Fuel Cell Electrolyte Shunt Migration Management
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Solution Overview
Problem
Fuel cell stacks face challenges in maintaining adequate electrolyte distribution, leading to issues of flooding and drying out, particularly due to uneven temperature distribution and electrolyte migration between cells, which affects operational efficiency and longevity.
Innovation Solution
Incorporating a porous electrolyte supply near the anode of the first end fuel cell and a porous electrolyte collector near the cathode of the second end fuel cell, both integrated with coolers, to manage electrolyte levels and prevent dry out and flooding by optimizing electrolyte flow and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolers are placed at various locations within the stack, then cells closer to coolers are maintained at desired operating temperatures, but cells further from coolers are subject to higher temperatures and dry out more quickly
Solution Approach 1:
The patent applies local quality by providing different electrolyte management solutions to different locations in the stack. Specifically, end fuel cells receive electrolyte supply and collection systems while intermediate cells rely on natural distribution, addressing the specific thermal and electrolyte management needs of end cells that are subject to higher temperatures and faster electrolyte loss.
2Quantity of substance
If electrolyte is distributed throughout the stack, then adequate electrolyte is maintained in most cells, but electrolyte migration causes flooding in some cells and drying out in others
Solution Approach 1:
The patent extracts excess electrolyte from end fuel cells where it tends to accumulate due to migration, using electrolyte collection systems with porous materials that remove surplus electrolyte. This prevents flooding in cells that would otherwise receive excessive electrolyte through migration from adjacent cells.
Solution Approach 2:
The patent implements preliminary action by providing electrolyte supply systems at end fuel cells before electrolyte depletion occurs. The porous material in the supply systems pre-positioned at end cells ensures electrolyte is available to compensate for migration losses before dry-out conditions develop.
3Ease of operation
If porous material is used for electrolyte supply and collection, then electrolyte flow is optimized and distribution is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the porous material components to serve multiple functions simultaneously. The electrolyte supply and collection systems use porous materials that provide both electrolyte distribution and structural support, while also facilitating thermal management, thereby reducing the need for separate dedicated components for each function.
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 configuration effectively minimizes electrolyte loss and flooding, extending the operational life and enhancing performance of the fuel cell assembly by maintaining optimal electrolyte levels across the stack.
Implementation Method 1
pores of the electrolyte supply porous material have a pore size and distribution configured to allow electrolyte in the supply to move from the electrolyte supply into the anode of the first end fuel cell
Implementation Method 2
pores of the electrolyte collector porous material have a pore size and distribution configured to allow electrolyte in the cathode of the second end fuel cell to move into the electrolyte collector
Data Source
AI summary
An illustrative example fuel cell assembly includes a plurality of fuel cells arranged in a stack including a first end fuel cell near a first end of the stack and a second end fuel cell near a second end of the stack. Each of the fuel cells includes a matrix containing an electrolyte, an anode and a cathode on opposite sides of the matrix, and respective flow fields adjacent the anode and the cathode. An electrolyte supply associated with the anode flow field of the first end fuel cell includes a porous material containing electrolyte. An electrolyte collector associated with the cathode flow field of the second end fuel cell includes a porous material configured to collect electrolyte from at least the cathode of the second end fuel cell.