangs for improved sealing and electrical creepage distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer seals are used to seal the fuel cell stack, then sealing action is provided, but hydrogen permeability occurs leading to hydrogen loss
Solution Approach 1:
The patent applies composite materials by combining polymer seals with an electrically insulating casting material that has very low gas permeability. The casting material encapsulates the entire cell series, creating a composite sealing system that maintains the sealing action of polymer seals while adding a hydrogen-impermeable barrier layer that prevents hydrogen permeation and loss.
2Reliability
If polymer seals are used to seal the fuel cell stack, then sealing action is provided, but air penetration occurs during restart
Solution Approach 1:
The patent uses composite materials by combining polymer seals with an electrically insulating casting material that has very low gas permeability. The casting material encapsulates the entire cell series, creating a composite sealing system that maintains the sealing action of polymer seals while adding a hydrogen-impermeable barrier layer that prevents hydrogen permeation and loss.
3Reliability
If continuous ventilation is implemented to prevent hydrogen loss, then hydrogen safety is maintained, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for continuous ventilation systems by implementing a passive sealing solution. The electrically insulating casting material with very low gas permeability inherently prevents hydrogen loss without requiring active ventilation, thereby removing the ventilation system components and simplifying the overall device while maintaining hydrogen safety.
4Reliability
If cell series are clamped together with high pressing force, then contact pressure is achieved to reduce ohmic losses, but mechanical stability decreases
Solution Approach 1:
The patent applies composite materials by combining polymer seals with an electrically insulating casting material that has very low gas permeability. The casting material encapsulates the entire cell series, creating a composite sealing system that maintains the sealing action of polymer seals while adding a hydrogen-impermeable barrier layer that prevents hydrogen permeation and loss.
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 solution significantly reduces hydrogen loss and air ingress, enhances mechanical stability, and eliminates the need for ventilation, ensuring a tighter seal and compliance with hydrogen safety standards, thereby improving the overall performance and reliability of the fuel cell stack.
Implementation Method 1
materials with a very low H2 permeation or gas permeation may be advantageous, since these afford a more secure sealing against hydrogen and other gaseous media
Implementation Method 2
materials with a very low H2 permeation or gas permeation may be advantageous, since these afford a more secure sealing against hydrogen and other gaseous media
Implementation Method 3
the force of adhesion of the cells to each other is no longer due solely to the seal, but also the cell series is braced against the housing
Data Source
AI summary
A fuel cell stack comprises a cell series composed of multiple unit cells, being formed with internal media guides in the cell, and contained between two clamped together end plates in a fuel cell stack housing. The cell series present in the fuel cell stack housing is embedded entirely in an electrically insulating casting material. A method for producing a fuel cell stack is also provided.