External Fuel Plenum Layout for Uniform Fuel Cell Stack Distribution
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Solution Overview
Problem
Conventional fuel cell stacks face challenges with complex fuel distribution systems that reduce active area, cause cracks in ceramic electrolytes, and result in non-uniform fuel distribution, leading to fuel starvation and reduced stack yield and performance.
Innovation Solution
A fuel cell stack design featuring a cross-flow interconnect structure with aligned fuel inlet and outlet channels, eliminating internal fuel manifolds, and a fuel plenum with aligned inlet and outlet conduits, along with a compression assembly and side baffles for improved fuel and air distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If internal fuel manifolds are used to distribute fuel to each cell, then fuel distribution is achieved, but the active area is reduced and cracks in ceramic electrolytes occur
Solution Approach 1:
The patent removes the internal fuel manifold structure from within the stack and extracts this function to an external fuel plenum system. The fuel plenum is positioned outside the active stack area and distributes fuel through simplified pathways, eliminating the space-consuming internal manifolds that reduced active area while maintaining fuel distribution capability.
Solution Approach 2:
The fuel distribution system is segmented into separate functional components: an external fuel plenum for storage and pressure regulation, and simplified fuel inlet structures at each cell. This segmentation allows the fuel distribution function to be achieved without requiring complex internal manifold structures that consume active area and create stress concentration points.
2Ease of manufacture
If complex fuel distribution systems are implemented, then fuel delivery is achieved, but manufacturing complexity increases and cracks in ceramic electrolytes occur
Solution Approach 1:
The complex fuel distribution functionality is extracted from the delicate ceramic electrolyte structure and placed in a separate, robust external fuel plenum. This allows the fuel distribution system to be manufactured independently using simpler processes, eliminating the need to integrate complex fuel channels within the ceramic cells, thereby reducing manufacturing complexity and eliminating stress-induced cracks.
Solution Approach 2:
The external fuel plenum design provides a cushioning effect by decoupling the fuel distribution function from the fragile ceramic electrolyte structure. This protective separation prevents mechanical stresses from fuel distribution components from transmitting to the ceramic electrolyte, thereby preventing cracks before they can occur.
3Ease of manufacture
If conventional fuel distribution systems are used, then fuel supply is achieved, but non-uniform fuel distribution occurs leading to fuel starvation
Solution Approach 1:
The external fuel plenum is designed to maintain uniform fuel pressure across all distribution outlets by creating an equipotential fuel reservoir. This ensures that fuel is delivered uniformly to each cell inlet, preventing the non-uniform distribution and fuel starvation that occurs with conventional internal manifold systems where pressure drops vary across different locations.
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 uniform fuel distribution, maximizes fuel utilization, and increases the active area without increasing the system footprint, while reducing manufacturing complexity and potential cracks in ceramic electrolytes.
Implementation Method 1
The fuel cell, operating at a typical temperature between 750° C. and 950° C., enables the transport of negatively charged oxygen ions from the cathode flow stream to the anode flow stream
Implementation Method 2
The fuel cell, operating at a typical temperature between 750° C. and 950° C., enables the transport of negatively charged oxygen ions from the cathode flow stream to the anode flow stream, where the ion combines with either free hydrogen or hydrogen in a hydrocarbon molecule to form water vapor and/or with carbon monoxide to form carbon dioxide
Data Source
AI summary
A fuel cell stack fuel plenum includes a base plate including an inlet hole and an outlet hole, a dielectric layer disposed on the base plate and including an inlet hole and an outlet hole, a cover plate disposed on the dielectric layer and including an inlet hole and an outlet hole, a seal plate disposed on the cover plate and including an inlet hole and an outlet hole, and a manifold plate disposed on the seal plate. The manifold plate includes a bottom inlet hole and a bottom outlet hole formed in a bottom surface of the manifold plate, top outlet holes and top inlet holes formed in opposing sides of a top surface of the manifold plate, outlet channels fluidly connecting the top outlet holes to the bottom inlet hole, and inlet channels fluidly connecting the top inlet holes to the bottom outlet hole.