Fuel Cell Stack Dummy Cell End Plate Thermal Management
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Solution Overview
Problem
Fuel cell stacks experience voltage drops due to temperature reduction and freezing issues at the end cell, especially when operating in environments below freezing temperatures, leading to inefficient self-heating and performance deterioration.
Innovation Solution
Incorporating a dummy cell with a conductive plate and separators similar to the electricity-generating cells, which acts as a heat-insulating layer and prevents excessive cooling, along with a coolant flow path and flow rate limiting mechanism to maintain end cell temperature and prevent voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant flow path is provided for cooling the end cell, then temperature reduction is prevented, but excessive cooling occurs causing condensation and voltage drop
Solution Approach 1:
The coolant flow path is segmented into multiple regions: a first coolant flow path for the central electricity-generating cells and a second coolant flow path for the end cell. This segmentation allows independent temperature control, preventing excessive cooling at the end cell while maintaining adequate cooling for the central cells.
Solution Approach 2:
Different cooling strategies are applied to different regions: the central cells receive active coolant cooling, while the end cell is provided with heat-insulating structures and a separate, limited coolant flow path. This local differentiation prevents condensation at the end cell while maintaining overall system cooling efficiency.
2Temperature
If heat-insulating structure is added to prevent excessive cooling, then temperature is maintained, but device complexity increases
Solution Approach 1:
The end plate is designed to serve multiple functions: it provides structural support for the stacked cells, acts as a heat-insulating barrier to prevent excessive cooling, and incorporates the second coolant flow path for temperature regulation. This multi-functionality reduces the need for additional dedicated heat-insulating components.
Solution Approach 2:
The heat-insulating function is merged with the existing end plate structure rather than being implemented as a separate component. The end plate incorporates insulating materials and structures that work together with the coolant flow path to maintain temperature, simplifying the overall design.
3Reliability
If dummy cell is added to prevent voltage drop, then low-temperature performance is improved, but manufacturing cost increases
Solution Approach 1:
The dummy cell replicates the basic structural configuration of the electricity-generating cells, including separators, gaskets, and connection to the coolant flow path. This copying of the structural pattern allows the dummy cell to be integrated into the existing manufacturing process without requiring entirely new components or assembly procedures.
Solution Approach 2:
The dummy cell uses simplified components compared to full electricity-generating cells. It contains separators and gaskets but omits the expensive membrane electrode assembly, making it a cost-effective solution for improving low-temperature performance without significantly increasing manufacturing costs.
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 effectively prevents voltage drops and improves low-temperature operating characteristics by maintaining end cell temperature and reducing excessive cooling, enhancing the overall performance and economic feasibility of the fuel cell stack.
Implementation Method 1
the dummy cell itself can be functioning as a heat-insulating layer so as to prevent effectively preventing the time lag of temperature-rising at an end cell
Implementation Method 2
the fuel gas supplied to the anode side electrode, e.g. gas containing mainly hydrogen (hereinafter also referred to as 'hydrogen-contained gas') is ionized on an electrode catalyst, and the ionized gas is moved to the cathode side electrode through an electrolyte. The electrons produced during said processes are extracted by an external circuit so as to be used in direct electric energy form.
Implementation Method 3
the ionized gas is moved to the cathode side electrode through an electrolyte
Implementation Method 4
since an oxidizer gas, for instance, gas containing mainly oxygen or air (hereinafter referred to as 'oxygen-containing gas') is supplied to the cathode side electrode, water can be produced under the reaction of hydrogen ions, electrons and oxygen with one another.
Data Source
AI summary
A fuel cell stack 10 includes a stacked structure 14 composed of a plurality of electricity-generating cells stacked successively, and dummy cells arranged at both ends in a stacking direction of the stacked structure 14. Each dummy cell 16 each includes a conductive plate 52 and first and second metallic separators 54, 56 which sandwich the conductive plate 52. The conductive plate 52 is formed of a metallic plate having substantially the same shape as that of the electrolytic membrane electrode assembly 22. The first and second metallic separators 54, 56 are structured in the same manner as the first and second metallic separators 24, 26 of the electricity-generating cell 12.